Hi Peter,

Thanks for the review!

On Fri, Jun 29, 2018 at 06:45:19AM +0200, Peter Rosin wrote:
> On June 28, 2018 8:10:41 PM GMT+02:00, Manivannan Sadhasivam 
> <[email protected]> wrote:
> >Add Actions Semi OWL family S900 I2C driver.
> >
> >Signed-off-by: Manivannan Sadhasivam <[email protected]>
> >---
> > drivers/i2c/busses/Kconfig   |   7 +
> > drivers/i2c/busses/Makefile  |   1 +
> > drivers/i2c/busses/i2c-owl.c | 471 +++++++++++++++++++++++++++++++++++
> > 3 files changed, 479 insertions(+)
> > create mode 100644 drivers/i2c/busses/i2c-owl.c
> >
> >diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> >index 4f8df2ec87b1..2062da17e33b 100644
> >--- a/drivers/i2c/busses/Kconfig
> >+++ b/drivers/i2c/busses/Kconfig
> >@@ -762,6 +762,13 @@ config I2C_OMAP
> >       Like OMAP1510/1610/1710/5912 and OMAP242x.
> >       For details see http://www.ti.com/omap.
> > 
> >+config I2C_OWL
> >+    tristate "OWL I2C Controller"
> >+    depends on ARCH_ACTIONS || COMPILE_TEST
> >+    help
> >+      Say Y here if you want to use the I2C bus controller on
> >+      the Actions Semi OWL SoCs.
> >+
> > config I2C_PASEMI
> >     tristate "PA Semi SMBus interface"
> >     depends on PPC_PASEMI && PCI
> >diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> >index 5a869144a0c5..b71618f77880 100644
> >--- a/drivers/i2c/busses/Makefile
> >+++ b/drivers/i2c/busses/Makefile
> >@@ -76,6 +76,7 @@ obj-$(CONFIG_I2C_MXS)              += i2c-mxs.o
> > obj-$(CONFIG_I2C_NOMADIK)   += i2c-nomadik.o
> > obj-$(CONFIG_I2C_OCORES)    += i2c-ocores.o
> > obj-$(CONFIG_I2C_OMAP)              += i2c-omap.o
> >+obj-$(CONFIG_I2C_OWL)               += i2c-owl.o
> > obj-$(CONFIG_I2C_PASEMI)    += i2c-pasemi.o
> > obj-$(CONFIG_I2C_PCA_PLATFORM)      += i2c-pca-platform.o
> > obj-$(CONFIG_I2C_PMCMSP)    += i2c-pmcmsp.o
> >diff --git a/drivers/i2c/busses/i2c-owl.c
> >b/drivers/i2c/busses/i2c-owl.c
> >new file mode 100644
> >index 000000000000..12320fca6755
> >--- /dev/null
> >+++ b/drivers/i2c/busses/i2c-owl.c
> >@@ -0,0 +1,471 @@
> >+// SPDX-License-Identifier: GPL-2.0+
> >+/*
> >+ * OWL SoC's I2C driver
> >+ *
> >+ * Copyright (c) 2014 Actions Semi Inc.
> >+ * Author: David Liu <[email protected]>
> >+ *
> >+ * Copyright (c) 2018 Linaro Ltd.
> >+ * Author: Manivannan Sadhasivam <[email protected]>
> >+ */
> >+
> >+#include <linux/clk.h>
> >+#include <linux/delay.h>
> >+#include <linux/i2c.h>
> >+#include <linux/interrupt.h>
> >+#include <linux/module.h>
> >+#include <linux/of_device.h>
> >+#include <linux/io.h>
> 
> I would have kept this list fully sorted.
> 

Ack.

