Re: [PATCH v6 5/6] iio: adc: ad7192: Add clock provider

[Alexandru Ardelean <aardelean@baylibre.com>]

On Mon, Jun 24, 2024 at 3:51 PM Alisa-Dariana Roman
<alisadariana@gmail.com> wrote:
>
> Internal clock of AD719X devices can be made available on MCLK2 pin. Add
> clock provider to support this functionality.
>

Just a question that should be addressed by the failing of the
clock-provider registration.
With that addressed:

Reviewed-by: Alexandru Ardelean <aardelean@baylibre.com>

> Signed-off-by: Alisa-Dariana Roman <alisa.roman@analog.com>
> ---
>  drivers/iio/adc/ad7192.c | 89 ++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 89 insertions(+)
>
> diff --git a/drivers/iio/adc/ad7192.c b/drivers/iio/adc/ad7192.c
> index 940517df5429..90763c14679d 100644
> --- a/drivers/iio/adc/ad7192.c
> +++ b/drivers/iio/adc/ad7192.c
> @@ -8,6 +8,7 @@
>  #include <linux/interrupt.h>
>  #include <linux/bitfield.h>
>  #include <linux/clk.h>
> +#include <linux/clk-provider.h>
>  #include <linux/device.h>
>  #include <linux/kernel.h>
>  #include <linux/slab.h>
> @@ -201,6 +202,7 @@ struct ad7192_chip_info {
>  struct ad7192_state {
>         const struct ad7192_chip_info   *chip_info;
>         struct clk                      *mclk;
> +       struct clk_hw                   int_clk_hw;
>         u16                             int_vref_mv;
>         u32                             aincom_mv;
>         u32                             fclk;
> @@ -401,6 +403,88 @@ static const char *const ad7192_clock_names[] = {
>         "mclk"
>  };
>
> +static struct ad7192_state *clk_hw_to_ad7192(struct clk_hw *hw)
> +{
> +       return container_of(hw, struct ad7192_state, int_clk_hw);
> +}
> +
> +static unsigned long ad7192_clk_recalc_rate(struct clk_hw *hw,
> +                                           unsigned long parent_rate)
> +{
> +       return AD7192_INT_FREQ_MHZ;
> +}
> +
> +static int ad7192_clk_output_is_enabled(struct clk_hw *hw)
> +{
> +       struct ad7192_state *st = clk_hw_to_ad7192(hw);
> +
> +       return st->clock_sel == AD7192_CLK_INT_CO;
> +}
> +
> +static int ad7192_clk_prepare(struct clk_hw *hw)
> +{
> +       struct ad7192_state *st = clk_hw_to_ad7192(hw);
> +       int ret;
> +
> +       st->mode &= ~AD7192_MODE_CLKSRC_MASK;
> +       st->mode |= AD7192_CLK_INT_CO;
> +
> +       ret = ad_sd_write_reg(&st->sd, AD7192_REG_MODE, 3, st->mode);
> +       if (ret)
> +               return ret;
> +
> +       st->clock_sel = AD7192_CLK_INT_CO;
> +
> +       return 0;
> +}
> +
> +static void ad7192_clk_unprepare(struct clk_hw *hw)
> +{
> +       struct ad7192_state *st = clk_hw_to_ad7192(hw);
> +       int ret;
> +
> +       st->mode &= ~AD7192_MODE_CLKSRC_MASK;
> +       st->mode |= AD7192_CLK_INT;
> +
> +       ret = ad_sd_write_reg(&st->sd, AD7192_REG_MODE, 3, st->mode);
> +       if (ret)
> +               return;
> +
> +       st->clock_sel = AD7192_CLK_INT;
> +}
> +
> +static const struct clk_ops ad7192_int_clk_ops = {
> +       .recalc_rate = ad7192_clk_recalc_rate,
> +       .is_enabled = ad7192_clk_output_is_enabled,
> +       .prepare = ad7192_clk_prepare,
> +       .unprepare = ad7192_clk_unprepare,
> +};
> +
> +static int ad7192_register_clk_provider(struct ad7192_state *st)
> +{
> +       struct device *dev = &st->sd.spi->dev;
> +       struct clk_init_data init = {};
> +       int ret;
> +
> +       if (!IS_ENABLED(CONFIG_COMMON_CLK))
> +               return 0;
> +
> +       init.name = devm_kasprintf(dev, GFP_KERNEL, "%s-clk",
> +                                  fwnode_get_name(dev_fwnode(dev)));
> +       if (!init.name)
> +               return -ENOMEM;
> +
> +       init.ops = &ad7192_int_clk_ops;
> +
> +       st->int_clk_hw.init = &init;
> +       ret = devm_clk_hw_register(dev, &st->int_clk_hw);
> +       if (ret)
> +               return ret;
> +
> +       return devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get,
> +                                          &st->int_clk_hw);
> +}
> +
>  static int ad7192_clock_setup(struct ad7192_state *st)
>  {
>         struct device *dev = &st->sd.spi->dev;
> @@ -412,6 +496,11 @@ static int ad7192_clock_setup(struct ad7192_state *st)
>         if (ret < 0) {
>                 st->clock_sel = AD7192_CLK_INT;
>                 st->fclk = AD7192_INT_FREQ_MHZ;
> +
> +               ret = ad7192_register_clk_provider(st);
> +               if (ret)
> +                       return dev_err_probe(dev, ret,
> +                                            "Failed to register clock provider\n");

A question here: do we want to fail the probe of this driver when it
cannot register a clock provider?
Or should we ignore it?
No preference from my side.

>         } else {
>                 st->clock_sel = AD7192_CLK_EXT_MCLK1_2 + ret;
>
> --
> 2.34.1
>
>