LXR linux/drivers/video/backlight/jornada720

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *
   4 * Backlight driver for HP Jornada 700 series (710/720/728)
   5 * Copyright (C) 2006-2009 Kristoffer Ericson <kristoffer.ericson@gmail.com>
   6 */
   7
   8#include <linux/backlight.h>
   9#include <linux/device.h>
  10#include <linux/fb.h>
  11#include <linux/kernel.h>
  12#include <linux/module.h>
  13#include <linux/platform_device.h>
  14
  15#include <mach/jornada720.h>
  16#include <mach/hardware.h>
  17
  18#include <video/s1d13xxxfb.h>
  19
  20#define BL_MAX_BRIGHT   255
  21#define BL_DEF_BRIGHT   25
  22
  23static int jornada_bl_get_brightness(struct backlight_device *bd)
  24{
  25        int ret;
  26
  27        /* check if backlight is on */
  28        if (!(PPSR & PPC_LDD1))
  29                return 0;
  30
  31        jornada_ssp_start();
  32
  33        /* cmd should return txdummy */
  34        ret = jornada_ssp_byte(GETBRIGHTNESS);
  35
  36        if (jornada_ssp_byte(GETBRIGHTNESS) != TXDUMMY) {
  37                dev_err(&bd->dev, "get brightness timeout\n");
  38                jornada_ssp_end();
  39                return -ETIMEDOUT;
  40        }
  41
  42        /* exchange txdummy for value */
  43        ret = jornada_ssp_byte(TXDUMMY);
  44
  45        jornada_ssp_end();
  46
  47        return BL_MAX_BRIGHT - ret;
  48}
  49
  50static int jornada_bl_update_status(struct backlight_device *bd)
  51{
  52        int ret = 0;
  53
  54        jornada_ssp_start();
  55
  56        /* If backlight is off then really turn it off */
  57        if (backlight_is_blank(bd)) {
  58                ret = jornada_ssp_byte(BRIGHTNESSOFF);
  59                if (ret != TXDUMMY) {
  60                        dev_info(&bd->dev, "brightness off timeout\n");
  61                        /* turn off backlight */
  62                        PPSR &= ~PPC_LDD1;
  63                        PPDR |= PPC_LDD1;
  64                        ret = -ETIMEDOUT;
  65                }
  66        } else  /* turn on backlight */
  67                PPSR |= PPC_LDD1;
  68
  69        /* send command to our mcu */
  70        if (jornada_ssp_byte(SETBRIGHTNESS) != TXDUMMY) {
  71                dev_info(&bd->dev, "failed to set brightness\n");
  72                ret = -ETIMEDOUT;
  73                goto out;
  74        }
  75
  76        /*
  77         * at this point we expect that the mcu has accepted
  78         * our command and is waiting for our new value
  79         * please note that maximum brightness is 255,
  80         * but due to physical layout it is equal to 0, so we simply
  81         * invert the value (MAX VALUE - NEW VALUE).
  82         */
  83        if (jornada_ssp_byte(BL_MAX_BRIGHT - bd->props.brightness)
  84                != TXDUMMY) {
  85                dev_err(&bd->dev, "set brightness failed\n");
  86                ret = -ETIMEDOUT;
  87        }
  88
  89        /*
  90         * If infact we get an TXDUMMY as output we are happy and dont
  91         * make any further comments about it
  92         */
  93out:
  94        jornada_ssp_end();
  95
  96        return ret;
  97}
  98
  99static const struct backlight_ops jornada_bl_ops = {
 100        .get_brightness = jornada_bl_get_brightness,
 101        .update_status = jornada_bl_update_status,
 102        .options = BL_CORE_SUSPENDRESUME,
 103};
 104
 105static int jornada_bl_probe(struct platform_device *pdev)
 106{
 107        struct backlight_properties props;
 108        int ret;
 109        struct backlight_device *bd;
 110
 111        memset(&props, 0, sizeof(struct backlight_properties));
 112        props.type = BACKLIGHT_RAW;
 113        props.max_brightness = BL_MAX_BRIGHT;
 114
 115        bd = devm_backlight_device_register(&pdev->dev, S1D_DEVICENAME,
 116                                        &pdev->dev, NULL, &jornada_bl_ops,
 117                                        &props);
 118        if (IS_ERR(bd)) {
 119                ret = PTR_ERR(bd);
 120                dev_err(&pdev->dev, "failed to register device, err=%x\n", ret);
 121                return ret;
 122        }
 123
 124        bd->props.power = FB_BLANK_UNBLANK;
 125        bd->props.brightness = BL_DEF_BRIGHT;
 126        /*
 127         * note. make sure max brightness is set otherwise
 128         * you will get seemingly non-related errors when
 129         * trying to change brightness
 130         */
 131        jornada_bl_update_status(bd);
 132
 133        platform_set_drvdata(pdev, bd);
 134        dev_info(&pdev->dev, "HP Jornada 700 series backlight driver\n");
 135
 136        return 0;
 137}
 138
 139static struct platform_driver jornada_bl_driver = {
 140        .probe          = jornada_bl_probe,
 141        .driver = {
 142                .name   = "jornada_bl",
 143        },
 144};
 145
 146module_platform_driver(jornada_bl_driver);
 147
 148MODULE_AUTHOR("Kristoffer Ericson <kristoffer.ericson>");
 149MODULE_DESCRIPTION("HP Jornada 710/720/728 Backlight driver");
 150MODULE_LICENSE("GPL");
 151