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authorAlexander Shiyan <shc_work@mail.ru>2014-03-28 14:14:46 +0400
committerMarc Kleine-Budde <mkl@pengutronix.de>2014-04-25 00:54:15 +0400
commitee967fffd91031f18dbe36bf6a273d8a75f663cf (patch)
tree4b503a52143461c679e0df9c40122b04a976b903 /drivers/net/can
parentff06d611a31c4b687c7859e3c7516a38194d4d25 (diff)
downloadlinux-ee967fffd91031f18dbe36bf6a273d8a75f663cf.tar.xz
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')
-rw-r--r--drivers/net/can/mcp251x.c33
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)