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SubjectRe: [PATCH v5 08/18] thermal: sun8i: support mod clocks
On Fri, Aug 9, 2019 at 10:31 PM Yangtao Li <tiny.windzz@gmail.com> wrote:
>
> H3 has extra clock, so introduce something in ths_thermal_chip/ths_device
> and adds the process of the clock.
>
> This is pre-work for supprt it.
>
> Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
> ---
> drivers/thermal/sun8i_thermal.c | 17 ++++++++++++++++-
> 1 file changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/thermal/sun8i_thermal.c b/drivers/thermal/sun8i_thermal.c
> index b934bc81eba7..6f4294c2aba7 100644
> --- a/drivers/thermal/sun8i_thermal.c
> +++ b/drivers/thermal/sun8i_thermal.c
> @@ -54,6 +54,7 @@ struct tsensor {
> };
>
> struct ths_thermal_chip {
> + bool has_mod_clk;
> int sensor_num;
> int offset;
> int scale;
> @@ -69,6 +70,7 @@ struct ths_device {
> struct regmap *regmap;
> struct reset_control *reset;
> struct clk *bus_clk;
> + struct clk *mod_clk;
> struct tsensor sensor[MAX_SENSOR_NUM];
> };
>
> @@ -274,6 +276,12 @@ static int sun8i_ths_resource_init(struct ths_device *tmdev)
> if (IS_ERR(tmdev->bus_clk))
> return PTR_ERR(tmdev->bus_clk);
>
> + if (tmdev->chip->has_mod_clk) {
> + tmdev->mod_clk = devm_clk_get(&pdev->dev, "mod");
> + if (IS_ERR(tmdev->mod_clk))
> + return PTR_ERR(tmdev->mod_clk);
> + }
> +
> ret = reset_control_deassert(tmdev->reset);
> if (ret)
> return ret;
> @@ -282,12 +290,18 @@ static int sun8i_ths_resource_init(struct ths_device *tmdev)
> if (ret)
> goto assert_reset;
>
> - ret = sun50i_ths_calibrate(tmdev);
> + ret = clk_prepare_enable(tmdev->mod_clk);

You have to set rate of modclk before enabling it since you can't rely
on whatever bootloader left for you.

Also I found that parameters you're using for PC_TEMP_PERIOD, ACQ0 and
ACQ1 are too aggressive and may result in high interrupt rate to the
point when it may stall RCU. I changed driver a bit to use params from
Philipp Rossak's work (modclk set to 4MHz, PC_TEMP_PERIOD is 7, ACQ0
is 255, ACQ1 is 63) and it fixed RCU stalls for me, see [1] for
details.

[1] https://github.com/anarsoul/linux-2.6/commit/46b8bb0fe2ccd1cd88fa9181a2ecbf79e8d513b2


> if (ret)
> goto bus_disable;
>
> + ret = sun50i_ths_calibrate(tmdev);
> + if (ret)
> + goto mod_disable;
> +
> return 0;
>
> +mod_disable:
> + clk_disable_unprepare(tmdev->mod_clk);
> bus_disable:
> clk_disable_unprepare(tmdev->bus_clk);
> assert_reset:
> @@ -395,6 +409,7 @@ static int sun8i_ths_remove(struct platform_device *pdev)
> {
> struct ths_device *tmdev = platform_get_drvdata(pdev);
>
> + clk_disable_unprepare(tmdev->mod_clk);
> clk_disable_unprepare(tmdev->bus_clk);
> reset_control_assert(tmdev->reset);
>
> --
> 2.17.1
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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