Add Nuvoton NPCM BMC I2C controller driver. Signed-off-by: Tali Perry <tali.per...@gmail.com> --- drivers/i2c/busses/Kconfig | 9 + drivers/i2c/busses/Makefile | 1 + drivers/i2c/busses/i2c-npcm7xx.c | 1853 ++++++++++++++++++++++++++++++ 3 files changed, 1863 insertions(+) create mode 100644 drivers/i2c/busses/i2c-npcm7xx.c
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 2ddca08f8a76..a2cfc555c284 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -791,6 +791,15 @@ config I2C_NOMADIK I2C interface from ST-Ericsson's Nomadik and Ux500 architectures, as well as the STA2X11 PCIe I/O HUB. +config I2C_NPCM7XX + tristate "Nuvoton I2C Controller" + depends on ARCH_NPCM7XX || COMPILE_TEST + help + If you say yes to this option, support will be included for the + Nuvoton I2C controller, which is available on the NPCM7xx BMC + controller. + Driver can also support slave mode (select I2C_SLAVE). + config I2C_OCORES tristate "OpenCores I2C Controller" help diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index 25d60889713c..8f3dfd376bec 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -81,6 +81,7 @@ obj-$(CONFIG_I2C_MT7621) += i2c-mt7621.o obj-$(CONFIG_I2C_MV64XXX) += i2c-mv64xxx.o obj-$(CONFIG_I2C_MXS) += i2c-mxs.o obj-$(CONFIG_I2C_NOMADIK) += i2c-nomadik.o +obj-$(CONFIG_I2C_NPCM7XX) += i2c-npcm7xx.o obj-$(CONFIG_I2C_OCORES) += i2c-ocores.o obj-$(CONFIG_I2C_OMAP) += i2c-omap.o obj-$(CONFIG_I2C_OWL) += i2c-owl.o diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c new file mode 100644 index 000000000000..e732c40f0cf3 --- /dev/null +++ b/drivers/i2c/busses/i2c-npcm7xx.c @@ -0,0 +1,1853 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Nuvoton NPCM7xx I2C Controller driver + * + * Copyright (C) 2020 Nuvoton Technologies tali.pe...@nuvoton.com + */ +#include <linux/bitfield.h> +#include <linux/clk.h> +#if IS_ENABLED(CONFIG_DEBUG_FS) +#include <linux/debugfs.h> +#endif +#include <linux/errno.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/iopoll.h> +#include <linux/irq.h> +#include <linux/jiffies.h> +#include <linux/kernel.h> +#include <linux/mfd/syscon.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> + +//#define _I2C_DEBUG_ + +enum i2c_mode { + I2C_MASTER, + I2C_SLAVE, +}; + +/* + * External I2C Interface driver xfer indication values, which indicate status + * of the bus. + */ +enum i2c_state_ind { + I2C_NO_STATUS_IND = 0, + I2C_SLAVE_RCV_IND, + I2C_SLAVE_XMIT_IND, + I2C_SLAVE_XMIT_MISSING_DATA_IND, + I2C_SLAVE_RESTART_IND, + I2C_SLAVE_DONE_IND, + I2C_MASTER_DONE_IND, + I2C_NACK_IND, + I2C_BUS_ERR_IND, + I2C_WAKE_UP_IND, + I2C_BLOCK_BYTES_ERR_IND, + I2C_SLAVE_RCV_MISSING_DATA_IND, +}; + +// Operation type values (used to define the operation currently held) +// module is interrupt driven, on each interrupt the current operation is +// checked to see if the module is currently reading or writing. +enum i2c_oper { + I2C_NO_OPER = 0, + I2C_WRITE_OPER, + I2C_READ_OPER, +}; + +// I2C Bank (module had 2 banks of registers) +enum i2c_bank { + I2C_BANK_0 = 0, + I2C_BANK_1, +}; + +// Internal I2C states values (for the I2C module state machine). +enum i2c_state { + I2C_DISABLE = 0, + I2C_IDLE, + I2C_MASTER_START, + I2C_SLAVE_MATCH, + I2C_OPER_STARTED, + I2C_STOP_PENDING, +}; + +// init register and default value required to enable module +#define NPCM_I2CSEGCTL 0xE4 +#define NPCM_I2CSEGCTL_INIT_VAL 0x0333F000 + +// Common regs +#define NPCM_I2CSDA 0x00 +#define NPCM_I2CST 0x02 +#define NPCM_I2CCST 0x04 +#define NPCM_I2CCTL1 0x06 +#define NPCM_I2CADDR1 0x08 +#define NPCM_I2CCTL2 0x0A +#define NPCM_I2CADDR2 0x0C +#define NPCM_I2CCTL3 0x0E +#define NPCM_I2CCST2 0x18 +#define NPCM_I2CCST3 0x19 +#define I2C_VER 0x1F + +// BANK 0 regs +#define NPCM_I2CADDR3 0x10 +#define NPCM_I2CADDR7 0x11 +#define NPCM_I2CADDR4 0x12 +#define NPCM_I2CADDR8 0x13 +#define NPCM_I2CADDR5 0x14 +#define NPCM_I2CADDR9 0x15 +#define NPCM_I2CADDR6 0x16 +#define NPCM_I2CADDR10 0x17 + +#define NPCM_I2CCTL4 0x1A +#define NPCM_I2CCTL5 0x1B +#define NPCM_I2CSCLLT 0x1C // SCL Low Time +#define NPCM_I2CFIF_CTL 0x1D // FIFO Control +#define NPCM_I2CSCLHT 0x1E // SCL High Time + +// BANK 1 regs +#define NPCM_I2CFIF_CTS 0x10 // Both FIFOs Control and status +#define NPCM_I2CTXF_CTL 0x12 // Tx-FIFO Control +#define NPCM_I2CT_OUT 0x14 // Bus T.O. +#define NPCM_I2CPEC 0x16 // PEC Data +#define NPCM_I2CTXF_STS 0x1A // Tx-FIFO Status +#define NPCM_I2CRXF_STS 0x1C // Rx-FIFO Status +#define NPCM_I2CRXF_CTL 0x1E // Rx-FIFO Control + +// NPCM_I2CST reg fields +#define NPCM_I2CST_XMIT BIT(0) +#define NPCM_I2CST_MASTER BIT(1) +#define NPCM_I2CST_NMATCH BIT(2) +#define NPCM_I2CST_STASTR BIT(3) +#define NPCM_I2CST_NEGACK BIT(4) +#define NPCM_I2CST_BER BIT(5) +#define NPCM_I2CST_SDAST BIT(6) +#define NPCM_I2CST_SLVSTP BIT(7) + +// NPCM_I2CCST reg fields +#define NPCM_I2CCST_BUSY BIT(0) +#define NPCM_I2CCST_BB BIT(1) +#define NPCM_I2CCST_MATCH BIT(2) +#define NPCM_I2CCST_GCMATCH BIT(3) +#define NPCM_I2CCST_TSDA BIT(4) +#define NPCM_I2CCST_TGSCL BIT(5) +#define NPCM_I2CCST_MATCHAF BIT(6) +#define NPCM_I2CCST_ARPMATCH BIT(7) + +// NPCM_I2CCTL1 reg fields +#define NPCM_I2CCTL1_START BIT(0) +#define NPCM_I2CCTL1_STOP BIT(1) +#define NPCM_I2CCTL1_INTEN BIT(2) +#define NPCM_I2CCTL1_EOBINTE BIT(3) +#define NPCM_I2CCTL1_ACK BIT(4) +#define NPCM_I2CCTL1_GCMEN BIT(5) +#define NPCM_I2CCTL1_NMINTE BIT(6) +#define NPCM_I2CCTL1_STASTRE BIT(7) + +// RW1S fields (inside a RW reg): +#define NPCM_I2CCTL1_RWS \ + (NPCM_I2CCTL1_START | NPCM_I2CCTL1_STOP | NPCM_I2CCTL1_ACK) + +// npcm_i2caddr reg fields +#define NPCM_I2CADDR_A GENMASK(6, 0) +#define NPCM_I2CADDR_SAEN BIT(7) + +// NPCM_I2CCTL2 reg fields +#define I2CCTL2_ENABLE BIT(0) +#define I2CCTL2_SCLFRQ6_0 GENMASK(7, 1) + +// NPCM_I2CCTL3 reg fields +#define I2CCTL3_SCLFRQ8_7 GENMASK(1, 0) +#define I2CCTL3_ARPMEN BIT(2) +#define I2CCTL3_IDL_START BIT(3) +#define I2CCTL3_400K_MODE BIT(4) +#define I2CCTL3_BNK_SEL BIT(5) +#define I2CCTL3_SDA_LVL BIT(6) +#define I2CCTL3_SCL_LVL BIT(7) + +// NPCM_I2CCST2 reg fields +#define NPCM_I2CCST2_MATCHA1F BIT(0) +#define NPCM_I2CCST2_MATCHA2F BIT(1) +#define NPCM_I2CCST2_MATCHA3F BIT(2) +#define NPCM_I2CCST2_MATCHA4F BIT(3) +#define NPCM_I2CCST2_MATCHA5F BIT(4) +#define NPCM_I2CCST2_MATCHA6F BIT(5) +#define NPCM_I2CCST2_MATCHA7F