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hwmon: (w83795) Refactor bank selection

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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>
This commit is contained in:
Jean Delvare 2010-10-28 20:31:45 +02:00 committed by Jean Delvare
parent 093d1a4794
commit b2469f422f
1 changed files with 48 additions and 41 deletions
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89
drivers/hwmon/w83795.c
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@ -360,60 +360,67 @@ struct w83795_data {
/*
* 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)