leds: Add ASIC3 LED support

Add LED support for the HTC ASIC3. Underlying support is provided by the mfd/asic3 and leds/leds-asic3 drivers. An example configuration is provided by the pxa/hx4700 platform.

Signed-off-by: Paul Parsons <lost.distance@yahoo.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 165 insertions, 0 deletions

diff --git a/drivers/leds/leds-asic3.c b/drivers/leds/leds-asic3.c
new file mode 100644
index 00000000000..22f847c890c
--- /dev/null
+++ b/drivers/leds/leds-asic3.c
@@ -0,0 +1,165 @@
+/*
+ *  Copyright (C) 2011 Paul Parsons <lost.distance@yahoo.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/leds.h>
+#include <linux/slab.h>
+
+#include <linux/mfd/asic3.h>
+#include <linux/mfd/core.h>
+
+/*
+ *	The HTC ASIC3 LED GPIOs are inputs, not outputs.
+ *	Hence we turn the LEDs on/off via the TimeBase register.
+ */
+
+/*
+ *	When TimeBase is 4 the clock resolution is about 32Hz.
+ *	This driver supports hardware blinking with an on+off
+ *	period from 62ms (2 clocks) to 125s (4000 clocks).
+ */
+#define MS_TO_CLK(ms)	DIV_ROUND_CLOSEST(((ms)*1024), 32000)
+#define CLK_TO_MS(clk)	(((clk)*32000)/1024)
+#define MAX_CLK		4000            /* Fits into 12-bit Time registers */
+#define MAX_MS		CLK_TO_MS(MAX_CLK)
+
+static const unsigned int led_n_base[ASIC3_NUM_LEDS] = {
+	[0] = ASIC3_LED_0_Base,
+	[1] = ASIC3_LED_1_Base,
+	[2] = ASIC3_LED_2_Base,
+};
+
+static void brightness_set(struct led_classdev *cdev,
+	enum led_brightness value)
+{
+	struct platform_device *pdev = to_platform_device(cdev->dev->parent);
+	const struct mfd_cell *cell = mfd_get_cell(pdev);
+	struct asic3 *asic = dev_get_drvdata(pdev->dev.parent);
+	u32 timebase;
+	unsigned int base;
+
+	timebase = (value == LED_OFF) ? 0 : (LED_EN|0x4);
+
+	base = led_n_base[cell->id];
+	asic3_write_register(asic, (base + ASIC3_LED_PeriodTime), 32);
+	asic3_write_register(asic, (base + ASIC3_LED_DutyTime), 32);
+	asic3_write_register(asic, (base + ASIC3_LED_AutoStopCount), 0);
+	asic3_write_register(asic, (base + ASIC3_LED_TimeBase), timebase);
+}
+
+static int blink_set(struct led_classdev *cdev,
+	unsigned long *delay_on,
+	unsigned long *delay_off)
+{
+	struct platform_device *pdev = to_platform_device(cdev->dev->parent);
+	const struct mfd_cell *cell = mfd_get_cell(pdev);
+	struct asic3 *asic = dev_get_drvdata(pdev->dev.parent);
+	u32 on;
+	u32 off;
+	unsigned int base;
+
+	if (*delay_on > MAX_MS || *delay_off > MAX_MS)
+		return -EINVAL;
+
+	if (*delay_on == 0 && *delay_off == 0) {
+		/* If both are zero then a sensible default should be chosen */
+		on = MS_TO_CLK(500);
+		off = MS_TO_CLK(500);
+	} else {
+		on = MS_TO_CLK(*delay_on);
+		off = MS_TO_CLK(*delay_off);
+		if ((on + off) > MAX_CLK)
+			return -EINVAL;
+	}
+
+	base = led_n_base[cell->id];
+	asic3_write_register(asic, (base + ASIC3_LED_PeriodTime), (on + off));
+	asic3_write_register(asic, (base + ASIC3_LED_DutyTime), on);
+	asic3_write_register(asic, (base + ASIC3_LED_AutoStopCount), 0);
+	asic3_write_register(asic, (base + ASIC3_LED_TimeBase), (LED_EN|0x4));
+
+	*delay_on = CLK_TO_MS(on);
+	*delay_off = CLK_TO_MS(off);
+
+	return 0;
+}
+
+static int __devinit asic3_led_probe(struct platform_device *pdev)
+{
+	struct asic3_led *led = pdev->dev.platform_data;
+	int ret;
+
+	ret = mfd_cell_enable(pdev);
+	if (ret < 0)
+		goto ret0;
+
+	led->cdev = kzalloc(sizeof(struct led_classdev), GFP_KERNEL);
+	if (!led->cdev) {
+		ret = -ENOMEM;
+		goto ret1;
+	}
+
+	led->cdev->name = led->name;
+	led->cdev->default_trigger = led->default_trigger;
+	led->cdev->brightness_set = brightness_set;
+	led->cdev->blink_set = blink_set;
+
+	ret = led_classdev_register(&pdev->dev, led->cdev);
+	if (ret < 0)
+		goto ret2;
+
+	return 0;
+
+ret2:
+	kfree(led->cdev);
+ret1:
+	(void) mfd_cell_disable(pdev);
+ret0:
+	return ret;
+}
+
+static int __devexit asic3_led_remove(struct platform_device *pdev)
+{
+	struct asic3_led *led = pdev->dev.platform_data;
+
+	led_classdev_unregister(led->cdev);
+
+	kfree(led->cdev);
+
+	return mfd_cell_disable(pdev);
+}
+
+static struct platform_driver asic3_led_driver = {
+	.probe		= asic3_led_probe,
+	.remove		= __devexit_p(asic3_led_remove),
+	.driver		= {
+		.name	= "leds-asic3",
+		.owner	= THIS_MODULE,
+	},
+};
+
+MODULE_ALIAS("platform:leds-asic3");
+
+static int __init asic3_led_init(void)
+{
+	return platform_driver_register(&asic3_led_driver);
+}
+
+static void __exit asic3_led_exit(void)
+{
+	platform_driver_unregister(&asic3_led_driver);
+}
+
+module_init(asic3_led_init);
+module_exit(asic3_led_exit);
+
+MODULE_AUTHOR("Paul Parsons <lost.distance@yahoo.com>");
+MODULE_DESCRIPTION("HTC ASIC3 LED driver");
+MODULE_LICENSE("GPL");