diff options
| author | Alexander Shiyan <shc_work@mail.ru> | 2014-03-28 14:14:46 +0400 |
|---|---|---|
| committer | Marc Kleine-Budde <mkl@pengutronix.de> | 2014-04-24 22:54:15 +0200 |
| commit | ee967fffd91031f18dbe36bf6a273d8a75f663cf (patch) | |
| tree | 4b503a52143461c679e0df9c40122b04a976b903 /drivers/net/can/mcp251x.c | |
| parent | ff06d611a31c4b687c7859e3c7516a38194d4d25 (diff) | |
can: mcp251x: Improve mcp251x_hw_probe()
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>
Diffstat (limited to 'drivers/net/can/mcp251x.c')
| -rw-r--r-- | drivers/net/can/mcp251x.c | 33 |
1 files changed, 16 insertions, 17 deletions
diff --git a/drivers/net/can/mcp251x.c b/drivers/net/can/mcp251x.c index 9a8fd9456979..bc235f9dc754 100644 --- a/drivers/net/can/mcp251x.c +++ b/drivers/net/can/mcp251x.c @@ -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, "CANCTRL 0x%02x\n", ctrl); - dev_dbg(&spi->dev, "CANSTAT 0x%02x CANCTRL 0x%02x\n", st1, st2); + /* Check for power up default value */ + if ((ctrl & 0x17) != 0x07) + return -ENODEV; - /* Check for power up default values */ - return (st1 == 0x80 && st2 == 0x07) ? 1 : 0; + 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) |