With i2c rawio driver, you can read/write registers from any i2c client(slave) device via debug fs interface. This driver is based on the rawio framework.
Signed-off-by: Bin Gao <bin....@intel.com> --- drivers/misc/rawio/Kconfig | 11 ++ drivers/misc/rawio/Makefile | 1 + drivers/misc/rawio/rawio_i2c.c | 224 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 236 insertions(+) create mode 100644 drivers/misc/rawio/rawio_i2c.c diff --git a/drivers/misc/rawio/Kconfig b/drivers/misc/rawio/Kconfig index 38e8a52..9ffbc5d 100644 --- a/drivers/misc/rawio/Kconfig +++ b/drivers/misc/rawio/Kconfig @@ -45,4 +45,15 @@ config RAWIO_IOMEM To compile this driver as a module, choose M: the module will be called rawio_iomem. +config RAWIO_I2C + tristate "rawio I2C driver" + depends on RAWIO && I2C + default no + help + This option enables the rawio I2C driver. + With this driver, you can read or write any I2C device's + register debugfs interface. + To compile this driver as a module, choose M: the module will + be called rawio_i2c. + endif # RAWIO diff --git a/drivers/misc/rawio/Makefile b/drivers/misc/rawio/Makefile index 5f86257..9e33aec 100644 --- a/drivers/misc/rawio/Makefile +++ b/drivers/misc/rawio/Makefile @@ -1,3 +1,4 @@ obj-$(CONFIG_RAWIO) += rawio.o obj-$(CONFIG_RAWIO_PCI) += rawio_pci.o obj-$(CONFIG_RAWIO_IOMEM) += rawio_iomem.o +obj-$(CONFIG_RAWIO_I2C) += rawio_i2c.o diff --git a/drivers/misc/rawio/rawio_i2c.c b/drivers/misc/rawio/rawio_i2c.c new file mode 100644 index 0000000..f872602 --- /dev/null +++ b/drivers/misc/rawio/rawio_i2c.c @@ -0,0 +1,224 @@ +/* + * rawio_i2c.c - rawio I2C driver. + * Read or write a I2C device's register, based on the rawio framework. + * + * Copyright (c) 2013 Bin Gao <bin....@intel.com> + * + * This file is released under the GPLv2 + * + * + * read i2c registers: + * echo "r i2c <bus_num> <slace_addr> <reg> [<len>]" > + * /sys/kernel/debug/rawio_cmd + * cat /sys/kernel/debug/rawio_output + * e.g. echo "r i2c 3 0x6b 0x84 5" > /sys/kernel/debug/rawio_cmd + * cat /sys/kernel/debug/rawio_output + * + * write a i2c register: + * echo "w i2c <bus_num> <slace_addr> <reg> <val>" > + * /sys/kernel/debug/rawio_cmd + * cat /sys/kernel/debug/rawio_output + * e.g. echo "w i2c 4 0x70 0x4 0xfa" > /sys/kernel/debug/rawio_cmd + * cat /sys/kernel/debug/rawio_output + * + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/types.h> +#include <linux/slab.h> +#include <linux/pm_runtime.h> +#include <linux/i2c.h> +#include <linux/rawio.h> + +static int i2c_prepare(u8 i2c_bus, u16 i2c_addr, u16 i2c_reg, u16 len, + int ten_bit_addr, struct i2c_adapter **ppadap) +{ + struct i2c_adapter *adap; + + adap = i2c_get_adapter((int)i2c_bus); + if (!adap) { + rawio_err("can't find bus adapter for i2c bus %d\n", + i2c_bus); + return -ENODEV; + } + + if ((!ten_bit_addr && (i2c_addr > 128)) || (i2c_addr > 1024)) { + rawio_err("register address is out of range, forgot 't' for 10bit addr?\n"); + return -EINVAL; + } + + if ((!ten_bit_addr && ((i2c_addr + len) > 128)) || + ((i2c_addr + len) > 1024)) { + rawio_err("register address is out of range, forgot 't' for 10bit addr?\n"); + return -EINVAL; + } + + *ppadap = adap; + return 0; +} + +static int rawio_i2c_read(struct rawio_driver *driver, int width, u64 *input, + u8 *postfix, int input_num, void **output, int *output_num) +{ + int ret, len; + struct i2c_adapter *adap; + u16 i2c_addr, i2c_reg; + struct i2c_msg msg[2]; + u8 i2c_bus, buf[2], *out_buf, ten_bit_addr, sixteen_bit_reg; + + i2c_bus = (u8)input[0]; + i2c_addr = (u16)input[1]; + i2c_reg = (u16)input[2]; + + len = 1; + if (input_num == 4) + len = (u16)input[3]; + + ten_bit_addr = postfix[1]; + sixteen_bit_reg = postfix[2]; + + ret = i2c_prepare(i2c_bus, i2c_addr, i2c_reg, len, ten_bit_addr, &adap); + if (ret) + return ret; + + out_buf = kzalloc(sizeof(u8) * len, GFP_KERNEL); + if (buf == NULL) { + rawio_err("can't alloc memory\n"); + return -ENOMEM; + } + buf[0] = i2c_reg & 0xff; + buf[1] = (i2c_reg >> 8) & 0xff; + + /* write i2c reg address */ + msg[0].addr = i2c_addr; + msg[0].flags = ten_bit_addr ? I2C_M_TEN : 0; + msg[0].len = sixteen_bit_reg ? 