[PATCH 60/94] ARM: EXYNOS: Add support for clock handling in power domain

From: Sam Asadi
Date: Tue Jul 15 2014 - 13:09:28 EST

From: Prathyush K <prathyush.k@xxxxxxxxxxx>

While powering on/off a local powerdomain in exynos5 chipsets, the
input clocks to each device gets modified. This behaviour is based
on the SYSCLK_SYS_PWR_REG registers.
E.g. SYSCLK_MFC_SYS_PWR_REG = 0x0, the parent of input clock to MFC
(aclk333) gets modified to oscclk
= 0x1, no change in clocks.
The recommended value of SYSCLK_SYS_PWR_REG before power gating any
domain is 0x0. So we must also restore the clocks while powering on
a domain everytime.

This patch adds the framework for getting the required mux and parent
clocks through a power domain device node. With this patch, while
powering off a domain, parent is set to oscclk and while powering back
on, its re-set to the correct parent which is as per the recommended
pd on/off sequence.

Signed-off-by: Prathyush K <prathyush.k@xxxxxxxxxxx>
Signed-off-by: Andrew Bresticker <abrestic@xxxxxxxxxxxx>
Signed-off-by: Arun Kumar K <arun.kk@xxxxxxxxxxx>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@xxxxxxxxxxx>
Reviewed-by: Tomasz Figa <t.figa@xxxxxxxxxxx>
Signed-off-by: Kukjin Kim <kgene.kim@xxxxxxxxxxx>
Signed-off-by: sam-the-6 <asadi.samuel@xxxxxxxxx>
---
.../bindings/arm/exynos/power_domain.txt | 20 +++++++
arch/arm/mach-exynos/pm_domains.c | 61 +++++++++++++++++++-
2 files changed, 80 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt
index 5216b41..8b4f7b7f 100644
--- a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt
+++ b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt
@@ -9,6 +9,18 @@ Required Properties:
- reg: physical base address of the controller and length of memory mapped
region.

+Optional Properties:
+- clocks: List of clock handles. The parent clocks of the input clocks to the
+ devices in this power domain are set to oscclk before power gating
+ and restored back after powering on a domain. This is required for
+ all domains which are powered on and off and not required for unused
+ 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.
+
Node of a device using power domains must have a samsung,power-domain property
defined with a phandle to respective power domain.

@@ -19,6 +31,14 @@ Example:
reg = <0x10023C00 0x10>;
};

+ 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";
+ };
+
Example of the node using power domain:

node {
diff --git a/arch/arm/mach-exynos/pm_domains.c b/arch/arm/mach-exynos/pm_domains.c
index fe6570e..797cb13 100644
--- a/arch/arm/mach-exynos/pm_domains.c
+++ b/arch/arm/mach-exynos/pm_domains.c
@@ -17,6 +17,7 @@
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/pm_domain.h>
+#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
@@ -24,6 +25,8 @@

#include "regs-pmu.h"

+#define MAX_CLK_PER_DOMAIN 4
+
/*
* Exynos specific wrapper around the generic power domain
*/
@@ -32,6 +35,9 @@ struct exynos_pm_domain {
char const *name;
bool is_off;
struct generic_pm_domain pd;
+ struct clk *oscclk;
+ struct clk *clk[MAX_CLK_PER_DOMAIN];
+ struct clk *pclk[MAX_CLK_PER_DOMAIN];
};

static int exynos_pd_power(struct generic_pm_domain *domain, bool power_on)
@@ -44,6 +50,19 @@ static int exynos_pd_power(struct generic_pm_domain *domain, bool power_on)
pd = container_of(domain, struct exynos_pm_domain, pd);
base = pd->base;

+ /* Set oscclk before powering off a domain*/
+ if (!power_on) {
+ int i;
+
+ for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
+ if (IS_ERR(pd->clk[i]))
+ break;
+ if (clk_set_parent(pd->clk[i], pd->oscclk))
+ pr_err("%s: error setting oscclk as parent to clock %d\n",
+ pd->name, i);
+ }
+ }
+
pwr = power_on ? S5P_INT_LOCAL_PWR_EN : 0;
__raw_writel(pwr, base);

@@ -60,6 +79,20 @@ static int exynos_pd_power(struct generic_pm_domain *domain, bool power_on)
cpu_relax();
usleep_range(80, 100);
}
+
+ /* Restore clocks after powering on a domain*/
+ if (power_on) {
+ int i;
+
+ for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
+ if (IS_ERR(pd->clk[i]))
+ break;
+ if (clk_set_parent(pd->clk[i], pd->pclk[i]))
+ pr_err("%s: error setting parent to clock%d\n",
+ pd->name, i);
+ }
+ }
+
return 0;
}

@@ -152,9 +185,11 @@ static __init int exynos4_pm_init_power_domain(void)

for_each_compatible_node(np, NULL, "samsung,exynos4210-pd") {
struct exynos_pm_domain *pd;
- int on;
+ int on, i;
+ struct device *dev;

pdev = of_find_device_by_node(np);
+ dev = &pdev->dev;

pd = kzalloc(sizeof(*pd), GFP_KERNEL);
if (!pd) {
@@ -170,6 +205,30 @@ static __init int exynos4_pm_init_power_domain(void)
pd->pd.power_on = exynos_pd_power_on;
pd->pd.of_node = np;

+ pd->oscclk = clk_get(dev, "oscclk");
+ if (IS_ERR(pd->oscclk))
+ goto no_clk;
+
+ for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
+ char clk_name[8];
+
+ snprintf(clk_name, sizeof(clk_name), "clk%d", i);
+ 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;
+ }
+ }
+
+ if (IS_ERR(pd->clk[0]))
+ clk_put(pd->oscclk);
+
+no_clk:
platform_set_drvdata(pdev, pd);

on = __raw_readl(pd->base + 0x4) & S5P_INT_LOCAL_PWR_EN;
--
1.7.10.4

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