Hi Sricharan,
On 11/18/2016 02:28 PM, Sricharan R wrote:
> From: Rajendra Nayak <rnayak@xxxxxxxxxxxxxx>
>
> Some GDSCs might support a HW control mode, where in the power
> domain (gdsc) is brought in and out of low power state (while
> unsued) without any SW assistance, saving power.
> Such GDSCs can be configured in a HW control mode when powered on
> until they are explicitly requested to be powered off by software.
>
> Signed-off-by: Rajendra Nayak <rnayak@xxxxxxxxxxxxxx>
> Signed-off-by: Sricharan R <sricharan@xxxxxxxxxxxxxx>
> ---
> [V2] Fixed to take care of the return value of gdsc_hwctrl
>
> drivers/clk/qcom/gdsc.c | 19 +++++++++++++++++++
> drivers/clk/qcom/gdsc.h | 1 +
> 2 files changed, 20 insertions(+)
>
> diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
> index f12d7b2..57c7c1b 100644
> --- a/drivers/clk/qcom/gdsc.c
> +++ b/drivers/clk/qcom/gdsc.c
> @@ -55,6 +55,13 @@ static int gdsc_is_enabled(struct gdsc *sc, unsigned int reg)
> return !!(val & PWR_ON_MASK);
> }
>
> +static int gdsc_hwctrl(struct gdsc *sc, bool en)
> +{
> + u32 val = en ? HW_CONTROL_MASK : 0;
> +
> + return regmap_update_bits(sc->regmap, sc->gdscr, HW_CONTROL_MASK, val);
> +}
> +
> static int gdsc_toggle_logic(struct gdsc *sc, bool en)
> {
> int ret;
> @@ -164,16 +171,28 @@ static int gdsc_enable(struct generic_pm_domain *domain)
> */
> udelay(1);
>
> + /* Turn on HW trigger mode if supported */
> + if (sc->flags & HW_CTRL)
> + return gdsc_hwctrl(sc, true);
> +
> return 0;
> }
>
> static int gdsc_disable(struct generic_pm_domain *domain)
> {
> struct gdsc *sc = domain_to_gdsc(domain);
> + int ret;
>
> if (sc->pwrsts == PWRSTS_ON)
> return gdsc_assert_reset(sc);
>
> + /* Turn off HW trigger mode if supported */
> + if (sc->flags & HW_CTRL) {
> + ret = gdsc_hwctrl(sc, false);
Looking in the downstream implementation the disabling of the hw control
bit shouldn't be enough.
After disabling hw control bit we must have a 1us delay and polling for
enabled PWR_ON bit with timeout of 100us, only then we should continue
with disabling the GDSC in software controlled mode.
--
regards,
Stan
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