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backlight: add driver for Bachmann's ot200
Add backlight driver for Bachmann's ot200 visualisation device. The driver uses MFGPT 7 of CS5535 silicon to regulate the backlight. [akpm@linux-foundation.org: remove redundant test of `brightness'] Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com> Cc: Lars-Peter Clausen <lars@metafoo.de> Cc: Andres Salomon <dilinger@queued.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Christian Gmeiner
Linus Torvalds
parent
7be865ab86
commit
c8df742863
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@ -341,6 +341,13 @@ config BACKLIGHT_LP855X
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This supports TI LP8550, LP8551, LP8552, LP8553 and LP8556
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backlight driver.
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config BACKLIGHT_OT200
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tristate "Backlight driver for ot200 visualisation device"
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depends on BACKLIGHT_CLASS_DEVICE && CS5535_MFGPT
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help
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To compile this driver as a module, choose M here: the module will be
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called ot200_bl.
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endif # BACKLIGHT_CLASS_DEVICE
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endif # BACKLIGHT_LCD_SUPPORT
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@ -39,4 +39,4 @@ obj-$(CONFIG_BACKLIGHT_ADP8870) += adp8870_bl.o
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obj-$(CONFIG_BACKLIGHT_88PM860X) += 88pm860x_bl.o
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obj-$(CONFIG_BACKLIGHT_PCF50633) += pcf50633-backlight.o
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obj-$(CONFIG_BACKLIGHT_AAT2870) += aat2870_bl.o
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obj-$(CONFIG_BACKLIGHT_OT200) += ot200_bl.o
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@ -0,0 +1,175 @@
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/*
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* Copyright (C) 2012 Bachmann electronic GmbH
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* Christian Gmeiner <christian.gmeiner@gmail.com>
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*
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* Backlight driver for ot200 visualisation device from
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* Bachmann electronic GmbH.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/fb.h>
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#include <linux/backlight.h>
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#include <linux/gpio.h>
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#include <linux/cs5535.h>
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static struct cs5535_mfgpt_timer *pwm_timer;
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/* this array defines the mapping of brightness in % to pwm frequency */
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static const u8 dim_table[101] = {0, 0, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2,
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2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4,
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4, 5, 5, 5, 5, 6, 6, 6, 7, 7, 7, 8, 8, 9, 9,
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10, 10, 11, 11, 12, 12, 13, 14, 15, 15, 16,
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17, 18, 19, 20, 21, 22, 23, 24, 26, 27, 28,
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30, 31, 33, 35, 37, 39, 41, 43, 45, 47, 50,
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53, 55, 58, 61, 65, 68, 72, 75, 79, 84, 88,
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93, 97, 103, 108, 114, 120, 126, 133, 140,
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147, 155, 163};
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struct ot200_backlight_data {
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int current_brightness;
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};
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#define GPIO_DIMM 27
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#define SCALE 1
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#define CMP1MODE 0x2 /* compare on GE; output high on compare
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* greater than or equal */
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#define PWM_SETUP (SCALE | CMP1MODE << 6 | MFGPT_SETUP_CNTEN)
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#define MAX_COMP2 163
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static int ot200_backlight_update_status(struct backlight_device *bl)
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{
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struct ot200_backlight_data *data = bl_get_data(bl);
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int brightness = bl->props.brightness;
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if (bl->props.state & BL_CORE_FBBLANK)
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brightness = 0;
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/* enable or disable PWM timer */
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if (brightness == 0)
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cs5535_mfgpt_write(pwm_timer, MFGPT_REG_SETUP, 0);
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else if (data->current_brightness == 0) {
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cs5535_mfgpt_write(pwm_timer, MFGPT_REG_COUNTER, 0);
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cs5535_mfgpt_write(pwm_timer, MFGPT_REG_SETUP,
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MFGPT_SETUP_CNTEN);
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}
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/* apply new brightness value */
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cs5535_mfgpt_write(pwm_timer, MFGPT_REG_CMP1,
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MAX_COMP2 - dim_table[brightness]);
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data->current_brightness = brightness;
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return 0;
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}
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static int ot200_backlight_get_brightness(struct backlight_device *bl)
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{
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struct ot200_backlight_data *data = bl_get_data(bl);
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return data->current_brightness;
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}
