[PATCH 2/2] pwm: meson: support meson A1 SoC family
George Stark
gnstark at salutedevices.com
Tue Apr 23 16:00:20 PDT 2024
Hello Jerome
Thanks for the review
On 4/23/24 20:35, Jerome Brunet wrote:
>
> On Tue 23 Apr 2024 at 19:10, George Stark <gnstark at salutedevices.com> wrote:
>
>> From: George Stark <gnstark at sberdevices.ru>
>>
>> Add a compatible string and configuration for the meson A1 SoC family
>> PWM. Additionally, provide an external clock initialization helper
>> specifically designed for these PWM IPs.
>>
>> Signed-off-by: George Stark <gnstark at sberdevices.ru>
>> Signed-off-by: Dmitry Rokosov <ddrokosov at salutedevices.com>
>> ---
>> drivers/pwm/pwm-meson.c | 35 +++++++++++++++++++++++++++++++++++
>> 1 file changed, 35 insertions(+)
>>
>> diff --git a/drivers/pwm/pwm-meson.c b/drivers/pwm/pwm-meson.c
>> index ea96c5973488..529a541ba7b6 100644
>> --- a/drivers/pwm/pwm-meson.c
>> +++ b/drivers/pwm/pwm-meson.c
>> @@ -462,6 +462,33 @@ static int meson_pwm_init_channels_meson8b_v2(struct pwm_chip *chip)
>> return meson_pwm_init_clocks_meson8b(chip, mux_parent_data);
>> }
>>
>> +static int meson_pwm_init_channels_ext_clock(struct pwm_chip *chip)
>
> That kind on naming (ext) is almost sure to clash with whatever comes next.
> Just use the name of the first SoC using the method, a1 for instance.
It's true that pwm core in a1 s4, t7 etc is the same AFAWK.
I just want to clarify your proposal:
I add a1 compatible to the dt-bindings with s4 as fallback,
t7 compatible will be added later in the same way.
Here in the driver I don't mention a1 at all and use s4-centric naming e.g.:
{
.compatible = "amlogic,meson-s4-pwm",
.data = &pwm_meson_s4_data
},
static const struct meson_pwm_data pwm_meson_s4_data = {
.channels_init = meson_pwm_init_channels_s4,
};
right?
>> +{
>> + struct device *dev = pwmchip_parent(chip);
>> + struct meson_pwm *meson = to_meson_pwm(chip);
>> + struct meson_pwm_channel *channels = meson->channels;
>> + struct clk_bulk_data *clks = NULL;
>> + unsigned int i;
>> + int res;
>> +
>> + res = devm_clk_bulk_get_all(dev, &clks);
>> + if (res < 0) {
>> + dev_err(dev, "can't get device clocks\n");
>> + return res;
>> + }
>
> I don't think allocating the 'clk_bulk_data *clks' is necessary or safe.
> We know exactly how many clocks we expect, there is no need for a get all.
>
>> +
>> + if (res != MESON_NUM_PWMS) {
>> + dev_err(dev, "clock count must be %d, got %d\n",
>> + MESON_NUM_PWMS, res);
>> + return -EINVAL;
>> + }
>
> ... and this only catches the problem after the fact.
>
> It is probably convinient but not necessary.
>
>> +
>> + for (i = 0; i < MESON_NUM_PWMS; i++)
>> + channels[i].clk = clks[i].clk;
>
> channels[i].clk could be assigned directly of_clk_get() using clock
> indexes. No extra allocation needed.
if we use of_clk_get then we'll have to free the clock objects in the
end. Could we use devm_clk_bulk_get instead?
>> +
>> + return 0;
>> +}
>> +
>> static const struct meson_pwm_data pwm_meson8b_data = {
>> .parent_names = { "xtal", NULL, "fclk_div4", "fclk_div3" },
>> .channels_init = meson_pwm_init_channels_meson8b_legacy,
>> @@ -500,11 +527,19 @@ static const struct meson_pwm_data pwm_meson8_v2_data = {
>> .channels_init = meson_pwm_init_channels_meson8b_v2,
>> };
>>
>> +static const struct meson_pwm_data pwm_meson_ext_clock_data = {
>> + .channels_init = meson_pwm_init_channels_ext_clock,
>> +};
>> +
>> static const struct of_device_id meson_pwm_matches[] = {
>> {
>> .compatible = "amlogic,meson8-pwm-v2",
>> .data = &pwm_meson8_v2_data
>> },
>> + {
>> + .compatible = "amlogic,meson-a1-pwm",
>> + .data = &pwm_meson_ext_clock_data
>> + },
>> /* The following compatibles are obsolete */
>> {
>> .compatible = "amlogic,meson8b-pwm",
>
>
--
Best regards
George
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