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Subject[PATCH v4 2/3] pinctrl: exynos: Fix GPIO setup failure because domain clock being gated
Date
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>
Tested-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
---
.../bindings/pinctrl/samsung-pinctrl.txt | 6 ++
drivers/pinctrl/samsung/pinctrl-samsung.c | 111 +++++++++++++++++++--
drivers/pinctrl/samsung/pinctrl-samsung.h | 2 +
3 files changed, 112 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..85e487fe43ec 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 +1146,23 @@ 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);
+
+ if (drvdata->clk)
+ clk_unprepare(drvdata->clk);

return 0;
}
@@ -1102,6 +1180,13 @@ 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 +1218,8 @@ static void samsung_pinctrl_suspend_dev(

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

/**
@@ -1148,6 +1235,13 @@ 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 +1275,8 @@ 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 +1360,7 @@ 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


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