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>
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@ -29,6 +29,7 @@
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#define NMK_GPIO_SLPC 0x1c
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#define NMK_GPIO_AFSLA 0x20
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#define NMK_GPIO_AFSLB 0x24
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#define NMK_GPIO_LOWEMI 0x28
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#define NMK_GPIO_RIMSC 0x40
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#define NMK_GPIO_FIMSC 0x44
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@ -105,6 +105,12 @@ typedef unsigned long pin_cfg_t;
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#define PIN_SLPM_VAL_LOW ((1 + 0) << PIN_SLPM_VAL_SHIFT)
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#define PIN_SLPM_VAL_HIGH ((1 + 1) << PIN_SLPM_VAL_SHIFT)
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#define PIN_LOWEMI_SHIFT 25
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#define PIN_LOWEMI_MASK (0x1 << PIN_LOWEMI_SHIFT)
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#define PIN_LOWEMI(x) (((x) & PIN_LOWEMI_MASK) >> PIN_LOWEMI_SHIFT)
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#define PIN_LOWEMI_DISABLED (0 << PIN_LOWEMI_SHIFT)
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#define PIN_LOWEMI_ENABLED (1 << PIN_LOWEMI_SHIFT)
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/* Shortcuts. Use these instead of separate DIR, PULL, and VAL. */
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#define PIN_INPUT_PULLDOWN (PIN_DIR_INPUT | PIN_PULL_DOWN)
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#define PIN_INPUT_PULLUP (PIN_DIR_INPUT | PIN_PULL_UP)
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@ -61,6 +61,7 @@ struct nmk_gpio_chip {
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u32 rimsc;
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u32 fimsc;
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u32 pull_up;
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u32 lowemi;
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};
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static struct nmk_gpio_chip *
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@ -125,6 +126,24 @@ static void __nmk_gpio_set_pull(struct nmk_gpio_chip *nmk_chip,
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}
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}
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static void __nmk_gpio_set_lowemi(struct nmk_gpio_chip *nmk_chip,
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unsigned offset, bool lowemi)
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{
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u32 bit = BIT(offset);
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bool enabled = nmk_chip->lowemi & bit;
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if (lowemi == enabled)
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return;
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if (lowemi)
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nmk_chip->lowemi |= bit;
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else
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nmk_chip->lowemi &= ~bit;
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writel_relaxed(nmk_chip->lowemi,
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nmk_chip->addr + NMK_GPIO_LOWEMI);
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}
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static void __nmk_gpio_make_input(struct nmk_gpio_chip *nmk_chip,
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unsigned offset)
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{
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@ -269,6 +288,8 @@ static void __nmk_config_pin(struct nmk_gpio_chip *nmk_chip, unsigned offset,
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__nmk_gpio_set_pull(nmk_chip, offset, pull);
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}
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__nmk_gpio_set_lowemi(nmk_chip, offset, PIN_LOWEMI(cfg));
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/*
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* If the pin is switching to altfunc, and there was an interrupt
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* installed on it which has been lazy disabled, actually mask the
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@ -1181,6 +1202,10 @@ static int __devinit nmk_gpio_probe(struct platform_device *dev)
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chip->dev = &dev->dev;
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chip->owner = THIS_MODULE;
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clk_enable(nmk_chip->clk);
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nmk_chip->lowemi = readl_relaxed(nmk_chip->addr + NMK_GPIO_LOWEMI);
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clk_disable(nmk_chip->clk);
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ret = gpiochip_add(&nmk_chip->chip);
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if (ret)
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goto out_free;
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