ARM: EXYNOS: Get current parent clock for power domain on/off

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>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Kukjin Kim <kgene@kernel.org>

diff --git a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt
index 5da38c5ed476ee2248432314c0bf886305f6cc13..e151057d92f0804fd577a471d937df688e61f6c9 100644 (file)
--- 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 440324c94d28dece60300c6cace75831c4185ca9..1639645bddeb516625a39373b1279e57ee047f40 100644 (file)
--- 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);
@@ -90,6 +91,9 @@ 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;
+
+                       if (IS_ERR(pd->clk[i]))
+                               continue; /* Skip on first power up */
                        if (clk_set_parent(pd->clk[i], pd->pclk[i]))
                                pr_err("%s: error setting parent to clock%d\n",
                                                pd->name, i);
@@ -182,13 +186,11 @@ 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;
-                       }
+                       /*
+                        * Skip setting parent on first power up.
+                        * The parent at this time may not be useful at all.
+                        */
+                       pd->pclk[i] = ERR_PTR(-EINVAL);
                }
 
                if (IS_ERR(pd->clk[0]))