Re: [PATCH v2 07/10] regulator: Add driver for Maxim 77802 PMIC regulators

Javier Martinez Canillas
2014-06-17T10:50:08Z

Hello Mark,

Thanks a lot for your feedback.

On 06/16/2014 09:25 PM, Mark Brown wrote:
> On Mon, Jun 16, 2014 at 08:02:35PM +0200, Javier Martinez Canillas wrote:
>
>> --- a/drivers/mfd/max77802.c
>> +++ b/drivers/mfd/max77802.c
>> @@ -37,6 +37,7 @@
>> #include <linux/err.h>
>>
>> static const struct mfd_cell max77802_devs[] = {
>> + { .name = "max77802-pmic", },
>> };
>>
>> static bool max77802_pmic_is_accessible_reg(struct device *dev,
>
> Please don't do things like this, it makes it harder to apply your
> series. Just register all the devices in the MFD when you add the MFD
> driver.
>

Ok, I'll do that. After all mfd core just omits the devices that don't match.

>> + default:
>> + pr_warn("%s: regulator_suspend_mode : 0x%x not supported\n",
>> + rdev->desc->name, mode);
>> + return -EINVAL;
>
> dev_warn().
>

Ok.

>> +static void max77802_copy_reg(struct device *dev, struct regmap *regmap,
>> + int from_reg, int to_reg)
>> +{
>> + int val;
>> + int ret;
>> +
>> + if (from_reg == to_reg)
>> + return;
>> +
>> + ret = regmap_read(regmap, from_reg, &val);
>> + if (!ret)
>> + ret = regmap_write(regmap, to_reg, val);
>> +
>> + if (ret)
>> + dev_warn(dev, "Copy err %d => %d (%d)\n",
>> + from_reg, to_reg, ret);
>> +}
>
> Again, this looks like it should be generic.
>

Yes, I missed this from your previous feedback, sorry about that.

I'll add a regmap_copy_reg() function to drivers/base/regmap/regmap.c instead.

>> +static int max77802_pmic_probe(struct platform_device *pdev)
>> +{
>
>> + dev_dbg(&pdev->dev, "%s\n", __func__);
>
> This isn't adding anything, just remove it - the core already logs
> probes if you want.
>

Ok.

>> + config.dev = &pdev->dev;
>
> Are you sure this shouldn't be the MFD?
>

I just looked at regulator_register() and saw that it does rdev->dev.parent =
dev, so yes this has to be the MFD.

>> + for (i = 0; i < MAX77802_MAX_REGULATORS; i++) {
>> + struct regulator_dev *rdev;
>> + int id = pdata->regulators[i].id;
>> +
>> + config.init_data = pdata->regulators[i].initdata;
>> + config.of_node = pdata->regulators[i].of_node;
>> +
>> + max77802->opmode[id] = MAX77802_OPMODE_NORMAL;
>
> Why isn't this being read from the hardware, this may lead to a
> configuration change the first time we pay attention?
>

The original Chrome OS driver [0] had a "regulator-op-mode" property similar to
"op_mode" in Documentation/devicetree/bindings/regulator/s5m8767-regulator.txt
to specify the operating mode using DT.

But I removed that since I didn't want to have a specific property for what
appears to be a generic need. I wanted to re-post something along the lines of
what was discussed in [1] and add operating mode support to the generic
regulator code.

So, for now I thought it made sense to set the operating mode to normal on
probe() but I'll change it to read from the hardware if that is better.

I guess I should check in the datasheet if a sane default operating mode for
LDOs is expected when the chip is reseted or if this is left undefined and also
if the bootloader already set this.

Best regards,
Javier

[0]:
https://chromium.googlesource.com/chromiumos/third_party/kernel/+/chromeos-3.8/Documentation/devicetree/bindings/mfd/max77xxx.txt
[1]: https://patchwork.kernel.org/patch/1855331/