[PATCH] LED: add LED device support for ixp4xx devices

NEW_LEDS support for ixp4xx boards where LEDs are connected to the GPIO lines.

This includes a new generic ixp4xx driver (leds-ixp4xx-gpio.c name
"IXP4XX-GPIO-LED")

Signed-off-by: John Bowler <jbowler@acm.org>
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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 000000000000..30ced150e4cf
--- /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");