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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: Johannes Poehlmann <johannes.poehlmann@izt-labs.de>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johannes Poehlmann 2017-07-25 13:27:11 +02:00 committed by Greg Kroah-Hartman
parent d7b3cf892a
commit 242b476f82
2 changed files with 36 additions and 11 deletions
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23
drivers/w1/masters/ds1wm.c
View File

@ -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;

24
include/linux/mfd/ds1wm.h
View File

@ -1,13 +1,23 @@
/* 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;
};