diff options
Diffstat (limited to 'drivers/video/backlight/pcf50633-backlight.c')
| -rw-r--r-- | drivers/video/backlight/pcf50633-backlight.c | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/drivers/video/backlight/pcf50633-backlight.c b/drivers/video/backlight/pcf50633-backlight.c new file mode 100644 index 000000000..540dd3380 --- /dev/null +++ b/drivers/video/backlight/pcf50633-backlight.c @@ -0,0 +1,155 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de> + * PCF50633 backlight device driver + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/platform_device.h> + +#include <linux/backlight.h> +#include <linux/fb.h> + +#include <linux/mfd/pcf50633/core.h> +#include <linux/mfd/pcf50633/backlight.h> + +struct pcf50633_bl { + struct pcf50633 *pcf; + struct backlight_device *bl; + + unsigned int brightness; + unsigned int brightness_limit; +}; + +/* + * pcf50633_bl_set_brightness_limit + * + * Update the brightness limit for the pc50633 backlight. The actual brightness + * will not go above the limit. This is useful to limit power drain for example + * on low battery. + * + * @dev: Pointer to a pcf50633 device + * @limit: The brightness limit. Valid values are 0-63 + */ +int pcf50633_bl_set_brightness_limit(struct pcf50633 *pcf, unsigned int limit) +{ + struct pcf50633_bl *pcf_bl = platform_get_drvdata(pcf->bl_pdev); + + if (!pcf_bl) + return -ENODEV; + + pcf_bl->brightness_limit = limit & 0x3f; + backlight_update_status(pcf_bl->bl); + + return 0; +} + +static int pcf50633_bl_update_status(struct backlight_device *bl) +{ + struct pcf50633_bl *pcf_bl = bl_get_data(bl); + unsigned int new_brightness; + + + if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK) || + bl->props.power != FB_BLANK_UNBLANK) + new_brightness = 0; + else if (bl->props.brightness < pcf_bl->brightness_limit) + new_brightness = bl->props.brightness; + else + new_brightness = pcf_bl->brightness_limit; + + + if (pcf_bl->brightness == new_brightness) + return 0; + + if (new_brightness) { + pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDOUT, + new_brightness); + if (!pcf_bl->brightness) + pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDENA, 1); + } else { + pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDENA, 0); + } + + pcf_bl->brightness = new_brightness; + + return 0; +} + +static int pcf50633_bl_get_brightness(struct backlight_device *bl) +{ + struct pcf50633_bl *pcf_bl = bl_get_data(bl); + + return pcf_bl->brightness; +} + +static const struct backlight_ops pcf50633_bl_ops = { + .get_brightness = pcf50633_bl_get_brightness, + .update_status = pcf50633_bl_update_status, + .options = BL_CORE_SUSPENDRESUME, +}; + +static int pcf50633_bl_probe(struct platform_device *pdev) +{ + struct pcf50633_bl *pcf_bl; + struct device *parent = pdev->dev.parent; + struct pcf50633_platform_data *pcf50633_data = dev_get_platdata(parent); + struct pcf50633_bl_platform_data *pdata = pcf50633_data->backlight_data; + struct backlight_properties bl_props; + + pcf_bl = devm_kzalloc(&pdev->dev, sizeof(*pcf_bl), GFP_KERNEL); + if (!pcf_bl) + return -ENOMEM; + + memset(&bl_props, 0, sizeof(bl_props)); + bl_props.type = BACKLIGHT_RAW; + bl_props.max_brightness = 0x3f; + bl_props.power = FB_BLANK_UNBLANK; + + if (pdata) { + bl_props.brightness = pdata->default_brightness; + pcf_bl->brightness_limit = pdata->default_brightness_limit; + } else { + bl_props.brightness = 0x3f; + pcf_bl->brightness_limit = 0x3f; + } + + pcf_bl->pcf = dev_to_pcf50633(pdev->dev.parent); + + pcf_bl->bl = devm_backlight_device_register(&pdev->dev, pdev->name, + &pdev->dev, pcf_bl, + &pcf50633_bl_ops, &bl_props); + + if (IS_ERR(pcf_bl->bl)) + return PTR_ERR(pcf_bl->bl); + + platform_set_drvdata(pdev, pcf_bl); + + pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDDIM, pdata->ramp_time); + + /* + * Should be different from bl_props.brightness, so we do not exit + * update_status early the first time it's called + */ + pcf_bl->brightness = pcf_bl->bl->props.brightness + 1; + + backlight_update_status(pcf_bl->bl); + + return 0; +} + +static struct platform_driver pcf50633_bl_driver = { + .probe = pcf50633_bl_probe, + .driver = { + .name = "pcf50633-backlight", + }, +}; + +module_platform_driver(pcf50633_bl_driver); + +MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); +MODULE_DESCRIPTION("PCF50633 backlight driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:pcf50633-backlight"); |