[PATCH v2 3/5] pinctrl: exynos: Fix GPIO setup failure because domain clock being gated

Krzysztof Kozlowski
2014-11-26T14:24:52Z

The audio subsystem on Exynos 5420 has separate clocks and GPIO. To
operate properly on GPIOs the main block clock 'mau_epll' must be
enabled.

This was observed on Peach Pi/Pit and Arndale Octa (after enabling i2s0)
after introducing runtime PM to pl330 DMA driver. After that commit the
'mau_epll' was gated, because the "amba" clock was disabled and there
were no more users of mau_epll.

The system hang just before probing i2s0 because
samsung_pinmux_setup() tried to access memory from audss block which was
gated.

Add a clock property to the pinctrl driver and enable the clock during
GPIO setup. During normal GPIO operations (set, get, set_direction) the
clock is not enabled.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
---
.../bindings/pinctrl/samsung-pinctrl.txt | 6 ++
drivers/pinctrl/samsung/pinctrl-samsung.c | 110 +++++++++++++++++++--
drivers/pinctrl/samsung/pinctrl-samsung.h | 2 +
3 files changed, 111 insertions(+), 7 deletions(-)

diff --git a/Documentation/devicetree/bindings/pinctrl/samsung-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/samsung-pinctrl.txt
index 8425838a6dff..eb121daabe9d 100644
--- a/Documentation/devicetree/bindings/pinctrl/samsung-pinctrl.txt
+++ b/Documentation/devicetree/bindings/pinctrl/samsung-pinctrl.txt
@@ -93,6 +93,12 @@ Required Properties:
pin configuration should use the bindings listed in the "pinctrl-bindings.txt"
file.

+Optional Properties:
+- clocks: Optional clock needed to access the block. Will be enabled/disabled
+ during GPIO configuration, suspend and resume but not during GPIO operations
+ (like set, get, set direction).
+- clock-names: Must be "block".
+
External GPIO and Wakeup Interrupts:

The controller supports two types of external interrupts over gpio. The first
diff --git a/drivers/pinctrl/samsung/pinctrl-samsung.c b/drivers/pinctrl/samsung/pinctrl-samsung.c
index ec580af35856..96419aba7650 100644
--- a/drivers/pinctrl/samsung/pinctrl-samsung.c
+++ b/drivers/pinctrl/samsung/pinctrl-samsung.c
@@ -24,6 +24,7 @@
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/slab.h>
+#include <linux/clk.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/irqdomain.h>
@@ -55,6 +56,32 @@ static LIST_HEAD(drvdata_list);

static unsigned int pin_base;

+static int pctl_clk_enable(struct pinctrl_dev *pctldev)
+{
+ struct samsung_pinctrl_drv_data *drvdata;
+ int ret;
+
+ drvdata = pinctrl_dev_get_drvdata(pctldev);
+ if (!drvdata->clk)
+ return 0;
+
+ ret = clk_enable(drvdata->clk);
+ if (ret)
+ dev_err(pctldev->dev, "failed to enable clock: %d\n", ret);
+
+ return ret;
+}
+
+static void pctl_clk_disable(struct pinctrl_dev *pctldev)
+{
+ struct samsung_pinctrl_drv_data *drvdata;
+
+ drvdata = pinctrl_dev_get_drvdata(pctldev);
+
+ /* clk/core.c does the check if clk != NULL */
+ clk_disable(drvdata->clk);
+}
+
static inline struct samsung_pin_bank *gc_to_pin_bank(struct gpio_chip *gc)
{
return container_of(gc, struct samsung_pin_bank, gpio_chip);
@@ -374,7 +401,9 @@ static void samsung_pinmux_setup(struct pinctrl_dev *pctldev, unsigned selector,
const struct samsung_pmx_func *func;
const struct samsung_pin_group *grp;

+ pctl_clk_enable(pctldev);
drvdata = pinctrl_dev_get_drvdata(pctldev);
+
func = &drvdata->pmx_functions[selector];
grp = &drvdata->pin_groups[group];

@@ -398,6 +427,8 @@ static void samsung_pinmux_setup(struct pinctrl_dev *pctldev, unsigned selector,
writel(data, reg + type->reg_offset[PINCFG_TYPE_FUNC]);

spin_unlock_irqrestore(&bank->slock, flags);
+
+ pctl_clk_disable(pctldev);
}

/* enable a specified pinmux by writing to registers */
@@ -469,20 +500,37 @@ static int samsung_pinconf_set(struct pinctrl_dev *pctldev, unsigned int pin,
{
int i, ret;

+ ret = pctl_clk_enable(pctldev);
+ if (ret)
+ goto out;
+
for (i = 0; i < num_configs; i++) {
ret = samsung_pinconf_rw(pctldev, pin, &configs[i], true);
if (ret < 0)
- return ret;
+ goto out;
} /* for each config */

- return 0;
+out:
+ pctl_clk_disable(pctldev);
+
+ return ret;
}

/* get the pin config settings for a specified pin */
static int samsung_pinconf_get(struct pinctrl_dev *pctldev, unsigned int pin,
unsigned long *config)
{
- return samsung_pinconf_rw(pctldev, pin, config, false);
+ int ret;
+
+ ret = pctl_clk_enable(pctldev);
+ if (ret)
+ return ret;
+
+ ret = samsung_pinconf_rw(pctldev, pin, config, false);
+
+ pctl_clk_disable(pctldev);
+
+ return ret;
}

