clk: qcom: add common gdsc_gx_do_nothing_enable for gpucc drivers

All gpucc drivers need this, so move it to common code instead of
duplicating it in every gpucc driver.

Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Tested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20200709135251.643-10-jonathan@marek.ca
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/qcom/gdsc.c

@@ -433,3 +433,28 @@ void gdsc_unregister(struct gdsc_desc *desc)
 	}
 	of_genpd_del_provider(dev->of_node);
 }
+
+/*
+ * On SDM845+ the GPU GX domain is *almost* entirely controlled by the GMU
+ * running in the CX domain so the CPU doesn't need to know anything about the
+ * GX domain EXCEPT....
+ *
+ * Hardware constraints dictate that the GX be powered down before the CX. If
+ * the GMU crashes it could leave the GX on. In order to successfully bring back
+ * the device the CPU needs to disable the GX headswitch. There being no sane
+ * way to reach in and touch that register from deep inside the GPU driver we
+ * need to set up the infrastructure to be able to ensure that the GPU can
+ * ensure that the GX is off during this super special case. We do this by
+ * defining a GX gdsc with a dummy enable function and a "default" disable
+ * function.
+ *
+ * This allows us to attach with genpd_dev_pm_attach_by_name() in the GPU
+ * driver. During power up, nothing will happen from the CPU (and the GMU will
+ * power up normally but during power down this will ensure that the GX domain
+ * is *really* off - this gives us a semi standard way of doing what we need.
+ */
+int gdsc_gx_do_nothing_enable(struct generic_pm_domain *domain)
+{
+	/* Do nothing but give genpd the impression that we were successful */
+	return 0;
+}

drivers/clk/qcom/gdsc.h

@@ -68,6 +68,7 @@ struct gdsc_desc {
 int gdsc_register(struct gdsc_desc *desc, struct reset_controller_dev *,
 		  struct regmap *);
 void gdsc_unregister(struct gdsc_desc *desc);
+int gdsc_gx_do_nothing_enable(struct generic_pm_domain *domain);
 #else
 static inline int gdsc_register(struct gdsc_desc *desc,
 				struct reset_controller_dev *rcdev,

drivers/clk/qcom/gpucc-sc7180.c

@@ -170,37 +170,12 @@ static struct gdsc cx_gdsc = {
 	.flags = VOTABLE,
 };
 
-/*
- * On SC7180 the GPU GX domain is *almost* entirely controlled by the GMU
- * running in the CX domain so the CPU doesn't need to know anything about the
- * GX domain EXCEPT....
- *
- * Hardware constraints dictate that the GX be powered down before the CX. If
- * the GMU crashes it could leave the GX on. In order to successfully bring back
- * the device the CPU needs to disable the GX headswitch. There being no sane
- * way to reach in and touch that register from deep inside the GPU driver we
- * need to set up the infrastructure to be able to ensure that the GPU can
- * ensure that the GX is off during this super special case. We do this by
- * defining a GX gdsc with a dummy enable function and a "default" disable
- * function.
- *
- * This allows us to attach with genpd_dev_pm_attach_by_name() in the GPU
- * driver. During power up, nothing will happen from the CPU (and the GMU will
- * power up normally but during power down this will ensure that the GX domain
- * is *really* off - this gives us a semi standard way of doing what we need.
- */
-static int gx_gdsc_enable(struct generic_pm_domain *domain)
-{
-	/* Do nothing but give genpd the impression that we were successful */
-	return 0;
-}
-
 static struct gdsc gx_gdsc = {
 	.gdscr = 0x100c,
 	.clamp_io_ctrl = 0x1508,
 	.pd = {
 		.name = "gx_gdsc",
-		.power_on = gx_gdsc_enable,
+		.power_on = gdsc_gx_do_nothing_enable,
 	},
 	.pwrsts = PWRSTS_OFF_ON,
 	.flags = CLAMP_IO,

drivers/clk/qcom/gpucc-sdm845.c

@@ -131,37 +131,12 @@ static struct gdsc gpu_cx_gdsc = {
 	.flags = VOTABLE,
 };
 
-/*
- * On SDM845 the GPU GX domain is *almost* entirely controlled by the GMU
- * running in the CX domain so the CPU doesn't need to know anything about the
- * GX domain EXCEPT....
- *
- * Hardware constraints dictate that the GX be powered down before the CX. If
- * the GMU crashes it could leave the GX on. In order to successfully bring back
- * the device the CPU needs to disable the GX headswitch. There being no sane
- * way to reach in and touch that register from deep inside the GPU driver we
- * need to set up the infrastructure to be able to ensure that the GPU can
- * ensure that the GX is off during this super special case. We do this by
- * defining a GX gdsc with a dummy enable function and a "default" disable
- * function.
- *
- * This allows us to attach with genpd_dev_pm_attach_by_name() in the GPU
- * driver. During power up, nothing will happen from the CPU (and the GMU will
- * power up normally but during power down this will ensure that the GX domain
- * is *really* off - this gives us a semi standard way of doing what we need.
- */
-static int gx_gdsc_enable(struct generic_pm_domain *domain)
-{
-	/* Do nothing but give genpd the impression that we were successful */
-	return 0;
-}
-
 static struct gdsc gpu_gx_gdsc = {
 	.gdscr = 0x100c,
 	.clamp_io_ctrl = 0x1508,
 	.pd = {
 		.name = "gpu_gx_gdsc",
-		.power_on = gx_gdsc_enable,
+		.power_on = gdsc_gx_do_nothing_enable,
 	},
 	.pwrsts = PWRSTS_OFF_ON,
 	.flags = CLAMP_IO | AON_RESET | POLL_CFG_GDSCR,