linux-kernel - [PATCH v4] phy: samsung: Use readl_poll

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Date:   Mon, 13 Jul 2020 07:42:43 +0000
From:   Anand Moon <linux.amoon@...il.com>
To:     linux-arm-kernel@...ts.infradead.org, linux-usb@...r.kernel.org,
        linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Kishon Vijay Abraham I <kishon@...com>,
        Vinod Koul <vkoul@...nel.org>, Kukjin Kim <kgene@...nel.org>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Marek Szyprowski <m.szyprowski@...sung.com>
Subject: [PATCH v4] phy: samsung: Use readl_poll_timeout function

Instead of a busy waiting while loop using udelay
use readl_poll_timeout function to check the condition
is met or timeout occurs in crport_handshake function.
readl_poll_timeout is called in non atomic context so
it safe to sleep until the condition is met.

Fixes: d8c80bb3b55b ("phy: exynos5-usbdrd: Calibrate LOS levels for exynos5420/5800")
Signed-off-by: Anand Moon <linux.amoon@...il.com>
---
Changes v4:
Rebased on to of patch [0] https://patchwork.kernel.org/patch/11651673/
--Fix the commit message.
--Fix the error timeout condition for -ETIMEDOUT
---
Changes v3:
--Fix the commit message.
--Drop the variable, used the value directly.
Changes v2:
--used the default timeout values.
--Added missing Fixed tags.
---
 drivers/phy/samsung/phy-exynos5-usbdrd.c | 39 ++++++++----------------
 1 file changed, 12 insertions(+), 27 deletions(-)

diff --git a/drivers/phy/samsung/phy-exynos5-usbdrd.c b/drivers/phy/samsung/phy-exynos5-usbdrd.c
index 7f6279fb4f8f..ad81aa65cdff 100644
--- a/drivers/phy/samsung/phy-exynos5-usbdrd.c
+++ b/drivers/phy/samsung/phy-exynos5-usbdrd.c
@@ -16,6 +16,7 @@
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_device.h>
+#include <linux/iopoll.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
 #include <linux/mutex.h>
@@ -556,41 +557,25 @@ static int exynos5_usbdrd_phy_power_off(struct phy *phy)
 static int crport_handshake(struct exynos5_usbdrd_phy *phy_drd,
 			    u32 val, u32 cmd)
 {
-	u32 usec = 100;
 	unsigned int result;
+	int err;
 
 	writel(val | cmd, phy_drd->reg_phy + EXYNOS5_DRD_PHYREG0);
 
-	do {
-		result = readl(phy_drd->reg_phy + EXYNOS5_DRD_PHYREG1);
-		if (result & PHYREG1_CR_ACK)
-			break;
-
-		udelay(1);
-	} while (usec-- > 0);
-
-	if (!usec) {
-		dev_err(phy_drd->dev,
-			"CRPORT handshake timeout1 (0x%08x)\n", val);
-		return -ETIME;
+	err = readl_poll_timeout(phy_drd->reg_phy + EXYNOS5_DRD_PHYREG1,
+			result,	(result & PHYREG1_CR_ACK), 1, 100);
+	if (err == -ETIMEDOUT) {
+		dev_err(phy_drd->dev, "CRPORT handshake timeout1 (0x%08x)\n", val);
+		return err;
 	}
 
-	usec = 100;
-
 	writel(val, phy_drd->reg_phy + EXYNOS5_DRD_PHYREG0);
 
-	do {
-		result = readl(phy_drd->reg_phy + EXYNOS5_DRD_PHYREG1);
-		if (!(result & PHYREG1_CR_ACK))
-			break;
-
-		udelay(1);
-	} while (usec-- > 0);
-
-	if (!usec) {
-		dev_err(phy_drd->dev,
-			"CRPORT handshake timeout2 (0x%08x)\n", val);
-		return -ETIME;
+	err = readl_poll_timeout(phy_drd->reg_phy + EXYNOS5_DRD_PHYREG1,
+			result,	!(result & PHYREG1_CR_ACK), 1, 100);
+	if (err == -ETIMEDOUT) {
+		dev_err(phy_drd->dev, "CRPORT handshake timeout2 (0x%08x)\n", val);
+		return err;
 	}
 
 	return 0;
-- 
2.27.0