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authorEdward A. James <eajames@us.ibm.com>2017-10-27 11:55:05 -0500
committerGuenter Roeck <linux@roeck-us.net>2017-10-29 18:35:54 -0700
commit6dcf2fb5e8db3704f50af1f198256cb4e2453f8b (patch)
tree2f7353f4a43eb7dce9c1e9ebdd62443b69408854 /drivers/hwmon
parent0b07194bb55ed836c2cc7c22e866b87a14681984 (diff)
downloadlinux-6dcf2fb5e8db3704f50af1f198256cb4e2453f8b.tar.bz2
hwmon: (pmbus/core) Prevent unintentional setting of page to 0xFF
The pmbus core may call read/write word data functions with a page value of -1, intending to perform the operation without setting the page. However, the read/write word data functions accept only unsigned 8-bit page numbers, and therefore cannot check for negative page number to avoid setting the page. This results in setting the page number to 0xFF. This may result in errors or undefined behavior of some devices (specifically the ir35221, which allows the page to be set to 0xFF, but some subsequent operations to read registers may fail). Switch the pmbus_set_page page parameter to an integer and perform the check for negative page there. Make read/write functions consistent in accepting an integer page number parameter. Signed-off-by: Edward A. James <eajames@us.ibm.com> Fixes: cbcdec6202c9 ("hwmon: (pmbus): Access word data for STATUS_WORD") Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon')
-rw-r--r--drivers/hwmon/pmbus/pmbus.h6
-rw-r--r--drivers/hwmon/pmbus/pmbus_core.c25
2 files changed, 14 insertions, 17 deletions
diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
index 4efa2bd4f6d8..fa613bd209e3 100644
--- a/drivers/hwmon/pmbus/pmbus.h
+++ b/drivers/hwmon/pmbus/pmbus.h
@@ -404,9 +404,9 @@ extern const struct regulator_ops pmbus_regulator_ops;
/* Function declarations */
void pmbus_clear_cache(struct i2c_client *client);
-int pmbus_set_page(struct i2c_client *client, u8 page);
-int pmbus_read_word_data(struct i2c_client *client, u8 page, u8 reg);
-int pmbus_write_word_data(struct i2c_client *client, u8 page, u8 reg, u16 word);
+int pmbus_set_page(struct i2c_client *client, int page);
+int pmbus_read_word_data(struct i2c_client *client, int page, u8 reg);
+int pmbus_write_word_data(struct i2c_client *client, int page, u8 reg, u16 word);
int pmbus_read_byte_data(struct i2c_client *client, int page, u8 reg);
int pmbus_write_byte(struct i2c_client *client, int page, u8 value);
int pmbus_write_byte_data(struct i2c_client *client, int page, u8 reg,
diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index 302f0aef59de..52a58b8b6e1b 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -136,13 +136,13 @@ void pmbus_clear_cache(struct i2c_client *client)
}
EXPORT_SYMBOL_GPL(pmbus_clear_cache);
-int pmbus_set_page(struct i2c_client *client, u8 page)
+int pmbus_set_page(struct i2c_client *client, int page)
{
struct pmbus_data *data = i2c_get_clientdata(client);
int rv = 0;
int newpage;
- if (page != data->currpage) {
+ if (page >= 0 && page != data->currpage) {
rv = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page);
newpage = i2c_smbus_read_byte_data(client, PMBUS_PAGE);
if (newpage != page)
@@ -158,11 +158,9 @@ int pmbus_write_byte(struct i2c_client *client, int page, u8 value)
{
int rv;
- if (page >= 0) {
- rv = pmbus_set_page(client, page);
- if (rv < 0)
- return rv;
- }
+ rv = pmbus_set_page(client, page);
+ if (rv < 0)
+ return rv;
return i2c_smbus_write_byte(client, value);
}
@@ -186,7 +184,8 @@ static int _pmbus_write_byte(struct i2c_client *client, int page, u8 value)
return pmbus_write_byte(client, page, value);
}
-int pmbus_write_word_data(struct i2c_client *client, u8 page, u8 reg, u16 word)
+int pmbus_write_word_data(struct i2c_client *client, int page, u8 reg,
+ u16 word)
{
int rv;
@@ -219,7 +218,7 @@ static int _pmbus_write_word_data(struct i2c_client *client, int page, int reg,
return pmbus_write_word_data(client, page, reg, word);
}
-int pmbus_read_word_data(struct i2c_client *client, u8 page, u8 reg)
+int pmbus_read_word_data(struct i2c_client *client, int page, u8 reg)
{
int rv;
@@ -255,11 +254,9 @@ int pmbus_read_byte_data(struct i2c_client *client, int page, u8 reg)
{
int rv;
- if (page >= 0) {
- rv = pmbus_set_page(client, page);
- if (rv < 0)
- return rv;
- }
+ rv = pmbus_set_page(client, page);
+ if (rv < 0)
+ return rv;
return i2c_smbus_read_byte_data(client, reg);
}