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Linux/drivers/leds/leds-asic3.c

  1 /*
  2  *  Copyright (C) 2011 Paul Parsons <lost.distance@yahoo.com>
  3  *
  4  *  This program is free software; you can redistribute it and/or modify
  5  *  it under the terms of the GNU General Public License version 2 as
  6  *  published by the Free Software Foundation.
  7  */
  8 
  9 #include <linux/kernel.h>
 10 #include <linux/platform_device.h>
 11 #include <linux/leds.h>
 12 #include <linux/slab.h>
 13 
 14 #include <linux/mfd/asic3.h>
 15 #include <linux/mfd/core.h>
 16 #include <linux/module.h>
 17 
 18 /*
 19  *      The HTC ASIC3 LED GPIOs are inputs, not outputs.
 20  *      Hence we turn the LEDs on/off via the TimeBase register.
 21  */
 22 
 23 /*
 24  *      When TimeBase is 4 the clock resolution is about 32Hz.
 25  *      This driver supports hardware blinking with an on+off
 26  *      period from 62ms (2 clocks) to 125s (4000 clocks).
 27  */
 28 #define MS_TO_CLK(ms)   DIV_ROUND_CLOSEST(((ms)*1024), 32000)
 29 #define CLK_TO_MS(clk)  (((clk)*32000)/1024)
 30 #define MAX_CLK         4000            /* Fits into 12-bit Time registers */
 31 #define MAX_MS          CLK_TO_MS(MAX_CLK)
 32 
 33 static const unsigned int led_n_base[ASIC3_NUM_LEDS] = {
 34         [0] = ASIC3_LED_0_Base,
 35         [1] = ASIC3_LED_1_Base,
 36         [2] = ASIC3_LED_2_Base,
 37 };
 38 
 39 static void brightness_set(struct led_classdev *cdev,
 40         enum led_brightness value)
 41 {
 42         struct platform_device *pdev = to_platform_device(cdev->dev->parent);
 43         const struct mfd_cell *cell = mfd_get_cell(pdev);
 44         struct asic3 *asic = dev_get_drvdata(pdev->dev.parent);
 45         u32 timebase;
 46         unsigned int base;
 47 
 48         timebase = (value == LED_OFF) ? 0 : (LED_EN|0x4);
 49 
 50         base = led_n_base[cell->id];
 51         asic3_write_register(asic, (base + ASIC3_LED_PeriodTime), 32);
 52         asic3_write_register(asic, (base + ASIC3_LED_DutyTime), 32);
 53         asic3_write_register(asic, (base + ASIC3_LED_AutoStopCount), 0);
 54         asic3_write_register(asic, (base + ASIC3_LED_TimeBase), timebase);
 55 }
 56 
 57 static int blink_set(struct led_classdev *cdev,
 58         unsigned long *delay_on,
 59         unsigned long *delay_off)
 60 {
 61         struct platform_device *pdev = to_platform_device(cdev->dev->parent);
 62         const struct mfd_cell *cell = mfd_get_cell(pdev);
 63         struct asic3 *asic = dev_get_drvdata(pdev->dev.parent);
 64         u32 on;
 65         u32 off;
 66         unsigned int base;
 67 
 68         if (*delay_on > MAX_MS || *delay_off > MAX_MS)
 69                 return -EINVAL;
 70 
 71         if (*delay_on == 0 && *delay_off == 0) {
 72                 /* If both are zero then a sensible default should be chosen */
 73                 on = MS_TO_CLK(500);
 74                 off = MS_TO_CLK(500);
 75         } else {
 76                 on = MS_TO_CLK(*delay_on);
 77                 off = MS_TO_CLK(*delay_off);
 78                 if ((on + off) > MAX_CLK)
 79                         return -EINVAL;
 80         }
 81 
 82         base = led_n_base[cell->id];
 83         asic3_write_register(asic, (base + ASIC3_LED_PeriodTime), (on + off));
 84         asic3_write_register(asic, (base + ASIC3_LED_DutyTime), on);
 85         asic3_write_register(asic, (base + ASIC3_LED_AutoStopCount), 0);
 86         asic3_write_register(asic, (base + ASIC3_LED_TimeBase), (LED_EN|0x4));
 87 
 88         *delay_on = CLK_TO_MS(on);
 89         *delay_off = CLK_TO_MS(off);
 90 
 91         return 0;
 92 }
 93 
 94 static int asic3_led_probe(struct platform_device *pdev)
 95 {
 96         struct asic3_led *led = dev_get_platdata(&pdev->dev);
 97         int ret;
 98 
 99         ret = mfd_cell_enable(pdev);
100         if (ret < 0)
101                 return ret;
102 
103         led->cdev = devm_kzalloc(&pdev->dev, sizeof(struct led_classdev),
104                                 GFP_KERNEL);
105         if (!led->cdev) {
106                 ret = -ENOMEM;
107                 goto out;
108         }
109 
110         led->cdev->name = led->name;
111         led->cdev->flags = LED_CORE_SUSPENDRESUME;
112         led->cdev->brightness_set = brightness_set;
113         led->cdev->blink_set = blink_set;
114         led->cdev->default_trigger = led->default_trigger;
115 
116         ret = led_classdev_register(&pdev->dev, led->cdev);
117         if (ret < 0)
118                 goto out;
119 
120         return 0;
121 
122 out:
123         (void) mfd_cell_disable(pdev);
124         return ret;
125 }
126 
127 static int asic3_led_remove(struct platform_device *pdev)
128 {
129         struct asic3_led *led = dev_get_platdata(&pdev->dev);
130 
131         led_classdev_unregister(led->cdev);
132 
133         return mfd_cell_disable(pdev);
134 }
135 
136 #ifdef CONFIG_PM_SLEEP
137 static int asic3_led_suspend(struct device *dev)
138 {
139         struct platform_device *pdev = to_platform_device(dev);
140         const struct mfd_cell *cell = mfd_get_cell(pdev);
141         int ret;
142 
143         ret = 0;
144         if (cell->suspend)
145                 ret = (*cell->suspend)(pdev);
146 
147         return ret;
148 }
149 
150 static int asic3_led_resume(struct device *dev)
151 {
152         struct platform_device *pdev = to_platform_device(dev);
153         const struct mfd_cell *cell = mfd_get_cell(pdev);
154         int ret;
155 
156         ret = 0;
157         if (cell->resume)
158                 ret = (*cell->resume)(pdev);
159 
160         return ret;
161 }
162 #endif
163 
164 static SIMPLE_DEV_PM_OPS(asic3_led_pm_ops, asic3_led_suspend, asic3_led_resume);
165 
166 static struct platform_driver asic3_led_driver = {
167         .probe          = asic3_led_probe,
168         .remove         = asic3_led_remove,
169         .driver         = {
170                 .name   = "leds-asic3",
171                 .owner  = THIS_MODULE,
172                 .pm     = &asic3_led_pm_ops,
173         },
174 };
175 
176 module_platform_driver(asic3_led_driver);
177 
178 MODULE_AUTHOR("Paul Parsons <lost.distance@yahoo.com>");
179 MODULE_DESCRIPTION("HTC ASIC3 LED driver");
180 MODULE_LICENSE("GPL");
181 MODULE_ALIAS("platform:leds-asic3");
182 

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