BIT(5) +#define NPCM_I2CCST2_INTSTS BIT(7) + +// NPCM_I2CCST3 reg fields +#define NPCM_I2CCST3_MATCHA8F BIT(0) +#define NPCM_I2CCST3_MATCHA9F BIT(1) +#define NPCM_I2CCST3_MATCHA10F BIT(2) +#define NPCM_I2CCST3_EO_BUSY BIT(7) + +// NPCM_I2CCTL4 reg fields +#define I2CCTL4_HLDT GENMASK(5, 0) +#define I2CCTL4_LVL_WE BIT(7) + +// NPCM_I2CCTL5 reg fields +#define I2CCTL5_DBNCT GENMASK(3, 0) + +// NPCM_I2CFIF_CTS reg fields +#define NPCM_I2CFIF_CTS_RXF_TXE BIT(1) +#define NPCM_I2CFIF_CTS_RFTE_IE BIT(3) +#define NPCM_I2CFIF_CTS_CLR_FIFO BIT(6) +#define NPCM_I2CFIF_CTS_SLVRSTR BIT(7) + +// NPCM_I2CTXF_CTL reg fields +#define NPCM_I2CTXF_CTL_TX_THR GENMASK(4, 0) +#define NPCM_I2CTXF_CTL_THR_TXIE BIT(6) + +// NPCM_I2CT_OUT reg fields +#define NPCM_I2CT_OUT_TO_CKDIV GENMASK(5, 0) +#define NPCM_I2CT_OUT_T_OUTIE BIT(6) +#define NPCM_I2CT_OUT_T_OUTST BIT(7) + +// NPCM_I2CTXF_STS reg fields +#define NPCM_I2CTXF_STS_TX_BYTES GENMASK(4, 0) +#define NPCM_I2CTXF_STS_TX_THST BIT(6) + +// NPCM_I2CRXF_STS reg fields +#define NPCM_I2CRXF_STS_RX_BYTES GENMASK(4, 0) +#define NPCM_I2CRXF_STS_RX_THST BIT(6) + +// NPCM_I2CFIF_CTL reg fields +#define NPCM_I2CFIF_CTL_FIFO_EN BIT(4) + +// NPCM_I2CRXF_CTL reg fields +#define NPCM_I2CRXF_CTL_RX_THR GENMASK(4, 0) +#define NPCM_I2CRXF_CTL_LAST_PEC BIT(5) +#define NPCM_I2CRXF_CTL_THR_RXIE BIT(6) + +#define I2C_HW_FIFO_SIZE 16 + +// I2C_VER reg fields +#define I2C_VER_VERSION GENMASK(6, 0) +#define I2C_VER_FIFO_EN BIT(7) + +// stall/stuck timeout in us +#define DEFAULT_STALL_COUNT 25 + +// supported clk settings. values in KHz. +#define I2C_FREQ_MIN 10 +#define I2C_FREQ_MAX 1000 + +// SCLFRQ field position +#define SCLFRQ_0_TO_6 GENMASK(6, 0) +#define SCLFRQ_7_TO_8 GENMASK(8, 7) + +#define I2C_NUM_OF_ADDR 10 + +// Status of one I2C module +struct npcm_i2c { + struct i2c_adapter adap; + struct device *dev; + unsigned char __iomem *reg; + spinlock_t lock; // IRQ synchronization + struct completion cmd_complete; + int irq; + int cmd_err; + struct i2c_msg *msgs; + int msgs_num; + int num; + u32 apb_clk; + struct i2c_bus_recovery_info rinfo; + enum i2c_state state; + enum i2c_oper operation; + enum i2c_mode master_or_slave; + enum i2c_state_ind stop_ind; + u8 dest_addr; + u8 *rd_buf; + u16 rd_size; + u16 rd_ind; + u8 *wr_buf; + u16 wr_size; + u16 wr_ind; + bool fifo_use; + u16 PEC_mask; // PEC bit mask per slave address + bool PEC_use; + bool read_block_use; + u8 int_cnt; + u32 clk_period_us; + unsigned long int_time_stamp; + unsigned long bus_freq; // in kHz + u32 xmits; +#if IS_ENABLED(CONFIG_DEBUG_FS) + struct dentry *debugfs;/* debugfs device directory */ + uint64_t ber_count; + uint64_t rec_succ_count; + uint64_t rec_fail_count; + uint64_t nack_count; + uint64_t timeout_count; +#endif +}; + +#if IS_ENABLED(CONFIG_DEBUG_FS) +static struct dentry *npcm_i2c_debugfs_dir; /* i2c debugfs directory */ +static const char *ber_cnt_name = "ber_count"; +static const char *rec_succ_cnt_name = "rec_succ_count"; +static const char *rec_fail_cnt_name = "rec_fail_count"; +static const char *nack_cnt_name = "nack_count"; +static const char *timeout_cnt_name = "timeout_count"; +#endif + +static inline void npcm_i2c_select_bank(struct npcm_i2c *bus, + enum i2c_bank bank) +{ + u8 i2cctl3 = ioread8(bus->reg + NPCM_I2CCTL3); + + if (bank == I2C_BANK_0) + i2cctl3 = i2cctl3 & ~I2CCTL3_BNK_SEL; + else + i2cctl3 = i2cctl3 | I2CCTL3_BNK_SEL; + iowrite8(i2cctl3, bus->reg + NPCM_I2CCTL3); +} + +static void npcm_i2c_init_params(struct npcm_i2c *bus) +{ + bus->stop_ind = I2C_NO_STATUS_IND; + bus->rd_size = 0; + bus->wr_size = 0; + bus->rd_ind = 0; + bus->wr_ind = 0; + bus->int_cnt = 0; + bus->read_block_use = false; + bus->int_time_stamp = 0; + bus->PEC_use = false; + bus->PEC_mask = 0; +} + +static inline void npcm_i2c_wr_byte(struct npcm_i2c *bus, u8 data) +{ + iowrite8(data, bus->reg + NPCM_I2CSDA); +} + +static inline u8 npcm_i2c_rd_byte(struct npcm_i2c *bus) +{ + return ioread8(bus->reg + NPCM_I2CSDA); +} + +static int npcm_i2c_get_SCL(struct i2c_adapter *_adap) +{ + struct npcm_i2c *bus = container_of(_adap, struct npcm_i2c, adap); + + return !!(I2CCTL3_SCL_LVL & ioread32(bus->reg + NPCM_I2CCTL3)); + +} + +static int npcm_i2c_get_SDA(struct i2c_adapter *_adap) +{ + struct npcm_i2c *bus = container_of(_adap, struct npcm_i2c, adap); + + return !!(I2CCTL3_SDA_LVL & ioread32(bus->reg + NPCM_I2CCTL3)); + +} + +static inline u16 npcm_i2c_get_index(struct npcm_i2c *bus) +{ + if (bus->operation == I2C_READ_OPER) + return bus->rd_ind; + if (bus->operation == I2C_WRITE_OPER) + return bus->wr_ind; + return 0; +} + +// quick protocol (just address): +static inline bool npcm_i2c_is_quick(struct npcm_i2c *bus) +{ + return bus->wr_size == 0 && bus->rd_size == 0; +} + +static void npcm_i2c_disable(struct npcm_i2c *bus) +{ + u8 i2cctl2; + + // Disable module. + i2cctl2 = ioread8(bus->reg + NPCM_I2CCTL2); + i2cctl2 = i2cctl2 & ~I2CCTL2_ENABLE; + iowrite8(i2cctl2, bus->reg + NPCM_I2CCTL2); + + bus->state = I2C_DISABLE; +} + +static void npcm_i2c_enable(struct npcm_i2c *bus) +{ + u8 i2cctl2 = ioread8(bus->reg + NPCM_I2CCTL2); + + i2cctl2 = i2cctl2 | I2CCTL2_ENABLE; + iowrite8(i2cctl2, bus->reg + NPCM_I2CCTL2); + bus->state = I2C_IDLE; +} + +// enable\disable end of busy (EOB) interrupt +static inline void npcm_i2c_eob_int(struct npcm_i2c *bus, bool enable) +{ + u8 val; + + // Clear EO_BUSY pending bit: + val = ioread8(bus->reg + NPCM_I2CCST3); + val = val | NPCM_I2CCST3_EO_BUSY; + iowrite8(val, bus->reg + NPCM_I2CCST3); + + val = ioread8(bus->reg + NPCM_I2CCTL1); + val &= ~NPCM_I2CCTL1_RWS; + if (enable) + val |= NPCM_I2CCTL1_EOBINTE; + else + val &= ~NPCM_I2CCTL1_EOBINTE; + iowrite8(val, bus->reg + NPCM_I2CCTL1); +} + +static inline bool npcm_i2c_tx_fifo_empty(struct npcm_i2c *bus) +{ + u8 tx_fifo_sts; + + tx_fifo_sts = ioread8(bus->reg + NPCM_I2CTXF_STS); + // check if TX FIFO is not empty + if ((tx_fifo_sts & NPCM_I2CTXF_STS_TX_BYTES) == 0) + return false; + + // check if TX FIFO status bit is set: + return !!FIELD_GET(NPCM_I2CTXF_STS_TX_THST, tx_fifo_sts); +} + +static inline bool npcm_i2c_rx_fifo_full(struct npcm_i2c *bus) +{ + u8 rx_fifo_sts; + + rx_fifo_sts = ioread8(bus->reg + NPCM_I2CRXF_STS); + // check if RX FIFO is not empty: + if ((rx_fifo_sts & NPCM_I2CRXF_STS_RX_BYTES) == 