diff options
Diffstat (limited to 'drivers/gpio/gpio-ftgpio010.c')
| -rw-r--r-- | drivers/gpio/gpio-ftgpio010.c | 115 |
1 files changed, 111 insertions, 4 deletions
diff --git a/drivers/gpio/gpio-ftgpio010.c b/drivers/gpio/gpio-ftgpio010.c index 868bf8501560..95f578804b0e 100644 --- a/drivers/gpio/gpio-ftgpio010.c +++ b/drivers/gpio/gpio-ftgpio010.c @@ -15,6 +15,7 @@ #include <linux/interrupt.h> #include <linux/platform_device.h> #include <linux/bitops.h> +#include <linux/clk.h> /* GPIO registers definition */ #define GPIO_DATA_OUT 0x00 @@ -40,11 +41,14 @@ * struct ftgpio_gpio - Gemini GPIO state container * @dev: containing device for this instance * @gc: gpiochip for this instance + * @base: remapped I/O-memory base + * @clk: silicon clock */ struct ftgpio_gpio { struct device *dev; struct gpio_chip gc; void __iomem *base; + struct clk *clk; }; static void ftgpio_gpio_ack_irq(struct irq_data *d) @@ -157,6 +161,73 @@ static void ftgpio_gpio_irq_handler(struct irq_desc *desc) chained_irq_exit(irqchip, desc); } +static int ftgpio_gpio_set_config(struct gpio_chip *gc, unsigned int offset, + unsigned long config) +{ + enum pin_config_param param = pinconf_to_config_param(config); + u32 arg = pinconf_to_config_argument(config); + struct ftgpio_gpio *g = gpiochip_get_data(gc); + unsigned long pclk_freq; + u32 deb_div; + u32 val; + + if (param != PIN_CONFIG_INPUT_DEBOUNCE) + return -ENOTSUPP; + + /* + * Debounce only works if interrupts are enabled. The manual + * states that if PCLK is 66 MHz, and this is set to 0x7D0, then + * PCLK is divided down to 33 kHz for the debounce timer. 0x7D0 is + * 2000 decimal, so what they mean is simply that the PCLK is + * divided by this value. + * + * As we get a debounce setting in microseconds, we calculate the + * desired period time and see if we can get a suitable debounce + * time. + */ + pclk_freq = clk_get_rate(g->clk); + deb_div = DIV_ROUND_CLOSEST(pclk_freq, arg); + + /* This register is only 24 bits wide */ + if (deb_div > (1 << 24)) + return -ENOTSUPP; + + dev_dbg(g->dev, "prescale divisor: %08x, resulting frequency %lu Hz\n", + deb_div, (pclk_freq/deb_div)); + + val = readl(g->base + GPIO_DEBOUNCE_PRESCALE); + if (val == deb_div) { + /* + * The debounce timer happens to already be set to the + * desireable value, what a coincidence! We can just enable + * debounce on this GPIO line and return. This happens more + * often than you think, for example when all GPIO keys + * on a system are requesting the same debounce interval. + */ + val = readl(g->base + GPIO_DEBOUNCE_EN); + val |= BIT(offset); + writel(val, g->base + GPIO_DEBOUNCE_EN); + return 0; + } + + val = readl(g->base + GPIO_DEBOUNCE_EN); + if (val) { + /* + * Oh no! Someone is already using the debounce with + * another setting than what we need. Bummer. + */ + return -ENOTSUPP; + } + + /* First come, first serve */ + writel(deb_div, g->base + GPIO_DEBOUNCE_PRESCALE); + /* Enable debounce */ + val |= BIT(offset); + writel(val, g->base + GPIO_DEBOUNCE_EN); + + return 0; +} + static int ftgpio_gpio_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; @@ -180,6 +251,19 @@ static int ftgpio_gpio_probe(struct platform_device *pdev) if (irq <= 0) return irq ? irq : -EINVAL; + g->clk = devm_clk_get(dev, NULL); + if (!IS_ERR(g->clk)) { + ret = clk_prepare_enable(g->clk); + if (ret) + return ret; + } else if (PTR_ERR(g->clk) == -EPROBE_DEFER) { + /* + * Percolate deferrals, for anything else, + * just live without the clocking. + */ + return PTR_ERR(g->clk); + } + ret = bgpio_init(&g->gc, dev, 4, g->base + GPIO_DATA_IN, g->base + GPIO_DATA_SET, @@ -189,7 +273,7 @@ static int ftgpio_gpio_probe(struct platform_device *pdev) 0); if (ret) { dev_err(dev, "unable to init generic GPIO\n"); - return ret; + goto dis_clk; } g->gc.label = "FTGPIO010"; g->gc.base = -1; @@ -197,28 +281,50 @@ static int ftgpio_gpio_probe(struct platform_device *pdev) g->gc.owner = THIS_MODULE; /* ngpio is set by bgpio_init() */ + /* We need a silicon clock to do debounce */ + if (!IS_ERR(g->clk)) + g->gc.set_config = ftgpio_gpio_set_config; + ret = devm_gpiochip_add_data(dev, &g->gc, g); if (ret) - return ret; + goto dis_clk; /* Disable, unmask and clear all interrupts */ writel(0x0, g->base + GPIO_INT_EN); writel(0x0, g->base + GPIO_INT_MASK); writel(~0x0, g->base + GPIO_INT_CLR); + /* Clear any use of debounce */ + writel(0x0, g->base + GPIO_DEBOUNCE_EN); + ret = gpiochip_irqchip_add(&g->gc, &ftgpio_gpio_irqchip, 0, handle_bad_irq, IRQ_TYPE_NONE); if (ret) { dev_info(dev, "could not add irqchip\n"); - return ret; + goto dis_clk; } gpiochip_set_chained_irqchip(&g->gc, &ftgpio_gpio_irqchip, irq, ftgpio_gpio_irq_handler); + platform_set_drvdata(pdev, g); dev_info(dev, "FTGPIO010 @%p registered\n", g->base); return 0; + +dis_clk: + if (!IS_ERR(g->clk)) + clk_disable_unprepare(g->clk); + return ret; +} + +static int ftgpio_gpio_remove(struct platform_device *pdev) +{ + struct ftgpio_gpio *g = platform_get_drvdata(pdev); + + if (!IS_ERR(g->clk)) + clk_disable_unprepare(g->clk); + return 0; } static const struct of_device_id ftgpio_gpio_of_match[] = { @@ -239,6 +345,7 @@ static struct platform_driver ftgpio_gpio_driver = { .name = "ftgpio010-gpio", .of_match_table = of_match_ptr(ftgpio_gpio_of_match), }, - .probe = ftgpio_gpio_probe, + .probe = ftgpio_gpio_probe, + .remove = ftgpio_gpio_remove, }; builtin_platform_driver(ftgpio_gpio_driver); |