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Commit f6a8249f authored by Tomasz Figa's avatar Tomasz Figa Committed by Linus Walleij
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pinctrl: exynos: Lock GPIOs as interrupts when used as EINTs 



Currently after configuring a GPIO pin as an interrupt related pinmux
registers are changed, but there is no protection from calling
gpio_direction_*() in a badly written driver, which would cause the same
pinmux register to be reconfigured for regular input/output and this
disabling interrupt capability of the pin.

This patch addresses this issue by moving pinmux reconfiguration to
.irq_{request,release}_resources() callback of irq_chip and calling
gpio_lock_as_irq() helper to prevent reconfiguration of pin direction.

Setting up a GPIO interrupt on Samsung SoCs is a two-step operation -
in addition to trigger configuration in a dedicated register, the pinmux
must be also reconfigured to GPIO interrupt, which is a different function
than normal GPIO input, although I/O-wise they both behave in the same way
and gpio_get_value() can be used on a pin configured as IRQ as well.

Such design implies subtleties such as gpio_direction_input() not having
to fail if a pin is already configured as an interrupt nor change the
configuration to normal input. But the FLAG_USED_AS_IRQ set in gpiolib by
gpio_lock_as_irq() is only used to check that gpio_direction_output() is
not called, it's not used to prevent gpio_direction_input() to be called.
So this is not a complete solution for Samsung SoCs but it's definitely a
move in the right direction.

Signed-off-by: default avatarTomasz Figa <t.figa@samsung.com>
[javier: use request resources instead of startup and expand commit message]
Signed-off-by: default avatarJavier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 4b6fe45a

drivers/pinctrl/samsung/pinctrl-exynos.c

+63 −6
Original line number Diff line number Diff line
@@ -127,14 +127,10 @@ static int exynos_irq_set_type(struct irq_data *irqd, unsigned int type) 
	struct irq_chip *chip = irq_data_get_irq_chip(irqd);

	struct exynos_irq_chip *our_chip = to_exynos_irq_chip(chip);

	struct samsung_pin_bank *bank = irq_data_get_irq_chip_data(irqd);

	struct samsung_pin_bank_type *bank_type = bank->type;

	struct samsung_pinctrl_drv_data *d = bank->drvdata;

	unsigned int pin = irqd->hwirq;

	unsigned int shift = EXYNOS_EINT_CON_LEN * pin;

	unsigned int shift = EXYNOS_EINT_CON_LEN * irqd->hwirq;

	unsigned int con, trig_type;

	unsigned long reg_con = our_chip->eint_con + bank->eint_offset;

	unsigned long flags;

	unsigned int mask;



	switch (type) {

	case IRQ_TYPE_EDGE_RISING:
@@ -167,8 +163,32 @@ static int exynos_irq_set_type(struct irq_data *irqd, unsigned int type) 
	con |= trig_type << shift;

	writel(con, d->virt_base + reg_con);



	return 0;

}



static int exynos_irq_request_resources(struct irq_data *irqd)

{

	struct irq_chip *chip = irq_data_get_irq_chip(irqd);

	struct exynos_irq_chip *our_chip = to_exynos_irq_chip(chip);

	struct samsung_pin_bank *bank = irq_data_get_irq_chip_data(irqd);

	struct samsung_pin_bank_type *bank_type = bank->type;

	struct samsung_pinctrl_drv_data *d = bank->drvdata;

	unsigned int shift = EXYNOS_EINT_CON_LEN * irqd->hwirq;

	unsigned long reg_con = our_chip->eint_con + bank->eint_offset;

	unsigned long flags;

	unsigned int mask;

	unsigned int con;

	int ret;



	ret = gpio_lock_as_irq(&bank->gpio_chip, irqd->hwirq);

	if (ret) {

		dev_err(bank->gpio_chip.dev, "unable to lock pin %s-%lu IRQ\n",

			bank->name, irqd->hwirq);

		return ret;

	}



	reg_con = bank->pctl_offset + bank_type->reg_offset[PINCFG_TYPE_FUNC];

	shift = pin * bank_type->fld_width[PINCFG_TYPE_FUNC];

	shift = irqd->hwirq * bank_type->fld_width[PINCFG_TYPE_FUNC];

	mask = (1 << bank_type->fld_width[PINCFG_TYPE_FUNC]) - 1;



	spin_lock_irqsave(&bank->slock, flags);
@@ -180,9 +200,42 @@ static int exynos_irq_set_type(struct irq_data *irqd, unsigned int type) 


	spin_unlock_irqrestore(&bank->slock, flags);



	exynos_irq_unmask(irqd);



	return 0;

}



static void exynos_irq_release_resources(struct irq_data *irqd)

{

	struct irq_chip *chip = irq_data_get_irq_chip(irqd);

	struct exynos_irq_chip *our_chip = to_exynos_irq_chip(chip);

	struct samsung_pin_bank *bank = irq_data_get_irq_chip_data(irqd);

	struct samsung_pin_bank_type *bank_type = bank->type;

	struct samsung_pinctrl_drv_data *d = bank->drvdata;

	unsigned int shift = EXYNOS_EINT_CON_LEN * irqd->hwirq;

	unsigned long reg_con = our_chip->eint_con + bank->eint_offset;

	unsigned long flags;

	unsigned int mask;

	unsigned int con;



	reg_con = bank->pctl_offset + bank_type->reg_offset[PINCFG_TYPE_FUNC];

	shift = irqd->hwirq * bank_type->fld_width[PINCFG_TYPE_FUNC];

	mask = (1 << bank_type->fld_width[PINCFG_TYPE_FUNC]) - 1;



	exynos_irq_mask(irqd);



	spin_lock_irqsave(&bank->slock, flags);



	con = readl(d->virt_base + reg_con);

	con &= ~(mask << shift);

	con |= FUNC_INPUT << shift;

	writel(con, d->virt_base + reg_con);



	spin_unlock_irqrestore(&bank->slock, flags);



	gpio_unlock_as_irq(&bank->gpio_chip, irqd->hwirq);

}



/*

 * irq_chip for gpio interrupts.

 */
@@ -193,6 +246,8 @@ static struct exynos_irq_chip exynos_gpio_irq_chip = { 
		.irq_mask = exynos_irq_mask,

		.irq_ack = exynos_irq_ack,

		.irq_set_type = exynos_irq_set_type,

		.irq_request_resources = exynos_irq_request_resources,

		.irq_release_resources = exynos_irq_release_resources,

	},

	.eint_con = EXYNOS_GPIO_ECON_OFFSET,

	.eint_mask = EXYNOS_GPIO_EMASK_OFFSET,
@@ -336,6 +391,8 @@ static struct exynos_irq_chip exynos_wkup_irq_chip = { 
		.irq_ack = exynos_irq_ack,

		.irq_set_type = exynos_irq_set_type,

		.irq_set_wake = exynos_wkup_irq_set_wake,

		.irq_request_resources = exynos_irq_request_resources,

		.irq_release_resources = exynos_irq_release_resources,

	},

	.eint_con = EXYNOS_WKUP_ECON_OFFSET,

	.eint_mask = EXYNOS_WKUP_EMASK_OFFSET,

drivers/pinctrl/samsung/pinctrl-samsung.h

+1 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#include <linux/gpio.h>



/* pinmux function number for pin as gpio output line */

#define FUNC_INPUT	0x0

#define FUNC_OUTPUT	0x1



/**