2 : 1; + msg[0].buf = buf; + + /* read i2c reg */ + msg[1].addr = i2c_addr; + msg[1].flags = I2C_M_RD | (ten_bit_addr ? I2C_M_TEN : 0); + msg[1].len = len; + msg[1].buf = out_buf; + + ret = i2c_transfer(adap, msg, 2); + if (ret != 2) { + rawio_err("i2c_transfer() failed, ret = %d\n", ret); + kfree(out_buf); + return -EIO; + } + + *output = out_buf; + *output_num = len; + return 0; +} + +static int rawio_i2c_write(struct rawio_driver *driver, int width, u64 *input, + u8 *postfix, int input_num) +{ + int ret; + struct i2c_adapter *adap; + u16 i2c_addr, i2c_reg; + struct i2c_msg msg; + u8 value, i2c_bus, buf[2], buf16[3], ten_bit_addr, sixteen_bit_reg; + + i2c_bus = (u8)input[0]; + i2c_addr = (u8)input[1]; + i2c_reg = (u16)input[2]; + value = (u8)input[3]; + + ten_bit_addr = postfix[1]; + sixteen_bit_reg = postfix[2]; + + ret = i2c_prepare(i2c_bus, i2c_addr, i2c_reg, 0, ten_bit_addr, &adap); + if (ret) + return ret; + + if (sixteen_bit_reg) { + buf16[0] = (i2c_reg >> 8) & 0xff; /* high 8 bit reg addr */ + buf16[1] = i2c_reg & 0xff; /* low 8 bit reg addr */ + buf16[2] = value; + msg.len = 3; + msg.buf = buf16; + } else { + buf[0] = i2c_reg & 0xff; /* low 8 bit reg addr */ + buf[1] = value; + msg.len = 2; + msg.buf = buf; + } + + msg.addr = i2c_addr; + msg.flags = ten_bit_addr ? I2C_M_TEN : 0; + + ret = i2c_transfer(adap, &msg, 1); + if (ret != 1) { + rawio_err("i2c_transfer() failed, ret = %d\n", ret); + return -EIO; + } + + return 0; +} + +static struct rawio_ops rawio_i2c_ops = { + rawio_i2c_read, + NULL, + rawio_i2c_write, +}; + +static struct rawio_driver rawio_i2c = { + {NULL, NULL}, /* list node */ + "i2c", /* driver name */ + + /* read */ + 4, /* max args */ + {TYPE_U8, TYPE_U16, TYPE_U16, TYPE_U8}, /* type of read args */ + 3, /* min args */ + { 0, 't', 's', 0 }, /* args postfix */ + + /* write */ + 4, /* max args */ + {TYPE_U8, TYPE_U16, TYPE_U16, TYPE_U8}, /* type of write args */ + 4, /* min args */ + { 0, 't', 's', 0 }, /* args postfix */ + + 2, /* index of arg that specifies the register or memory address */ + + WIDTH_1, /* supported width */ + WIDTH_1, /* default width */ + + /* + * Slave address with postfix 't' indicates 10 bit slave address, + * otherwise it's 7 bit address by default. + * Register offset with postfix 's' indicates register offset is + * 16 bit, otherwise it's 8 bit offset by default. + * For example "r i2c 5 0x108t 0x0394s 2" means 10 bit slave address + * and 16 bit register offset, and "r i2c 5 0x28 0x74" means 7 bit + * slave address and 8 bit register offset. + */ + "r i2c <bus> <addr>[t] <reg>[s] [<len>]\n" + "w i2c <bus> <addr>[t] <reg>[s] <val>\n", + &rawio_i2c_ops, + NULL +}; + +static int __init rawio_i2c_init(void) +{ + if (rawio_register_driver(&rawio_i2c)) + return -ENODEV; + + return 0; +} +module_init(rawio_i2c_init); + +static void __exit rawio_i2c_exit(void) +{ + rawio_unregister_driver(&rawio_i2c); +} +module_exit(rawio_i2c_exit); + +MODULE_DESCRIPTION("Rawio I2C driver"); +MODULE_VERSION("1.0"); +MODULE_AUTHOR("Bin Gao <bin....@intel.com>"); +MODULE_LICENSE("GPL v2"); -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/