> >+
> >+/* I2C registers */
> >+#define OWL_I2C_REG_CTL             0x0000
> >+#define OWL_I2C_REG_CLKDIV  0x0004
> >+#define OWL_I2C_REG_STAT    0x0008
> >+#define OWL_I2C_REG_ADDR    0x000C
> >+#define OWL_I2C_REG_TXDAT   0x0010
> >+#define OWL_I2C_REG_RXDAT   0x0014
> >+#define OWL_I2C_REG_CMD             0x0018
> >+#define OWL_I2C_REG_FIFOCTL 0x001C
> >+#define OWL_I2C_REG_FIFOSTAT        0x0020
> >+#define OWL_I2C_REG_DATCNT  0x0024
> >+#define OWL_I2C_REG_RCNT    0x0028
> >+
> >+/* I2Cx_CTL Bit Mask */
> >+#define OWL_I2C_CTL_RB              BIT(1)
> >+#define OWL_I2C_CTL_GBCC(x) (((x) & 0x3) << 2)
> >+#define     OWL_I2C_CTL_GBCC_NONE   OWL_I2C_CTL_GBCC(0)
> >+#define     OWL_I2C_CTL_GBCC_START  OWL_I2C_CTL_GBCC(1)
> >+#define     OWL_I2C_CTL_GBCC_STOP   OWL_I2C_CTL_GBCC(2)
> >+#define     OWL_I2C_CTL_GBCC_RSTART OWL_I2C_CTL_GBCC(3)
> >+#define OWL_I2C_CTL_IRQE    BIT(5)
> >+#define OWL_I2C_CTL_EN              BIT(7)
> >+#define OWL_I2C_CTL_AE              BIT(8)
> >+#define OWL_I2C_CTL_SHSM    BIT(10)
> >+
> >+#define OWL_I2C_DIV_FACTOR(x)       ((x) & 0xff)
> >+
> >+/* I2Cx_STAT Bit Mask */
> >+#define OWL_I2C_STAT_RACK   BIT(0)
> >+#define OWL_I2C_STAT_BEB    BIT(1)
> >+#define OWL_I2C_STAT_IRQP   BIT(2)
> >+#define OWL_I2C_STAT_LAB    BIT(3)
> >+#define OWL_I2C_STAT_STPD   BIT(4)
> >+#define OWL_I2C_STAT_STAD   BIT(5)
> >+#define OWL_I2C_STAT_BBB    BIT(6)
> >+#define OWL_I2C_STAT_TCB    BIT(7)
> >+#define OWL_I2C_STAT_LBST   BIT(8)
> >+#define OWL_I2C_STAT_SAMB   BIT(9)
> >+#define OWL_I2C_STAT_SRGC   BIT(10)
> >+
> >+/* I2Cx_CMD Bit Mask */
> >+#define OWL_I2C_CMD_SBE             BIT(0)
> >+#define OWL_I2C_CMD_RBE             BIT(4)
> >+#define OWL_I2C_CMD_DE              BIT(8)
> >+#define OWL_I2C_CMD_NS              BIT(9)
> >+#define OWL_I2C_CMD_SE              BIT(10)
> >+#define OWL_I2C_CMD_MSS             BIT(11)
> >+#define OWL_I2C_CMD_WRS             BIT(12)
> >+#define OWL_I2C_CMD_SECL    BIT(15)
> >+
> >+#define OWL_I2C_CMD_AS(x)   (((x) & 0x7) << 1)
> >+#define OWL_I2C_CMD_SAS(x)  (((x) & 0x7) << 5)
> >+
> >+/* I2Cx_FIFOCTL Bit Mask */
> >+#define OWL_I2C_FIFOCTL_NIB BIT(0)
> >+#define OWL_I2C_FIFOCTL_RFR BIT(1)
> >+#define OWL_I2C_FIFOCTL_TFR BIT(2)
> >+
> >+/* I2Cc_FIFOSTAT Bit Mask */
> >+#define OWL_I2C_FIFOSTAT_RNB        BIT(1)
> >+#define OWL_I2C_FIFOSTAT_RFE        BIT(2)
> >+#define OWL_I2C_FIFOSTAT_TFF        BIT(5)
> >+#define OWL_I2C_FIFOSTAT_TFD        GENMASK(23, 16)
> >+#define OWL_I2C_FIFOSTAT_RFD        GENMASK(15, 8)
> >+
> >+/* I2C bus timeout */
> >+#define OWL_I2C_TIMEOUT             msecs_to_jiffies(4 * 1000)
> >+
> >+#define OWL_I2C_MAX_RETRIES 50
> >+
> >+#define OWL_I2C_DEFAULT_SPEED       100000
> >+#define OWL_I2C_MAX_SPEED   400000
> >+
> >+struct owl_i2c_dev {
> >+    struct i2c_adapter      adap;
> >+    struct i2c_msg          *msg;
> >+    struct completion       msg_complete;
> >+    struct clk              *clk;
> >+    void __iomem            *base;
> >+    unsigned long           clk_rate;
> >+    u32                     bus_freq;
> >+    u32                     msg_ptr;
> >+};
> >+
> >+static void owl_i2c_update_reg(void __iomem *base, unsigned int val,
> >bool state)
> 
> Is base really a good name here? I would go with reg.
>

Okay, will change it to reg.

