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Commit 5d9452e7 authored by Grygorii Strashko's avatar Grygorii Strashko Committed by Linus Walleij
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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: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: default avatarSantosh Shilimkar <ssantosh@kernel.org>
Tested-by: default avatarTony Lindgren <tony@atomide.com>
Signed-off-by: default avatarGrygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 235f1eb1

drivers/gpio/gpio-omap.c

+18 −9
Original line number Diff line number Diff line
@@ -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;

}