[PATCH V2] i2c: s3c2410 : Add polling mode support
Yuvaraj Kumar
yuvaraj.cd at gmail.com
Fri Dec 13 04:21:13 EST 2013
Dear Wolfram,
Can you take this into your tree?
On Fri, Nov 22, 2013 at 11:32 AM, Yuvaraj Kumar <yuvaraj.cd at gmail.com> wrote:
> 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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