diff options
| author | Johannes Poehlmann <johannes.poehlmann@izt-labs.de> | 2017-07-25 13:27:11 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-08-28 17:20:01 +0200 |
| commit | 242b476f821b055ed0fb70a8eb6defa85baada9c (patch) | |
| tree | dc5912f31f643b2d11265cd03e21b4a05f5e256c | |
| parent | d7b3cf892abd94423af02e03f2d6e4a671617328 (diff) | |
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>
| -rw-r--r-- | drivers/w1/masters/ds1wm.c | 23 | ||||
| -rw-r--r-- | include/linux/mfd/ds1wm.h | 24 |
2 files changed, 36 insertions, 11 deletions
diff --git a/drivers/w1/masters/ds1wm.c b/drivers/w1/masters/ds1wm.c index fd2e9da27c4b..401e53e0482a 100644 --- a/drivers/w1/masters/ds1wm.c +++ b/drivers/w1/masters/ds1wm.c @@ -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; diff --git a/include/linux/mfd/ds1wm.h b/include/linux/mfd/ds1wm.h index 38a372a0e285..79a01e8dc83f 100644 --- a/include/linux/mfd/ds1wm.h +++ b/include/linux/mfd/ds1wm.h @@ -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; }; |