0) + return false; + + // check if rx fifo full status is set: + return !!FIELD_GET(NPCM_I2CRXF_STS_RX_THST, rx_fifo_sts); +} + +static inline void npcm_i2c_clear_fifo_int(struct npcm_i2c *bus) +{ + u8 val; + + val = ioread8(bus->reg + NPCM_I2CFIF_CTS); + val = (val & NPCM_I2CFIF_CTS_SLVRSTR) | NPCM_I2CFIF_CTS_RXF_TXE; + iowrite8(val, bus->reg + NPCM_I2CFIF_CTS); +} + +static inline void npcm_i2c_clear_tx_fifo(struct npcm_i2c *bus) +{ + u8 val; + + val = ioread8(bus->reg + NPCM_I2CTXF_STS); + val = val | NPCM_I2CTXF_STS_TX_THST; + iowrite8(val, bus->reg + NPCM_I2CTXF_STS); +} + +static inline void npcm_i2c_clear_rx_fifo(struct npcm_i2c *bus) +{ + u8 val; + + val = ioread8(bus->reg + NPCM_I2CRXF_STS); + val = val | NPCM_I2CRXF_STS_RX_THST; + iowrite8(val, bus->reg + NPCM_I2CRXF_STS); +} + +static void npcm_i2c_int_enable(struct npcm_i2c *bus, bool enable) +{ + u8 val; + + val = ioread8(bus->reg + NPCM_I2CCTL1); + val &= ~NPCM_I2CCTL1_RWS; + if (enable) + val |= NPCM_I2CCTL1_INTEN; + else + val &= ~NPCM_I2CCTL1_INTEN; + iowrite8(val, bus->reg + NPCM_I2CCTL1); +} + +static inline void npcm_i2c_master_start(struct npcm_i2c *bus) +{ + u8 val; + + val = ioread8(bus->reg + NPCM_I2CCTL1); + val &= ~(NPCM_I2CCTL1_STOP | NPCM_I2CCTL1_ACK); + val |= NPCM_I2CCTL1_START; + iowrite8(val, bus->reg + NPCM_I2CCTL1); +} + +static inline void npcm_i2c_master_stop(struct npcm_i2c *bus) +{ + u8 val; + + /* + * override HW issue: I2C may fail to supply stop condition in Master + * Write operation. + * Need to delay at least 5 us from the last int, before issueing a stop + */ + udelay(10); + val = ioread8(bus->reg + NPCM_I2CCTL1); + val &= ~(NPCM_I2CCTL1_START | NPCM_I2CCTL1_ACK); + val |= NPCM_I2CCTL1_STOP; + iowrite8(val, bus->reg + NPCM_I2CCTL1); + + if (!bus->fifo_use) + return; + + npcm_i2c_select_bank(bus, I2C_BANK_1); + + if (bus->operation == I2C_READ_OPER) + npcm_i2c_clear_rx_fifo(bus); + else + npcm_i2c_clear_tx_fifo(bus); + + npcm_i2c_clear_fifo_int(bus); + + iowrite8(0, bus->reg + NPCM_I2CTXF_CTL); + +} + +static inline void npcm_i2c_stall_after_start(struct npcm_i2c *bus, bool stall) +{ + u8 val; + + val = ioread8(bus->reg + NPCM_I2CCTL1); + val &= ~NPCM_I2CCTL1_RWS; + if (stall) + val |= NPCM_I2CCTL1_STASTRE; + else + val &= ~NPCM_I2CCTL1_STASTRE; + iowrite8(val, bus->reg + NPCM_I2CCTL1); +} + +static inline void npcm_i2c_nack(struct npcm_i2c *bus) +{ + u8 val; + + val = ioread8(bus->reg + NPCM_I2CCTL1); + val &= ~(NPCM_I2CCTL1_STOP | NPCM_I2CCTL1_START); + val |= NPCM_I2CCTL1_ACK; + iowrite8(val, bus->reg + NPCM_I2CCTL1); +} + +static void npcm_i2c_reset(struct npcm_i2c *bus) +{ + // Save I2CCTL1 relevant bits. It is being cleared when the module + // is disabled + u8 i2cctl1; + u8 i2cctl2; + + i2cctl1 = ioread8(bus->reg + NPCM_I2CCTL1); + i2cctl2 = ioread8(bus->reg + NPCM_I2CCTL2); + + npcm_i2c_disable(bus); + npcm_i2c_enable(bus); + + // Restore NPCM_I2CCTL1 status + i2cctl1 &= ~NPCM_I2CCTL1_RWS; + iowrite8(i2cctl1, bus->reg + NPCM_I2CCTL1); + + // Clear BB (BUS BUSY) bit + iowrite8(NPCM_I2CCST_BB, bus->reg + NPCM_I2CCST); + iowrite8(0xFF, bus->reg + NPCM_I2CST); + + // Clear EOB bit + iowrite8(NPCM_I2CCST3_EO_BUSY, bus->reg + NPCM_I2CCST3); + + // Clear all fifo bits: + iowrite8(NPCM_I2CFIF_CTS_CLR_FIFO, bus->reg + NPCM_I2CFIF_CTS); + + bus->state = I2C_IDLE; +} + +static inline bool npcm_i2c_is_master(struct npcm_i2c *bus) +{ + return !!FIELD_GET(NPCM_I2CST_MASTER, ioread8(bus->reg + NPCM_I2CST)); +} + +static void npcm_i2c_callback(struct npcm_i2c *bus, + enum i2c_state_ind op_status, u16 info) +{ + struct i2c_msg *msgs; + int msgs_num; + + msgs = bus->msgs; + msgs_num = bus->msgs_num; + // check that transaction was not timed-out, and msgs still + // holds a valid value. + if (!msgs) + return; + + if (completion_done(&bus->cmd_complete)) + return; + + switch (op_status) { + case I2C_MASTER_DONE_IND: + bus->cmd_err = bus->msgs_num; + fallthrough; + case I2C_BLOCK_BYTES_ERR_IND: + // Master transaction finished and all transmit bytes were sent + if (bus->msgs) { + if (msgs[0].flags & I2C_M_RD) + msgs[0].len = info; + else if (msgs_num == 2 && + msgs[1].flags & I2C_M_RD) + msgs[1].len = info; + } + if (completion_done(&bus->cmd_complete) == false) + complete(&bus->cmd_complete); + break; + + case I2C_NACK_IND: + // MASTER transmit got a NACK before tx all bytes + // info: number of transmitted bytes + bus->cmd_err = -ENXIO; + if (bus->master_or_slave == I2C_MASTER) + complete(&bus->cmd_complete); + + break; + case I2C_BUS_ERR_IND: + // Bus error + bus->cmd_err = -EAGAIN; + if (bus->master_or_slave == I2C_MASTER) + complete(&bus->cmd_complete); + + break; + case I2C_WAKE_UP_IND: + // I2C wake up + break; + default: + break; + } + + bus->operation = I2C_NO_OPER; +} + +static u32 npcm_i2c_fifo_usage(struct npcm_i2c *bus) +{ + if (bus->operation == I2C_WRITE_OPER) + return FIELD_GET(NPCM_I2CTXF_STS_TX_BYTES, + ioread8(bus->reg + NPCM_I2CTXF_STS)); + if (bus->operation == I2C_READ_OPER) + return FIELD_GET(NPCM_I2CRXF_STS_RX_BYTES, + ioread8(bus->reg + NPCM_I2CRXF_STS)); + return 0; +} + +static void npcm_i2c_write_to_fifo_master(struct npcm_i2c *bus, + u16 max_bytes_to_send) +{ + // Fill the FIFO, while the FIFO is not full and there are more bytes to + // write + while ((max_bytes_to_send--) && + (I2C_HW_FIFO_SIZE - npcm_i2c_fifo_usage(bus))) { + if (bus->wr_ind < bus->wr_size) + npcm_i2c_wr_byte(bus, bus->wr_buf[bus->wr_ind++]); + else + npcm_i2c_wr_byte(bus, 0xFF); + } +} + +/* + * configure the FIFO before using it. If nread is -1 RX FIFO will not be + * configured. same for nwrite + */ +static void npcm_i2c_set_fifo(struct npcm_i2c *bus, int nread, int nwrite) +{ + u8 rxf_ctl = 0; + + if (!bus->fifo_use) + return; + npcm_i2c_select_bank(bus, I2C_BANK_1); + npcm_i2c_clear_tx_fifo(bus); + npcm_i2c_clear_rx_fifo(bus); + + // configure RX FIFO + if (nread > 0) { + rxf_ctl = min_t(int, nread, I2C_HW_FIFO_SIZE); + + // set LAST bit. if LAST is set enxt FIFO packet is nacked + // regular read of less then buffer size: + if (nread <= I2C_HW_FIFO_SIZE) + rxf_ctl |= NPCM_I2CRXF_CTL_LAST_PEC; + // if we are about to read the first byte in blk rd mode, + // don't NACK it. BTW, if slave return zero size HW can't NACK + // it immidiattly, it will read extra byte