[PATCH 1/2] iio: mxs: Add MX23 support into the IIO driver

[Michał Mirosław]

2013/1/21 Marek Vasut <marex at denx.de>:
> Dear Michał Mirosław,
>
>> 2013/1/21 Marek Vasut <marex at denx.de>:
>> > This patch adds support for i.MX23 into the LRADC driver. The LRADC
>> > block on MX23 is not much different from the one on MX28, thus this
>> > is only a few changes fixing the parts that are specific to MX23.
>>
>> [...]
>>
>> > +struct mxs_lradc_of_config {
>> > +       const int               irq_count;
>> > +       const char * const      *irq_name;
>> > +};
>> > +
>> > +static const struct mxs_lradc_of_config const mxs_lradc_of_config[] = {
>> > +       [IMX23_LRADC] = {
>> > +               .irq_count      = ARRAY_SIZE(mx23_lradc_irq_names),
>> > +               .irq_name       = mx23_lradc_irq_names,
>> > +       },
>> > +       [IMX28_LRADC] = {
>> > +               .irq_count      = ARRAY_SIZE(mx28_lradc_irq_names),
>> > +               .irq_name       = mx28_lradc_irq_names,
>> > +       },
>> > +};
>> > +
>> >
>> >  enum mxs_lradc_ts {
>> >
>> >         MXS_LRADC_TOUCHSCREEN_NONE = 0,
>> >         MXS_LRADC_TOUCHSCREEN_4WIRE,
>> >
>> > @@ -857,8 +890,19 @@ static void mxs_lradc_hw_stop(struct mxs_lradc
>> > *lradc)
>> >
>> >                 writel(0, lradc->base + LRADC_DELAY(i));
>> >
>> >  }
>> >
>> > +static const struct of_device_id mxs_lradc_dt_ids[] = {
>> > +       { .compatible = "fsl,imx23-lradc", .data = (void *)IMX23_LRADC,
>> > }, +       { .compatible = "fsl,imx28-lradc", .data = (void
>> > *)IMX28_LRADC, }, +       { /* sentinel */ }
>> > +};
>> > +MODULE_DEVICE_TABLE(of, mxs_lradc_dt_ids);
>> > +
>>
>> Why not s/(void \*)\(IMX.._LRADC\)/\&mxs_lradc_of_config[\1]/ ?
>
> Check the register layout, it differs between MX23 and MX28, that's one reason,
> since were we to access differently placed registers, we can do it easily as in
> the SSP/I2C drivers.
>
> Moreover, there are some features on the MX28 that are not on the MX23 (like
> voltage treshold triggers and touchbuttons), with this setup, we can easily
> check what we're running at at runtime and determine to disallow these.
>
> From my point of view, using the number (IMX23_LRADC / IMX28_LRADC) is much more
> convenient in the long run.

I'm asking, because you don't use this number anywhere other than in
mxs_lradc_probe()
and there only to dereference the irq-names table. After that the
structure and number
are forgotten.

Sure, it's just an insn or two, so no strong opinion here --- just curious.

Best Regards,
Michał Mirosław