can: mcp251x: Use readx_poll_timeout() helper

We may use special helper macro to poll IO till condition or timeout occurs.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200217161038.25009-1-andriy.shevchenko@linux.intel.comSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/spi/mcp251x.c

@@ -32,6 +32,7 @@
 #include <linux/gpio/driver.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/iopoll.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/netdevice.h>
@@ -376,6 +377,15 @@ static void mcp251x_write_bits(struct spi_device *spi, u8 reg,
 	mcp251x_spi_trans(spi, 4);
 }
 
+static u8 mcp251x_read_stat(struct spi_device *spi)
+{
+	return mcp251x_read_reg(spi, CANSTAT) & CANCTRL_REQOP_MASK;
+}
+
+#define mcp251x_read_stat_poll_timeout(addr, val, cond, delay_us, timeout_us) \
+	readx_poll_timeout(mcp251x_read_stat, addr, val, cond, \
+			   delay_us, timeout_us)
+
 #ifdef CONFIG_GPIOLIB
 enum {
 	MCP251X_GPIO_TX0RTS = 0,		/* inputs */
@@ -709,7 +719,8 @@ static void mcp251x_hw_sleep(struct spi_device *spi)
 /* May only be called when device is sleeping! */
 static int mcp251x_hw_wake(struct spi_device *spi)
 {
-	unsigned long timeout;
+	u8 value;
+	int ret;
 
 	/* Force wakeup interrupt to wake device, but don't execute IST */
 	disable_irq(spi->irq);
@@ -722,14 +733,12 @@ static int mcp251x_hw_wake(struct spi_device *spi)
 	mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_CONF);
 
 	/* Wait for the device to enter config mode */
-	timeout = jiffies + HZ;
-	while ((mcp251x_read_reg(spi, CANSTAT) & CANCTRL_REQOP_MASK) !=
-			CANCTRL_REQOP_CONF) {
-		schedule();
-		if (time_after(jiffies, timeout)) {
-			dev_err(&spi->dev, "MCP251x didn't enter in config mode\n");
-			return -EBUSY;
-		}
+	ret = mcp251x_read_stat_poll_timeout(spi, value, value == CANCTRL_REQOP_CONF,
+					     MCP251X_OST_DELAY_MS * 1000,
+					     USEC_PER_SEC);
+	if (ret) {
+		dev_err(&spi->dev, "MCP251x didn't enter in config mode\n");
+		return ret;
 	}
 
 	/* Disable and clear pending interrupts */
@@ -784,7 +793,8 @@ static int mcp251x_do_set_mode(struct net_device *net, enum can_mode mode)
 static int mcp251x_set_normal_mode(struct spi_device *spi)
 {
 	struct mcp251x_priv *priv = spi_get_drvdata(spi);
-	unsigned long timeout;
+	u8 value;
+	int ret;
 
 	/* Enable interrupts */
 	mcp251x_write_reg(spi, CANINTE,
@@ -802,13 +812,12 @@ static int mcp251x_set_normal_mode(struct spi_device *spi)
 		mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_NORMAL);
 
 		/* Wait for the device to enter normal mode */
-		timeout = jiffies + HZ;
-		while (mcp251x_read_reg(spi, CANSTAT) & CANCTRL_REQOP_MASK) {
-			schedule();
-			if (time_after(jiffies, timeout)) {
-				dev_err(&spi->dev, "MCP251x didn't enter in normal mode\n");
-				return -EBUSY;
-			}
+		ret = mcp251x_read_stat_poll_timeout(spi, value, value == 0,
+						     MCP251X_OST_DELAY_MS * 1000,
+						     USEC_PER_SEC);
+		if (ret) {
+			dev_err(&spi->dev, "MCP251x didn't enter in normal mode\n");
+			return ret;
 		}
 	}
 	priv->can.state = CAN_STATE_ERROR_ACTIVE;
@@ -852,7 +861,7 @@ static int mcp251x_setup(struct net_device *net, struct spi_device *spi)
 static int mcp251x_hw_reset(struct spi_device *spi)
 {
 	struct mcp251x_priv *priv = spi_get_drvdata(spi);
-	unsigned long timeout;
+	u8 value;
 	int ret;
 
 	/* Wait for oscillator startup timer after power up */
@@ -867,19 +876,12 @@ static int mcp251x_hw_reset(struct spi_device *spi)
 	mdelay(MCP251X_OST_DELAY_MS);
 
 	/* Wait for reset to finish */
-	timeout = jiffies + HZ;
-	while ((mcp251x_read_reg(spi, CANSTAT) & CANCTRL_REQOP_MASK) !=
-	       CANCTRL_REQOP_CONF) {
-		usleep_range(MCP251X_OST_DELAY_MS * 1000,
-			     MCP251X_OST_DELAY_MS * 1000 * 2);
-
-		if (time_after(jiffies, timeout)) {
-			dev_err(&spi->dev,
-				"MCP251x didn't enter in conf mode after reset\n");
-			return -EBUSY;
-		}
-	}
-	return 0;
+	ret = mcp251x_read_stat_poll_timeout(spi, value, value == CANCTRL_REQOP_CONF,
+					     MCP251X_OST_DELAY_MS * 1000,
+					     USEC_PER_SEC);
+	if (ret)
+		dev_err(&spi->dev, "MCP251x didn't enter in conf mode after reset\n");
+	return ret;
 }
 
 static int mcp251x_hw_probe(struct spi_device *spi)