3.16.79-rc1 review patch. If anyone has any objections, please let me know.
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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; }