> >+{
> >+    unsigned int regval;
> >+
> >+    regval = readl(base);
> >+
> >+    if (state)
> >+            regval |= val;
> >+    else
> >+            regval &= ~val;
> >+
> >+    writel(regval, base);
> >+}
> >+
> >+static int owl_i2c_reset(struct owl_i2c_dev *i2c_dev)
> >+{
> >+    unsigned int val, timeout = 0;
> >+
> >+    owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL,
> >+                            OWL_I2C_CTL_EN, false);
> >+    mdelay(1);
> >+    owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL,
> >+                            OWL_I2C_CTL_EN, true);
> >+
> >+    /* Reset FIFO */
> >+    owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_FIFOCTL,
> >+                            OWL_I2C_FIFOCTL_RFR | OWL_I2C_FIFOCTL_TFR,
> >+                            true);
> >+
> >+    /* Wait 50ms for FIFO reset complete */
> >+    do {
> >+            val = readl(i2c_dev->base + OWL_I2C_REG_FIFOCTL);
> >+            if (!(val & (OWL_I2C_FIFOCTL_RFR | OWL_I2C_FIFOCTL_TFR)))
> >+                    break;
> >+            mdelay(1);
> >+    } while (timeout++ < OWL_I2C_MAX_RETRIES);
> >+
> >+    if (timeout > OWL_I2C_MAX_RETRIES) {
> >+            dev_err(&i2c_dev->adap.dev, "FIFO reset timeout");
> >+            return -ETIMEDOUT;
> >+    }
> >+
> >+    /* Clear status registers */
> >+    writel(0, i2c_dev->base + OWL_I2C_REG_STAT);
> >+
> >+    return 0;
> >+}
> 
> This ..._reset function does a number of unlocked read-modify-write cycles, 
> and it is called from an interrupt. Is that safe? What if a spurious 
> interrupt happen?
>

hmmm, nice catch. I think it is safe to remove the rest function from
the handler. Anyhow we call reset during the start of the transfer so
it doesn't makes any difference IMO.