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static const struct backlight_ops ot200_backlight_ops = {
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.update_status = ot200_backlight_update_status,
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.get_brightness = ot200_backlight_get_brightness,
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};
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static int ot200_backlight_probe(struct platform_device *pdev)
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{
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struct backlight_device *bl;
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struct ot200_backlight_data *data;
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struct backlight_properties props;
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int retval = 0;
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/* request gpio */
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if (gpio_request(GPIO_DIMM, "ot200 backlight dimmer") < 0) {
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dev_err(&pdev->dev, "failed to request GPIO %d\n", GPIO_DIMM);
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return -ENODEV;
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}
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/* request timer */
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pwm_timer = cs5535_mfgpt_alloc_timer(7, MFGPT_DOMAIN_ANY);
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if (!pwm_timer) {
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dev_err(&pdev->dev, "MFGPT 7 not available\n");
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retval = -ENODEV;
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goto error_mfgpt_alloc;
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}
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data = kzalloc(sizeof(*data), GFP_KERNEL);
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if (!data) {
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retval = -ENOMEM;
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goto error_kzalloc;
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}
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/* setup gpio */
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cs5535_gpio_set(GPIO_DIMM, GPIO_OUTPUT_ENABLE);
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cs5535_gpio_set(GPIO_DIMM, GPIO_OUTPUT_AUX1);
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/* setup timer */
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cs5535_mfgpt_write(pwm_timer, MFGPT_REG_CMP1, 0);
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cs5535_mfgpt_write(pwm_timer, MFGPT_REG_CMP2, MAX_COMP2);
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cs5535_mfgpt_write(pwm_timer, MFGPT_REG_SETUP, PWM_SETUP);
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data->current_brightness = 100;
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props.max_brightness = 100;
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props.brightness = 100;
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props.type = BACKLIGHT_RAW;
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bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, data,
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&ot200_backlight_ops, &props);
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if (IS_ERR(bl)) {
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dev_err(&pdev->dev, "failed to register backlight\n");
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retval = PTR_ERR(bl);
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goto error_backlight_device_register;
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}
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platform_set_drvdata(pdev, bl);
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return 0;
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error_backlight_device_register:
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kfree(data);
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error_kzalloc:
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cs5535_mfgpt_free_timer(pwm_timer);
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error_mfgpt_alloc:
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gpio_free(GPIO_DIMM);
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return retval;
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}
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static int ot200_backlight_remove(struct platform_device *pdev)
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{
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struct backlight_device *bl = platform_get_drvdata(pdev);
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struct ot200_backlight_data *data = bl_get_data(bl);
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backlight_device_unregister(bl);
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/* on module unload set brightness to 100% */
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cs5535_mfgpt_write(pwm_timer, MFGPT_REG_COUNTER, 0);
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cs5535_mfgpt_write(pwm_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
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cs5535_mfgpt_write(pwm_timer, MFGPT_REG_CMP1,
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MAX_COMP2 - dim_table[100]);
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cs5535_mfgpt_free_timer(pwm_timer);
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gpio_free(GPIO_DIMM);
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kfree(data);
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return 0;
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}
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static struct platform_driver ot200_backlight_driver = {
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.driver = {
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.name = "ot200-backlight",
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.owner = THIS_MODULE,
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},
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.probe = ot200_backlight_probe,
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.remove = ot200_backlight_remove,
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};
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module_platform_driver(ot200_backlight_driver);
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MODULE_DESCRIPTION("backlight driver for ot200 visualisation device");
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MODULE_AUTHOR("Christian Gmeiner <christian.gmeiner@gmail.com>");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:ot200-backlight");
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