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authorJohannes Poehlmann <johannes.poehlmann@izt-labs.de>2017-07-25 13:27:11 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-08-28 17:20:01 +0200
commit242b476f821b055ed0fb70a8eb6defa85baada9c (patch)
treedc5912f31f643b2d11265cd03e21b4a05f5e256c /drivers/w1
parentd7b3cf892abd94423af02e03f2d6e4a671617328 (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>
Diffstat (limited to 'drivers/w1')
-rw-r--r--drivers/w1/masters/ds1wm.c23
1 files changed, 19 insertions, 4 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;