Re: [PATCH V2] i2c: s3c2410 : Add polling mode support

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On Fri, Dec 13, 2013 at 2:51 PM, Yuvaraj Kumar <yuvaraj.cd@xxxxxxxxx> wrote:
> Dear Wolfram,
>  Can you take this into your tree?
>
> On Fri, Nov 22, 2013 at 11:32 AM, Yuvaraj Kumar <yuvaraj.cd@xxxxxxxxx> wrote:
>> Any comments on this patch?
>>
>> On Mon, Nov 11, 2013 at 4:50 PM, Yuvaraj Kumar C D <yuvaraj.cd@xxxxxxxxx> wrote:
>>> From: Vasanth Ananthan <vasanthananthan@xxxxxxxxx>
>>>
>>> This patch adds polling mode support for i2c-s3c2410 driver.The
>>> SATA PHY controller's CMU and TRSV block's are of I2C register
>>> map in exynos5250.These blocks can be configured using i2c.
>>>
>>> But i2c controller instance on which these block's sits lacks an
>>> interrupt line.Also the current i2c-s3c2410 driver is only interrupt
>>> driven, thus a polling mode support is required in the driver for
>>> supporting this controller. This patch adds this support to the driver.
>>>
>>> Changes from V1:
>>>         1.Changed the is_ack() to have even period b/w polls and
>>>           used usleep_range() instead of udelay().
>>>
>>> Signed-off-by: Vasanth Ananthan <vasanth.a@xxxxxxxxxxx>
>>> Signed-off-by: Yuvaraj Kumar C D <yuvaraj.cd@xxxxxxxxxxx>
>>> ---
>>>  .../devicetree/bindings/i2c/i2c-s3c2410.txt        |    2 +
>>>  drivers/i2c/busses/i2c-s3c2410.c                   |   66 +++++++++++++++++---
>>>  2 files changed, 58 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/i2c/i2c-s3c2410.txt b/Documentation/devicetree/bindings/i2c/i2c-s3c2410.txt
>>> index 296eb45..278de8e 100644
>>> --- a/Documentation/devicetree/bindings/i2c/i2c-s3c2410.txt
>>> +++ b/Documentation/devicetree/bindings/i2c/i2c-s3c2410.txt
>>> @@ -10,6 +10,8 @@ Required properties:
>>>            inside HDMIPHY block found on several samsung SoCs
>>>        (d) "samsung, exynos5440-i2c", for s3c2440-like i2c used
>>>            on EXYNOS5440 which does not need GPIO configuration.
>>> +      (e) "samsung, exynos5-sata-phy-i2c", for s3c2440-like i2c used as
>>> +          a host to SATA PHY controller on an internal bus.
>>>    - reg: physical base address of the controller and length of memory mapped
>>>      region.
>>>    - interrupts: interrupt number to the cpu.
>>> diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
>>> index 3747b9b..08ed126 100644
>>> --- a/drivers/i2c/busses/i2c-s3c2410.c
>>> +++ b/drivers/i2c/busses/i2c-s3c2410.c
>>> @@ -85,6 +85,7 @@
>>>  #define QUIRK_S3C2440          (1 << 0)
>>>  #define QUIRK_HDMIPHY          (1 << 1)
>>>  #define QUIRK_NO_GPIO          (1 << 2)
>>> +#define QUIRK_POLL             (1 << 3)
>>>
>>>  /* Max time to wait for bus to become idle after a xfer (in us) */
>>>  #define S3C2410_IDLE_TIMEOUT   5000
>>> @@ -141,6 +142,8 @@ static struct platform_device_id s3c24xx_driver_ids[] = {
>>>  };
>>>  MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids);
>>>
>>> +static int i2c_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat);
>>> +
>>>  #ifdef CONFIG_OF
>>>  static const struct of_device_id s3c24xx_i2c_match[] = {
>>>         { .compatible = "samsung,s3c2410-i2c", .data = (void *)0 },
>>> @@ -149,6 +152,8 @@ static const struct of_device_id s3c24xx_i2c_match[] = {
>>>           .data = (void *)(QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO) },
>>>         { .compatible = "samsung,exynos5440-i2c",
>>>           .data = (void *)(QUIRK_S3C2440 | QUIRK_NO_GPIO) },
>>> +       { .compatible = "samsung,exynos5-sata-phy-i2c",
>>> +         .data = (void *)(QUIRK_S3C2440 | QUIRK_POLL | QUIRK_NO_GPIO) },
>>>         {},
>>>  };
>>>  MODULE_DEVICE_TABLE(of, s3c24xx_i2c_match);
>>> @@ -187,7 +192,8 @@ static inline void s3c24xx_i2c_master_complete(struct s3c24xx_i2c *i2c, int ret)
>>>         if (ret)
>>>                 i2c->msg_idx = ret;
>>>
>>> -       wake_up(&i2c->wait);
>>> +       if (!(i2c->quirks & QUIRK_POLL))
