From 3737de42afb8d76f405689a4699e8e5dd5e2ef96 Mon Sep 17 00:00:00 2001 From: Laxman Dewangan Date: Mon, 25 Apr 2016 16:08:34 +0530 Subject: [PATCH] gpio: tegra: Add support for gpio debounce NVIDIA's Tegra210 support the HW debounce in the GPIO controller for all its GPIO pins. Add support for setting debounce timing by implementing the set_debounce callback of gpiochip. Signed-off-by: Laxman Dewangan Reviewed-by: Stephen Warren Reviewed-by: Alexandre Courbot Signed-off-by: Linus Walleij --- drivers/gpio/gpio-tegra.c | 69 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 68 insertions(+), 1 deletion(-) diff --git a/drivers/gpio/gpio-tegra.c b/drivers/gpio/gpio-tegra.c index 653825db4baa..b3ddd922290d 100644 --- a/drivers/gpio/gpio-tegra.c +++ b/drivers/gpio/gpio-tegra.c @@ -46,10 +46,13 @@ #define GPIO_INT_ENB(t, x) (GPIO_REG(t, x) + 0x50) #define GPIO_INT_LVL(t, x) (GPIO_REG(t, x) + 0x60) #define GPIO_INT_CLR(t, x) (GPIO_REG(t, x) + 0x70) +#define GPIO_DBC_CNT(t, x) (GPIO_REG(t, x) + 0xF0) + #define GPIO_MSK_CNF(t, x) (GPIO_REG(t, x) + t->soc->upper_offset + 0x00) #define GPIO_MSK_OE(t, x) (GPIO_REG(t, x) + t->soc->upper_offset + 0x10) #define GPIO_MSK_OUT(t, x) (GPIO_REG(t, x) + t->soc->upper_offset + 0X20) +#define GPIO_MSK_DBC_EN(t, x) (GPIO_REG(t, x) + t->soc->upper_offset + 0x30) #define GPIO_MSK_INT_STA(t, x) (GPIO_REG(t, x) + t->soc->upper_offset + 0x40) #define GPIO_MSK_INT_ENB(t, x) (GPIO_REG(t, x) + t->soc->upper_offset + 0x50) #define GPIO_MSK_INT_LVL(t, x) (GPIO_REG(t, x) + t->soc->upper_offset + 0x60) @@ -67,6 +70,7 @@ struct tegra_gpio_bank { int bank; int irq; spinlock_t lvl_lock[4]; + spinlock_t dbc_lock[4]; /* Lock for updating debounce count register */ #ifdef CONFIG_PM_SLEEP u32 cnf[4]; u32 out[4]; @@ -74,11 +78,14 @@ struct tegra_gpio_bank { u32 int_enb[4]; u32 int_lvl[4]; u32 wake_enb[4]; + u32 dbc_enb[4]; #endif + u32 dbc_cnt[4]; struct tegra_gpio_info *tgi; }; struct tegra_gpio_soc_config { + bool debounce_supported; u32 bank_stride; u32 upper_offset; }; @@ -184,6 +191,39 @@ static int tegra_gpio_direction_output(struct gpio_chip *chip, unsigned offset, return 0; } +static int tegra_gpio_set_debounce(struct gpio_chip *chip, unsigned int offset, + unsigned int debounce) +{ + struct tegra_gpio_info *tgi = gpiochip_get_data(chip); + struct tegra_gpio_bank *bank = &tgi->bank_info[GPIO_BANK(offset)]; + unsigned int debounce_ms = DIV_ROUND_UP(debounce, 1000); + unsigned long flags; + int port; + + if (!debounce_ms) { + tegra_gpio_mask_write(tgi, GPIO_MSK_DBC_EN(tgi, offset), + offset, 0); + return 0; + } + + debounce_ms = min(debounce_ms, 255U); + port = GPIO_PORT(offset); + + /* There is only one debounce count register per port and hence + * set the maximum of current and requested debounce time. + */ + spin_lock_irqsave(&bank->dbc_lock[port], flags); + if (bank->dbc_cnt[port] < debounce_ms) { + tegra_gpio_writel(tgi, debounce_ms, GPIO_DBC_CNT(tgi, offset)); + bank->dbc_cnt[port] = debounce_ms; + } + spin_unlock_irqrestore(&bank->dbc_lock[port], flags); + + tegra_gpio_mask_write(tgi, GPIO_MSK_DBC_EN(tgi, offset), offset, 1); + + return 0; +} + static int tegra_gpio_to_irq(struct gpio_chip *chip, unsigned offset) { struct tegra_gpio_info *tgi = gpiochip_get_data(chip); @@ -350,6 +390,14 @@ static int tegra_gpio_resume(struct device *dev) unsigned int gpio = (b<<5) | (p<<3); tegra_gpio_writel(tgi, bank->cnf[p], GPIO_CNF(tgi, gpio)); + + if (tgi->soc->debounce_supported) { + tegra_gpio_writel(tgi, bank->dbc_cnt[p], + GPIO_DBC_CNT(tgi, gpio)); + tegra_gpio_writel(tgi, bank->dbc_enb[p], + GPIO_MSK_DBC_EN(tgi, gpio)); + } + tegra_gpio_writel(tgi, bank->out[p], GPIO_OUT(tgi, gpio)); tegra_gpio_writel(tgi, bank->oe[p], @@ -385,6 +433,13 @@ static int tegra_gpio_suspend(struct device *dev) GPIO_OUT(tgi, gpio)); bank->oe[p] = tegra_gpio_readl(tgi, GPIO_OE(tgi, gpio)); + if (tgi->soc->debounce_supported) { + bank->dbc_enb[p] = tegra_gpio_readl(tgi, + GPIO_MSK_DBC_EN(tgi, gpio)); + bank->dbc_enb[p] = (bank->dbc_enb[p] << 8) | + bank->dbc_enb[p]; + } + bank->int_enb[p] = tegra_gpio_readl(tgi, GPIO_INT_ENB(tgi, gpio)); bank->int_lvl[p] = tegra_gpio_readl(tgi, @@ -538,6 +593,9 @@ static int tegra_gpio_probe(struct platform_device *pdev) platform_set_drvdata(pdev, tgi); + if (config->debounce_supported) + tgi->gc.set_debounce = tegra_gpio_set_debounce; + tgi->bank_info = devm_kzalloc(&pdev->dev, tgi->bank_count * sizeof(*tgi->bank_info), GFP_KERNEL); if (!tgi->bank_info) @@ -597,8 +655,10 @@ static int tegra_gpio_probe(struct platform_device *pdev) irq_set_chained_handler_and_data(bank->irq, tegra_gpio_irq_handler, bank); - for (j = 0; j < 4; j++) + for (j = 0; j < 4; j++) { spin_lock_init(&bank->lvl_lock[j]); + spin_lock_init(&bank->dbc_lock[j]); + } } tegra_gpio_debuginit(tgi); @@ -616,7 +676,14 @@ static const struct tegra_gpio_soc_config tegra30_gpio_config = { .upper_offset = 0x80, }; +static const struct tegra_gpio_soc_config tegra210_gpio_config = { + .debounce_supported = true, + .bank_stride = 0x100, + .upper_offset = 0x80, +}; + static const struct of_device_id tegra_gpio_of_match[] = { + { .compatible = "nvidia,tegra210-gpio", .data = &tegra210_gpio_config }, { .compatible = "nvidia,tegra30-gpio", .data = &tegra30_gpio_config }, { .compatible = "nvidia,tegra20-gpio", .data = &tegra20_gpio_config }, { },