From: Youngmin Nam <youngmin.nam@samsung.com>
Date: Thu, 2 Jul 2015 12:11:13 +0000 (+0900)
Subject: i2c: s3c2410: add the new h/w init sequence
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=d2a72e08534957018e09516086ea368ea64a2c39;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

i2c: s3c2410: add the new h/w init sequence

To recover from "cannot get bus (error -110)" error,
add the new h/w init sequence. This init sequence initialize
i2c bus (sda and scl), through clearing S3C2410_IICSTAT_TXRXEN.

Change-Id: Id76af5a3c4baa18685b3104095fa3eb36942349f
Signed-off-by: Hyunki Koo <hyunki00.koo@samsung.com>
Signed-off-by: Youngmin Nam <youngmin.nam@samsung.com>
---

diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index 3e5d67b0a7f4..e31b73e63398 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -93,6 +93,10 @@ static LIST_HEAD(drvdata_list);
 
 #define S3C2440_IICINT_BUSHOLD_CLEAR	(1 << 8)
 
+#define S3C2410_NEED_REG_INIT		(1 << 0)
+#define S3C2410_NEED_BUS_INIT		(2 << 0)
+#define S3C2410_NEED_FULL_INIT		(3 << 0)
+
 /* Treat S3C2410 as baseline hardware, anything else is supported via quirks */
 #define QUIRK_S3C2440		(1 << 0)
 #define QUIRK_HDMIPHY		(1 << 1)
@@ -780,6 +784,7 @@ static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c,
 	ret = s3c24xx_i2c_set_master(i2c);
 	if (ret != 0) {
 		dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
+		i2c->need_hw_init = S3C2410_NEED_FULL_INIT;
 		ret = -EAGAIN;
 		goto out;
 	}
@@ -847,11 +852,12 @@ static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
 	if (ret)
 		return ret;
 
-	if (i2c->need_hw_init)
-		s3c24xx_i2c_init(i2c);
 
 	for (retry = 0; retry < adap->retries; retry++) {
 
+		if (i2c->need_hw_init & S3C2410_NEED_FULL_INIT)
+			s3c24xx_i2c_init(i2c);
+
 		ret = s3c24xx_i2c_doxfer(i2c, msgs, num);
 
 		if (ret != -EAGAIN) {
@@ -1057,14 +1063,20 @@ static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c)
 static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
 {
 	struct s3c2410_platform_i2c *pdata;
+	unsigned long iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 	unsigned int freq;
 
 	/* get the plafrom data */
 
 	pdata = i2c->pdata;
 
-	/* write slave address */
+	if (i2c->need_hw_init & S3C2410_NEED_BUS_INIT) {
+		/* reset i2c bus to recover from "cannot get bus" */
+		iicstat &= ~S3C2410_IICSTAT_TXRXEN;
+		writel(iicstat, i2c->regs + S3C2410_IICSTAT);
+	}
 
+	/* write slave address */
 	writeb(pdata->slave_addr, i2c->regs + S3C2410_IICADD);
 
 	dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr);
@@ -1126,7 +1138,7 @@ static int s3c24xx_i2c_notifier(struct notifier_block *self,
 	switch (cmd) {
 	case LPA_EXIT:
 		list_for_each_entry(i2c, &drvdata_list, node)
-			i2c->need_hw_init = 1;
+			i2c->need_hw_init = S3C2410_NEED_REG_INIT;
 		break;
 	}
 
@@ -1225,7 +1237,7 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
-	i2c->need_hw_init = 1;
+	i2c->need_hw_init = S3C2410_NEED_REG_INIT;
 
 	/* find the IRQ for this unit (note, this relies on the init call to
 	 * ensure no current IRQs pending
@@ -1318,7 +1330,7 @@ static int s3c24xx_i2c_resume_noirq(struct device *dev)
 	int ret;
 
 	i2c->suspended = 0;
-	i2c->need_hw_init = 1;
+	i2c->need_hw_init = S3C2410_NEED_REG_INIT;
 
 	return 0;
 }
@@ -1331,7 +1343,7 @@ static int s3c24xx_i2c_runtime_resume(struct device *dev)
 	struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
 
 	if (i2c->quirks & QUIRK_FIMC_I2C)
-		i2c->need_hw_init = 1;
+		i2c->need_hw_init = S3C2410_NEED_REG_INIT;
 
 	return 0;
 }