Re: [PATCH 05/16] iio: adc: sun4i-gpadc-iio: rework: support clocks and reset

[Philipp Rossak]

On 28.01.2018 09:50, Jonathan Cameron wrote:
> On Fri, 26 Jan 2018 16:19:30 +0100
> Philipp Rossak <embed3d@xxxxxxxxx> wrote:
>
> > For adding newer sensor some basic rework of the code is necessary.
> >
> > The SoCs after H3 has newer thermal sensor ADCs, which have two clock
> > inputs (bus clock and sampling clock) and a reset. The registers are
> > also re-arranged.
> >
> > This commit reworks the code, adds the process of the clocks and
> > resets.
> >
> > Signed-off-by: Philipp Rossak <embed3d@xxxxxxxxx>
> > Signed-off-by: Icenowy Zheng <icenowy@xxxxxxx>
>
> Both clock and reset code is safe against null parameters, so you can
> drop a lot of 'is it here' checks in this.  They could be argued to
> act as documentation of the fact we really don't expect them in some cases
> I suppose...
Ok, this sounds good for me!
I will fix that in the next version of this patch series.

> > ---
> >   drivers/iio/adc/sun4i-gpadc-iio.c | 80 +++++++++++++++++++++++++++++++++++++++
> >   1 file changed, 80 insertions(+)
> >
> > diff --git a/drivers/iio/adc/sun4i-gpadc-iio.c b/drivers/iio/adc/sun4i-gpadc-iio.c
> > index 363936b37c5a..1a80744bd472 100644
> > --- a/drivers/iio/adc/sun4i-gpadc-iio.c
> > +++ b/drivers/iio/adc/sun4i-gpadc-iio.c
> > @@ -22,6 +22,7 @@
> >    * shutdown for not being used.
> >    */
> >   
> > +#include <linux/clk.h>
> >   #include <linux/completion.h>
> >   #include <linux/interrupt.h>
> >   #include <linux/io.h>
> > @@ -31,6 +32,7 @@
> >   #include <linux/platform_device.h>
> >   #include <linux/pm_runtime.h>
> >   #include <linux/regmap.h>
> > +#include <linux/reset.h>
> >   #include <linux/thermal.h>
> >   #include <linux/delay.h>
> >   
> > @@ -75,6 +77,9 @@ struct gpadc_data {
> >   	u32		ctrl2_map;
> >   	u32		sensor_en_map;
> >   	u32		filter_map;
> > +	bool		has_bus_clk;
> > +	bool		has_bus_rst;
> > +	bool		has_mod_clk;
> >   };
> >   
> >   static const struct gpadc_data sun4i_gpadc_data = {
> > @@ -134,6 +139,9 @@ struct sun4i_gpadc_iio {
> >   	atomic_t			ignore_temp_data_irq;
> >   	const struct gpadc_data		*data;
> >   	bool				no_irq;
> > +	struct clk			*bus_clk;
> > +	struct clk			*mod_clk;
> > +	struct reset_control		*reset;
> >   	/* prevents concurrent reads of temperature and ADC */
> >   	struct mutex			mutex;
> >   	struct thermal_zone_device	*tzd;
> > @@ -435,6 +443,12 @@ static int sun4i_gpadc_runtime_suspend(struct device *dev)
> >   {
> >   	struct sun4i_gpadc_iio *info = iio_priv(dev_get_drvdata(dev));
> >   
> > +	if (info->data->has_mod_clk)
> > +		clk_disable(info->mod_clk);
>
> Safe against null parameter... (see below)
>
> > +
> > +	if (info->data->has_bus_clk)
> > +		clk_disable(info->bus_clk);
> > +
> >   	return info->data->sample_end(info);
> >   }
> >   
> > @@ -483,6 +497,12 @@ static int sun4i_gpadc_runtime_resume(struct device *dev)
> >   {
> >   	struct sun4i_gpadc_iio *info = iio_priv(dev_get_drvdata(dev));
> >   
> > +	if (info->data->has_mod_clk)
> > +		clk_enable(info->mod_clk);
>
> clk_enable is safe against null parameter so could do without the checks.
>
> > +
> > +	if (info->data->has_bus_clk)
> > +		clk_enable(info->bus_clk);
> > +
> >   	return info->data->sample_start(info);
> >   }
> >   
> > @@ -597,10 +617,61 @@ static int sun4i_gpadc_probe_dt(struct platform_device *pdev,
> >   		return ret;
> >   	}
> >   
> > +	if (info->data->has_bus_rst) {
> > +		info->reset = devm_reset_control_get(&pdev->dev, NULL);
> > +		if (IS_ERR(info->reset)) {
> > +			ret = PTR_ERR(info->reset);
> > +			return ret;
> > +		}
> > +
> > +		ret = reset_control_deassert(info->reset);
> > +		if (ret)
> > +			return ret;
> > +	}
> > +
> > +	if (info->data->has_bus_clk) {
> > +		info->bus_clk = devm_clk_get(&pdev->dev, "bus");
> > +		if (IS_ERR(info->bus_clk)) {
> > +			ret = PTR_ERR(info->bus_clk);
> > +			goto assert_reset;
> > +		}
> > +
> > +		ret = clk_prepare_enable(info->bus_clk);
> > +		if (ret)
> > +			goto assert_reset;
> > +	}
> > +
> > +	if (info->data->has_mod_clk) {
> > +		info->mod_clk = devm_clk_get(&pdev->dev, "mod");
> > +		if (IS_ERR(info->mod_clk)) {
> > +			ret = PTR_ERR(info->mod_clk);
> > +			goto disable_bus_clk;
> > +		}
> > +
> > +		/* Running at 6MHz */
> > +		ret = clk_set_rate(info->mod_clk, 4000000);
> > +		if (ret)
> > +			goto disable_bus_clk;
> > +
> > +		ret = clk_prepare_enable(info->mod_clk);
> > +		if (ret)
> > +			goto disable_bus_clk;
> > +	}
> > +
> >   	if (IS_ENABLED(CONFIG_THERMAL_OF))
> >   		info->sensor_device = &pdev->dev;
> >   
> >   	return 0;
> > +
> > +disable_bus_clk:
> > +	if (info->data->has_bus_clk)
> > +		clk_disable_unprepare(info->bus_clk);
> > +
> > +assert_reset:
> > +	if (info->data->has_bus_rst)
> > +		reset_control_assert(info->reset);
> > +
> > +	return ret;
> >   }
> >   
> >   static int sun4i_gpadc_probe_mfd(struct platform_device *pdev,
> > @@ -766,6 +837,15 @@ static int sun4i_gpadc_remove(struct platform_device *pdev)
> >   	if (!info->no_irq)
> >   		iio_map_array_unregister(indio_dev);
> >   
> > +	if (info->data->has_mod_clk)
> > +		clk_disable_unprepare(info->mod_clk);
>
> clk_disable_unprepare is safe against a null parameter
> so I don't think the checks are needed.
>
> > +
> > +	if (info->data->has_bus_clk)
> > +		clk_disable_unprepare(info->bus_clk);
> > +
> > +	if (info->data->has_bus_rst)
> > +		reset_control_assert(info->reset);
>
> Safe against null parameter...
>
> > +
> >   	return 0;
> >   }
> >   
Thanks,
Philipp