linux-kernel - Re: [PATCH v2 2/2] iio: frequency: adf4350: add clk provider

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Message-ID: <20240608161515.0d63a803@jic23-huawei>
Date: Sat, 8 Jun 2024 16:15:15 +0100
From: Jonathan Cameron <jic23@...nel.org>
To: Antoniu Miclaus <antoniu.miclaus@...log.com>
Cc: Lars-Peter Clausen <lars@...afoo.de>, Michael Hennerich
 <Michael.Hennerich@...log.com>, "Rob Herring" <robh@...nel.org>, Krzysztof
 Kozlowski <krzk+dt@...nel.org>, "Conor Dooley" <conor+dt@...nel.org>,
 <linux-iio@...r.kernel.org>, <devicetree@...r.kernel.org>,
 <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/2] iio: frequency: adf4350: add clk provider

On Fri, 7 Jun 2024 12:57:53 +0300
Antoniu Miclaus <antoniu.miclaus@...log.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@...log.com>
> ---
> changes in v2:
>  - rework commit title
>  drivers/iio/frequency/adf4350.c | 129 ++++++++++++++++++++++++++++++++
>  1 file changed, 129 insertions(+)
> 
> diff --git a/drivers/iio/frequency/adf4350.c b/drivers/iio/frequency/adf4350.c
> index 4abf80f75ef5..1eb8bce71fe1 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>
> @@ -31,11 +32,21 @@ enum {
>  	ADF4350_PWRDOWN,
>  };
>  
> +struct adf4350_output {
I can't see why this is needed.  Looks to me like you only ever
go from hw here to the state. Use container_of to do that.
> +	struct clk_hw hw;
> +	struct iio_dev *indio_dev;

I wouldn't expect this clk_hw path to need the generic iio structure.
I think you only did this to make the lookup of adf4350_state possible?
If so, as above, container_of() is your friend.

> +};
> +
> +#define to_output(_hw) container_of(_hw, struct adf4350_output, hw)
> +
>  struct adf4350_state {
>  	struct spi_device		*spi;
>  	struct gpio_desc		*lock_detect_gpiod;
>  	struct adf4350_platform_data	*pdata;
>  	struct clk			*clk;
> +	struct clk			*clkout;
> +	const char			*clk_out_name;
> +	struct adf4350_output		output;
>  	unsigned long			clkin;
>  	unsigned long			chspc; /* Channel Spacing */
>  	unsigned long			fpfd; /* Phase Frequency Detector */
> @@ -264,6 +275,10 @@ static ssize_t adf4350_write(struct iio_dev *indio_dev,
>  	mutex_lock(&st->lock);
>  	switch ((u32)private) {
>  	case ADF4350_FREQ:
> +		if (st->clkout) {
> +			ret = clk_set_rate(st->clkout, readin);
> +			break;
> +		}
>  		ret = adf4350_set_freq(st, readin);
>  		break;
>  	case ADF4350_FREQ_REFIN:
> @@ -381,6 +396,115 @@ 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 iio_dev *indio_dev = to_output(hw)->indio_dev;

You have the output in the state, so use container_of() to get to the
containing structure.

> +	struct adf4350_state *st = iio_priv(indio_dev);
> +	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;
> +}