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>
diff --git a/drivers/net/can/mcp251x.c b/drivers/net/can/mcp251x.c
index 9a8fd94..bc235f9 100644
--- a/drivers/net/can/mcp251x.c
+++ b/drivers/net/can/mcp251x.c
@@ -649,23 +649,22 @@
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 @@
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 @@
devm_can_led_init(net);
- return ret;
+ return 0;
error_probe:
if (mcp251x_enable_dma)