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Subject[PATCH 3.16 17/72] can: mcp251x: mcp251x_hw_reset(): allow more time after a reset
3.16.79-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Marc Kleine-Budde <mkl@pengutronix.de>

commit d84ea2123f8d27144e3f4d58cd88c9c6ddc799de upstream.

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()")
Tested-by: Sean Nyekjaer <sean@geanix.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/net/can/spi/mcp251x.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)

--- a/drivers/net/can/spi/mcp251x.c
+++ b/drivers/net/can/spi/mcp251x.c
@@ -626,7 +626,7 @@ static int mcp251x_setup(struct net_devi
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 */
@@ -640,10 +640,19 @@ static int mcp251x_hw_reset(struct spi_d
/* 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;
}

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