151 lines
3.5 KiB
C
151 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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*
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* Backlight driver for HP Jornada 700 series (710/720/728)
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* Copyright (C) 2006-2009 Kristoffer Ericson <kristoffer.ericson@gmail.com>
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*/
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#include <linux/backlight.h>
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#include <linux/device.h>
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#include <linux/fb.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <mach/jornada720.h>
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#include <mach/hardware.h>
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#include <video/s1d13xxxfb.h>
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#define BL_MAX_BRIGHT 255
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#define BL_DEF_BRIGHT 25
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static int jornada_bl_get_brightness(struct backlight_device *bd)
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{
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int ret;
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/* check if backlight is on */
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if (!(PPSR & PPC_LDD1))
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return 0;
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jornada_ssp_start();
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/* cmd should return txdummy */
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ret = jornada_ssp_byte(GETBRIGHTNESS);
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if (jornada_ssp_byte(GETBRIGHTNESS) != TXDUMMY) {
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dev_err(&bd->dev, "get brightness timeout\n");
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jornada_ssp_end();
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return -ETIMEDOUT;
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}
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/* exchange txdummy for value */
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ret = jornada_ssp_byte(TXDUMMY);
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jornada_ssp_end();
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return BL_MAX_BRIGHT - ret;
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}
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static int jornada_bl_update_status(struct backlight_device *bd)
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{
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int ret = 0;
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jornada_ssp_start();
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/* If backlight is off then really turn it off */
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if (backlight_is_blank(bd)) {
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ret = jornada_ssp_byte(BRIGHTNESSOFF);
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if (ret != TXDUMMY) {
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dev_info(&bd->dev, "brightness off timeout\n");
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/* turn off backlight */
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PPSR &= ~PPC_LDD1;
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PPDR |= PPC_LDD1;
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ret = -ETIMEDOUT;
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}
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} else /* turn on backlight */
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PPSR |= PPC_LDD1;
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/* send command to our mcu */
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if (jornada_ssp_byte(SETBRIGHTNESS) != TXDUMMY) {
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dev_info(&bd->dev, "failed to set brightness\n");
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ret = -ETIMEDOUT;
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goto out;
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}
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/*
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* at this point we expect that the mcu has accepted
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* our command and is waiting for our new value
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* please note that maximum brightness is 255,
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* but due to physical layout it is equal to 0, so we simply
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* invert the value (MAX VALUE - NEW VALUE).
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*/
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if (jornada_ssp_byte(BL_MAX_BRIGHT - bd->props.brightness)
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!= TXDUMMY) {
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dev_err(&bd->dev, "set brightness failed\n");
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ret = -ETIMEDOUT;
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}
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/*
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* If infact we get an TXDUMMY as output we are happy and dont
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* make any further comments about it
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*/
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out:
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jornada_ssp_end();
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return ret;
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}
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static const struct backlight_ops jornada_bl_ops = {
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.get_brightness = jornada_bl_get_brightness,
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.update_status = jornada_bl_update_status,
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.options = BL_CORE_SUSPENDRESUME,
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};
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static int jornada_bl_probe(struct platform_device *pdev)
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{
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struct backlight_properties props;
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int ret;
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struct backlight_device *bd;
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memset(&props, 0, sizeof(struct backlight_properties));
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props.type = BACKLIGHT_RAW;
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props.max_brightness = BL_MAX_BRIGHT;
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bd = devm_backlight_device_register(&pdev->dev, S1D_DEVICENAME,
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&pdev->dev, NULL, &jornada_bl_ops,
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&props);
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if (IS_ERR(bd)) {
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ret = PTR_ERR(bd);
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dev_err(&pdev->dev, "failed to register device, err=%x\n", ret);
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return ret;
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}
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bd->props.power = FB_BLANK_UNBLANK;
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bd->props.brightness = BL_DEF_BRIGHT;
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/*
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* note. make sure max brightness is set otherwise
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* you will get seemingly non-related errors when
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* trying to change brightness
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*/
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jornada_bl_update_status(bd);
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platform_set_drvdata(pdev, bd);
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dev_info(&pdev->dev, "HP Jornada 700 series backlight driver\n");
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return 0;
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}
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static struct platform_driver jornada_bl_driver = {
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.probe = jornada_bl_probe,
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.driver = {
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.name = "jornada_bl",
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},
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};
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module_platform_driver(jornada_bl_driver);
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MODULE_AUTHOR("Kristoffer Ericson <kristoffer.ericson>");
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MODULE_DESCRIPTION("HP Jornada 710/720/728 Backlight driver");
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MODULE_LICENSE("GPL");
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