Re: [alsa-devel] [PATCH 05/15] video: backlight: add new locomo backlight driver

On Tuesday, October 28, 2014 9:02 AM, Dmitry Eremin-Solenikov wrote:

Add new simple backlight driver - it cares only about PWM/frontlight part of LoCoMo, it does not touch TFT settings and does not export TFT power control.

Signed-off-by: Dmitry Eremin-Solenikov dbaryshkov@gmail.com

drivers/video/backlight/Kconfig | 6 +- drivers/video/backlight/Makefile | 2 +- drivers/video/backlight/locomo_bl.c | 171 ++++++++++++++++++++++++++++++++++++ 3 files changed, 175 insertions(+), 4 deletions(-) create mode 100644 drivers/video/backlight/locomo_bl.c

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig index 8d03924..03b77b33 100644 --- a/drivers/video/backlight/Kconfig +++ b/drivers/video/backlight/Kconfig @@ -218,12 +218,12 @@ config BACKLIGHT_LM3533 levels.

config BACKLIGHT_LOCOMO

• tristate "Sharp LOCOMO LCD/Backlight Driver"
• depends on SHARP_LOCOMO

• tristate "Sharp LOCOMO Backlight Driver"
• depends on MFD_LOCOMO default y help If you have a Sharp Zaurus SL-5500 (Collie) or SL-5600 (Poodle) say y to

•  enable the LCD/backlight driver.
  

•  enable the backlight driver.
  
  

config BACKLIGHT_OMAP1 tristate "OMAP1 PWL-based LCD Backlight" diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile index fcd50b73..2a61b7e 100644 --- a/drivers/video/backlight/Makefile +++ b/drivers/video/backlight/Makefile @@ -39,7 +39,7 @@ obj-$(CONFIG_BACKLIGHT_IPAQ_MICRO) += ipaq_micro_bl.o obj-$(CONFIG_BACKLIGHT_LM3533) += lm3533_bl.o obj-$(CONFIG_BACKLIGHT_LM3630A) += lm3630a_bl.o obj-$(CONFIG_BACKLIGHT_LM3639) += lm3639_bl.o -obj-$(CONFIG_BACKLIGHT_LOCOMO) += locomolcd.o +obj-$(CONFIG_BACKLIGHT_LOCOMO) += locomo_bl.o obj-$(CONFIG_BACKLIGHT_LP855X) += lp855x_bl.o obj-$(CONFIG_BACKLIGHT_LP8788) += lp8788_bl.o obj-$(CONFIG_BACKLIGHT_LV5207LP) += lv5207lp.o diff --git a/drivers/video/backlight/locomo_bl.c b/drivers/video/backlight/locomo_bl.c new file mode 100644 index 0000000..cec1b51 --- /dev/null +++ b/drivers/video/backlight/locomo_bl.c @@ -0,0 +1,171 @@ +/*

• • Backlight control code for Sharp Zaurus SL-5500
• • Copyright 2005 John Lenz lenz@cs.wisc.edu
• • Maintainer: Pavel Machek pavel@ucw.cz (unless John wants to :-)
• • GPL v2
• • This driver assumes single CPU. That's okay, because collie is
• • slightly old hardware, and no one is going to retrofit second CPU to
• • old PDA.
• */

+#include <linux/module.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/fb.h> +#include <linux/backlight.h> +#include <linux/err.h> +#include <linux/gpio.h> +#include <linux/delay.h> +#include <linux/mfd/locomo.h>

Please, re-order these headers alphabetically. It enhances the readability.

+struct locomo_bl {

• void __iomem *regs;
• int current_intensity;
• int gpio_fl_vr;

+};

+static const struct {

• u16 duty, bpwf;
• bool vr;

+} locomo_bl_pwm[] = {

• { 0, 161, false },
• { 117, 161, false },
• { 163, 148, false },
• { 194, 161, false },
• { 194, 161, true },

+};

+static int locomo_bl_set_intensity(struct backlight_device *bd) +{

• int intensity = bd->props.brightness;
• struct locomo_bl *bl = dev_get_drvdata(&bd->dev);
• if (bd->props.power != FB_BLANK_UNBLANK)

• intensity = 0;
  

• if (bd->props.fb_blank != FB_BLANK_UNBLANK)

• intensity = 0;
  

• if (bd->props.state & BL_CORE_SUSPENDED)

• intensity = 0;
  

• gpio_set_value(bl->gpio_fl_vr, locomo_bl_pwm[intensity].vr);
• writew(locomo_bl_pwm[intensity].bpwf, bl->regs + LOCOMO_ALS);
• udelay(100);
• writew(locomo_bl_pwm[intensity].duty, bl->regs + LOCOMO_ALD);
• udelay(100);

How about changing udelay() to usleep_range()?

