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Commit 242b476f authored by Johannes Poehlmann's avatar Johannes Poehlmann Committed by Greg Kroah-Hartman
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w1: ds1wm: fix register offset (bus shift) calculation 



Replace incorrect register offsett calculation by
direct configuration of bus_shift in mfd-cell.

Indirect definition of address-shift by resource size
was unobvious and was wrong (should have used a binary log).

Signed-off-by: default avatarJohannes Poehlmann <johannes.poehlmann@izt-labs.de>
Acked-by: default avatarEvgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d7b3cf89

drivers/w1/masters/ds1wm.c

+19 −4
Original line number Diff line number Diff line
@@ -95,7 +95,7 @@ static struct { 


struct ds1wm_data {

	void     __iomem *map;

	int      bus_shift; /* # of shifts to calc register offsets */

	unsigned int      bus_shift; /* # of shifts to calc register offsets */

	struct platform_device *pdev;

	const struct mfd_cell   *cell;

	int      irq;
@@ -473,9 +473,6 @@ static int ds1wm_probe(struct platform_device *pdev) 
	if (!ds1wm_data->map)

		return -ENOMEM;



	/* calculate bus shift from mem resource */

	ds1wm_data->bus_shift = resource_size(res) >> 3;



	ds1wm_data->pdev = pdev;

	ds1wm_data->cell = mfd_get_cell(pdev);

	if (!ds1wm_data->cell)
@@ -484,6 +481,24 @@ static int ds1wm_probe(struct platform_device *pdev) 
	if (!plat)

		return -ENODEV;



	/* how many bits to shift register number to get register offset */

	if (plat->bus_shift > 2) {

		dev_err(&ds1wm_data->pdev->dev,

			"illegal bus shift %d, not written",

			ds1wm_data->bus_shift);

		return -EINVAL;

	}



	ds1wm_data->bus_shift = plat->bus_shift;

	/* make sure resource has space for 8 registers */

	if ((8 << ds1wm_data->bus_shift) > resource_size(res)) {

		dev_err(&ds1wm_data->pdev->dev,

			"memory resource size %d to small, should be %d\n",

			(int)resource_size(res),

			8 << ds1wm_data->bus_shift);

		return -EINVAL;

	}



	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);

	if (!res)

		return -ENXIO;

include/linux/mfd/ds1wm.h

+17 −7
Original line number Diff line number Diff line 
/* MFD cell driver data for the DS1WM driver */

/* MFD cell driver data for the DS1WM driver

 *

 * to be defined in the MFD device that is

 * using this driver for one of his sub devices

 */



struct ds1wm_driver_data {

	int active_high;

	int clock_rate;

	/* in milliseconds, the amount of time to */

	/* sleep following a reset pulse. Zero    */

	/* should work if your bus devices recover*/

	/* time respects the 1-wire spec since the*/

	/* ds1wm implements the precise timings of*/

	/* a reset pulse/presence detect sequence.*/

	/* in milliseconds, the amount of time to

	 * sleep following a reset pulse. Zero

	 * should work if your bus devices recover

	 * time respects the 1-wire spec since the

	 * ds1wm implements the precise timings of

	 * a reset pulse/presence detect sequence.

	 */

	unsigned int reset_recover_delay;



	/* left shift of register number to get register address offsett.

	 * Only 0,1,2 allowed for 8,16 or 32 bit bus width respectively

	 */

	unsigned int bus_shift;

};