Re: [PATCH v7 4/4] iio: adc: ad7192: Add clock provider

["Nuno Sá" <noname.nuno@gmail.com>]

On Thu, 2024-07-18 at 00:25 +0300, Alisa-Dariana Roman wrote:
> Internal clock of AD719X devices can be made available on MCLK2 pin. Add
> clock provider to support this functionality when clock cells property
> is present.
> 
> Signed-off-by: Alisa-Dariana Roman <alisa.roman@analog.com>
> ---

minor thing below you may consider if a re-spin is needed...

Reviewed-by: Nuno Sa <nuno.sa@analog.com>

>  drivers/iio/adc/ad7192.c | 92 ++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 92 insertions(+)
> 
> diff --git a/drivers/iio/adc/ad7192.c b/drivers/iio/adc/ad7192.c
> index 042319f0c641..3f803b1eefcc 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;
> @@ -406,6 +408,91 @@ 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 (!device_property_present(dev, "#clock-cells"))
> +		return 0;
> +
> +	if (!IS_ENABLED(CONFIG_COMMON_CLK))
> +		return 0;
> 

nit: This could be the first test to do. No point in calling
device_property_present() if CONFIG_COMMON_CLK is disabled. FWIW, the compiler should
be smart enough to sort things out but it would still be better (for readability) to
have this first.

- Nuno Sá