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SubjectRe: [PATCH v2 05/16] iio: adc: sun4i-gpadc-iio: rework: support clocks and reset
On Mon, Jan 29, 2018 at 12:29:08AM +0100, Philipp Rossak 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@gmail.com>
> Signed-off-by: Icenowy Zheng <icenowy@aosc.io>

Same remark for the SoB

> ---
> drivers/iio/adc/sun4i-gpadc-iio.c | 71 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 71 insertions(+)
>
> diff --git a/drivers/iio/adc/sun4i-gpadc-iio.c b/drivers/iio/adc/sun4i-gpadc-iio.c
> index db57d9fffe48..51ec0104d678 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>
>
> @@ -68,6 +70,9 @@ struct gpadc_data {
> unsigned int temp_data;
> int (*sample_start)(struct sun4i_gpadc_iio *info);
> int (*sample_end)(struct sun4i_gpadc_iio *info);
> + bool has_bus_clk;
> + bool has_bus_rst;
> + bool has_mod_clk;

Is there SoCs where this insn't all true, or all false?

> };
>
> static const struct gpadc_data sun4i_gpadc_data = {
> @@ -127,6 +132,9 @@ 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;
> @@ -420,6 +428,10 @@ static int sun4i_gpadc_runtime_suspend(struct device *dev)
> {
> struct sun4i_gpadc_iio *info = iio_priv(dev_get_drvdata(dev));
>
> + clk_disable(info->mod_clk);
> +

Why clk_disable?

> + clk_disable(info->bus_clk);
> +

You can tie the bus_clk to the regmap directly, instead of having to
maintain it yourself here.

And you can probably put the device in reset and out of reset here as
well.

> return info->data->sample_end(info);
> }
>
> @@ -446,6 +458,10 @@ static int sun4i_gpadc_runtime_resume(struct device *dev)
> {
> struct sun4i_gpadc_iio *info = iio_priv(dev_get_drvdata(dev));
>
> + clk_enable(info->mod_clk);
> +
> + clk_enable(info->bus_clk);
> +
> return info->data->sample_start(info);
> }
>
> @@ -560,10 +576,59 @@ 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);

Your comment and the line below doesn't really make much sense :)

Maxime

--
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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