> >+
> >+static int owl_i2c_set_freq(struct owl_i2c_dev *i2c_dev)
> >+{
> >+    unsigned int val;
> >+
> >+    val = (i2c_dev->clk_rate + i2c_dev->bus_freq * 16 - 1) /
> >+                            (i2c_dev->bus_freq * 16);
> >+
> >+    /* Set clock divider factor */
> >+    writel(OWL_I2C_DIV_FACTOR(val), i2c_dev->base + OWL_I2C_REG_CLKDIV);
> >+
> >+    return 0;
> >+}
> >+
> >+static int owl_i2c_hw_init(struct owl_i2c_dev *i2c_dev)
> >+{
> >+    int ret;
> >+
> >+    /* Reset I2C controller */
> >+    ret = owl_i2c_reset(i2c_dev);
> >+    if (ret)
> >+            return ret;
> >+
> >+    /* Set bus frequency */
> >+    return owl_i2c_set_freq(i2c_dev);
> >+}
> >+
> >+static irqreturn_t owl_i2c_interrupt(int irq, void *_dev)
> >+{
> >+    struct owl_i2c_dev *i2c_dev = _dev;
> >+    struct i2c_msg *msg = i2c_dev->msg;
> >+    unsigned int stat, fifostat;
> >+
> >+    fifostat = readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT);
> >+    if (fifostat & OWL_I2C_FIFOSTAT_RNB) {
> >+            dev_dbg(&i2c_dev->adap.dev, "received NACK from device");
> >+            owl_i2c_reset(i2c_dev);
> >+            goto stop;
> >+    }
> >+
> >+    stat = readl(i2c_dev->base + OWL_I2C_REG_STAT);
> >+    if (stat & OWL_I2C_STAT_BEB) {
> >+            dev_dbg(&i2c_dev->adap.dev, "bus error");
> >+            owl_i2c_reset(i2c_dev);
> >+            goto stop;
> >+    }
> >+
> >+    /* Handle FIFO read */
> >+    if (msg->flags & I2C_M_RD) {
> >+            while ((readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT) &
> >+                            OWL_I2C_FIFOSTAT_RFE) &&
> >+                            (i2c_dev->msg_ptr < msg->len)) {
> >+                    msg->buf[i2c_dev->msg_ptr++] = readl(i2c_dev->base +
> >+                                                    OWL_I2C_REG_RXDAT);
> >+            }
> >+    } else {
> >+            /* Handle the remaining bytes which were not sent */
> >+            while (!(readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT) &
> >+                            OWL_I2C_FIFOSTAT_TFF) &&
> >+                            i2c_dev->msg_ptr < msg->len) {
> >+                    writel(msg->buf[i2c_dev->msg_ptr++], i2c_dev->base +
> >+                                                    OWL_I2C_REG_TXDAT);
> >+            }
> >+    }
> >+
> >+stop:
> >+    /* Clear pending interrupts */
> >+    owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_STAT,
> >+                            OWL_I2C_STAT_IRQP, true);
> >+
> >+    complete_all(&i2c_dev->msg_complete);
> >+
> >+    return IRQ_HANDLED;
> >+}
> >+
> >+static u32 owl_i2c_func(struct i2c_adapter *adap)
> >+{
> >+    return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
> >+}
> >+
> >+static int owl_i2c_check_bus_busy(struct i2c_adapter *adap)
> >+{
> >+    struct owl_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
> >+    unsigned long timeout;
> >+    unsigned int val;
> >+
> >+    /* Check for Arbitration lost */
> >+    val = readl(i2c_dev->base + OWL_I2C_REG_STAT);
> >+    if (val & OWL_I2C_STAT_LAB) {
> >+            val &= ~OWL_I2C_STAT_LAB;
> >+            writel(val, i2c_dev->base + OWL_I2C_REG_STAT);
> >+            return -EAGAIN;
> >+    }
> >+
> >+    /* Check for Bus busy */
> >+    timeout = jiffies + OWL_I2C_TIMEOUT;
> >+    while (readl(i2c_dev->base + OWL_I2C_REG_STAT) & OWL_I2C_STAT_BBB) {
> >+            if (time_after(jiffies, timeout)) {
> >+                    dev_err(&adap->dev, "Bus busy timeout");
> >+                    return -ETIMEDOUT;
> >+            }
> >+    }
> >+
> >+    return 0;
> >+}
> >+
> >+static int owl_i2c_master_xfer(struct i2c_adapter *adap, struct
> >i2c_msg *msgs,
> >+                            int num)
> >+{
> >+    struct owl_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
> >+    struct i2c_msg *msg;
> >+    unsigned long time_left;
> >+    unsigned int i2c_cmd;
> >+    unsigned int addr;
> >+    int ret = 0, idx;
> >+
> >+    ret = owl_i2c_hw_init(i2c_dev);
> >+    if (ret)
> >+            return ret;
> >+
> >+    ret = owl_i2c_check_bus_busy(adap);
> >+    if (ret)
> >+            return ret;
> >+
> >+    reinit_completion(&i2c_dev->msg_complete);
> >+
> >+    /* Enable I2C controller interrupt */
> >+    owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL,
> >+                            OWL_I2C_CTL_IRQE, true);
> >+
> >+    /*
> >+     * Select: FIFO enable, Master mode, Stop enable, Data count enable,
> >+     * Send start bit
> >+     */
> >+    i2c_cmd = (OWL_I2C_CMD_SECL | OWL_I2C_CMD_MSS | OWL_I2C_CMD_SE
> >+                    | OWL_I2C_CMD_NS | OWL_I2C_CMD_DE | OWL_I2C_CMD_SBE);
> >+
> >+    /* Handle repeated start condition */
> >+    if (num > 1) {
> >+            /* Set internal address length and enable repeated start */
> >+            i2c_cmd |= (OWL_I2C_CMD_AS(msgs[0].len + 1)
> >+                            | OWL_I2C_CMD_SAS(1) | OWL_I2C_CMD_RBE);
> >+
> >+            /* Write slave address */
> >+            addr = i2c_8bit_addr_from_msg(&msgs[0]);
> >+            writel(addr, i2c_dev->base + OWL_I2C_REG_TXDAT);
> >+
> >+            /* Write internal register address */
> >+            for (idx = 0; idx < msgs[0].len; idx++)
> >+                    writel(msgs[0].buf[idx], i2c_dev->base +
> >+                                            OWL_I2C_REG_TXDAT);
> >+
> >+            msg = &msgs[1];
> >+    } else {
> >+            /* Set address length */
> >+            i2c_cmd |= OWL_I2C_CMD_AS(1);
> >+            msg = &msgs[0];
> >+    }
> >+
> >+    i2c_dev->msg = msg;
> >+    i2c_dev->msg_ptr = 0;
> >+
> >+    /* Set data count for the message */
> >+    writel(msg->len, i2c_dev->base + OWL_I2C_REG_DATCNT);
> >+
> >+    addr = i2c_8bit_addr_from_msg(msg);
> >+    writel(addr, i2c_dev->base + OWL_I2C_REG_TXDAT);
> >+
> >+    if (!(msg->flags & I2C_M_RD)) {
> >+            /* Write data to FIFO */
> >+            for (idx = 0; idx < msg->len; idx++) {
> >+                    /* Check for FIFO full */
> >+                    if (readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT)
> >+                                    & OWL_I2C_FIFOSTAT_TFF)
> 
> You should cleanup here, and return some error. I think? Or, why do you break 
> out of the loop early?
> 

