Commit ebc6178d authored by Rabin Vincent's avatar Rabin Vincent Committed by Linus Walleij
Browse files

gpio/nomadik: support low EMI mode 



Low EMI (Electro-Magnetic Interference) mode means lower slew
rate on the signals. The Nomadik GPIO controller supports
this so create an interface to enable it.

Signed-off-by: default avatarRabin Vincent <rabin.vincent@stericsson.com>
Reviewed-by: default avatarSrinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 6c42ad1c

arch/arm/plat-nomadik/include/plat/gpio-nomadik.h

+1 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#define NMK_GPIO_SLPC	0x1c

#define NMK_GPIO_AFSLA	0x20

#define NMK_GPIO_AFSLB	0x24

#define NMK_GPIO_LOWEMI	0x28



#define NMK_GPIO_RIMSC	0x40

#define NMK_GPIO_FIMSC	0x44

arch/arm/plat-nomadik/include/plat/pincfg.h

+6 −0
Original line number Diff line number Diff line
@@ -105,6 +105,12 @@ typedef unsigned long pin_cfg_t; 
#define PIN_SLPM_VAL_LOW	((1 + 0) << PIN_SLPM_VAL_SHIFT)

#define PIN_SLPM_VAL_HIGH	((1 + 1) << PIN_SLPM_VAL_SHIFT)



#define PIN_LOWEMI_SHIFT	25

#define PIN_LOWEMI_MASK		(0x1 << PIN_LOWEMI_SHIFT)

#define PIN_LOWEMI(x)		(((x) & PIN_LOWEMI_MASK) >> PIN_LOWEMI_SHIFT)

#define PIN_LOWEMI_DISABLED	(0 << PIN_LOWEMI_SHIFT)

#define PIN_LOWEMI_ENABLED	(1 << PIN_LOWEMI_SHIFT)



/* Shortcuts.  Use these instead of separate DIR, PULL, and VAL.  */

#define PIN_INPUT_PULLDOWN	(PIN_DIR_INPUT | PIN_PULL_DOWN)

#define PIN_INPUT_PULLUP	(PIN_DIR_INPUT | PIN_PULL_UP)

drivers/gpio/gpio-nomadik.c

+25 −0
Original line number Diff line number Diff line
@@ -61,6 +61,7 @@ struct nmk_gpio_chip { 
	u32 rimsc;

	u32 fimsc;

	u32 pull_up;

	u32 lowemi;

};



static struct nmk_gpio_chip *
@@ -125,6 +126,24 @@ static void __nmk_gpio_set_pull(struct nmk_gpio_chip *nmk_chip, 
	}

}



static void __nmk_gpio_set_lowemi(struct nmk_gpio_chip *nmk_chip,

				  unsigned offset, bool lowemi)

{

	u32 bit = BIT(offset);

	bool enabled = nmk_chip->lowemi & bit;



	if (lowemi == enabled)

		return;



	if (lowemi)

		nmk_chip->lowemi |= bit;

	else

		nmk_chip->lowemi &= ~bit;



	writel_relaxed(nmk_chip->lowemi,

		       nmk_chip->addr + NMK_GPIO_LOWEMI);

}



static void __nmk_gpio_make_input(struct nmk_gpio_chip *nmk_chip,

				  unsigned offset)

{
@@ -269,6 +288,8 @@ static void __nmk_config_pin(struct nmk_gpio_chip *nmk_chip, unsigned offset, 
		__nmk_gpio_set_pull(nmk_chip, offset, pull);

	}



	__nmk_gpio_set_lowemi(nmk_chip, offset, PIN_LOWEMI(cfg));



	/*

	 * If the pin is switching to altfunc, and there was an interrupt

	 * installed on it which has been lazy disabled, actually mask the
@@ -1181,6 +1202,10 @@ static int __devinit nmk_gpio_probe(struct platform_device *dev) 
	chip->dev = &dev->dev;

	chip->owner = THIS_MODULE;



	clk_enable(nmk_chip->clk);

	nmk_chip->lowemi = readl_relaxed(nmk_chip->addr + NMK_GPIO_LOWEMI);

	clk_disable(nmk_chip->clk);



	ret = gpiochip_add(&nmk_chip->chip);

	if (ret)

		goto out_free;

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