/* set the pin config settings for a specified pin group */
@@ -1057,10 +1105,23 @@ static int samsung_pinctrl_probe(struct platform_device *pdev)
}
drvdata->dev = dev;

+ drvdata->clk = clk_get(&pdev->dev, "block");
+ if (!IS_ERR(drvdata->clk)) {
+ ret = clk_prepare_enable(drvdata->clk);
+ if (ret) {
+ dev_err(dev, "failed to enable clk: %d\n", ret);
+ return ret;
+ }
+ } else {
+ drvdata->clk = NULL;
+ }
+
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
drvdata->virt_base = devm_ioremap_resource(&pdev->dev, res);
- if (IS_ERR(drvdata->virt_base))
- return PTR_ERR(drvdata->virt_base);
+ if (IS_ERR(drvdata->virt_base)) {
+ ret = PTR_ERR(drvdata->virt_base);
+ goto err;
+ }

res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
if (res)
@@ -1068,12 +1129,12 @@ static int samsung_pinctrl_probe(struct platform_device *pdev)

ret = samsung_gpiolib_register(pdev, drvdata);
if (ret)
- return ret;
+ goto err;

ret = samsung_pinctrl_register(pdev, drvdata);
if (ret) {
samsung_gpiolib_unregister(pdev, drvdata);
- return ret;
+ goto err;
}

if (ctrl->eint_gpio_init)
@@ -1085,6 +1146,22 @@ static int samsung_pinctrl_probe(struct platform_device *pdev)

/* Add to the global list */
list_add_tail(&drvdata->node, &drvdata_list);
+ clk_disable(drvdata->clk); /* Leave prepared */
+
+ return 0;
+
+err:
+ if (drvdata->clk)
+ clk_disable_unprepare(drvdata->clk);
+
+ return ret;
+}
+
+static int samsung_pinctrl_remove(struct platform_device *pdev)
+{
+ struct samsung_pinctrl_drv_data *drvdata = platform_get_drvdata(pdev);
+
+ clk_disable_unprepare(drvdata->clk);

return 0;
}
@@ -1102,6 +1179,13 @@ static void samsung_pinctrl_suspend_dev(
void __iomem *virt_base = drvdata->virt_base;
int i;

+ if (drvdata->clk) {
+ if (clk_enable(drvdata->clk)) {
+ dev_err(drvdata->dev, "failed to enable clock\n");
+ return;
+ }
+ }
+
for (i = 0; i < drvdata->nr_banks; i++) {
struct samsung_pin_bank *bank = &drvdata->pin_banks[i];
void __iomem *reg = virt_base + bank->pctl_offset;
@@ -1133,6 +1217,8 @@ static void samsung_pinctrl_suspend_dev(

if (drvdata->suspend)
drvdata->suspend(drvdata);
+
+ clk_disable(drvdata->clk);
}

/**
@@ -1148,6 +1234,13 @@ static void samsung_pinctrl_resume_dev(struct samsung_pinctrl_drv_data *drvdata)
void __iomem *virt_base = drvdata->virt_base;
int i;

+ if (drvdata->clk) {
+ if (clk_enable(drvdata->clk)) {
+ dev_err(drvdata->dev, "failed to enable clock\n");
+ return;
+ }
+ }
+
if (drvdata->resume)
drvdata->resume(drvdata);

@@ -1181,6 +1274,8 @@ static void samsung_pinctrl_resume_dev(struct samsung_pinctrl_drv_data *drvdata)
if (widths[type])
writel(bank->pm_save[type], reg + offs[type]);
}
+
+ clk_disable(drvdata->clk);
}

/**
@@ -1264,6 +1359,7 @@ MODULE_DEVICE_TABLE(of, samsung_pinctrl_dt_match);

static struct platform_driver samsung_pinctrl_driver = {
.probe = samsung_pinctrl_probe,
+ .remove = samsung_pinctrl_remove,
.driver = {
.name = "samsung-pinctrl",
.of_match_table = samsung_pinctrl_dt_match,
diff --git a/drivers/pinctrl/samsung/pinctrl-samsung.h b/drivers/pinctrl/samsung/pinctrl-samsung.h
index 1b8c0139d604..666cb23eb9f2 100644
--- a/drivers/pinctrl/samsung/pinctrl-samsung.h
+++ b/drivers/pinctrl/samsung/pinctrl-samsung.h
@@ -201,6 +201,7 @@ struct samsung_pin_ctrl {
* struct samsung_pinctrl_drv_data: wrapper for holding driver data together.
* @node: global list node
* @virt_base: register base address of the controller.
+ * @clk: Optional clock to enable/disable during setup. May be NULL.
* @dev: device instance representing the controller.
* @irq: interrpt number used by the controller to notify gpio interrupts.
* @ctrl: pin controller instance managed by the driver.
@@ -218,6 +219,7 @@ struct samsung_pinctrl_drv_data {
void __iomem *virt_base;
struct device *dev;
int irq;
+ struct clk *clk;

struct pinctrl_desc pctl;
struct pinctrl_dev *pctl_dev;
--
1.9.1