diff options
Diffstat (limited to 'drivers/leds/leds-ixp4xx-gpio.c')
| -rw-r--r-- | drivers/leds/leds-ixp4xx-gpio.c | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/drivers/leds/leds-ixp4xx-gpio.c b/drivers/leds/leds-ixp4xx-gpio.c new file mode 100644 index 00000000000..30ced150e4c --- /dev/null +++ b/drivers/leds/leds-ixp4xx-gpio.c @@ -0,0 +1,215 @@ +/* + * IXP4XX GPIO driver LED driver + * + * Author: John Bowler <jbowler@acm.org> + * + * Copyright (c) 2006 John Bowler + * + * Permission is hereby granted, free of charge, to any + * person obtaining a copy of this software and associated + * documentation files (the "Software"), to deal in the + * Software without restriction, including without + * limitation the rights to use, copy, modify, merge, + * publish, distribute, sublicense, and/or sell copies of + * the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the + * following conditions: + * + * The above copyright notice and this permission notice + * shall be included in all copies or substantial portions + * of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF + * ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED + * TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A + * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT + * SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR + * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR + * OTHER DEALINGS IN THE SOFTWARE. + * + */ + +#include <linux/config.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/spinlock.h> +#include <linux/leds.h> +#include <asm/arch/hardware.h> + +extern spinlock_t gpio_lock; + +/* Up to 16 gpio lines are possible. */ +#define GPIO_MAX 16 +static struct ixp4xxgpioled_device { + struct led_classdev ancestor; + int flags; +} ixp4xxgpioled_devices[GPIO_MAX]; + +void ixp4xxgpioled_brightness_set(struct led_classdev *pled, + enum led_brightness value) +{ + const struct ixp4xxgpioled_device *const ixp4xx_dev = + container_of(pled, struct ixp4xxgpioled_device, ancestor); + const u32 gpio_pin = ixp4xx_dev - ixp4xxgpioled_devices; + + if (gpio_pin < GPIO_MAX && ixp4xx_dev->ancestor.name != 0) { + /* Set or clear the 'gpio_pin' bit according to the style + * and the required setting (value > 0 == on) + */ + const int gpio_value = + (value > 0) == (ixp4xx_dev->flags != IXP4XX_GPIO_LOW) ? + IXP4XX_GPIO_HIGH : IXP4XX_GPIO_LOW; + + { + unsigned long flags; + spin_lock_irqsave(&gpio_lock, flags); + gpio_line_set(gpio_pin, gpio_value); + spin_unlock_irqrestore(&gpio_lock, flags); + } + } +} + +/* LEDs are described in resources, the following iterates over the valid + * LED resources. + */ +#define for_all_leds(i, pdev) \ + for (i=0; i<pdev->num_resources; ++i) \ + if (pdev->resource[i].start < GPIO_MAX && \ + pdev->resource[i].name != 0) + +/* The following applies 'operation' to each LED from the given platform, + * the function always returns 0 to allow tail call elimination. + */ +static int apply_to_all_leds(struct platform_device *pdev, + void (*operation)(struct led_classdev *pled)) +{ + int i; + + for_all_leds(i, pdev) + operation(&ixp4xxgpioled_devices[pdev->resource[i].start].ancestor); + return 0; +} + +#ifdef CONFIG_PM +static int ixp4xxgpioled_suspend(struct platform_device *pdev, + pm_message_t state) +{ + return apply_to_all_leds(pdev, led_classdev_suspend); +} + +static int ixp4xxgpioled_resume(struct platform_device *pdev) +{ + return apply_to_all_leds(pdev, led_classdev_resume); +} +#endif + +static void ixp4xxgpioled_remove_one_led(struct led_classdev *pled) +{ + led_classdev_unregister(pled); + pled->name = 0; +} + +static int ixp4xxgpioled_remove(struct platform_device *pdev) +{ + return apply_to_all_leds(pdev, ixp4xxgpioled_remove_one_led); +} + +static int ixp4xxgpioled_probe(struct platform_device *pdev) +{ + /* The board level has to tell the driver where the + * LEDs are connected - there is no way to find out + * electrically. It must also say whether the GPIO + * lines are active high or active low. + * + * To do this read the num_resources (the number of + * LEDs) and the struct resource (the data for each + * LED). The name comes from the resource, and it + * isn't copied. + */ + int i; + + for_all_leds(i, pdev) { + const u8 gpio_pin = pdev->resource[i].start; + int rc; + + if (ixp4xxgpioled_devices[gpio_pin].ancestor.name == 0) { + unsigned long flags; + + spin_lock_irqsave(&gpio_lock, flags); + gpio_line_config(gpio_pin, IXP4XX_GPIO_OUT); + /* The config can, apparently, reset the state, + * I suspect the gpio line may be an input and + * the config may cause the line to be latched, + * so the setting depends on how the LED is + * connected to the line (which affects how it + * floats if not driven). + */ + gpio_line_set(gpio_pin, IXP4XX_GPIO_HIGH); + spin_unlock_irqrestore(&gpio_lock, flags); + + ixp4xxgpioled_devices[gpio_pin].flags = + pdev->resource[i].flags & IORESOURCE_BITS; + + ixp4xxgpioled_devices[gpio_pin].ancestor.name = + pdev->resource[i].name; + + /* This is how a board manufacturer makes the LED + * come on on reset - the GPIO line will be high, so + * make the LED light when the line is low... + */ + if (ixp4xxgpioled_devices[gpio_pin].flags != IXP4XX_GPIO_LOW) + ixp4xxgpioled_devices[gpio_pin].ancestor.brightness = 100; + else + ixp4xxgpioled_devices[gpio_pin].ancestor.brightness = 0; + + ixp4xxgpioled_devices[gpio_pin].ancestor.flags = 0; + + ixp4xxgpioled_devices[gpio_pin].ancestor.brightness_set = + ixp4xxgpioled_brightness_set; + + ixp4xxgpioled_devices[gpio_pin].ancestor.default_trigger = 0; + } + + rc = led_classdev_register(&pdev->dev, + &ixp4xxgpioled_devices[gpio_pin].ancestor); + if (rc < 0) { + ixp4xxgpioled_devices[gpio_pin].ancestor.name = 0; + ixp4xxgpioled_remove(pdev); + return rc; + } + } + + return 0; +} + +static struct platform_driver ixp4xxgpioled_driver = { + .probe = ixp4xxgpioled_probe, + .remove = ixp4xxgpioled_remove, +#ifdef CONFIG_PM + .suspend = ixp4xxgpioled_suspend, + .resume = ixp4xxgpioled_resume, +#endif + .driver = { + .name = "IXP4XX-GPIO-LED", + }, +}; + +static int __init ixp4xxgpioled_init(void) +{ + return platform_driver_register(&ixp4xxgpioled_driver); +} + +static void __exit ixp4xxgpioled_exit(void) +{ + platform_driver_unregister(&ixp4xxgpioled_driver); +} + +module_init(ixp4xxgpioled_init); +module_exit(ixp4xxgpioled_exit); + +MODULE_AUTHOR("John Bowler <jbowler@acm.org>"); +MODULE_DESCRIPTION("IXP4XX GPIO LED driver"); +MODULE_LICENSE("Dual MIT/GPL"); |