omap1_bl.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Backlight driver for OMAP based boards.
  4 *
  5 * Copyright (c) 2006 Andrzej Zaborowski  <balrog@zabor.org>
  6 */
  7
  8#include <linux/module.h>
  9#include <linux/kernel.h>
 10#include <linux/init.h>
 11#include <linux/platform_device.h>
 12#include <linux/backlight.h>
 13#include <linux/slab.h>
 14#include <linux/platform_data/omap1_bl.h>
 15
 16#include <linux/soc/ti/omap1-io.h>
 17#include <linux/soc/ti/omap1-mux.h>
 18
 19#define OMAPBL_MAX_INTENSITY		0xff
 20
 21struct omap_backlight {
 22	bool enabled;
 23	int current_intensity;
 24
 25	struct device *dev;
 26	struct omap_backlight_config *pdata;
 27};
 28
 29static inline void omapbl_send_intensity(int intensity)
 30{
 31	omap_writeb(intensity, OMAP_PWL_ENABLE);
 32}
 33
 34static inline void omapbl_send_enable(int enable)
 35{
 36	omap_writeb(enable, OMAP_PWL_CLK_ENABLE);
 37}
 38
 39static void omapbl_enable(struct omap_backlight *bl, bool enable)
 40{
 41	if (enable) {
 42		omapbl_send_intensity(bl->current_intensity);
 43		omapbl_send_enable(1);
 44	} else {
 45		omapbl_send_intensity(0);
 46		omapbl_send_enable(0);
 47	}
 48}
 49
 50#ifdef CONFIG_PM_SLEEP
 51static int omapbl_suspend(struct device *dev)
 52{
 53	struct backlight_device *bl_dev = dev_get_drvdata(dev);
 54	struct omap_backlight *bl = bl_get_data(bl_dev);
 55
 56	omapbl_enable(bl, false);
 57	return 0;
 58}
 59
 60static int omapbl_resume(struct device *dev)
 61{
 62	struct backlight_device *bl_dev = dev_get_drvdata(dev);
 63	struct omap_backlight *bl = bl_get_data(bl_dev);
 64
 65	omapbl_enable(bl, bl->enabled);
 66	return 0;
 67}
 68#endif
 69
 70static void omapbl_set_enabled(struct backlight_device *dev, bool enable)
 71{
 72	struct omap_backlight *bl = bl_get_data(dev);
 73
 74	omapbl_enable(bl, enable);
 75	bl->enabled = enable;
 76}
 77
 78static int omapbl_update_status(struct backlight_device *dev)
 79{
 80	struct omap_backlight *bl = bl_get_data(dev);
 81	bool enable;
 82
 83	if (bl->current_intensity != dev->props.brightness) {
 84		if (bl->enabled)
 85			omapbl_send_intensity(dev->props.brightness);
 86		bl->current_intensity = dev->props.brightness;
 87	}
 88
 89	enable = !backlight_is_blank(dev);
 90
 91	if (enable != bl->enabled)
 92		omapbl_set_enabled(dev, enable);
 93
 94	return 0;
 95}
 96
 97static int omapbl_get_intensity(struct backlight_device *dev)
 98{
 99	struct omap_backlight *bl = bl_get_data(dev);
100
101	return bl->current_intensity;
102}
103
104static const struct backlight_ops omapbl_ops = {
105	.get_brightness = omapbl_get_intensity,
106	.update_status  = omapbl_update_status,
107};
108
109static int omapbl_probe(struct platform_device *pdev)
110{
111	struct backlight_properties props;
112	struct backlight_device *dev;
113	struct omap_backlight *bl;
114	struct omap_backlight_config *pdata = dev_get_platdata(&pdev->dev);
115
116	if (!pdata)
117		return -ENXIO;
118
119	bl = devm_kzalloc(&pdev->dev, sizeof(struct omap_backlight),
120			  GFP_KERNEL);
121	if (unlikely(!bl))
122		return -ENOMEM;
123
124	memset(&props, 0, sizeof(struct backlight_properties));
125	props.type = BACKLIGHT_RAW;
126	props.max_brightness = OMAPBL_MAX_INTENSITY;
127	dev = devm_backlight_device_register(&pdev->dev, "omap-bl", &pdev->dev,
128					bl, &omapbl_ops, &props);
129	if (IS_ERR(dev))
130		return PTR_ERR(dev);
131
132	bl->enabled = false;
133	bl->current_intensity = 0;
134
135	bl->pdata = pdata;
136	bl->dev = &pdev->dev;
137
138	platform_set_drvdata(pdev, dev);
139
140	omap_cfg_reg(PWL);	/* Conflicts with UART3 */
141
142	dev->props.brightness = pdata->default_intensity;
143	omapbl_update_status(dev);
144
145	dev_info(&pdev->dev, "OMAP LCD backlight initialised\n");
146
147	return 0;
148}
149
150static SIMPLE_DEV_PM_OPS(omapbl_pm_ops, omapbl_suspend, omapbl_resume);
151
152static struct platform_driver omapbl_driver = {
153	.probe		= omapbl_probe,
154	.driver		= {
155		.name	= "omap-bl",
156		.pm	= &omapbl_pm_ops,
157	},
158};
159
160module_platform_driver(omapbl_driver);
161
162MODULE_AUTHOR("Andrzej Zaborowski <balrog@zabor.org>");
163MODULE_DESCRIPTION("OMAP LCD Backlight driver");
164MODULE_LICENSE("GPL");