clk: qcom: gdsc: enable optional power domain support

On sm8250 dispcc and videocc registers are powered up by the MMCX power
domain. Currently we use a regulator to enable this domain on demand,
however this has some consequences, as genpd code is not reentrant.

Make gdsc code also use pm_runtime calls to ensure that registers are
accessible during the gdsc_enable/gdsc_disable operations.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210829154757.784699-6-dmitry.baryshkov@linaro.org
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
index 4ece326..7e1dd8c 100644 (file)
--- a/drivers/clk/qcom/gdsc.c
+++ b/drivers/clk/qcom/gdsc.c
@@ -11,6 +11,7 @@
 #include <linux/kernel.h>
 #include <linux/ktime.h>
 #include <linux/pm_domain.h>
+#include <linux/pm_runtime.h>
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
 #include <linux/reset-controller.h>
@@ -50,6 +51,22 @@ enum gdsc_status {
        GDSC_ON
 };
 
+static int gdsc_pm_runtime_get(struct gdsc *sc)
+{
+       if (!sc->dev)
+               return 0;
+
+       return pm_runtime_resume_and_get(sc->dev);
+}
+
+static int gdsc_pm_runtime_put(struct gdsc *sc)
+{
+       if (!sc->dev)
+               return 0;
+
+       return pm_runtime_put_sync(sc->dev);
+}
+
 /* Returns 1 if GDSC status is status, 0 if not, and < 0 on error */
 static int gdsc_check_status(struct gdsc *sc, enum gdsc_status status)
 {
@@ -232,9 +249,8 @@ static void gdsc_retain_ff_on(struct gdsc *sc)
        regmap_update_bits(sc->regmap, sc->gdscr, mask, mask);
 }
 
-static int gdsc_enable(struct generic_pm_domain *domain)
+static int _gdsc_enable(struct gdsc *sc)
 {
-       struct gdsc *sc = domain_to_gdsc(domain);
        int ret;
 
        if (sc->pwrsts == PWRSTS_ON)
@@ -290,11 +306,22 @@ static int gdsc_enable(struct generic_pm_domain *domain)
        return 0;
 }
 
-static int gdsc_disable(struct generic_pm_domain *domain)
+static int gdsc_enable(struct generic_pm_domain *domain)
 {
        struct gdsc *sc = domain_to_gdsc(domain);
        int ret;
 
+       ret = gdsc_pm_runtime_get(sc);
+       if (ret)
+               return ret;
+
+       return _gdsc_enable(sc);
+}
+
+static int _gdsc_disable(struct gdsc *sc)
+{
+       int ret;
+
        if (sc->pwrsts == PWRSTS_ON)
                return gdsc_assert_reset(sc);
 
@@ -329,6 +356,18 @@ static int gdsc_disable(struct generic_pm_domain *domain)
        return 0;
 }
 
+static int gdsc_disable(struct generic_pm_domain *domain)
+{
+       struct gdsc *sc = domain_to_gdsc(domain);
+       int ret;
+
+       ret = _gdsc_disable(sc);
+
+       gdsc_pm_runtime_put(sc);
+
+       return ret;
+}
+
 static int gdsc_init(struct gdsc *sc)
 {
        u32 mask, val;
@@ -443,6 +482,8 @@ int gdsc_register(struct gdsc_desc *desc,
        for (i = 0; i < num; i++) {
                if (!scs[i])
                        continue;
+               if (pm_runtime_enabled(dev))
+                       scs[i]->dev = dev;
                scs[i]->regmap = regmap;
                scs[i]->rcdev = rcdev;
                ret = gdsc_init(scs[i]);
@@ -457,6 +498,8 @@ int gdsc_register(struct gdsc_desc *desc,
                        continue;
                if (scs[i]->parent)
                        pm_genpd_add_subdomain(scs[i]->parent, &scs[i]->pd);
+               else if (!IS_ERR_OR_NULL(dev->pm_domain))
+                       pm_genpd_add_subdomain(pd_to_genpd(dev->pm_domain), &scs[i]->pd);
        }
 
        return of_genpd_add_provider_onecell(dev->of_node, data);
@@ -475,6 +518,8 @@ void gdsc_unregister(struct gdsc_desc *desc)
                        continue;
                if (scs[i]->parent)
                        pm_genpd_remove_subdomain(scs[i]->parent, &scs[i]->pd);
+               else if (!IS_ERR_OR_NULL(dev->pm_domain))
+                       pm_genpd_remove_subdomain(pd_to_genpd(dev->pm_domain), &scs[i]->pd);
        }
        of_genpd_del_provider(dev->of_node);
 }

diff --git a/drivers/clk/qcom/gdsc.h b/drivers/clk/qcom/gdsc.h
index 5bb396b..d7cc4c2 100644 (file)
--- a/drivers/clk/qcom/gdsc.h
+++ b/drivers/clk/qcom/gdsc.h
@@ -25,6 +25,7 @@ struct reset_controller_dev;
  * @resets: ids of resets associated with this gdsc
  * @reset_count: number of @resets
  * @rcdev: reset controller
+ * @dev: the device holding the GDSC, used for pm_runtime calls
  */
 struct gdsc {
        struct generic_pm_domain        pd;
@@ -58,6 +59,7 @@ struct gdsc {
 
        const char                      *supply;
        struct regulator                *rsupply;
+       struct device                   *dev;
 };
 
 struct gdsc_desc {