lkml.org 
[lkml]   [2012]   [Apr]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4/9] gpio/nomadik: support low EMI mode
Date
From: Rabin Vincent <rabin.vincent@stericsson.com>

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>
---
arch/arm/plat-nomadik/include/plat/gpio-nomadik.h | 1 +
arch/arm/plat-nomadik/include/plat/pincfg.h | 6 +++++
drivers/gpio/gpio-nomadik.c | 25 +++++++++++++++++++++
3 files changed, 32 insertions(+)

diff --git a/arch/arm/plat-nomadik/include/plat/gpio-nomadik.h b/arch/arm/plat-nomadik/include/plat/gpio-nomadik.h
index 9605bf2..3e8b7f1 100644
--- a/arch/arm/plat-nomadik/include/plat/gpio-nomadik.h
+++ b/arch/arm/plat-nomadik/include/plat/gpio-nomadik.h
@@ -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
diff --git a/arch/arm/plat-nomadik/include/plat/pincfg.h b/arch/arm/plat-nomadik/include/plat/pincfg.h
index 22cb97d..da6b1e3 100644
--- a/arch/arm/plat-nomadik/include/plat/pincfg.h
+++ b/arch/arm/plat-nomadik/include/plat/pincfg.h
@@ -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)
diff --git a/drivers/gpio/gpio-nomadik.c b/drivers/gpio/gpio-nomadik.c
index 681daee..7b45d88 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;
--
1.7.9.2


\
 
 \ /
  Last update: 2012-04-23 11:23    [W:0.024 / U:50.816 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site