Re: [PATCH v6 6/9] mfd: axp20x: Add support for RSB based AXP223 PMIC

[Lee Jones <lee.jones-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>]

On Mon, 11 Jan 2016, Chen-Yu Tsai wrote:

> On Mon, Jan 11, 2016 at 8:09 PM, Lee Jones <lee.jones-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> wrote:
> > On Mon, 11 Jan 2016, Chen-Yu Tsai wrote:
> >> On Mon, Jan 11, 2016 at 5:24 PM, Lee Jones <lee.jones-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> wrote:
> >> > On Thu, 17 Dec 2015, Chen-Yu Tsai wrote:
> >> >
> >> >> The AXP223 is a new PMIC commonly paired with Allwinner A23/A33 SoCs.
> >> >> It is functionally identical to AXP221; only the regulator default
> >> >> voltage/status and the external host interface are different.
> >> >>
> >> >> Signed-off-by: Chen-Yu Tsai <wens-jdAy2FN1RRM@public.gmane.org>
> >> >> ---
> >> >>  drivers/mfd/Kconfig        | 11 +++++++
> >> >>  drivers/mfd/Makefile       |  1 +
> >> >>  drivers/mfd/axp20x-rsb.c   | 78 ++++++++++++++++++++++++++++++++++++++++++++++
> >> >>  drivers/mfd/axp20x.c       |  2 ++
> >> >>  include/linux/mfd/axp20x.h |  1 +
> >> >>  5 files changed, 93 insertions(+)
> >> >>  create mode 100644 drivers/mfd/axp20x-rsb.c
> >
> > [...]
> >
> >> >> +static int axp20x_rsb_probe(struct sunxi_rsb_device *rdev)
> >> >> +{
> >> >> +     struct axp20x_dev *axp20x;
> >> >> +     int ret;
> >> >> +
> >> >> +     axp20x = devm_kzalloc(&rdev->dev, sizeof(*axp20x), GFP_KERNEL);
> >> >> +     if (!axp20x)
> >> >> +             return -ENOMEM;
> >> >> +
> >> >> +     axp20x->dev = &rdev->dev;
> >> >> +     axp20x->irq = rdev->irq;
> >> >> +     sunxi_rsb_device_set_drvdata(rdev, axp20x);
> >> >
> >> > What's the point of this call?  Why do you need a sunxi_ variant?
> >>
> >> This is an inline call defined in include/linux/sunxi-rsb.h,
> >> which is equivalent to dev_set_drvdata(&rdev->dev, data).
> >>
> >> It seems many subsystems or bus drivers have this pattern.
> >>
> >>     git grep void.*_set_drvdata include/linux/ | wc -l
> >>
> >> yields 34, not including dev_set_drvdata itself and this sunxi_rsb
> >> variant.
> >
> > That doesn't answer my question.  Why is it required?
> >
> > Looks like superfluous churn to me.  Aggregation for the sake of it.
> 
> I assumed it better to use functions matching the specific bus, and also
> matching sunxi_rsb_device_get_drvdata() in the remove function.

There are seldom good reasons to do that, since the generic calls do an
outstanding job already.

> But since we already get "struct device" two lines above, it's already
> leaking the implementation, which beats the purpose of the wrapper. I'll
> replace it with dev_set_drvdata() in the next version.

Much better, thank you.

> >> >> +     ret = axp20x_match_device(axp20x);
> >> >> +     if (ret)
> >> >> +             return ret;
> >> >> +
> >> >> +     axp20x->regmap = devm_regmap_init_sunxi_rsb(rdev, axp20x->regmap_cfg);
> >> >> +     if (IS_ERR(axp20x->regmap)) {
> >> >> +             ret = PTR_ERR(axp20x->regmap);
> >> >> +             dev_err(&rdev->dev, "regmap init failed: %d\n", ret);
> >> >> +             return ret;
> >> >> +     }
> >> >> +
> >> >> +     return axp20x_device_probe(axp20x);
> >> >> +}
> >> >> +
> >> >> +static int axp20x_rsb_remove(struct sunxi_rsb_device *rdev)
> >> >> +{
> >> >> +     struct axp20x_dev *axp20x = sunxi_rsb_device_get_drvdata(rdev);
> >> >> +
> >> >> +     return axp20x_device_remove(axp20x);
> >> >> +}
> >> >> +
> >> >> +static const struct of_device_id axp20x_rsb_of_match[] = {
> >> >> +     { .compatible = "x-powers,axp223", .data = (void *)AXP223_ID },
> >> >> +     { },
> >> >> +};
> >> >> +MODULE_DEVICE_TABLE(of, axp20x_rsb_of_match);
> >> >> +
> >> >> +static struct sunxi_rsb_driver axp20x_rsb_driver = {
> >> >> +     .driver = {
> >> >> +             .name   = "axp20x-rsb",
> >> >> +             .of_match_table = of_match_ptr(axp20x_rsb_of_match),
> >> >> +     },
> >> >> +     .probe  = axp20x_rsb_probe,
> >> >> +     .remove = axp20x_rsb_remove,
> >> >> +};
> >> >> +module_sunxi_rsb_driver(axp20x_rsb_driver);
> >> >> +
> >> >> +MODULE_DESCRIPTION("PMIC MFD sunXi RSB driver for AXP20X");
> >> >> +MODULE_AUTHOR("Chen-Yu Tsai <wens-jdAy2FN1RRM@public.gmane.org>");
> >> >> +MODULE_LICENSE("GPL v2");
> >> >> diff --git a/drivers/mfd/axp20x.c b/drivers/mfd/axp20x.c
> >> >> index 54a00168da26..968d77fb95d8 100644
> >> >> --- a/drivers/mfd/axp20x.c
> >> >> +++ b/drivers/mfd/axp20x.c
> >> >> @@ -33,6 +33,7 @@ static const char * const axp20x_model_names[] = {
> >> >>       "AXP202",
> >> >>       "AXP209",
> >> >>       "AXP221",
> >> >> +     "AXP223",
> >> >>       "AXP288",
> >> >>  };
> >> >>
> >> >> @@ -616,6 +617,7 @@ int axp20x_match_device(struct axp20x_dev *axp20x)
> >> >>               axp20x->regmap_irq_chip = &axp20x_regmap_irq_chip;
> >> >>               break;
> >> >>       case AXP221_ID:
> >> >> +     case AXP223_ID:
> >> >>               axp20x->nr_cells = ARRAY_SIZE(axp22x_cells);
> >> >>               axp20x->cells = axp22x_cells;
> >> >>               axp20x->regmap_cfg = &axp22x_regmap_config;
> >> >> diff --git a/include/linux/mfd/axp20x.h b/include/linux/mfd/axp20x.h
> >> >> index 00697c6ad8b0..d82e7d51372b 100644
> >> >> --- a/include/linux/mfd/axp20x.h
> >> >> +++ b/include/linux/mfd/axp20x.h
> >> >> @@ -18,6 +18,7 @@ enum {
> >> >>       AXP202_ID,
> >> >>       AXP209_ID,
> >> >>       AXP221_ID,
> >> >> +     AXP223_ID,
> >> >>       AXP288_ID,
> >> >>       NR_AXP20X_VARIANTS,
> >> >>  };
> >> >
> >

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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