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Date: Tue, 18 Aug 2015 14:10:56 +0300
From: Grygorii Strashko <grygorii.strashko@...com>
To: Linus Walleij <linus.walleij@...aro.org>,
Alexandre Courbot <gnurou@...il.com>, <ssantosh@...nel.org>,
Kevin Hilman <khilman@...prootsystems.com>, <tony@...mide.com>
CC: Javier Martinez Canillas <javier@...hile0.org>,
<linux-omap@...r.kernel.org>, <linux-gpio@...r.kernel.org>,
<linux-kernel@...r.kernel.org>,
Grygorii Strashko <grygorii.strashko@...com>
Subject: [PATCH 5/7] gpio: omap: fix clk_prepare/unprepare usage
As per CCF documentation (clk.txt) the clk_prepare/unprepare APIs
are not allowed in atomic context. But now OMAP GPIO driver
uses them while applying debounce settings and as part
of PM runtime irqsafe operations:
- omap_gpio_debounce() is holding the lock with IRQs off.
+ omap2_set_gpio_debounce()
+ clk_prepare_enable()
+ clk_prepare() this one might sleep.
- pm_runtime_get_sync() is holding the lock with IRQs off
+ omap_gpio_runtime_suspend()
+ raw_spin_lock_irqsave()
+ omap_gpio_dbck_disable()
+ clk_disable_unprepare()
Hence, fix it by moeving dbclk prepare/unprepare in OMAP GPIO
omap_gpio_probe/omap_gpio_remove. Also, while here, ensure that
debounce functionality is disabled if clk_get() failed,
because otherwise kernel will carsh in omap2_set_gpio_debounce().
Reported-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Signed-off-by: Grygorii Strashko <grygorii.strashko@...com>
---
drivers/gpio/gpio-omap.c | 27 ++++++++++++++++++---------
1 file changed, 18 insertions(+), 9 deletions(-)
diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
index 1f02acd..2ae0d47 100644
--- a/drivers/gpio/gpio-omap.c
+++ b/drivers/gpio/gpio-omap.c
@@ -176,7 +176,7 @@ static inline void omap_gpio_rmw(void __iomem *base, u32 reg, u32 mask, bool set
static inline void omap_gpio_dbck_enable(struct gpio_bank *bank)
{
if (bank->dbck_enable_mask && !bank->dbck_enabled) {
- clk_prepare_enable(bank->dbck);
+ clk_enable(bank->dbck);
bank->dbck_enabled = true;
writel_relaxed(bank->dbck_enable_mask,
@@ -194,7 +194,7 @@ static inline void omap_gpio_dbck_disable(struct gpio_bank *bank)
*/
writel_relaxed(0, bank->base + bank->regs->debounce_en);
- clk_disable_unprepare(bank->dbck);
+ clk_disable(bank->dbck);
bank->dbck_enabled = false;
}
}
@@ -227,7 +227,7 @@ static void omap2_set_gpio_debounce(struct gpio_bank *bank, unsigned offset,
l = BIT(offset);
- clk_prepare_enable(bank->dbck);
+ clk_enable(bank->dbck);
reg = bank->base + bank->regs->debounce;
writel_relaxed(debounce, reg);
@@ -241,7 +241,7 @@ static void omap2_set_gpio_debounce(struct gpio_bank *bank, unsigned offset,
bank->dbck_enable_mask = val;
writel_relaxed(val, reg);
- clk_disable_unprepare(bank->dbck);
+ clk_disable(bank->dbck);
/*
* Enable debounce clock per module.
* This call is mandatory because in omap_gpio_request() when
@@ -286,7 +286,7 @@ static void omap_clear_gpio_debounce(struct gpio_bank *bank, unsigned offset)
bank->context.debounce = 0;
writel_relaxed(bank->context.debounce, bank->base +
bank->regs->debounce);
- clk_disable_unprepare(bank->dbck);
+ clk_disable(bank->dbck);
bank->dbck_enabled = false;
}
}
@@ -1070,10 +1070,6 @@ static void omap_gpio_mod_init(struct gpio_bank *bank)
/* Initialize interface clk ungated, module enabled */
if (bank->regs->ctrl)
writel_relaxed(0, base + bank->regs->ctrl);
-
- bank->dbck = clk_get(bank->dev, "dbclk");
- if (IS_ERR(bank->dbck))
- dev_err(bank->dev, "Could not get gpio dbck\n");
}
static int omap_gpio_chip_init(struct gpio_bank *bank, struct irq_chip *irqc)
@@ -1234,6 +1230,17 @@ static int omap_gpio_probe(struct platform_device *pdev)
return PTR_ERR(bank->base);
}
+ if (bank->dbck_flag) {
+ bank->dbck = devm_clk_get(bank->dev, "dbclk");
+ if (IS_ERR(bank->dbck)) {
+ dev_err(bank->dev,
+ "Could not get gpio dbck. Disable debounce\n");
+ bank->dbck_flag = false;
+ } else {
+ clk_prepare(bank->dbck);
+ }
+ }
+
platform_set_drvdata(pdev, bank);
pm_runtime_enable(bank->dev);
@@ -1265,6 +1272,8 @@ static int omap_gpio_remove(struct platform_device *pdev)
list_del(&bank->node);
gpiochip_remove(&bank->chip);
pm_runtime_disable(bank->dev);
+ if (bank->dbck_flag)
+ clk_unprepare(bank->dbck);
return 0;
}
--
2.5.0
--
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