From d84ea2123f8d27144e3f4d58cd88c9c6ddc799de Mon Sep 17 00:00:00 2001
From: Marc Kleine-Budde <mkl@pengutronix.de>
Date: Tue, 13 Aug 2019 16:01:02 +0200
Subject: [PATCH] can: mcp251x: mcp251x_hw_reset(): allow more time after a reset
Git-commit: d84ea2123f8d27144e3f4d58cd88c9c6ddc799de
Patch-mainline: v5.4-rc1
References: bsc#1051510

Some boards take longer than 5ms to power up after a reset, so allow
some retries attempts before giving up.

Fixes: ff06d611a31c ("can: mcp251x: Improve mcp251x_hw_reset()")
Cc: linux-stable <stable@vger.kernel.org>
Tested-by: Sean Nyekjaer <sean@geanix.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/net/can/spi/mcp251x.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
index 1b3ac5f03f5b..74cb19a2bd08 100644
--- a/drivers/net/can/spi/mcp251x.c
+++ b/drivers/net/can/spi/mcp251x.c
@@ -606,7 +606,7 @@ 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);
-	u8 reg;
+	unsigned long timeout;
 	int ret;
 
 	/* Wait for oscillator startup timer after power up */
@@ -620,10 +620,19 @@ 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;
 }
 
-- 
2.16.4