Actually we break the loop once the FIFO is full. Since the total
number of messages handled (240 bytes) is greater than the FIFO depth
(128 bytes) we handle the remaining bytes in the handler.

> >+                            break;
> >+
> >+                    writel(msg->buf[idx],
> >+                                    i2c_dev->base + OWL_I2C_REG_TXDAT);
> >+            }
> >+
> >+            i2c_dev->msg_ptr = idx;
> >+    }
> >+
> >+    /* Ignore the NACK if needed */
> >+    if (msg->flags & I2C_M_IGNORE_NAK)
> >+            owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_FIFOCTL,
> >+                            OWL_I2C_FIFOCTL_NIB, true);
> >+    else
> >+            owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_FIFOCTL,
> >+                            OWL_I2C_FIFOCTL_NIB, false);
> >+
> >+    /* Start the transfer */
> >+    writel(i2c_cmd, i2c_dev->base + OWL_I2C_REG_CMD);
> >+
> >+    time_left = wait_for_completion_timeout(&i2c_dev->msg_complete,
> >+                                            adap->timeout);
> >+    if (time_left == 0) {
> >+            dev_err(&adap->dev, "Transaction timed out");
> >+            /* Send stop condition and release the bus */
> >+            owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL,
> >+                    OWL_I2C_CTL_GBCC_STOP | OWL_I2C_CTL_RB, true);
> >+            ret = -ETIMEDOUT;
> >+    }
> >+
> >+    /* Disable I2C controller */
> >+    owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL,
> >+                            OWL_I2C_CTL_EN, false);
> >+
> >+    return i2c_dev->msg_ptr ? num : i2c_dev->msg_ptr;
> 
> This is wrong. Should probably be
> 
>    return ret ?: num;
> 

Agree. But there is one more issue here. We may enter the handler and
do neither read nor write for cases like i2c-detect and returning num
for those cases will make no sense. I guess this can be handled as
below:

Let's assume ret = 0, then

        if (i2c_dev->msg_ptr == msg->len)
                ret = num;

        return ret;

What do you think?

