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Date: Mon, 16 Sep 2013 21:29:08 +0200
From: Jean Delvare <khali@...ux-fr.org>
To: Wei Ni <wni@...dia.com>
Cc: <linux@...ck-us.net>, <lm-sensors@...sensors.org>,
<linux-kernel@...r.kernel.org>, <linux-tegra@...r.kernel.org>
Subject: Re: [PATCH RESEND v4] hwmon: (lm90) split set&show temp as common
codes
Hi Wei,
On Tue, 6 Aug 2013 18:36:57 +0800, Wei Ni wrote:
> Split set&show temp codes as common functions, so we can use it
> directly when implement linux thermal framework.
> And handle error return value for the lm90_select_remote_channel
> and write_tempx, then set_temp8 and set_temp11 could return it
> to user-space.
>
> Signed-off-by: Wei Ni <wni@...dia.com>
> ---
> drivers/hwmon/lm90.c | 150 +++++++++++++++++++++++++++++++++-----------------
> 1 file changed, 99 insertions(+), 51 deletions(-)
>
> diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c
> index cdff742..6de8e01 100644
> --- a/drivers/hwmon/lm90.c
> +++ b/drivers/hwmon/lm90.c
> @@ -422,20 +422,29 @@ static int lm90_read16(struct i2c_client *client, u8 regh, u8 regl, u16 *value)
> * various registers have different meanings as a result of selecting a
> * non-default remote channel.
> */
> -static inline void lm90_select_remote_channel(struct i2c_client *client,
> +static inline int lm90_select_remote_channel(struct i2c_client *client,
> struct lm90_data *data,
> int channel)
> {
> u8 config;
> + int err = 0;
You don't have to initialize err, as you return immediately when an
error happens. You can just...
>
> if (data->kind == max6696) {
> lm90_read_reg(client, LM90_REG_R_CONFIG1, &config);
> config &= ~0x08;
> if (channel)
> config |= 0x08;
> - i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
> - config);
> + err = i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
> + config);
> + if (err < 0) {
> + dev_err(&client->dev,
> + "Failed to select remote channel %d, err %d\n",
> + channel, err);
> + return err;
> + }
> }
> +
> + return err;
... return 0 here.
> }
>
> /*
> @@ -702,29 +711,34 @@ static u16 temp_to_u16_adt7461(struct lm90_data *data, long val)
> * Sysfs stuff
> */
>
> -static ssize_t show_temp8(struct device *dev, struct device_attribute *devattr,
> - char *buf)
> +static int read_temp8(struct device *dev, int index)
> {
> - struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> struct lm90_data *data = lm90_update_device(dev);
> int temp;
>
> if (data->kind == adt7461)
> - temp = temp_from_u8_adt7461(data, data->temp8[attr->index]);
> + temp = temp_from_u8_adt7461(data, data->temp8[index]);
> else if (data->kind == max6646)
> - temp = temp_from_u8(data->temp8[attr->index]);
> + temp = temp_from_u8(data->temp8[index]);
> else
> - temp = temp_from_s8(data->temp8[attr->index]);
> + temp = temp_from_s8(data->temp8[index]);
>
> /* +16 degrees offset for temp2 for the LM99 */
> - if (data->kind == lm99 && attr->index == 3)
> + if (data->kind == lm99 && index == 3)
> temp += 16000;
>
> - return sprintf(buf, "%d\n", temp);
> + return temp;
> }
>
> -static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
> - const char *buf, size_t count)
> +static ssize_t show_temp8(struct device *dev, struct device_attribute *devattr,
> + char *buf)
> +{
> + struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> +
> + return sprintf(buf, "%d\n", read_temp8(dev, attr->index));
> +}
> +
> +static int write_temp8(struct device *dev, int index, long val)
> {
> static const u8 reg[8] = {
> LM90_REG_W_LOCAL_LOW,
> @@ -737,60 +751,79 @@ static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
> MAX6659_REG_W_REMOTE_EMERG,
> };
>
> - struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> struct i2c_client *client = to_i2c_client(dev);
> struct lm90_data *data = i2c_get_clientdata(client);
> - int nr = attr->index;
> - long val;
> int err;
>
> - err = kstrtol(buf, 10, &val);
> - if (err < 0)
> - return err;
> -
> /* +16 degrees offset for temp2 for the LM99 */
> - if (data->kind == lm99 && attr->index == 3)
> + if (data->kind == lm99 && index == 3)
> val -= 16000;
>
> mutex_lock(&data->update_lock);
> if (data->kind == adt7461)
> - data->temp8[nr] = temp_to_u8_adt7461(data, val);
> + data->temp8[index] = temp_to_u8_adt7461(data, val);
> else if (data->kind == max6646)
> - data->temp8[nr] = temp_to_u8(val);
> + data->temp8[index] = temp_to_u8(val);
> else
> - data->temp8[nr] = temp_to_s8(val);
> -
> - lm90_select_remote_channel(client, data, nr >= 6);
> - i2c_smbus_write_byte_data(client, reg[nr], data->temp8[nr]);
> - lm90_select_remote_channel(client, data, 0);
> + data->temp8[index] = temp_to_s8(val);
>
> + err = lm90_select_remote_channel(client, data, index >= 6);
> + err |= i2c_smbus_write_byte_data(client, reg[index], data->temp8[index]);
> + err |= lm90_select_remote_channel(client, data, 0);
You can't use |= for error codes. Imagine that
lm90_select_remote_channel() returns -EIO (-5) and
i2c_smbus_write_byte_data() returns -EAGAIN (-11), err will have value
-EPERM (-1) which makes no sense. You have to report errors as soon as
they happen so that the error code isn't lost.
