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gpio/nomadik: support low EMI mode

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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: Rabin Vincent <rabin.vincent@stericsson.com>
Reviewed-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Rabin Vincent 2011-09-28 15:49:11 +05:30 committed by Linus Walleij
parent 6c42ad1cf4
commit ebc6178dab
3 changed files with 32 additions and 0 deletions
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1
arch/arm/plat-nomadik/include/plat/gpio-nomadik.h
View file

@ -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

6
arch/arm/plat-nomadik/include/plat/pincfg.h
View file

@ -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)

25
drivers/gpio/gpio-nomadik.c
View file

@ -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;