[PATCH V2] i2c: s3c2410 : Add polling mode support
Yuvaraj Kumar
yuvaraj.cd at gmail.com
Fri Nov 22 01:02:42 EST 2013
Any comments on this patch?
On Mon, Nov 11, 2013 at 4:50 PM, Yuvaraj Kumar C D <yuvaraj.cd at gmail.com> wrote:
> From: Vasanth Ananthan <vasanthananthan at gmail.com>
>
> 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 at samsung.com>
> Signed-off-by: Yuvaraj Kumar C D <yuvaraj.cd at samsung.com>
> ---
> .../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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