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can: mcp251x: Improve mcp251x_hw_probe()

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This patch adds check for mcp251x_hw_reset() result on startup and
removes unnecessary checking for CANSTAT register since this value
is being checked in mcp251x_hw_reset().

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Tested-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Alexander Shiyan 2014-03-28 14:14:46 +04:00 committed by Marc Kleine-Budde
parent ff06d611a3
commit ee967fffd9
1 changed files with 16 additions and 17 deletions
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33
drivers/net/can/mcp251x.c
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@ -649,23 +649,22 @@ static int mcp251x_hw_reset(struct spi_device *spi)
static int mcp251x_hw_probe(struct spi_device *spi)
{
int st1, st2;
u8 ctrl;
int ret;
mcp251x_hw_reset(spi);
ret = mcp251x_hw_reset(spi);
if (ret)
return ret;
/*
* Please note that these are "magic values" based on after
* reset defaults taken from data sheet which allows us to see
* if we really have a chip on the bus (we avoid common all
* zeroes or all ones situations)
*/
st1 = mcp251x_read_reg(spi, CANSTAT) & 0xEE;
st2 = mcp251x_read_reg(spi, CANCTRL) & 0x17;
ctrl = mcp251x_read_reg(spi, CANCTRL);
dev_dbg(&spi->dev, "CANSTAT 0x%02x CANCTRL 0x%02x\n", st1, st2);
dev_dbg(&spi->dev, "CANCTRL 0x%02x\n", ctrl);
/* Check for power up default values */
return (st1 == 0x80 && st2 == 0x07) ? 1 : 0;
/* Check for power up default value */
if ((ctrl & 0x17) != 0x07)
return -ENODEV;
return 0;
}
static int mcp251x_power_enable(struct regulator *reg, int enable)
@ -1142,10 +1141,10 @@ static int mcp251x_can_probe(struct spi_device *spi)
SET_NETDEV_DEV(net, &spi->dev);
/* Here is OK to not lock the MCP, no one knows about it yet */
if (!mcp251x_hw_probe(spi)) {
ret = -ENODEV;
ret = mcp251x_hw_probe(spi);
if (ret)
goto error_probe;
}
mcp251x_hw_sleep(spi);
ret = register_candev(net);
@ -1154,7 +1153,7 @@ static int mcp251x_can_probe(struct spi_device *spi)
devm_can_led_init(net);
return ret;
return 0;
error_probe:
if (mcp251x_enable_dma)