Re: [PATCH v6 2/2] iio: frequency: adf4350: add clk provider

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 21 Jun 2024 15:13:59 +0300
Antoniu Miclaus <antoniu.miclaus@analog.com> wrote:

> Add clk provider feature for the adf4350.
> 
> Even though the driver was sent as an IIO driver in most cases the
> device is actually seen as a clock provider.
> 
> This patch aims to cover actual usecases requested by users in order to
> completely control the output frequencies from userspace.
> 
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
You addressed both of Nuno's comments and I didn't have anything to add,
 so I'll pick this up (can still add a tag though if Nuno wants to give one).

Series applied to the togreg branch of iio.git and pushed out as testing
for 0-day to have fun.

Thanks,

Jonathan

> ---
> changes in v6:
>  - rework `init.name` handling.
>  - simplify iio channels initialization.
>  drivers/iio/frequency/adf4350.c | 124 +++++++++++++++++++++++++++++++-
>  1 file changed, 122 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/frequency/adf4350.c b/drivers/iio/frequency/adf4350.c
> index 4abf80f75ef5..e13e64a5164c 100644
> --- a/drivers/iio/frequency/adf4350.c
> +++ b/drivers/iio/frequency/adf4350.c
> @@ -19,6 +19,7 @@
>  #include <linux/gpio/consumer.h>
>  #include <asm/div64.h>
>  #include <linux/clk.h>
> +#include <linux/clk-provider.h>
>  
>  #include <linux/iio/iio.h>
>  #include <linux/iio/sysfs.h>
> @@ -36,6 +37,9 @@ struct adf4350_state {
>  	struct gpio_desc		*lock_detect_gpiod;
>  	struct adf4350_platform_data	*pdata;
>  	struct clk			*clk;
> +	struct clk			*clkout;
> +	const char			*clk_out_name;
> +	struct clk_hw			hw;
>  	unsigned long			clkin;
>  	unsigned long			chspc; /* Channel Spacing */
>  	unsigned long			fpfd; /* Phase Frequency Detector */
> @@ -61,6 +65,8 @@ struct adf4350_state {
>  	__be32				val __aligned(IIO_DMA_MINALIGN);
>  };
>  
> +#define to_adf4350_state(_hw) container_of(_hw, struct adf4350_state, hw)
> +
>  static struct adf4350_platform_data default_pdata = {
>  	.channel_spacing = 10000,
>  	.r2_user_settings = ADF4350_REG2_PD_POLARITY_POS |
> @@ -381,6 +387,113 @@ static const struct iio_info adf4350_info = {
>  	.debugfs_reg_access = &adf4350_reg_access,
>  };
>  
> +static void adf4350_clk_del_provider(void *data)
> +{
> +	struct adf4350_state *st = data;
> +
> +	of_clk_del_provider(st->spi->dev.of_node);
> +}
> +
> +static unsigned long adf4350_clk_recalc_rate(struct clk_hw *hw,
> +					     unsigned long parent_rate)
> +{
> +	struct adf4350_state *st = to_adf4350_state(hw);
> +	unsigned long long tmp;
> +
> +	tmp = (u64)(st->r0_int * st->r1_mod + st->r0_fract) * st->fpfd;
> +	do_div(tmp, st->r1_mod * (1 << st->r4_rf_div_sel));
> +
> +	return tmp;
> +}
> +
> +static int adf4350_clk_set_rate(struct clk_hw *hw,
> +				unsigned long rate,
> +				unsigned long parent_rate)
> +{
> +	struct adf4350_state *st = to_adf4350_state(hw);
> +
