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Date: Sun, 28 Jan 2018 12:34:14 +0100
From: Philipp Rossak <embed3d@...il.com>
To: Jonathan Cameron <jic23@...nel.org>
Cc: lee.jones@...aro.org, robh+dt@...nel.org, mark.rutland@....com,
maxime.ripard@...e-electrons.com, wens@...e.org,
linux@...linux.org.uk, knaack.h@....de, lars@...afoo.de,
pmeerw@...erw.net, davem@...emloft.net, hans.verkuil@...co.com,
mchehab@...nel.org, rask@...melder.dk, clabbe.montjoie@...il.com,
sean@...s.org, krzk@...nel.org, quentin.schulz@...e-electrons.com,
icenowy@...c.io, edu.molinas@...il.com, singhalsimran0@...il.com,
linux-iio@...r.kernel.org, devicetree@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
linux-sunxi@...glegroups.com
Subject: Re: [PATCH 05/16] iio: adc: sun4i-gpadc-iio: rework: support clocks
and reset
On 28.01.2018 09:50, Jonathan Cameron wrote:
> On Fri, 26 Jan 2018 16:19:30 +0100
> Philipp Rossak <embed3d@...il.com> 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@...il.com>
>> Signed-off-by: Icenowy Zheng <icenowy@...c.io>
>
> 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
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