diff options
| author | Rabin Vincent <rabin.vincent@stericsson.com> | 2011-09-28 15:49:11 +0530 |
|---|---|---|
| committer | Linus Walleij <linus.walleij@linaro.org> | 2012-04-23 11:06:08 +0200 |
| commit | ebc6178dab43b38042f0e089526bad49081870e5 (patch) | |
| tree | 394a03b4d884ec7805424a7d12be0672b07ebe30 /drivers/gpio/gpio-nomadik.c | |
| parent | 6c42ad1cf4d7f22469eaecb2eee3b6442169d732 (diff) | |
| download | lwn-ebc6178dab43b38042f0e089526bad49081870e5.tar.gz lwn-ebc6178dab43b38042f0e089526bad49081870e5.zip | |
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: Rabin Vincent <rabin.vincent@stericsson.com>
Reviewed-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'drivers/gpio/gpio-nomadik.c')
| -rw-r--r-- | drivers/gpio/gpio-nomadik.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-nomadik.c b/drivers/gpio/gpio-nomadik.c index 681daee80291..7b45d88b4f44 100644 --- a/drivers/gpio/gpio-nomadik.c +++ b/drivers/gpio/gpio-nomadik.c @@ -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; |