[U-Boot] [PATCH 16/16] i2c: uniphier-f: use readl_poll_timeout() to poll registers

27 Jan 2017

The readl_poll_timeout() is a useful helper to poll registers
and error out if the condition is not met.
Signed-off-by: Masahiro Yamada yamada.masahiro@socionext.com
---
drivers/i2c/i2c-uniphier-f.c | 34 ++++++++++------------------------
 1 file changed, 10 insertions(+), 24 deletions(-)

diff --git a/drivers/i2c/i2c-uniphier-f.c b/drivers/i2c/i2c-uniphier-f.c
index e212c13..9f0df59 100644
--- a/drivers/i2c/i2c-uniphier-f.c
+++ b/drivers/i2c/i2c-uniphier-f.c
@@ -9,6 +9,7 @@
 #include <common.h>
 #include <linux/types.h>
 #include <linux/io.h>
+#include <linux/iopoll.h>
 #include <linux/sizes.h>
 #include <linux/errno.h>
 #include <dm/device.h>
@@ -69,26 +70,14 @@ struct uniphier_fi2c_dev {
    unsigned long timeout;			/* time out (us) */
 };
-static int poll_status(u32 __iomem *reg, u32 flag)
-{
-	int wait = 1000000; /* 1 sec is long enough */
-
-	while (readl(reg) & flag) {
-		if (wait-- < 0)
-			return -EREMOTEIO;
-		udelay(1);
-	}
-
-	return 0;
-}
-
 static int reset_bus(struct uniphier_fi2c_regs __iomem *regs)
 {
+	u32 val;
    int ret;
/* bus forcible reset */
    writel(I2C_RST_RST, &regs->rst);
-	ret = poll_status(&regs->rst, I2C_RST_RST);
+	ret = readl_poll_timeout(&regs->rst, val, !(val & I2C_RST_RST), 1);
    if (ret < 0)
    	debug("error: fail to reset I2C controller\n");
@@ -97,9 +86,10 @@ static int reset_bus(struct uniphier_fi2c_regs __iomem *regs)
static int check_device_busy(struct uniphier_fi2c_regs __iomem *regs)
 {
+	u32 val;
    int ret;
-	ret = poll_status(&regs->sr, I2C_SR_DB);
+	ret = readl_poll_timeout(&regs->sr, val, !(val & I2C_SR_DB), 100);
    if (ret < 0) {
    	debug("error: device busy too long. reset...\n");
    	ret = reset_bus(regs);
@@ -138,15 +128,11 @@ static int wait_for_irq(struct uniphier_fi2c_dev *dev, u32 flags,
    		bool *stop)
 {
    u32 irq;
-	unsigned long wait = dev->timeout;
-	int ret = -EREMOTEIO;
-
-	do {
-		udelay(1);
-		irq = readl(&dev->regs->intr);
-	} while (!(irq & flags) && wait--);
+	int ret;
-	if (wait < 0) {
+	ret = readl_poll_timeout(&dev->regs->intr, irq, irq & flags,
+				 dev->timeout);
+	if (ret < 0) {
    	debug("error: time out\n");
    	return ret;
    }
@@ -172,7 +158,7 @@ static int issue_stop(struct uniphier_fi2c_dev *dev, int old_ret)
    debug("stop condition\n");
    writel(I2C_CR_MST | I2C_CR_STO, &dev->regs->cr);
-	ret = poll_status(&dev->regs->sr, I2C_SR_DB);
+	ret = check_device_busy(dev->regs);
    if (ret < 0)
    	debug("error: device busy after operation\n");
-- 
2.7.4


    