>>> +               wake_up(&i2c->wait);
>>>  }
>>>
>>>  static inline void s3c24xx_i2c_disable_ack(struct s3c24xx_i2c *i2c)
>>> @@ -224,6 +230,22 @@ static inline void s3c24xx_i2c_enable_irq(struct s3c24xx_i2c *i2c)
>>>         writel(tmp | S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
>>>  }
>>>
>>> +static bool is_ack(struct s3c24xx_i2c *i2c)
>>> +{
>>> +       int tries;
>>> +
>>> +       for (tries = 50; tries; --tries) {
>>> +               if (readl(i2c->regs + S3C2410_IICCON)
>>> +                       & S3C2410_IICCON_IRQPEND) {
>>> +                       if (!(readl(i2c->regs + S3C2410_IICSTAT)
>>> +                               & S3C2410_IICSTAT_LASTBIT))
>>> +                               return true;
>>> +               }
>>> +               usleep_range(1000, 2000);
>>> +       }
>>> +       dev_err(i2c->dev, "ack was not recieved\n");
>>> +       return false;
>>> +}
>>>
>>>  /* s3c24xx_i2c_message_start
>>>   *
>>> @@ -268,6 +290,16 @@ static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c,
>>>
>>>         stat |= S3C2410_IICSTAT_START;
>>>         writel(stat, i2c->regs + S3C2410_IICSTAT);
>>> +
>>> +       if (i2c->quirks & QUIRK_POLL) {
>>> +               while ((i2c->msg_num != 0) && is_ack(i2c)) {
>>> +                       i2c_s3c_irq_nextbyte(i2c, stat);
>>> +                       stat = readl(i2c->regs + S3C2410_IICSTAT);
>>> +
>>> +                       if (stat & S3C2410_IICSTAT_ARBITR)
>>> +                               dev_err(i2c->dev, "deal with arbitration loss\n");
>>> +               }
>>> +       }
>>>  }
>>>
>>>  static inline void s3c24xx_i2c_stop(struct s3c24xx_i2c *i2c, int ret)
>>> @@ -675,6 +707,15 @@ static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c,
>>>         s3c24xx_i2c_enable_irq(i2c);
>>>         s3c24xx_i2c_message_start(i2c, msgs);
>>>
>>> +       if (i2c->quirks & QUIRK_POLL) {
>>> +               ret = i2c->msg_idx;
>>> +
>>> +               if (ret != num)
>>> +                       dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
>>> +
>>> +               goto out;
>>> +       }
>>> +
>>>         timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
>>>
>>>         ret = i2c->msg_idx;
>>> @@ -820,6 +861,9 @@ static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
>>>         if (div1 == 512)
>>>                 iiccon |= S3C2410_IICCON_TXDIV_512;
>>>
>>> +       if (i2c->quirks & QUIRK_POLL)
>>> +               iiccon |= S3C2410_IICCON_SCALE(2);
>>> +
>>>         writel(iiccon, i2c->regs + S3C2410_IICCON);
>>>
>>>         if (i2c->quirks & QUIRK_S3C2440) {
>>> @@ -1117,18 +1161,20 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev)
>>>          * ensure no current IRQs pending
>>>          */
>>>
>>> -       i2c->irq = ret = platform_get_irq(pdev, 0);
>>> -       if (ret <= 0) {
>>> -               dev_err(&pdev->dev, "cannot find IRQ\n");
>>> -               return ret;
>>> -       }
>>> +       if (!(i2c->quirks & QUIRK_POLL)) {
>>> +               i2c->irq = ret = platform_get_irq(pdev, 0);
>>> +               if (ret <= 0) {
>>> +                       dev_err(&pdev->dev, "cannot find IRQ\n");
>>> +                       return ret;
>>> +               }
>>>
>>>         ret = devm_request_irq(&pdev->dev, i2c->irq, s3c24xx_i2c_irq, 0,
>>> -                              dev_name(&pdev->dev), i2c);
>>> +                               dev_name(&pdev->dev), i2c);
>>>
>>> -       if (ret != 0) {
>>> -               dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq);
>>> -               return ret;
>>> +               if (ret != 0) {
>>> +                       dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq);
>>> +                       return ret;
>>> +               }
>>>         }
>>>
>>>         ret = s3c24xx_i2c_register_cpufreq(i2c);
>>> --
>>> 1.7.9.5
>>>
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