From b2469f422f9ee2054359c4ec609c3bdb1f2d52f5 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Thu, 28 Oct 2010 20:31:45 +0200 Subject: [PATCH] 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 --- drivers/hwmon/w83795.c | 93 +++++++++++++++++++++++++++----------------------- 1 file changed, 50 insertions(+), 43 deletions(-) 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 @@ 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; - - 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; - } + int err; + + /* 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 int w83795_write(struct i2c_client *client, u16 reg, u8 value) +static u8 w83795_read(struct i2c_client *client, u16 reg) { - struct w83795_data *data = i2c_get_clientdata(client); - int res; - u8 new_bank = reg >> 8; - - 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; - } + 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; +} - res = i2c_smbus_write_byte_data(client, reg & 0xff, value); -END: - return res; +/* Must be called with data->update_lock held, except during initialization */ +static int w83795_write(struct i2c_client *client, u16 reg, u8 value) +{ + int err; + + err = w83795_set_bank(client, reg >> 8); + if (err < 0) + return err; + + 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) -- 2.7.4