can: mcp251x: mcp251x_hw_reset(): allow more time after a reset

commit d84ea21 upstream. Some boards take longer than 5ms to power up after a reset, so allow some retries attempts before giving up. Fixes: ff06d61 ("can: mcp251x: Improve mcp251x_hw_reset()") Cc: linux-stable <[email protected]> Tested-by: Sean Nyekjaer <[email protected]> Signed-off-by: Marc Kleine-Budde <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
infectedmushi · Oct 17, 2019 · 62db62a · 62db62a
1 parent cc5d103
commit 62db62a
Showing 1 changed file with 14 additions and 5 deletions.
diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
@@ -627,7 +627,7 @@ static int mcp251x_setup(struct net_device *net, struct mcp251x_priv *priv,
 static int mcp251x_hw_reset(struct spi_device *spi)
 {
 	struct mcp251x_priv *priv = spi_get_drvdata(spi);
-	u8 reg;
+	unsigned long timeout;
 	int ret;
 
 	/* Wait for oscillator startup timer after power up */
@@ -641,10 +641,19 @@ static int mcp251x_hw_reset(struct spi_device *spi)
 	/* Wait for oscillator startup timer after reset */
 	mdelay(MCP251X_OST_DELAY_MS);
 
-	reg = mcp251x_read_reg(spi, CANSTAT);
-	if ((reg & CANCTRL_REQOP_MASK) != CANCTRL_REQOP_CONF)
-		return -ENODEV;
-
+	/* 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;
 }