• writew(locomo_bl_pwm[intensity].bpwf | LOCOMO_ALC_EN,

• 	bl->regs + LOCOMO_ALS);
  

• bl->current_intensity = intensity;
• if (bd->props.state & BL_CORE_SUSPENDED)

• writew(0x00, bl->regs + LOCOMO_ALS);
  

• return 0;

+}

+static int locomo_bl_get_intensity(struct backlight_device *bd) +{

• struct locomo_bl *bl = dev_get_drvdata(&bd->dev);
• return bl->current_intensity;

+}

+static const struct backlight_ops locomo_bl_ops = {

• .options = BL_CORE_SUSPENDRESUME,
• .get_brightness = locomo_bl_get_intensity,
• .update_status = locomo_bl_set_intensity,

+};

+static int locomo_bl_probe(struct platform_device *dev) +{

• struct backlight_properties props;
• struct resource *res;
• struct locomo_bl_platform_data *pdata;
• struct locomo_bl *bl;
• struct backlight_device *locomo_bl_device;
• int rc;
• bl = devm_kmalloc(&dev->dev, sizeof(struct locomo_bl), GFP_KERNEL);
• if (!bl)

• return -ENOMEM;
  

• res = platform_get_resource(dev, IORESOURCE_MEM, 0);
• if (!res)

• return -EINVAL;
  

There is no need to check this, because devm_ioremap_resource() will check this.

• bl->regs = devm_ioremap_resource(&dev->dev, res);
• if (!bl->regs)

• return -EINVAL;
  

The correct usage is as follows.

if (IS_ERR(base)) return PTR_ERR(base);

Please change it as below.

res = platform_get_resource(dev, IORESOURCE_MEM, 0); bl->regs = devm_ioremap_resource(&dev->dev, res); if (IS_ERR(bl->regs)) return PTR_ERR(bl->regs);

• pdata = dev_get_platdata(&dev->dev);
• if (!pdata)

• return -EINVAL;
  

• bl->gpio_fl_vr = pdata->gpio_fl_vr;
• rc = devm_gpio_request_one(&dev->dev, bl->gpio_fl_vr,

• 	GPIOF_OUT_INIT_LOW, "FL VR");
  

• if (rc)

• return rc;
  

• writew(0, bl->regs + LOCOMO_ALS);
• writew(0, bl->regs + LOCOMO_ALD);
• memset(&props, 0, sizeof(struct backlight_properties));
• props.type = BACKLIGHT_RAW;
• props.max_brightness = ARRAY_SIZE(locomo_bl_pwm) - 1;
• props.brightness = props.max_brightness / 2;
• locomo_bl_device = backlight_device_register("locomo-bl",

Please use devm_backlight_device_register().

• 				&dev->dev, bl,
  

• 				&locomo_bl_ops, &props);
  

• if (IS_ERR(locomo_bl_device))

• return PTR_ERR(locomo_bl_device);
  

• platform_set_drvdata(dev, locomo_bl_device);
• /* Set up frontlight so that screen is readable */
• backlight_update_status(locomo_bl_device);
• return 0;

+}

+static int locomo_bl_remove(struct platform_device *dev) +{

• struct backlight_device *locomo_bl_device = platform_get_drvdata(dev);
• locomo_bl_device->props.brightness = 0;
• locomo_bl_device->props.power = 0;
• locomo_bl_set_intensity(locomo_bl_device);
• backlight_device_unregister(locomo_bl_device);

If devm_backlight_device_register() is used in probe(), there is no need to call backlight_device_unregister() in remove().

• return 0;

+}

+static void locomo_bl_shutdown(struct platform_device *dev) +{

• struct backlight_device *locomo_bl_device = platform_get_drvdata(dev);
• locomo_bl_device->props.brightness = 0;
• locomo_bl_device->props.power = 0;
• locomo_bl_set_intensity(locomo_bl_device);

+}

+static struct platform_driver locomo_bl_driver = {

• .driver = {

• .name	= "locomo-backlight",
  

• .owner	= THIS_MODULE,
  

• },
• .probe = locomo_bl_probe,
• .remove = locomo_bl_remove,
• /* Turn off bl on power off/reboot */
• .shutdown = locomo_bl_shutdown,

+};

+module_platform_driver(locomo_bl_driver);

+MODULE_AUTHOR("John Lenz lenz@cs.wisc.edu, Pavel Machek pavel@ucw.cz");

This might make checkpatch warning. Please split these authors to lines as below.

MODULE_AUTHOR("John Lenz lenz@cs.wisc.edu"); MODULE_AUTHOR("Pavel Machek pavel@ucw.cz");

+MODULE_DESCRIPTION("Collie Backlight driver");

What does mean 'Collie'? 'Locomo' looks better.

+MODULE_LICENSE("GPL");

How about using "GPL v2"?

Thank you.

Best regards, Jingoo Han

+MODULE_ALIAS("platform:locomo-backlight");

2.1.1