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Commit ee967fff authored by Alexander Shiyan's avatar Alexander Shiyan Committed by Marc Kleine-Budde
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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: default avatarAlexander Shiyan <shc_work@mail.ru>
Tested-by: default avatarAlexander Shiyan <shc_work@mail.ru>
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent ff06d611

drivers/net/can/mcp251x.c

+16 −17
Original line number Diff line number Diff line
@@ -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)