[PATCH v2 1/2] ARM: EXYNOS: Get current parent clock for power domain on/off

[PATCH v2 1/2] ARM: EXYNOS: Get current parent clock for power domain on/off

[Krzysztof Kozlowski]

Using a fixed (by DTS) parent for clocks when turning on the power domain
may introduce issues in other drivers. For example when such driver
changes the parent during runtime and expects that he is the only place
of such change.

Do not rely on DTS providing the fixed parent for such clocks. Instead
before switching domain off, grab a current parent of a clock with
clk_get_parent().

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>

---

Changes since v1:
1. Drop "pclk" bindings entirely as suggested by Andrzej Hajda.
   This was significant change so I did not add Javier's
   reviewed/tested tags.
---
 Documentation/devicetree/bindings/arm/exynos/power_domain.txt | 7 ++++---
 arch/arm/mach-exynos/pm_domains.c                             | 9 ++-------
 2 files changed, 6 insertions(+), 10 deletions(-)

diff --git a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt
index 5da38c5ed476..e151057d92f0 100644
--- a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt
+++ b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt
@@ -19,9 +19,10 @@ Optional Properties:
 	domains.
 - clock-names: The following clocks can be specified:
 	- oscclk: Oscillator clock.
-	- pclkN, clkN: Pairs of parent of input clock and input clock to the
-		devices in this power domain. Maximum of 4 pairs (N = 0 to 3)
-		are supported currently.
+	- clkN: Input clocks to the devices in this power domain. These clocks
+		will be reparented to oscclk before swithing power domain off.
+		Their original parent will be brought back after turning on
+		the domain. Maximum of 4 clocks (N = 0 to 3) are supported.
 	- asbN: Clocks required by asynchronous bridges (ASB) present in
 		the power domain. These clock should be enabled during power
 		domain on/off operations.
diff --git a/arch/arm/mach-exynos/pm_domains.c b/arch/arm/mach-exynos/pm_domains.c
index cbe56b35aea0..056e0a09f381 100644
--- a/arch/arm/mach-exynos/pm_domains.c
+++ b/arch/arm/mach-exynos/pm_domains.c
@@ -62,6 +62,7 @@ static int exynos_pd_power(struct generic_pm_domain *domain, bool power_on)
 		for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
 			if (IS_ERR(pd->clk[i]))
 				break;
+			pd->pclk[i] = clk_get_parent(pd->clk[i]);
 			if (clk_set_parent(pd->clk[i], pd->oscclk))
 				pr_err("%s: error setting oscclk as parent to clock %d\n",
 						pd->name, i);
@@ -161,13 +162,7 @@ static __init int exynos4_pm_init_power_domain(void)
 			pd->clk[i] = clk_get(dev, clk_name);
 			if (IS_ERR(pd->clk[i]))
 				break;
-			snprintf(clk_name, sizeof(clk_name), "pclk%d", i);
-			pd->pclk[i] = clk_get(dev, clk_name);
-			if (IS_ERR(pd->pclk[i])) {
-				clk_put(pd->clk[i]);
-				pd->clk[i] = ERR_PTR(-EINVAL);
-				break;
-			}
+			pd->pclk[i] = clk_get_parent(pd->clk[i]);
 		}
 
 		if (IS_ERR(pd->clk[0]))
-- 
1.9.1

[PATCH v2 2/2] ARM: dts: Use last parent for clocks during power domain on/off

[Krzysztof Kozlowski]

Replace fixed parent with last parent (obtained with clk_get_parent())
of clocks for devices in mfc and disp power domains. This should improve
behavior if such clocks were reparented by the drivers and new parents
are different than those specified in DTS.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>

---

Changes since v1:
1. Add Javier's reviewed/tested tags. Thanks!
---
 arch/arm/boot/dts/exynos5420.dtsi | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/arch/arm/boot/dts/exynos5420.dtsi b/arch/arm/boot/dts/exynos5420.dtsi
index c7a44ee0ce06..b9b99305991b 100644
--- a/arch/arm/boot/dts/exynos5420.dtsi
+++ b/arch/arm/boot/dts/exynos5420.dtsi
@@ -264,9 +264,8 @@
 	mfc_pd: power-domain@10044060 {
 		compatible = "samsung,exynos4210-pd";
 		reg = <0x10044060 0x20>;
-		clocks = <&clock CLK_FIN_PLL>, <&clock CLK_MOUT_SW_ACLK333>,
-			<&clock CLK_MOUT_USER_ACLK333>;
-		clock-names = "oscclk", "pclk0", "clk0";
+		clocks = <&clock CLK_FIN_PLL>, <&clock CLK_MOUT_USER_ACLK333>;
+		clock-names = "oscclk", "clk0";
 		#power-domain-cells = <0>;
 	};
 
@@ -280,16 +279,12 @@
 		compatible = "samsung,exynos4210-pd";
 		reg = <0x100440C0 0x20>;
 		#power-domain-cells = <0>;
-		clocks = <&clock CLK_FIN_PLL>, <&clock CLK_MOUT_SW_ACLK200>,
+		clocks = <&clock CLK_FIN_PLL>,
 			 <&clock CLK_MOUT_USER_ACLK200_DISP1>,
-			 <&clock CLK_MOUT_SW_ACLK300>,
 			 <&clock CLK_MOUT_USER_ACLK300_DISP1>,
-			 <&clock CLK_MOUT_SW_ACLK400>,
 			 <&clock CLK_MOUT_USER_ACLK400_DISP1>,
 			 <&clock CLK_FIMD1>, <&clock CLK_MIXER>;
-		clock-names = "oscclk", "pclk0", "clk0",
-			      "pclk1", "clk1", "pclk2", "clk2",
-			      "asb0", "asb1";
+		clock-names = "oscclk", "clk0", "clk1", "clk2", "asb0", "asb1";
 	};
 
 	pinctrl_0: pinctrl@13400000 {
-- 
1.9.1

Re: [PATCH v2 1/2] ARM: EXYNOS: Get current parent clock for power domain on/off

[Javier Martinez Canillas]

Hello Krzysztof,

On 04/03/2015 11:33 AM, Krzysztof Kozlowski wrote:
> Using a fixed (by DTS) parent for clocks when turning on the power domain
> may introduce issues in other drivers. For example when such driver
> changes the parent during runtime and expects that he is the only place
> of such change.
> 
> Do not rely on DTS providing the fixed parent for such clocks. Instead
> before switching domain off, grab a current parent of a clock with
> clk_get_parent().
> 
> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
> 
> ---
> 
> Changes since v1:
> 1. Drop "pclk" bindings entirely as suggested by Andrzej Hajda.
>    This was significant change so I did not add Javier's
>    reviewed/tested tags.

Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>

on an Exynos5420 Peach Pit Chromebook:

Tested-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>

Best regards,
Javier