Re: [PATCH v2 2/2] staging: iio: frequency: ad9833: Load clock using clock framework

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 1 Feb 2019 17:01:38 +0200
Beniamin Bia <biabeniamin@outlook.com> wrote:

> From: Beniamin Bia <biabeniamin@gmail.com>
> 
> The clock frequency is loaded from device-tree using clock framework
> instead of statically value. The change allow configuration of
> the device via device-trees and better initialization sequence.
> This is part of broader effort to add device-tree support to this driver
> and take it out from staging.
> 
> Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>
Applied to the togreg branch of iio.git and pushed out as testing
for the autobuilders to play with it.

Thanks,

Jonathan

> ---
> Changes in v2:
>         -the intermidiate clk variable was replaced by the variable in
> 	 device state
>         -st variable may be uninitialized warning was fixed by adding a new
> 	 error label
>  drivers/staging/iio/frequency/ad9834.c | 35 ++++++++++++++++++--------
>  1 file changed, 24 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/staging/iio/frequency/ad9834.c b/drivers/staging/iio/frequency/ad9834.c
> index f4f5eaa15e30..f036f75d1f22 100644
> --- a/drivers/staging/iio/frequency/ad9834.c
> +++ b/drivers/staging/iio/frequency/ad9834.c
> @@ -6,6 +6,7 @@
>   * Licensed under the GPL-2.
>   */
>  
> +#include <linux/clk.h>
>  #include <linux/interrupt.h>
>  #include <linux/workqueue.h>
>  #include <linux/device.h>
> @@ -71,7 +72,7 @@
>  struct ad9834_state {
>  	struct spi_device		*spi;
>  	struct regulator		*reg;
> -	unsigned int			mclk;
> +	struct clk			*mclk;
>  	unsigned short			control;
>  	unsigned short			devid;
>  	struct spi_transfer		xfer;
> @@ -110,12 +111,15 @@ static unsigned int ad9834_calc_freqreg(unsigned long mclk, unsigned long fout)
>  static int ad9834_write_frequency(struct ad9834_state *st,
>  				  unsigned long addr, unsigned long fout)
>  {
> +	unsigned long clk_freq;
>  	unsigned long regval;
>  
> -	if (fout > (st->mclk / 2))
> +	clk_freq = clk_get_rate(st->mclk);
> +
> +	if (fout > (clk_freq / 2))
>  		return -EINVAL;
>  
> -	regval = ad9834_calc_freqreg(st->mclk, fout);
> +	regval = ad9834_calc_freqreg(clk_freq, fout);
>  
>  	st->freq_data[0] = cpu_to_be16(addr | (regval &
>  				       RES_MASK(AD9834_FREQ_BITS / 2)));
> @@ -415,7 +419,14 @@ static int ad9834_probe(struct spi_device *spi)
>  	spi_set_drvdata(spi, indio_dev);
>  	st = iio_priv(indio_dev);
>  	mutex_init(&st->lock);
> -	st->mclk = 25000000;
> +	st->mclk = devm_clk_get(&spi->dev, NULL);
> +
> +	ret = clk_prepare_enable(st->mclk);
> +	if (ret) {
> +		dev_err(&spi->dev, "Failed to enable master clock\n");
> +		goto error_disable_reg;
> +	}
> +
>  	st->spi = spi;
>  	st->devid = spi_get_device_id(spi)->driver_data;
>  	st->reg = reg;
> @@ -460,31 +471,32 @@ static int ad9834_probe(struct spi_device *spi)
>  	ret = spi_sync(st->spi, &st->msg);
>  	if (ret) {
>  		dev_err(&spi->dev, "device init failed\n");
> -		goto error_disable_reg;
> +		goto error_clock_unprepare;
>  	}
>  
>  	ret = ad9834_write_frequency(st, AD9834_REG_FREQ0, 1000000);
>  	if (ret)
> -		goto error_disable_reg;
> +		goto error_clock_unprepare;
>  
>  	ret = ad9834_write_frequency(st, AD9834_REG_FREQ1, 5000000);
>  	if (ret)
> -		goto error_disable_reg;
> +		goto error_clock_unprepare;
>  
>  	ret = ad9834_write_phase(st, AD9834_REG_PHASE0, 512);
>  	if (ret)
> -		goto error_disable_reg;
> +		goto error_clock_unprepare;
>  
>  	ret = ad9834_write_phase(st, AD9834_REG_PHASE1, 1024);
>  	if (ret)
> -		goto error_disable_reg;
> +		goto error_clock_unprepare;
>  
>  	ret = iio_device_register(indio_dev);
>  	if (ret)
> -		goto error_disable_reg;
> +		goto error_clock_unprepare;
>  
>  	return 0;
> -
> +error_clock_unprepare:
> +	clk_disable_unprepare(st->mclk);
>  error_disable_reg:
>  	regulator_disable(reg);
>  
> @@ -497,6 +509,7 @@ static int ad9834_remove(struct spi_device *spi)
>  	struct ad9834_state *st = iio_priv(indio_dev);
>  
>  	iio_device_unregister(indio_dev);
> +	clk_disable_unprepare(st->mclk);
>  	regulator_disable(st->reg);
>  
>  	return 0;