hwmon: (w83795) Refactor bank selection
Move the bank selection code to a separate function, to avoid
duplicating it in read and write functions. Improve error reporting
on register access error.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
diff --git a/drivers/hwmon/w83795.c b/drivers/hwmon/w83795.c
index d7e1d36..c7f6b1f 100644
--- a/drivers/hwmon/w83795.c
+++ b/drivers/hwmon/w83795.c
@@ -360,60 +360,67 @@
/*
* Hardware access
+ * We assume that nobdody can change the bank outside the driver.
*/
-/* Ignore the possibility that somebody change bank outside the driver
- * Must be called with data->update_lock held, except during initialization */
-static u8 w83795_read(struct i2c_client *client, u16 reg)
+/* Must be called with data->update_lock held, except during initialization */
+static int w83795_set_bank(struct i2c_client *client, u8 bank)
{
struct w83795_data *data = i2c_get_clientdata(client);
- u8 res = 0xff;
- u8 new_bank = reg >> 8;
+ int err;
- new_bank |= data->bank & 0xfc;
- if (data->bank != new_bank) {
- if (i2c_smbus_write_byte_data
- (client, W83795_REG_BANKSEL, new_bank) >= 0)
- data->bank = new_bank;
- else {
- dev_err(&client->dev,
- "set bank to %d failed, fall back "
- "to bank %d, read reg 0x%x error\n",
- new_bank, data->bank, reg);
- res = 0x0; /* read 0x0 from the chip */
- goto END;
- }
+ /* If the same bank is already set, nothing to do */
+ if ((data->bank & 0x07) == bank)
+ return 0;
+
+ /* Change to new bank, preserve all other bits */
+ bank |= data->bank & ~0x07;
+ err = i2c_smbus_write_byte_data(client, W83795_REG_BANKSEL, bank);
+ if (err < 0) {
+ dev_err(&client->dev,
+ "Failed to set bank to %d, err %d\n",
+ (int)bank, err);
+ return err;
}
- res = i2c_smbus_read_byte_data(client, reg & 0xff);
-END:
- return res;
+ data->bank = bank;
+
+ return 0;
+}
+
+/* Must be called with data->update_lock held, except during initialization */
+static u8 w83795_read(struct i2c_client *client, u16 reg)
+{
+ int err;
+
+ err = w83795_set_bank(client, reg >> 8);
+ if (err < 0)
+ return 0x00; /* Arbitrary */
+
+ err = i2c_smbus_read_byte_data(client, reg & 0xff);
+ if (err < 0) {
+ dev_err(&client->dev,
+ "Failed to read from register 0x%03x, err %d\n",
+ (int)reg, err);
+ return 0x00; /* Arbitrary */
+ }
+ return err;
}
/* Must be called with data->update_lock held, except during initialization */
static int w83795_write(struct i2c_client *client, u16 reg, u8 value)
{
- struct w83795_data *data = i2c_get_clientdata(client);
- int res;
- u8 new_bank = reg >> 8;
+ int err;
- new_bank |= data->bank & 0xfc;
- if (data->bank != new_bank) {
- res = i2c_smbus_write_byte_data(client, W83795_REG_BANKSEL,
- new_bank);
- if (res >= 0)
- data->bank = new_bank;
- else {
- dev_err(&client->dev,
- "set bank to %d failed, fall back "
- "to bank %d, write reg 0x%x error\n",
- new_bank, data->bank, reg);
- goto END;
- }
- }
+ err = w83795_set_bank(client, reg >> 8);
+ if (err < 0)
+ return err;
- res = i2c_smbus_write_byte_data(client, reg & 0xff, value);
-END:
- return res;
+ err = i2c_smbus_write_byte_data(client, reg & 0xff, value);
+ if (err < 0)
+ dev_err(&client->dev,
+ "Failed to write to register 0x%03x, err %d\n",
+ (int)reg, err);
+ return err;
}
static struct w83795_data *w83795_update_device(struct device *dev)