What you can do is:
if ((err = f1(...)) ||
(err = f2(...)) ||
(err = f3(...))) {
dev_err(...);
return err;
}
I think checkpatch will complain about that construct but me, I'm fine
with it.
> + if (err)
> + dev_err(dev, "write_temp8 failed!\n");
> mutex_unlock(&data->update_lock);
> +
> + return err;
> +}
> +
> +static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
> + const char *buf, size_t count)
> +{
> + struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> + int index = attr->index;
> + long val;
> + int err;
> +
> + err = kstrtol(buf, 10, &val);
> + if (err < 0)
> + return err;
> +
> + err = write_temp8(dev, index, val);
> + if (err < 0)
> + return err;
> +
> return count;
> }
>
> -static ssize_t show_temp11(struct device *dev, struct device_attribute *devattr,
> - char *buf)
> +static int read_temp11(struct device *dev, int index)
> {
> - struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
> struct lm90_data *data = lm90_update_device(dev);
> int temp;
>
> if (data->kind == adt7461)
> - temp = temp_from_u16_adt7461(data, data->temp11[attr->index]);
> + temp = temp_from_u16_adt7461(data, data->temp11[index]);
> else if (data->kind == max6646)
> - temp = temp_from_u16(data->temp11[attr->index]);
> + temp = temp_from_u16(data->temp11[index]);
> else
> - temp = temp_from_s16(data->temp11[attr->index]);
> + temp = temp_from_s16(data->temp11[index]);
>
> /* +16 degrees offset for temp2 for the LM99 */
> - if (data->kind == lm99 && attr->index <= 2)
> + if (data->kind == lm99 && index <= 2)
> temp += 16000;
>
> - return sprintf(buf, "%d\n", temp);
> + return temp;
> }
>
> -static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
> - const char *buf, size_t count)
> +static ssize_t show_temp11(struct device *dev, struct device_attribute *devattr,
> + char *buf)
> +{
> + struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
> +
> + return sprintf(buf, "%d\n", read_temp11(dev, attr->index));
> +}
> +
> +static int write_temp11(struct device *dev, int nr, int index, long val)
> {
> struct {
> u8 high;
> @@ -804,18 +837,10 @@ static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
> { LM90_REG_W_REMOTE_HIGHH, LM90_REG_W_REMOTE_HIGHL, 1 }
> };
>
> - struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
> struct i2c_client *client = to_i2c_client(dev);
> struct lm90_data *data = i2c_get_clientdata(client);
> - int nr = attr->nr;
> - int index = attr->index;
> - long val;
> int err;
>
> - err = kstrtol(buf, 10, &val);
> - if (err < 0)
> - return err;
> -
> /* +16 degrees offset for temp2 for the LM99 */
> if (data->kind == lm99 && index <= 2)
> val -= 16000;
> @@ -830,15 +855,38 @@ static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
> else
> data->temp11[index] = temp_to_s8(val) << 8;
>
> - lm90_select_remote_channel(client, data, reg[nr].channel);
> - i2c_smbus_write_byte_data(client, reg[nr].high,
> + err = lm90_select_remote_channel(client, data, reg[nr].channel);
> + err |= i2c_smbus_write_byte_data(client, reg[nr].high,
> data->temp11[index] >> 8);
> if (data->flags & LM90_HAVE_REM_LIMIT_EXT)
> - i2c_smbus_write_byte_data(client, reg[nr].low,
> - data->temp11[index] & 0xff);
> - lm90_select_remote_channel(client, data, 0);
> + err |= i2c_smbus_write_byte_data(client, reg[nr].low,
> + data->temp11[index] & 0xff);
> + err |= lm90_select_remote_channel(client, data, 0);
> + if (err)
> + dev_err(dev, "write_temp11 failed !\n");
Same here, you can't use |=.
Also, no space needed before exclamation marks in English.
>
> mutex_unlock(&data->update_lock);
> +
> + return err;
> +}
> +
> +static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
> + const char *buf, size_t count)
> +{
> + struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
> + int nr = attr->nr;
> + int index = attr->index;
> + long val;
> + int err;
> +
> + err = kstrtol(buf, 10, &val);
> + if (err < 0)
> + return err;
> +
> + err = write_temp11(dev, nr, index, val);
> + if (err < 0)
> + return err;
> +
> return count;
> }
>
--
Jean Delvare
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