From: Emanuele Ghidoli <emanuele.ghidoli@toradex.com>
Date: Fri, 18 Jul 2025 13:34:28 +0000 (+0200)
Subject: i2c: lpi2c: use readl_poll_timeout() for register polling
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8336f9de21f73bf4e7b4c2d641d82cd2f9b53e39;p=thirdparty%2Fkernel%2Fstable.git

i2c: lpi2c: use readl_poll_timeout() for register polling

Replaces polling loops with the readl_poll_timeout() helper macro.

Signed-off-by: Emanuele Ghidoli <emanuele.ghidoli@toradex.com>
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Reviewed-by: Carlos Song <carlos.song@nxp.com>
Tested-by: Primoz Fiser <primoz.fiser@norik.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20250718133429.67219-2-francesco@dolcini.it
---

diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c
index 717b617dbc2c..1a802a51853d 100644
--- a/drivers/i2c/busses/i2c-imx-lpi2c.c
+++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
@@ -16,6 +16,7 @@
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/iopoll.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
@@ -187,6 +188,10 @@ struct lpi2c_imx_struct {
 	struct i2c_client	*target;
 };
 
+#define lpi2c_imx_read_msr_poll_timeout(val, cond)                            \
+		  readl_poll_timeout(lpi2c_imx->base + LPI2C_MSR, val, cond,  \
+				     0, 500000)
+
 static void lpi2c_imx_intctrl(struct lpi2c_imx_struct *lpi2c_imx,
 			      unsigned int enable)
 {
@@ -195,33 +200,34 @@ static void lpi2c_imx_intctrl(struct lpi2c_imx_struct *lpi2c_imx,
 
 static int lpi2c_imx_bus_busy(struct lpi2c_imx_struct *lpi2c_imx)
 {
-	unsigned long orig_jiffies = jiffies;
 	unsigned int temp;
+	int err;
 
-	while (1) {
-		temp = readl(lpi2c_imx->base + LPI2C_MSR);
-
-		/* check for arbitration lost, clear if set */
-		if (temp & MSR_ALF) {
-			writel(temp, lpi2c_imx->base + LPI2C_MSR);
-			return -EAGAIN;
-		}
+	err = lpi2c_imx_read_msr_poll_timeout(temp,
+					      temp & (MSR_ALF | MSR_BBF | MSR_MBF));
 
-		if (temp & (MSR_BBF | MSR_MBF))
-			break;
+	/* check for arbitration lost, clear if set */
+	if (temp & MSR_ALF) {
+		writel(temp, lpi2c_imx->base + LPI2C_MSR);
+		return -EAGAIN;
+	}
 
-		if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
-			dev_dbg(&lpi2c_imx->adapter.dev, "bus not work\n");
-			if (lpi2c_imx->adapter.bus_recovery_info)
-				i2c_recover_bus(&lpi2c_imx->adapter);
-			return -ETIMEDOUT;
-		}
-		schedule();
+	/* check for bus not busy */
+	if (err) {
+		dev_dbg(&lpi2c_imx->adapter.dev, "bus not work\n");
+		if (lpi2c_imx->adapter.bus_recovery_info)
+			i2c_recover_bus(&lpi2c_imx->adapter);
+		return -ETIMEDOUT;
 	}
 
 	return 0;
 }
 
+static u32 lpi2c_imx_txfifo_cnt(struct lpi2c_imx_struct *lpi2c_imx)
+{
+	return readl(lpi2c_imx->base + LPI2C_MFSR) & 0xff;
+}
+
 static void lpi2c_imx_set_mode(struct lpi2c_imx_struct *lpi2c_imx)
 {
 	unsigned int bitrate = lpi2c_imx->bitrate;
@@ -259,25 +265,18 @@ static int lpi2c_imx_start(struct lpi2c_imx_struct *lpi2c_imx,
 
 static void lpi2c_imx_stop(struct lpi2c_imx_struct *lpi2c_imx)
 {
-	unsigned long orig_jiffies = jiffies;
 	unsigned int temp;
+	int err;
 
 	writel(GEN_STOP << 8, lpi2c_imx->base + LPI2C_MTDR);
 
-	do {
-		temp = readl(lpi2c_imx->base + LPI2C_MSR);
-		if (temp & MSR_SDF)
-			break;
+	err = lpi2c_imx_read_msr_poll_timeout(temp, temp & MSR_SDF);
 
-		if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
-			dev_dbg(&lpi2c_imx->adapter.dev, "stop timeout\n");
-			if (lpi2c_imx->adapter.bus_recovery_info)
-				i2c_recover_bus(&lpi2c_imx->adapter);
-			break;
-		}
-		schedule();
-
-	} while (1);
+	if (err) {
+		dev_dbg(&lpi2c_imx->adapter.dev, "stop timeout\n");
+		if (lpi2c_imx->adapter.bus_recovery_info)
+			i2c_recover_bus(&lpi2c_imx->adapter);
+	}
 }
 
 /* CLKLO = I2C_CLK_RATIO * CLKHI, SETHOLD = CLKHI, DATAVD = CLKHI/2 */
@@ -393,26 +392,23 @@ static int lpi2c_imx_pio_msg_complete(struct lpi2c_imx_struct *lpi2c_imx)
 
 static int lpi2c_imx_txfifo_empty(struct lpi2c_imx_struct *lpi2c_imx)
 {
-	unsigned long orig_jiffies = jiffies;
-	u32 txcnt;
-
-	do {
-		txcnt = readl(lpi2c_imx->base + LPI2C_MFSR) & 0xff;
+	unsigned int temp;
+	int err;
 
-		if (readl(lpi2c_imx->base + LPI2C_MSR) & MSR_NDF) {
-			dev_dbg(&lpi2c_imx->adapter.dev, "NDF detected\n");
-			return -EIO;
-		}
+	err = lpi2c_imx_read_msr_poll_timeout(temp,
+					      (temp & MSR_NDF) || !lpi2c_imx_txfifo_cnt(lpi2c_imx));
 
-		if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
-			dev_dbg(&lpi2c_imx->adapter.dev, "txfifo empty timeout\n");
-			if (lpi2c_imx->adapter.bus_recovery_info)
-				i2c_recover_bus(&lpi2c_imx->adapter);
-			return -ETIMEDOUT;
-		}
-		schedule();
+	if (temp & MSR_NDF) {
+		dev_dbg(&lpi2c_imx->adapter.dev, "NDF detected\n");
+		return -EIO;
+	}
 
-	} while (txcnt);
+	if (err) {
+		dev_dbg(&lpi2c_imx->adapter.dev, "txfifo empty timeout\n");
+		if (lpi2c_imx->adapter.bus_recovery_info)
+			i2c_recover_bus(&lpi2c_imx->adapter);
+		return -ETIMEDOUT;
+	}
 
 	return 0;
 }