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

Alexandru Ardelean
2024-06-25T05:48:38Z

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
>
>