Don't write back the configuration register if not needed. This is
important because on every write there's a delay before we can write
to the chip again.
Signed-off-by: Jean Delvare <khali at linux-fr.org>
---
drivers/hwmon/ds1621.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--- linux-2.6.26-rc9.orig/drivers/hwmon/ds1621.c 2008-07-07 16:33:38.000000000 +0200
+++ linux-2.6.26-rc9/drivers/hwmon/ds1621.c 2008-07-07 17:03:01.000000000 +0200
@@ -147,10 +147,10 @@ static int ds1621_write_value(struct i2c
static void ds1621_init_client(struct i2c_client *client)
{
struct ds1621_data *data = i2c_get_clientdata(client);
- int reg;
+ int old_reg, reg;
data->last_written = jiffies;
- reg = ds1621_read_value(client, DS1621_REG_CONF);
+ old_reg = reg = ds1621_read_value(client, DS1621_REG_CONF);
/* switch to continuous conversion mode */
reg &= ~ DS1621_REG_CONFIG_1SHOT;
@@ -160,7 +160,8 @@ static void ds1621_init_client(struct i2
else if (polarity == 1)
reg |= DS1621_REG_CONFIG_POLARITY;
- ds1621_write_value(client, DS1621_REG_CONF, reg);
+ if (reg != old_reg)
+ ds1621_write_value(client, DS1621_REG_CONF, reg);
/* start conversion */
i2c_smbus_write_byte(client, DS1621_COM_START);
--
Jean Delvare
