cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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jornada720_bl.c (3575B)

      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");