/* * 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");