Re: [PATCH 1/2] regulator: new driver for the AD5398 and AD5821

[Sonic Zhang]

On Tue, Jun 1, 2010 at 10:37 PM, Mark Brown
<broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> On Tue, Jun 01, 2010 at 09:33:58AM -0400, Mike Frysinger wrote:
>> From: Sonic Zhang <sonic.zhang@xxxxxxxxxx>
>
>> This driver supports both the AD5398 and the AD5821.  It adapts into the
>> voltage and current framework.  The generic userspace-consumer and virtual
>
> Might be useful to put something here saying what these chips do...
>

OK.

>> consumer should be selected to access devices via this driver.
>
> Please remove the comment about the userspace and virtual consumers from
> the driver, the driver should support all consumer drivers and the use
> of userspace consumers will normally be very unusual.
>

OK.

>> +static int ad5398_get(struct regulator_dev *rdev)
>> +{
>> +     struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
>> +     struct i2c_client *client = chip->client;
>> +     unsigned short data;
>> +     int ret;
>> +
>> +     ret = i2c_master_recv(client, (char *)&data, 2);
>> +     if (ret < 0) {
>> +             dev_err(&client->dev, "I2C read error\n");
>> +             return ret;
>> +     }
>
> I strongly suggest implementing register I/O functions rather than open
> coding with the I2C API each time.
>

No problem.

>> +
>> +     ret = (be16_to_cpu(data) & chip->current_mask) >> chip->current_offset;
>> +
>> +     return ad5398_calc_current(chip, ret);
>
> This function should really have a much clearer name than just plain
> _get() - it looks like it's intended to read the current limit.
>
>> +static int ad5398_set(struct regulator_dev *rdev, int min_uA, int max_uA)
>> +{
>
> Same here - this should have a much clearer name saying what's being
> set.
>

OK.

>> +     /* prepare register data */
>> +     selector = (selector << chip->current_offset) & chip->current_mask;
>> +     selector |= (data & CURRENT_EN_MASK);
>
> This CURRENT_EN_MASK configuration looks fishy, what does that setting
> do and why is it being unconditionally set?
>

CURRENT_EN_MASK is the power on control bit of these current regulator chip.
It is part of the current value register. It is not touched when
setting the current value.


>> +static struct regulator_ops ad5398_ops = {
>> +     .get_current_limit = ad5398_get,
>> +     .set_current_limit = ad5398_set,
>> +     .enable = ad5398_enable,
>> +     .disable = ad5398_disable,
>> +     .is_enabled = ad5398_is_enabled,
>> +     .set_suspend_enable = ad5398_enable,
>> +     .set_suspend_disable = ad5398_disable,
>
> If the chip does not have suspend mode configuration it should not
> supply any suspend mode configuration functions.
>

OK. I will remove them.

>> +     i2c_set_clientdata(client, chip);
>> +     dev_info(&client->dev, "%s regulator driver loaded\n", id->name);
>
> Remove this or tone it down to a debug level print.
>
>> +static int ad5398_remove(struct i2c_client *client)
>> +{
>> +     struct ad5398_chip_info *chip = i2c_get_clientdata(client);
>> +
>> +     if (chip) {
>> +             regulator_unregister(&chip->rdev);
>> +             kfree(chip);
>> +     }
>
> If you failed to register the regulator you should've failed the probe
> and therefore this check for chip should not be required.
>

OK.

>> +#define CURRENT_EN_MASK              0x8000
>> +#define CURRENT_BITS_MAX     16
>
> These defines should be namespaced.
>

No problem.

>> +/**
>> + * ad5398_platform_data - platform data for ad5398
>> + * @current_bits: effective bits in register
>> + * @current_offset: offset of effective bits in register
>> + * @ad5398_init_data: regulator init data
>> + */
>> +struct ad5398_platform_data {
>> +     unsigned short current_bits;
>> +     unsigned short current_offset;
>> +     struct regulator_init_data *regulator_data;
>> +};
>
> Why are the current bits and offset being suppied as platform data?  I
> would *very* strongly expect that the location of the control in the
> register will be fixed by the device type and should therefore be
> figured out by the driver.  Having the machine specifying this seems
> redundant and error prone.

Yes, define these data format information in driver for each supported
chip is a better way.

I will send out the new patch soon.

Sonic

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