From 117053f77a5a4d055ec4fc7b4f6639045a24fefd Mon Sep 17 00:00:00 2001 From: Vasanth Ananthan Date: Mon, 11 Nov 2013 16:50:20 +0530 Subject: [PATCH] i2c: s3c2410: Add polling mode support 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. Signed-off-by: Vasanth Ananthan Signed-off-by: Yuvaraj Kumar C D Signed-off-by: Wolfram Sang --- .../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 296eb4536129..278de8e64bbf 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 bf8fb94ebc5d..09f251d0716f 100644 --- a/drivers/i2c/busses/i2c-s3c2410.c +++ b/drivers/i2c/busses/i2c-s3c2410.c @@ -86,6 +86,7 @@ #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 @@ -142,6 +143,8 @@ 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 }, @@ -150,6 +153,8 @@ 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); @@ -188,7 +193,8 @@ 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) @@ -225,6 +231,22 @@ 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 * @@ -269,6 +291,16 @@ 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) @@ -676,6 +708,15 @@ 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; @@ -821,6 +862,9 @@ 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) { @@ -1118,18 +1162,20 @@ 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); -- 2.30.2