and then NACK. + if (bus->rd_ind == 0 && bus->read_block_use) { + // set fifo to read one byte, no last: + rxf_ctl = 1; + } + + // set fifo size: + iowrite8(rxf_ctl, bus->reg + NPCM_I2CRXF_CTL); + } + + // configure TX FIFO + if (nwrite > 0) { + if (nwrite > I2C_HW_FIFO_SIZE) + // data to send is more then FIFO size. + // Configure the FIFO int to be after of FIFO is cleared + iowrite8(I2C_HW_FIFO_SIZE, bus->reg + NPCM_I2CTXF_CTL); + else + iowrite8(nwrite, bus->reg + NPCM_I2CTXF_CTL); + + npcm_i2c_clear_tx_fifo(bus); + } +} + +static void npcm_i2c_read_from_fifo(struct npcm_i2c *bus, u8 bytes_in_fifo) +{ + u8 data; + + while (bytes_in_fifo--) { + data = npcm_i2c_rd_byte(bus); + + if (bus->master_or_slave == I2C_MASTER) { + if (bus->rd_ind < bus->rd_size) + bus->rd_buf[bus->rd_ind++] = data; + } + } +} + +static inline void npcm_i2c_clear_master_status(struct npcm_i2c *bus) +{ + u8 val; + + // Clear NEGACK, STASTR and BER bits + val = NPCM_I2CST_BER | NPCM_I2CST_NEGACK | NPCM_I2CST_STASTR; + iowrite8(val, bus->reg + NPCM_I2CST); +} + +static void npcm_i2c_master_abort(struct npcm_i2c *bus) +{ + // Only current master is allowed to issue a stop condition + if (npcm_i2c_is_master(bus)) { + npcm_i2c_eob_int(bus, true); + npcm_i2c_master_stop(bus); + npcm_i2c_clear_master_status(bus); + } +} + +static void npcm_i2c_master_fifo_read(struct npcm_i2c *bus) +{ + int rcount; + int fifo_bytes; + enum i2c_state_ind ind = I2C_MASTER_DONE_IND; + + fifo_bytes = npcm_i2c_fifo_usage(bus); + + rcount = bus->rd_size - bus->rd_ind; + + // In order not to change the RX_TRH during transaction (we found that + // this might be problematic if it takes too much time to read the FIFO) + // we read the data in the following way. If the number of bytes to + // read == FIFO Size + C (where C < FIFO Size)then first read C bytes + // and in the next int we read rest of the data. + if (rcount < (2 * I2C_HW_FIFO_SIZE) && rcount > I2C_HW_FIFO_SIZE) + fifo_bytes = rcount - I2C_HW_FIFO_SIZE; + + if (rcount <= fifo_bytes) { + // last bytes are about to be read - end of transaction. + // Stop should be set before reading last byte. + bus->state = I2C_STOP_PENDING; + bus->stop_ind = ind; + npcm_i2c_eob_int(bus, true); + npcm_i2c_master_stop(bus); + npcm_i2c_read_from_fifo(bus, fifo_bytes); + } else { + npcm_i2c_read_from_fifo(bus, fifo_bytes); + rcount = bus->rd_size - bus->rd_ind; + npcm_i2c_set_fifo(bus, rcount, -1); + } +} + +static void npcm_i2c_int_master_handler_write(struct npcm_i2c *bus) +{ + u16 wcount; + + if (bus->fifo_use) + npcm_i2c_clear_tx_fifo(bus); // clear the TX fifo status bit + + // Master write operation - last byte handling + if (bus->wr_ind == bus->wr_size) { + if (bus->fifo_use && npcm_i2c_fifo_usage(bus) > 0) + // No more bytes to send (to add to the FIFO), + // however the FIFO is not empty yet. It is + // still in the middle of tx. Currently there's nothing + // to do except for waiting to the end of the tx. + // We will get an int when the FIFO will get empty. + return; + + if (bus->rd_size == 0) { + // all bytes have been written, in a pure wr operation + npcm_i2c_eob_int(bus, true); + bus->state = I2C_STOP_PENDING; + bus->stop_ind = I2C_MASTER_DONE_IND; + npcm_i2c_master_stop(bus); + // Clear SDA Status bit (by writing dummy byte) + npcm_i2c_wr_byte(bus, 0xFF); + + } else { + // last write-byte written on previous int - need to + // restart & send slave address + npcm_i2c_set_fifo(bus, bus->rd_size, -1); + // Generate repeated start upon next write to SDA + npcm_i2c_master_start(bus); + if (bus->rd_size == 1) + // Receiving one byte only - stall after + // successful completion of send + // address byte. If we NACK here, + // and slave doesn't ACK the address, we + // might unintentionally NACK the next + // multi-byte read + npcm_i2c_stall_after_start(bus, true); + + // Next int will occur on read + bus->operation = I2C_READ_OPER; + // send the slave address in read direction + npcm_i2c_wr_byte(bus, bus->dest_addr | 0x1); + } + } else { + // write next byte not last byte and not slave address + if (!bus->fifo_use || bus->wr_size == 1) { + npcm_i2c_wr_byte(bus, bus->wr_buf[bus->wr_ind++]); + } else { + wcount = bus->wr_size - bus->wr_ind; + npcm_i2c_set_fifo(bus, -1, wcount); + if (wcount) + npcm_i2c_write_to_fifo_master(bus, wcount); + } + } +} + +static void npcm_i2c_int_master_handler_read(struct npcm_i2c *bus) +{ + u16 block_extra_bytes_size; + u8 data; + + // Master read operation (pure read or following a write operation). + + // added bytes to the packet: + block_extra_bytes_size = bus->read_block_use + bus->PEC_use; + + // Perform master read, distinguishing between last byte and the rest of + // the bytes. The last byte should be read when the clock is stopped + if (bus->rd_ind == 0) { //first byte handling: + // in block protocol first byte is the size + if (bus->read_block_use) { + // first byte in block protocol is the size: + data = npcm_i2c_rd_byte(bus); + data = clamp_val(data, 1, I2C_SMBUS_BLOCK_MAX); + bus->rd_size = data + block_extra_bytes_size; + bus->rd_buf[bus->rd_ind++] = data; + + // clear RX FIFO interrupt status: + if (bus->fifo_use) { + data = ioread8(bus->reg + NPCM_I2CFIF_CTS); + data = data | NPCM_I2CFIF_CTS_RXF_TXE; + iowrite8(data, bus->reg + NPCM_I2CFIF_CTS); + } + + npcm_i2c_set_fifo(bus, bus->rd_size - 1, -1); + npcm_i2c_stall_after_start(bus, false); + } else { + npcm_i2c_clear_tx_fifo(bus); + npcm_i2c_master_fifo_read(bus); + } + } else { + if (bus->rd_size == block_extra_bytes_size && + bus->read_block_use) { + bus->state = I2C_STOP_PENDING; + bus->stop_ind = I2C_BLOCK_BYTES_ERR_IND; + bus->cmd_err = -EIO; + npcm_i2c_eob_int(bus, true); + npcm_i2c_master_stop(bus); + npcm_i2c_read_from_fifo(bus, npcm_i2c_fifo_usage(bus)); + } else { + npcm_i2c_master_fifo_read(bus); + } + } +} + +static irqreturn_t npcm_i2c_int_master_handler(struct npcm_i2c *bus) +{ + irqreturn_t ret = IRQ_NONE; + u8 fif_cts; + u8 val; + u8 i2cst = ioread8(bus->reg + NPCM_I2CST); + + if (FIELD_GET(NPCM_I2CST_NMATCH, i2cst)) { + iowrite8(NPCM_I2CST_NMATCH, bus->reg + NPCM_I2CST); + npcm_i2c_nack(bus); + bus->stop_ind = I2C_BUS_ERR_IND; + npcm_i2c_callback(bus, bus->stop_ind, npcm_i2c_get_index(bus)); + + return IRQ_HANDLED; + } + // A NACK has occurred + if (FIELD_GET(NPCM_I2CST_NEGACK, i2cst)) { +#if IS_ENABLED(CONFIG_DEBUG_FS) + if (bus->nack_count == ULLONG_MAX) { + dev_dbg(bus->dev, "%s reaches maximum, reset to 0", + nack_cnt_name); + bus->nack_count = 0; + } + bus->nack_count++; +#endif + if (bus->fifo_use) { + // if there are still untransmitted bytes in TX FIFO + // reduce them from wr_ind + if (bus->operation == I2C_WRITE_OPER) + bus->wr_ind -= npcm_i2c_fifo_usage(bus); + + // clear the FIFO + iowrite8(NPCM_I2CFIF_CTS_CLR_FIFO, + bus->reg + NPCM_I2CFIF_CTS); + } + + // In master write operation, NACK is a problem + // number of bytes sent to master less than required + bus->stop_ind = I2C_NACK_IND; + // Only current master is allowed to issue Stop Condition + if (npcm_i2c_is_master(bus)) { + // stopping in the middle, not waiting for ints anymore + npcm_i2c_eob_int(bus, false); + + npcm_i2c_master_stop(bus); + + // The bus is released from stall only + // after the software clears NEGACK bit. + // Then a Stop condition is sent. + npcm_i2c_clear_master_status(bus); + + readx_poll_timeout_atomic(ioread8, + bus->reg + NPCM_I2CCST, val, + !(val & NPCM_I2CCST_BUSY), 10, + 200); + + } + bus->state = I2C_IDLE; + + // In Master mode, NACK should be cleared only after + // generating STOP. + // In such case, the bus is released from stall only after the + // software clears NACK bit. + // Then a Stop condition is sent. + npcm_i2c_callback(bus, bus->stop_ind, bus->wr_ind); + return IRQ_HANDLED; + } + + // Master mode: a Bus Error has been identified + if (FIELD_GET(NPCM_I2CST_BER, i2cst)) { +#if IS_ENABLED(CONFIG_DEBUG_FS) + if (bus->ber_count == ULLONG_MAX) { + dev_dbg(bus->dev, "%s reach max, reset", ber_cnt_name); + bus->ber_count = 0; + } + bus->ber_count++; +#endif + // Check whether bus arbitration or Start or Stop during data + // xfer bus arbitration problem should not result in recovery + bus->stop_ind = I2C_BUS_ERR_IND; + if (npcm_i2c_is_master(bus)) { + npcm_i2c_master_abort(bus); + } else { + npcm_i2c_clear_master_status(bus); + + // Clear BB (BUS BUSY) bit + iowrite8(NPCM_I2CCST_BB, bus->reg + NPCM_I2CCST); + + bus->cmd_err = -EAGAIN; + npcm_i2c_callback(bus, bus->stop_ind, + npcm_i2c_get_index(bus)); + } + bus->state = I2C_IDLE; + return IRQ_HANDLED; + } + + // A Master End of Busy (meaning Stop Condition happened) + // End of Busy int is on and End of Busy is set + if ((FIELD_GET(NPCM_I2CCTL1_EOBINTE, + ioread8(bus->reg + NPCM_I2CCTL1)) == 1) && + (FIELD_GET(NPCM_I2CCST3_EO_BUSY, + ioread8(bus->reg + NPCM_I2CCST3)))) { + npcm_i2c_eob_int(bus, false); + bus->state = I2C_IDLE; + npcm_i2c_callback(bus, bus->stop_ind, bus->rd_ind); + return IRQ_HANDLED; + } + + // Address sent and requested stall occurred (Master mode) + if (FIELD_GET(NPCM_I2CST_STASTR, i2cst)) { + if (npcm_i2c_is_quick(bus)) { + bus->state = I2C_STOP_PENDING; + bus->stop_ind = I2C_MASTER_DONE_IND; + npcm_i2c_eob_int(bus, true); + npcm_i2c_master_stop(bus); + } else if ((bus->rd_size == 1) && !bus->read_block_use) { + // Receiving one byte only - set NACK after ensuring + // slave ACKed the address byte + npcm_i2c_nack(bus); + } + + // Reset stall-after-address-byte + npcm_i2c_stall_after_start(bus, false); + + // Clear stall only after setting STOP + iowrite8(NPCM_I2CST_STASTR, bus->reg + NPCM_I2CST); + + ret = IRQ_HANDLED; + } + + // SDA status is set - TX or RX, master + if (FIELD_GET(NPCM_I2CST_SDAST, i2cst) || + (bus->fifo_use && + (npcm_i2c_tx_fifo_empty(bus) || npcm_i2c_rx_fifo_full(bus)))) { + // Status Bit is cleared by writing to or reading from SDA + // (depending on current direction) + + // Send address: + if (bus->state == I2C_IDLE) { + if (npcm_i2c_is_master(bus)) { + bus->stop_ind = I2C_WAKE_UP_IND; + + // test stall on start + if (npcm_i2c_is_quick(bus) || + bus->read_block_use) + // Need to stall after successful + // completion of sending address byte + npcm_i2c_stall_after_start(bus, true); + else + npcm_i2c_stall_after_start(bus, false); + + // Receiving one byte only - stall after + // successful completion of sending address byte + // If we NACK here, and slave doesn't ACK the + // address, we might unintentionally NACK + // the next multi-byte read + if (bus->wr_size == 0 && bus->rd_size == 1) + npcm_i2c_stall_after_start(bus, true); + + // Initiate I2C master transaction + // Generate a Start condition on the I2C + + // select bank 1 for FIFO regs + npcm_i2c_select_bank(bus, I2C_BANK_1); + + fif_cts = ioread8(bus->reg + NPCM_I2CFIF_CTS); + fif_cts = fif_cts & ~NPCM_I2CFIF_CTS_SLVRSTR; + + // clear FIFO and relevant status bits. + fif_cts = fif_cts | NPCM_I2CFIF_CTS_CLR_FIFO; + iowrite8(fif_cts, bus->reg + NPCM_I2CFIF_CTS); + + // and enable it + fif_cts = fif_cts | NPCM_I2CFIF_CTS_RXF_TXE; + iowrite8(fif_cts, bus->reg + NPCM_I2CFIF_CTS); + + // Configure the FIFO threshold + // according to the needed # of bytes to read. + // Note: due to HW limitation can't config the + // rx fifo before + // got and ACK on the restart. LAST bit will not + // be reset unless RX completed. + // It will stay set on the next tx. + if (bus->wr_size) + npcm_i2c_set_fifo(bus, -1, + bus->wr_size); + else + npcm_i2c_set_fifo(bus, bus->rd_size, + -1); + + bus->state = I2C_OPER_STARTED; + + if (npcm_i2c_is_quick(bus) || bus->wr_size) + npcm_i2c_wr_byte(bus, bus->dest_addr); + else + npcm_i2c_wr_byte(bus, bus->dest_addr | + 0x01); + } + + return IRQ_HANDLED; + // SDA status is set - transmit or receive: Handle master mode + } else { + if (!