> +	if (parent_rate == 0 || parent_rate > ADF4350_MAX_FREQ_REFIN)
> +		return -EINVAL;
> +
> +	st->clkin = parent_rate;
> +
> +	return adf4350_set_freq(st, rate);
> +}
> +
> +static int adf4350_clk_prepare(struct clk_hw *hw)
> +{
> +	struct adf4350_state *st = to_adf4350_state(hw);
> +
> +	st->regs[ADF4350_REG2] &= ~ADF4350_REG2_POWER_DOWN_EN;
> +
> +	return adf4350_sync_config(st);
> +}
> +
> +static void adf4350_clk_unprepare(struct clk_hw *hw)
> +{
> +	struct adf4350_state *st = to_adf4350_state(hw);
> +
> +	st->regs[ADF4350_REG2] |= ADF4350_REG2_POWER_DOWN_EN;
> +
> +	adf4350_sync_config(st);
> +}
> +
> +static int adf4350_clk_is_enabled(struct clk_hw *hw)
> +{
> +	struct adf4350_state *st = to_adf4350_state(hw);
> +
> +	return (st->regs[ADF4350_REG2] & ADF4350_REG2_POWER_DOWN_EN);
> +}
> +
> +static const struct clk_ops adf4350_clk_ops = {
> +	.recalc_rate = adf4350_clk_recalc_rate,
> +	.set_rate = adf4350_clk_set_rate,
> +	.prepare = adf4350_clk_prepare,
> +	.unprepare = adf4350_clk_unprepare,
> +	.is_enabled = adf4350_clk_is_enabled,
> +};
> +
> +static int adf4350_clk_register(struct adf4350_state *st)
> +{
> +	struct spi_device *spi = st->spi;
> +	struct clk_init_data init;
> +	struct clk *clk;
> +	const char *parent_name;
> +	int ret;
> +
> +	if (!device_property_present(&spi->dev, "#clock-cells"))
> +		return 0;
> +
> +	if (device_property_read_string(&spi->dev, "clock-output-names", &init.name)) {
> +		init.name = devm_kasprintf(&spi->dev, GFP_KERNEL, "%s-clk",
> +					   fwnode_get_name(dev_fwnode(&spi->dev)));
> +		if (!init.name)
> +			return -ENOMEM;
> +	}
> +
> +	parent_name = of_clk_get_parent_name(spi->dev.of_node, 0);
> +	if (!parent_name)
> +		return -EINVAL;
> +
> +	init.ops = &adf4350_clk_ops;
> +	init.parent_names = &parent_name;
> +	init.num_parents = 1;
> +	init.flags = CLK_SET_RATE_PARENT;
> +
> +	st->hw.init = &init;
> +	clk = devm_clk_register(&spi->dev, &st->hw);
> +	if (IS_ERR(clk))
> +		return PTR_ERR(clk);
> +
> +	ret = of_clk_add_provider(spi->dev.of_node, of_clk_src_simple_get, clk);
> +	if (ret)
> +		return ret;
> +
> +	st->clkout = clk;
> +
> +	return devm_add_action_or_reset(&spi->dev, adf4350_clk_del_provider, st);
> +}
> +
>  static struct adf4350_platform_data *adf4350_parse_dt(struct device *dev)
>  {
>  	struct adf4350_platform_data *pdata;
> @@ -522,8 +635,6 @@ static int adf4350_probe(struct spi_device *spi)
>  
>  	indio_dev->info = &adf4350_info;
>  	indio_dev->modes = INDIO_DIRECT_MODE;
> -	indio_dev->channels = &adf4350_chan;
> -	indio_dev->num_channels = 1;
>  
>  	mutex_init(&st->lock);
>  
> @@ -551,6 +662,15 @@ static int adf4350_probe(struct spi_device *spi)
>  			return ret;
>  	}
>  
> +	ret = adf4350_clk_register(st);
> +	if (ret)
> +		return ret;
> +
> +	if (!st->clkout) {
> +		indio_dev->channels = &adf4350_chan;
> +		indio_dev->num_channels = 1;
> +	}
> +
>  	ret = devm_add_action_or_reset(&spi->dev, adf4350_power_down, indio_dev);
>  	if (ret)
>  		return dev_err_probe(&spi->dev, ret,