Thanks,
Mani

> Cheers,
> Peter
> 
> >+}
> >+
> >+static const struct i2c_algorithm owl_i2c_algorithm = {
> >+    .master_xfer    = owl_i2c_master_xfer,
> >+    .functionality  = owl_i2c_func
> >+};
> >+
> >+static const struct i2c_adapter_quirks owl_i2c_quirks = {
> >+    .flags          = I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST,
> >+    .max_read_len   = 240,
> >+    .max_write_len  = 240,
> >+    .max_comb_1st_msg_len = 6,
> >+    .max_comb_2nd_msg_len = 240
> >+};
> >+
> >+static int owl_i2c_probe(struct platform_device *pdev)
> >+{
> >+    struct device *dev = &pdev->dev;
> >+    struct owl_i2c_dev *i2c_dev;
> >+    struct resource *res;
> >+    int ret, irq;
> >+
> >+    i2c_dev = devm_kzalloc(dev, sizeof(*i2c_dev), GFP_KERNEL);
> >+    if (!i2c_dev)
> >+            return -ENOMEM;
> >+
> >+    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> >+    i2c_dev->base = devm_ioremap_resource(dev, res);
> >+    if (IS_ERR(i2c_dev->base))
> >+            return PTR_ERR(i2c_dev->base);
> >+
> >+    irq = platform_get_irq(pdev, 0);
> >+    if (irq < 0) {
> >+            dev_err(dev, "failed to get IRQ number\n");
> >+            return irq;
> >+    }
> >+
> >+    if (of_property_read_u32(dev->of_node, "clock-frequency",
> >+                                    &i2c_dev->bus_freq))
> >+            i2c_dev->bus_freq = OWL_I2C_DEFAULT_SPEED;
> >+
> >+    /* We support only frequencies of 100k and 400k for now */
> >+    if (i2c_dev->bus_freq != OWL_I2C_DEFAULT_SPEED &&
> >+                    i2c_dev->bus_freq > OWL_I2C_MAX_SPEED) {
> >+            dev_err(dev, "invalid clock-frequency %d\n", i2c_dev->bus_freq);
> >+            return -EINVAL;
> >+    }
> >+
> >+    i2c_dev->clk = devm_clk_get(dev, NULL);
> >+    if (IS_ERR(i2c_dev->clk)) {
> >+            dev_err(dev, "failed to get clock\n");
> >+            return PTR_ERR(i2c_dev->clk);
> >+    }
> >+
> >+    ret = clk_prepare_enable(i2c_dev->clk);
> >+    if (ret)
> >+            return ret;
> >+
> >+    i2c_dev->clk_rate = clk_get_rate(i2c_dev->clk);
> >+    if (!i2c_dev->clk_rate) {
> >+            dev_err(dev, "input clock rate should not be zero\n");
> >+            ret = -EINVAL;
> >+            goto disable_clk;
> >+    }
> >+
> >+    init_completion(&i2c_dev->msg_complete);
> >+    i2c_dev->adap.owner = THIS_MODULE;
> >+    i2c_dev->adap.algo = &owl_i2c_algorithm;
> >+    i2c_dev->adap.timeout = OWL_I2C_TIMEOUT;
> >+    i2c_dev->adap.quirks = &owl_i2c_quirks;
> >+    i2c_dev->adap.dev.parent = dev;
> >+    i2c_dev->adap.dev.of_node = dev->of_node;
> >+    snprintf(i2c_dev->adap.name, sizeof(i2c_dev->adap.name),
> >+                    "%s", "OWL I2C adapter");
> >+    i2c_set_adapdata(&i2c_dev->adap, i2c_dev);
> >+
> >+    platform_set_drvdata(pdev, i2c_dev);
> >+
> >+    ret = devm_request_irq(dev, irq, owl_i2c_interrupt, 0, pdev->name,
> >+                            i2c_dev);
> >+    if (ret) {
> >+            dev_err(dev, "failed to request irq %d\n", irq);
> >+            goto disable_clk;
> >+    }
> >+
> >+    return i2c_add_adapter(&i2c_dev->adap);
> >+
> >+disable_clk:
> >+    clk_disable_unprepare(i2c_dev->clk);
> >+
> >+    return ret;
> >+}
> >+
> >+static const struct of_device_id owl_i2c_of_match[] = {
> >+    {.compatible = "actions,s900-i2c"},
> >+    { /* sentinel */ }
> >+};
> >+MODULE_DEVICE_TABLE(of, owl_i2c_of_match);
> >+
> >+static struct platform_driver owl_i2c_driver = {
> >+    .probe          = owl_i2c_probe,
> >+    .driver         = {
> >+            .name   = "owl-i2c",
> >+            .of_match_table = of_match_ptr(owl_i2c_of_match),
> >+    },
> >+};
> >+module_platform_driver(owl_i2c_driver);
> >+
> >+MODULE_AUTHOR("David Liu <[email protected]>");
> >+MODULE_AUTHOR("Manivannan Sadhasivam
> ><[email protected]>");
> >+MODULE_DESCRIPTION("Actions Semi OWL SoCs I2C driver");
> >+MODULE_LICENSE("GPL");
> 

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