(NPCM_I2CST_XMIT & i2cst)) { + bus->operation = I2C_READ_OPER; + npcm_i2c_int_master_handler_read(bus); + } else { + bus->operation = I2C_WRITE_OPER; + npcm_i2c_int_master_handler_write(bus); + } + } + ret = IRQ_HANDLED; + } + + return ret; +} + +// recovery using TGCLK functionality of the module +static int npcm_i2c_recovery_tgclk(struct i2c_adapter *_adap) +{ + u8 val; + u8 fif_cts; + bool done = false; + int status = -ENOTRECOVERABLE; + struct npcm_i2c *bus = container_of(_adap, struct npcm_i2c, adap); + // Allow 3 bytes (27 toggles) to be read from the slave: + int iter = 27; + + if ((npcm_i2c_get_SDA(_adap) == 1) && (npcm_i2c_get_SCL(_adap) == 1)) { + dev_dbg(bus->dev, "bus%d recovery skipped, bus not stuck", + bus->num); + npcm_i2c_reset(bus); + return status; + } + + // Disable int + npcm_i2c_int_enable(bus, false); + npcm_i2c_disable(bus); + npcm_i2c_enable(bus); + iowrite8(NPCM_I2CCST_BB, bus->reg + NPCM_I2CCST); + npcm_i2c_clear_tx_fifo(bus); + npcm_i2c_clear_rx_fifo(bus); + iowrite8(0, bus->reg + NPCM_I2CRXF_CTL); + iowrite8(0, bus->reg + NPCM_I2CTXF_CTL); + npcm_i2c_stall_after_start(bus, false); + + // select bank 1 for FIFO regs + npcm_i2c_select_bank(bus, I2C_BANK_1); + + // clear FIFO and relevant status bits. + fif_cts = ioread8(bus->reg + NPCM_I2CFIF_CTS); + fif_cts &= ~NPCM_I2CFIF_CTS_SLVRSTR; + fif_cts |= NPCM_I2CFIF_CTS_CLR_FIFO; + iowrite8(fif_cts, bus->reg + NPCM_I2CFIF_CTS); + npcm_i2c_set_fifo(bus, -1, 0); + + // Repeat the following sequence until SDA is released + do { + // Issue a single SCL toggle + iowrite8(NPCM_I2CCST_TGSCL, bus->reg + NPCM_I2CCST); + udelay(20); + // If SDA line is inactive (high), stop + if (npcm_i2c_get_SDA(_adap)) { + done = true; + status = 0; + } + } while (!done && iter--); + + // If SDA line is released: send start-addr-stop, to re-sync. + if (npcm_i2c_get_SDA(_adap)) { + // Send an address byte in write direction: + npcm_i2c_wr_byte(bus, bus->dest_addr); + npcm_i2c_master_start(bus); + // Wait until START condition is sent + status = readx_poll_timeout(npcm_i2c_get_SCL, _adap, val, !val, + 20, 200); + // If START condition was sent + if (npcm_i2c_is_master(bus) > 0) { + + udelay(20); + npcm_i2c_master_stop(bus); + udelay(200); + } + } + npcm_i2c_reset(bus); + npcm_i2c_int_enable(bus, true); + + if ((npcm_i2c_get_SDA(_adap) == 1) && (npcm_i2c_get_SCL(_adap) == 1)) + status = 0; + else + status = -ENOTRECOVERABLE; +#if IS_ENABLED(CONFIG_DEBUG_FS) + if (!status) { + if (bus->rec_succ_count == ULLONG_MAX) { + dev_dbg(bus->dev, + "%s reaches maximum, reset to 0", + rec_succ_cnt_name); + bus->rec_succ_count = 0; + } + bus->rec_succ_count++; + } else { + if (bus->rec_succ_count == ULLONG_MAX) { + dev_dbg(bus->dev, + "%s reaches maximum, reset to 0", + rec_succ_cnt_name); + bus->rec_fail_count = 0; + } + bus->rec_fail_count++; + } +#endif + return status; +} + +// recovery using bit banging functionality of the module +static int npcm_i2c_recovery_init(struct i2c_adapter *_adap) +{ + struct npcm_i2c *bus = container_of(_adap, struct npcm_i2c, adap); + struct i2c_bus_recovery_info *rinfo = &bus->rinfo; + + rinfo->recover_bus = npcm_i2c_recovery_tgclk; + rinfo->prepare_recovery = NULL; + rinfo->unprepare_recovery = NULL; + rinfo->set_scl = NULL; + rinfo->set_sda = NULL; + + dev_dbg(bus->dev, "init i2c recovery using TGCLK\n"); + + rinfo->get_scl = npcm_i2c_get_SCL; + rinfo->get_sda = npcm_i2c_get_SDA; + + _adap->bus_recovery_info = rinfo; + + return 0; +} + +// SCLFRQ min/max field values +#define SCLFRQ_MIN 10 +#define SCLFRQ_MAX 511 + +/* + * npcm_i2c_init_clk: init HW timing parameters. + * NPCM7XX i2c module timing parameters are depenent on module core clk (APB) + * and bus frequency. + * 100kHz bus requires tSCL = 4 * SCLFRQ * tCLK. LT and HT are simetric. + * 400kHz bus requires assymetric HT and LT. A different equation is recomended + * by the HW designer, given core clock range (equations in comments below). + * + */ +static int npcm_i2c_init_clk(struct npcm_i2c *bus, u32 bus_freq) +{ + u32 k1 = 0; + u32 k2 = 0; + u8 dbnct = 0; + u32 sclfrq = 0; + u8 hldt = 7; + bool fast_mode = false; + u32 src_clk_freq; // in KHz + + src_clk_freq = bus->apb_clk / 1000; + bus->bus_freq = bus_freq; + + // 100KHz and below: + if (bus_freq <= (I2C_MAX_STANDARD_MODE_FREQ / 1000)) { + sclfrq = src_clk_freq / (bus_freq * 4); + + if (sclfrq < SCLFRQ_MIN || sclfrq > SCLFRQ_MAX) + return -EDOM; + + if (src_clk_freq >= 40000) + hldt = 17; + else if (src_clk_freq >= 12500) + hldt = 15; + else + hldt = 7; + } + + // 400KHz: + else if (bus_freq <= (I2C_MAX_FAST_MODE_FREQ / 1000)) { + sclfrq = 0; + fast_mode = true; + + if (src_clk_freq < 7500) + // 400KHZ cannot be supported for core clock < 7.5 MHZ + return -EDOM; + + else if (src_clk_freq >= 50000) { + k1 = 80; + k2 = 48; + hldt = 12; + dbnct = 7; + } + + // Master or Slave with frequency > 25 MHZ + else if (src_clk_freq > 25000) { + hldt = (DIV_ROUND_UP(src_clk_freq * 300, + 1000000) + 7) & 0xFF; + + k1 = DIV_ROUND_UP(src_clk_freq * 1600, + 1000000); + k2 = DIV_ROUND_UP(src_clk_freq * 900, + 1000000); + k1 = round_up(k1, 2); + k2 = round_up(k2 + 1, 2); + if (k1 < SCLFRQ_MIN || k1 > SCLFRQ_MAX || + k2 < SCLFRQ_MIN || k2 > SCLFRQ_MAX) + return -EDOM; + } + } + + else if (bus_freq <= (I2C_MAX_FAST_MODE_PLUS_FREQ / 1000)) { + sclfrq = 0; + fast_mode = true; + + if (src_clk_freq < 24000) + // 1MHZ cannot be supported for master core clock < 15 MHZ + // or slave core clock < 24 MHZ + return -EDOM; + + k1 = round_up((DIV_ROUND_UP(src_clk_freq * 620, + 1000000)), 2); + k2 = round_up((DIV_ROUND_UP(src_clk_freq * 380, + 1000000) + 1), 2); + if (k1 < SCLFRQ_MIN || k1 > SCLFRQ_MAX || + k2 < SCLFRQ_MIN || k2 > SCLFRQ_MAX) + return -EDOM; + + // Core clk > 40 MHZ + if (src_clk_freq > 40000) { + // Set HLDT: + // SDA hold time: (HLDT-7) * T(CLK) >= 120 + // HLDT = 120/T(CLK) + 7 = 120 * FREQ(CLK) + 7 + hldt = (DIV_ROUND_UP(src_clk_freq * 120, + 1000000) + 7) & 0xFF; + } else { + hldt = 7; + dbnct = 2; + } + } + + // Frequency larger than 1 MHZ is not supported + else + return false; + + // After clock parameters calculation update reg (ENABLE should be 0): + iowrite8(FIELD_PREP(I2CCTL2_SCLFRQ6_0, sclfrq & 0x7F), + bus->reg + NPCM_I2CCTL2); + + // force to bank 0, set SCL and fast mode + iowrite8(FIELD_PREP(I2CCTL3_400K_MODE, fast_mode) | + FIELD_PREP(I2CCTL3_SCLFRQ8_7, (sclfrq >> 7) & 0x3), + bus->reg + NPCM_I2CCTL3); + + // Select Bank 0 to access NPCM_I2CCTL4/NPCM_I2CCTL5 + npcm_i2c_select_bank(bus, I2C_BANK_0); + + if (bus_freq >= (I2C_MAX_FAST_MODE_FREQ / 1000)) { + // Set SCL Low/High Time: + // k1 = 2 * SCLLT7-0 -> Low Time = k1 / 2 + // k2 = 2 * SCLLT7-0 -> High Time = k2 / 2 + iowrite8((u8)k1 / 2, bus->reg + NPCM_I2CSCLLT); + iowrite8((u8)k2 / 2, bus->reg + NPCM_I2CSCLHT); + + iowrite8(dbnct, bus->reg + NPCM_I2CCTL5); + } + + iowrite8(hldt, bus->reg + NPCM_I2CCTL4); + + // Return to Bank 1, and stay there by default: + npcm_i2c_select_bank(bus, I2C_BANK_1); + + return true; +} + +static bool npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode, + u32 bus_freq) +{ + u8 val; + + // Check whether module already enabled or frequency is out of bounds + if ((bus->state != I2C_DISABLE && bus->state != I2C_IDLE) || + bus_freq < I2C_FREQ_MIN || bus_freq > I2C_FREQ_MAX) + return false; + + npcm_i2c_disable(bus); + + // Configure FIFO mode : + if (FIELD_GET(I2C_VER_FIFO_EN, ioread8(bus->reg + I2C_VER))) { + bus->fifo_use = true; + npcm_i2c_select_bank(bus, I2C_BANK_0); + val = ioread8(bus->reg + NPCM_I2CFIF_CTL); + val |= NPCM_I2CFIF_CTL_FIFO_EN; + iowrite8(val, bus->reg + NPCM_I2CFIF_CTL); + npcm_i2c_select_bank(bus, I2C_BANK_1); + } else { + bus->fifo_use = false; + } + + // Configure I2C module clock frequency + if (!npcm_i2c_init_clk(bus, bus_freq)) { + dev_err(bus->dev, "npcm_i2c_init_clk failed\n"); + return false; + } + + // Enable module (before configuring CTL1) + npcm_i2c_enable(bus); + bus->state = I2C_IDLE; + val = ioread8(bus->reg + NPCM_I2CCTL1); + val = (val | NPCM_I2CCTL1_NMINTE) & ~NPCM_I2CCTL1_RWS; + iowrite8(val, bus->reg + NPCM_I2CCTL1); + + npcm_i2c_int_enable(bus, true); + + npcm_i2c_reset(bus); + + return true; +} + +static int __npcm_i2c_init(struct npcm_i2c *bus, struct platform_device *pdev) +{ + u32 clk_freq; + int ret; + + // Initialize the internal data structures + bus->state = I2C_DISABLE; + bus->master_or_slave = I2C_SLAVE; + bus->int_time_stamp = 0; + bus->xmits = 0; + + ret = device_property_read_u32(&pdev->dev, "bus-frequency", &clk_freq); + if (ret < 0) { + dev_info(&pdev->dev, "Could not read bus-frequency property\n"); + clk_freq = 100000; + } + + ret = npcm_i2c_init_module(bus, I2C_MASTER, clk_freq / 1000); + if (!ret) { + dev_err(&pdev->dev, "npcm_i2c_init_module failed\n"); + return ret; + } + + return 0; +} + +static irqreturn_t npcm_i2c_bus_irq(int irq, void *dev_id) +{ + irqreturn_t ret; + struct npcm_i2c *bus = dev_id; + + bus->int_cnt++; + + if (npcm_i2c_is_master(bus)) + bus->master_or_slave = I2C_MASTER; + + if (bus->master_or_slave == I2C_MASTER) { + bus->int_time_stamp = jiffies; + ret = npcm_i2c_int_master_handler(bus); + if (ret == IRQ_HANDLED) + return ret; + } + return IRQ_HANDLED; +} + +static bool npcm_i2c_master_start_xmit(struct npcm_i2c *bus, + u8 slave_addr, u16 nwrite, u16 nread, + u8 *write_data, u8 *read_data, + bool use_PEC, bool use_read_block) +{ + if (bus->state != I2C_IDLE) { + bus->cmd_err = -EBUSY; + return false; + } + bus->xmits++; + bus->dest_addr = (slave_addr << 1) & 0xFE; + bus->wr_buf = write_data; + bus->wr_size = nwrite; + bus->wr_ind = 0; + bus->rd_buf = read_data; + bus->rd_size = nread; + bus->rd_ind = 0; + bus->PEC_use = 0; + + // for write, PEC is appended to buffer from i2c IF. PEC flag is ignored + if (nread) + bus->PEC_use = use_PEC; + bus->read_block_use = use_read_block; + if (nread && !nwrite) + bus->operation = I2C_READ_OPER; + else + bus->operation = I2C_WRITE_OPER; + bus->int_cnt = 0; + if (bus->fifo_use) { + u8 i2cfif_cts; + + npcm_i2c_select_bank(bus, I2C_BANK_1); + // clear FIFO and relevant status bits. + i2cfif_cts = ioread8(bus->reg + NPCM_I2CFIF_CTS); + i2cfif_cts &= ~NPCM_I2CFIF_CTS_SLVRSTR; + i2cfif_cts |= NPCM_I2CFIF_CTS_CLR_FIFO; + iowrite8(i2cfif_cts, bus->reg + NPCM_I2CFIF_CTS); + } + + bus->state = I2C_IDLE; + + npcm_i2c_stall_after_start(bus, true); + npcm_i2c_master_start(bus); + + return true; +} + +static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, + int num) +{ + struct npcm_i2c *bus = container_of(adap, struct npcm_i2c, adap); + struct i2c_msg *msg0, *msg1; + unsigned long time_left, flags; + u16 nwrite, nread; + u8 *write_data, *read_data; + u8 slave_addr; + int timeout; + int ret = 0; + bool read_block = false; + bool read_PEC = false; + u8 bus_busy; + unsigned long timeout_usec; + + if (bus->state == I2C_DISABLE) { + dev_err(bus->dev, "I2C%d module is disabled", bus->num); + return -EINVAL; + } + + if (num > 2 || num < 1) { + dev_err(bus->dev, "I2C cmd not supported num of msgs=%d", num); + return -EINVAL; + } + + msg0 = &msgs[0]; + slave_addr = msg0->addr; + if (msg0->flags & I2C_M_RD) { // read + if (num == 2) { + dev_err(bus->dev, "num=2 but 1st msg rd instead of wr"); + return -EINVAL; + } + nwrite = 0; + write_data = NULL; + read_data = msg0->buf; + if (msg0->flags & I2C_M_RECV_LEN) { + nread = 1; + read_block = true; + if (msg0->flags & I2C_CLIENT_PEC) + read_PEC = true; + } else { + nread = msg0->len; + } + } else { // write + nwrite = msg0->len; + write_data = msg0->buf; + nread = 0; + read_data = NULL; + if (num == 2) { + msg1 = &msgs[1]; + read_data = msg1->buf; + if (slave_addr != msg1->addr) { + dev_err(bus->dev, + "SA==%02x but msg1->addr==%02x\n", + slave_addr, msg1->addr); + return -EINVAL; + } + if ((msg1->flags & I2C_M_RD) == 0) { + dev_err(bus->dev, + "num = 2 but both msg are write.\n"); + return -EINVAL; + } + if (msg1->flags & I2C_M_RECV_LEN) { + nread = 1; + read_block = true; + if (msg1->flags & I2C_CLIENT_PEC) + read_PEC = true; + } else { + nread = msg1->len; + read_block = false; + } + } + } + + /* Adaptive TimeOut: astimated time in usec + 100% margin */ + timeout_usec = (2 * 10000 / bus->bus_freq) * (2 + nread + nwrite); + timeout = max(msecs_to_jiffies(35), usecs_to_jiffies(timeout_usec)); + if (nwrite >= 32 * 1024 || nread >= 32 * 1024) { + dev_err(bus->dev, "i2c%d buffer too big\n", bus->num); + return -EINVAL; + } + + time_left = jiffies + + msecs_to_jiffies(DEFAULT_STALL_COUNT) + 1; + do { + /* we must clear slave address immediately when the bus is not + * busy, so we spinlock it, but we don't keep the lock for the + * entire while since it is too long. + */ + spin_lock_irqsave(&bus->lock, flags); + bus_busy = ioread8(bus->reg + NPCM_I2CCST) & NPCM_I2CCST_BB; + spin_unlock_irqrestore(&bus->lock, flags); + + } while (time_is_after_jiffies(time_left) && bus_busy); + + if (bus_busy) { + iowrite8(NPCM_I2CCST_BB, bus->reg + NPCM_I2CCST); + npcm_i2c_reset(bus); + i2c_recover_bus(adap); + return -EAGAIN; + } + + npcm_i2c_init_params(bus); + bus->dest_addr = slave_addr; + bus->msgs = msgs; + bus->msgs_num = num; + bus->cmd_err = 0; + bus->read_block_use = read_block; + + reinit_completion(&bus->cmd_complete); + + if (!npcm_i2c_master_start_xmit(bus, slave_addr, nwrite, nread, + write_data, read_data, read_PEC, + read_block)) + ret = -EBUSY; + + if (ret != -EBUSY) { + time_left = wait_for_completion_timeout(&bus->cmd_complete, + timeout); + + if (time_left == 0) { +#if IS_ENABLED(CONFIG_DEBUG_FS) + if (bus->timeout_count == ULLONG_MAX) { + dev_dbg(bus->dev, + "%s reaches to maximum, reset to 0", + timeout_cnt_name); + bus->timeout_count = 0; + } + bus->timeout_count++; +#endif + if (bus->master_or_slave == I2C_MASTER) { + i2c_recover_bus(adap); + bus->cmd_err = -EIO; + bus->state = I2C_IDLE; + } + } + } + ret = bus->cmd_err; + + // if there was BER, check if need to recover the bus: + if (bus->cmd_err == -EAGAIN) + ret = i2c_recover_bus(adap); + + return bus->cmd_err; +} + +static u32 npcm_i2c_functionality(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | + I2C_FUNC_SMBUS_EMUL | + I2C_FUNC_SMBUS_BLOCK_DATA | + I2C_FUNC_SMBUS_PEC | + I2C_FUNC_SLAVE; +} + +static const struct i2c_adapter_quirks npcm_i2c_quirks = { + .max_read_len = 32768, + .max_write_len = 32768, + .max_num_msgs = 2, + .flags = I2C_AQ_COMB_WRITE_THEN_READ, +}; + +static const struct i2c_algorithm npcm_i2c_algo = { + .master_xfer = npcm_i2c_master_xfer, + .functionality = npcm_i2c_functionality, +}; + +#if IS_ENABLED(CONFIG_DEBUG_FS) +static int i2c_debugfs_get(void *data, u64 *val) +{ + *val = *(u64 *)(data); + return 0; +} +DEFINE_DEBUGFS_ATTRIBUTE(i2c_debugfs_ops, i2c_debugfs_get, NULL, "0x%02llx\n"); + +static int i2c_init_debugfs(struct platform_device *pdev, struct npcm_i2c *bus) +{ + if (!npcm_i2c_debugfs_dir) + return -ENODEV; + + if (!pdev || !bus) + return -ENODEV; + + bus->debugfs = debugfs_create_dir(dev_name(&pdev->dev), + npcm_i2c_debugfs_dir); + + if (IS_ERR_OR_NULL(bus->debugfs)) { + bus->debugfs = NULL; + return -ENODEV; + } + + debugfs_create_file(ber_cnt_name, 0444, bus->debugfs, + &bus->ber_count, + &i2c_debugfs_ops); + + debugfs_create_file(rec_succ_cnt_name, 0444, bus->debugfs, + &bus->rec_succ_count, + &i2c_debugfs_ops); + + debugfs_create_file(rec_fail_cnt_name, 0444, bus->debugfs, + &bus->rec_fail_count, + &i2c_debugfs_ops); + + debugfs_create_file(nack_cnt_name, 0444, bus->debugfs, + &bus->nack_count, + &i2c_debugfs_ops); + + debugfs_create_file(timeout_cnt_name, 0444, bus->debugfs, + &bus->timeout_count, + &i2c_debugfs_ops); + + return 0; +} +#endif + +static int npcm_i2c_probe_bus(struct platform_device *pdev) +{ + struct npcm_i2c *bus; + struct i2c_adapter *adap; + struct clk *i2c_clk; + static struct regmap *gcr_regmap; + static struct regmap *clk_regmap; + int ret; + int num; + + bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL); + if (!bus) + return -ENOMEM; + + bus->dev = &pdev->dev; + + num = of_alias_get_id(pdev->dev.of_node, "i2c"); + bus->num = num; + // core clk must be acquired to calculate module timing settings + i2c_clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(i2c_clk)) + return PTR_ERR(i2c_clk); + bus->apb_clk = clk_get_rate(i2c_clk); + + gcr_regmap = syscon_regmap_lookup_by_compatible("nuvoton,npcm750-gcr"); + if (IS_ERR(gcr_regmap)) + return IS_ERR(gcr_regmap); + regmap_write(gcr_regmap, NPCM_I2CSEGCTL, NPCM_I2CSEGCTL_INIT_VAL); + + clk_regmap = syscon_regmap_lookup_by_compatible("nuvoton,npcm750-clk"); + if (IS_ERR(clk_regmap)) + return IS_ERR(clk_regmap); + + bus->reg = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(bus->reg)) + return PTR_ERR((bus)->reg); + + spin_lock_init(&bus->lock); + init_completion(&bus->cmd_complete); + + adap = &bus->adap; + adap->owner = THIS_MODULE; + adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD | I2C_CLIENT_SLAVE; + adap->retries = 3; + adap->timeout = HZ; + adap->algo = &npcm_i2c_algo; + adap->quirks = &npcm_i2c_quirks; + adap->algo_data = bus; + adap->dev.parent = &pdev->dev; + adap->dev.of_node = pdev->dev.of_node; + adap->nr = pdev->id; + + bus->irq = platform_get_irq(pdev, 0); + if (bus->irq < 0) { + dev_err(&pdev->dev, "failed to get IRQ number\n"); + return bus->irq; + } + + ret = devm_request_irq(&pdev->dev, bus->irq, npcm_i2c_bus_irq, 0, + dev_name(&pdev->dev), bus); + if (ret) { + dev_err(&pdev->dev, "failed to request irq %d\n", ret); + return ret; + } + + ret = __npcm_i2c_init(bus, pdev); + if (ret < 0) + return ret; + + ret = npcm_i2c_recovery_init(adap); + if (ret) + return ret; + + i2c_set_adapdata(adap, bus); + + snprintf(bus->adap.name, sizeof(bus->adap.name), "Nuvoton i2c"); + ret = i2c_add_numbered_adapter(&bus->adap); + if (ret < 0) { + dev_err(&pdev->dev, "failed to add numbered adapter %d\n", ret); + return ret; + } + platform_set_drvdata(pdev, bus); + +#if IS_ENABLED(CONFIG_DEBUG_FS) + ret = i2c_init_debugfs(pdev, bus); + if (ret < 0) + return ret; +#endif + return 0; +} + +static int npcm_i2c_remove_bus(struct platform_device *pdev) +{ + unsigned long lock_flags; + struct npcm_i2c *bus = platform_get_drvdata(pdev); + + spin_lock_irqsave(&bus->lock, lock_flags); + npcm_i2c_disable(bus); + spin_unlock_irqrestore(&bus->lock, lock_flags); + i2c_del_adapter(&bus->adap); + +#if IS_ENABLED(CONFIG_DEBUG_FS) + if (!!bus->debugfs) { + debugfs_remove_recursive(bus->debugfs); + bus->debugfs = NULL; + } +#endif + + return 0; +} + +static const struct of_device_id npcm_i2c_bus_of_table[] = { + { .compatible = "nuvoton,npcm750-i2c", }, + {} +}; +MODULE_DEVICE_TABLE(of, npcm_i2c_bus_of_table); + +static struct platform_driver npcm_i2c_bus_driver = { + .probe = npcm_i2c_probe_bus, + .remove = npcm_i2c_remove_bus, + .driver = { + .name = "nuvoton-i2c", + .of_match_table = npcm_i2c_bus_of_table, + } +}; +module_platform_driver(npcm_i2c_bus_driver); + +#if IS_ENABLED(CONFIG_DEBUG_FS) +static int __init npcm_i2c_init(void) +{ + npcm_i2c_debugfs_dir = debugfs_create_dir("i2c", NULL); + if (IS_ERR_OR_NULL(npcm_i2c_debugfs_dir)) { + pr_warn("i2c init of debugfs failed\n"); + npcm_i2c_debugfs_dir = NULL; + return -ENOMEM; + } + + return 0; +} + +static void __exit npcm_i2c_exit(void) +{ + if (!!npcm_i2c_debugfs_dir) { + debugfs_remove_recursive(npcm_i2c_debugfs_dir); + npcm_i2c_debugfs_dir = NULL; + } +} + +module_init(npcm_i2c_init); +module_exit(npcm_i2c_exit); +#endif + +MODULE_AUTHOR("Avi Fishman <avi.fish...@gmail.com>"); +MODULE_AUTHOR("Tali Perry <tali.pe...@nuvoton.com>"); +MODULE_AUTHOR("Tyrone Ting <kft...@nuvoton.com>"); +MODULE_DESCRIPTION("Nuvoton I2C Bus Driver"); +MODULE_LICENSE("GPL v2"); +MODULE_VERSION("0.1.2"); + -- 2.22.0