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SubjectRe: [PATCH 1/4] clk: qcom: gdsc: Handle GDSC regulator supplies
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Hi Stephen,

I think the upstream design always wanted the client/consumer to enable
the GPU Rail and then turn ON the GDSC?

Why are we going ahead with adding the support of regulator in the GDSC
driver?

On 3/19/2020 11:08 AM, Bjorn Andersson wrote:
> Certain GDSCs, such as the GPU_GX on MSM8996, requires that the upstream
> regulator supply is powered in order to be turned on.
>
> It's not guaranteed that the bootloader will leave these supplies on and
> the driver core will attempt to enable any GDSCs before allowing the
> individual drivers to probe defer on the PMIC regulator driver not yet
> being present.
>
> So the gdsc driver needs to be made aware of supplying regulators and
> probe defer on their absence, and it needs to enable and disable the
> regulator accordingly.
>
> Voltage adjustments of the supplying regulator are deferred to the
> client drivers themselves.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
> drivers/clk/qcom/gdsc.c | 24 ++++++++++++++++++++++++
> drivers/clk/qcom/gdsc.h | 4 ++++
> 2 files changed, 28 insertions(+)
>
> diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
> index a250f59708d8..3528789cc9d0 100644
> --- a/drivers/clk/qcom/gdsc.c
> +++ b/drivers/clk/qcom/gdsc.c
> @@ -13,6 +13,7 @@
> #include <linux/regmap.h>
> #include <linux/reset-controller.h>
> #include <linux/slab.h>
> +#include <linux/regulator/consumer.h>
> #include "gdsc.h"
>
> #define PWR_ON_MASK BIT(31)
> @@ -112,6 +113,12 @@ static int gdsc_toggle_logic(struct gdsc *sc, enum gdsc_status status)
> int ret;
> u32 val = (status == GDSC_ON) ? 0 : SW_COLLAPSE_MASK;
>
> + if (status == GDSC_ON && sc->rsupply) {
> + ret = regulator_enable(sc->rsupply);
> + if (ret < 0)
> + return ret;
> + }
> +
> ret = regmap_update_bits(sc->regmap, sc->gdscr, SW_COLLAPSE_MASK, val);
> if (ret)
> return ret;
> @@ -143,6 +150,13 @@ static int gdsc_toggle_logic(struct gdsc *sc, enum gdsc_status status)
>
> ret = gdsc_poll_status(sc, status);
> WARN(ret, "%s status stuck at 'o%s'", sc->pd.name, status ? "ff" : "n");
> +
> + if (!ret && status == GDSC_OFF && sc->rsupply) {
> + ret = regulator_disable(sc->rsupply);
> + if (ret < 0)
> + return ret;
> + }
> +
> return ret;
> }
>
> @@ -371,6 +385,16 @@ int gdsc_register(struct gdsc_desc *desc,
> if (!data->domains)
> return -ENOMEM;
>
> + /* Resolve any regulator supplies */
> + for (i = 0; i < num; i++) {
> + if (!scs[i] || !scs[i]->supply)
> + continue;
> +
> + scs[i]->rsupply = devm_regulator_get(dev, scs[i]->supply);
> + if (IS_ERR(scs[i]->rsupply))
> + return PTR_ERR(scs[i]->rsupply);
> + }
> +
> data->num_domains = num;
> for (i = 0; i < num; i++) {
> if (!scs[i])
> diff --git a/drivers/clk/qcom/gdsc.h b/drivers/clk/qcom/gdsc.h
> index 64cdc8cf0d4d..c36fc26dcdff 100644
> --- a/drivers/clk/qcom/gdsc.h
> +++ b/drivers/clk/qcom/gdsc.h
> @@ -10,6 +10,7 @@
> #include <linux/pm_domain.h>
>
> struct regmap;
> +struct regulator;
> struct reset_controller_dev;
>
> /**
> @@ -52,6 +53,9 @@ struct gdsc {
> struct reset_controller_dev *rcdev;
> unsigned int *resets;
> unsigned int reset_count;
> +
> + const char *supply;
> + struct regulator *rsupply;
> };
>
> struct gdsc_desc {
>

--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation.

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