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>
diff --git a/drivers/leds/leds-asic3.c b/drivers/leds/leds-asic3.c
new file mode 100644
index 0000000..22f847c
--- /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");