diff options
Diffstat (limited to 'drivers/leds/leds-asic3.c')
| -rw-r--r-- | drivers/leds/leds-asic3.c | 165 |
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"); |