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Diffstat (limited to 'drivers/video')
-rw-r--r--drivers/video/backlight/Kconfig2
-rw-r--r--drivers/video/backlight/pwm_bl.c159
2 files changed, 137 insertions, 24 deletions
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 2979292650d6..cf282763a8dc 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -245,7 +245,7 @@ config BACKLIGHT_CARILLO_RANCH
config BACKLIGHT_PWM
tristate "Generic PWM based Backlight Driver"
- depends on HAVE_PWM
+ depends on PWM
help
If you have a LCD backlight adjustable by PWM, say Y to enable
this driver.
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 342b7d7cbb63..995f0164c9b0 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -26,11 +26,13 @@ struct pwm_bl_data {
struct device *dev;
unsigned int period;
unsigned int lth_brightness;
+ unsigned int *levels;
int (*notify)(struct device *,
int brightness);
void (*notify_after)(struct device *,
int brightness);
int (*check_fb)(struct device *, struct fb_info *);
+ void (*exit)(struct device *);
};
static int pwm_backlight_update_status(struct backlight_device *bl)
@@ -52,9 +54,18 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
pwm_config(pb->pwm, 0, pb->period);
pwm_disable(pb->pwm);
} else {
- brightness = pb->lth_brightness +
- (brightness * (pb->period - pb->lth_brightness) / max);
- pwm_config(pb->pwm, brightness, pb->period);
+ int duty_cycle;
+
+ if (pb->levels) {
+ duty_cycle = pb->levels[brightness];
+ max = pb->levels[max];
+ } else {
+ duty_cycle = brightness;
+ }
+
+ duty_cycle = pb->lth_brightness +
+ (duty_cycle * (pb->period - pb->lth_brightness) / max);
+ pwm_config(pb->pwm, duty_cycle, pb->period);
pwm_enable(pb->pwm);
}
@@ -83,17 +94,98 @@ static const struct backlight_ops pwm_backlight_ops = {
.check_fb = pwm_backlight_check_fb,
};
+#ifdef CONFIG_OF
+static int pwm_backlight_parse_dt(struct device *dev,
+ struct platform_pwm_backlight_data *data)
+{
+ struct device_node *node = dev->of_node;
+ struct property *prop;
+ int length;
+ u32 value;
+ int ret;
+
+ if (!node)
+ return -ENODEV;
+
+ memset(data, 0, sizeof(*data));
+
+ /* determine the number of brightness levels */
+ prop = of_find_property(node, "brightness-levels", &length);
+ if (!prop)
+ return -EINVAL;
+
+ data->max_brightness = length / sizeof(u32);
+
+ /* read brightness levels from DT property */
+ if (data->max_brightness > 0) {
+ size_t size = sizeof(*data->levels) * data->max_brightness;
+
+ data->levels = devm_kzalloc(dev, size, GFP_KERNEL);
+ if (!data->levels)
+ return -ENOMEM;
+
+ ret = of_property_read_u32_array(node, "brightness-levels",
+ data->levels,
+ data->max_brightness);
+ if (ret < 0)
+ return ret;
+
+ ret = of_property_read_u32(node, "default-brightness-level",
+ &value);
+ if (ret < 0)
+ return ret;
+
+ if (value >= data->max_brightness) {
+ dev_warn(dev, "invalid default brightness level: %u, using %u\n",
+ value, data->max_brightness - 1);
+ value = data->max_brightness - 1;
+ }
+
+ data->dft_brightness = value;
+ data->max_brightness--;
+ }
+
+ /*
+ * TODO: Most users of this driver use a number of GPIOs to control
+ * backlight power. Support for specifying these needs to be
+ * added.
+ */
+
+ return 0;
+}
+
+static struct of_device_id pwm_backlight_of_match[] = {
+ { .compatible = "pwm-backlight" },
+ { }
+};
+
+MODULE_DEVICE_TABLE(of, pwm_backlight_of_match);
+#else
+static int pwm_backlight_parse_dt(struct device *dev,
+ struct platform_pwm_backlight_data *data)
+{
+ return -ENODEV;
+}
+#endif
+
static int pwm_backlight_probe(struct platform_device *pdev)
{
- struct backlight_properties props;
struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
+ struct platform_pwm_backlight_data defdata;
+ struct backlight_properties props;
struct backlight_device *bl;
struct pwm_bl_data *pb;
+ unsigned int max;
int ret;
if (!data) {
- dev_err(&pdev->dev, "failed to find platform data\n");
- return -EINVAL;
+ ret = pwm_backlight_parse_dt(&pdev->dev, &defdata);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to find platform data\n");
+ return ret;
+ }
+
+ data = &defdata;
}
if (data->init) {
@@ -109,21 +201,42 @@ static int pwm_backlight_probe(struct platform_device *pdev)
goto err_alloc;
}
- pb->period = data->pwm_period_ns;
+ if (data->levels) {
+ max = data->levels[data->max_brightness];
+ pb->levels = data->levels;
+ } else
+ max = data->max_brightness;
+
pb->notify = data->notify;
pb->notify_after = data->notify_after;
pb->check_fb = data->check_fb;
- pb->lth_brightness = data->lth_brightness *
- (data->pwm_period_ns / data->max_brightness);
+ pb->exit = data->exit;
pb->dev = &pdev->dev;
- pb->pwm = pwm_request(data->pwm_id, "backlight");
+ pb->pwm = pwm_get(&pdev->dev, NULL);
if (IS_ERR(pb->pwm)) {
- dev_err(&pdev->dev, "unable to request PWM for backlight\n");
- ret = PTR_ERR(pb->pwm);
- goto err_alloc;
- } else
- dev_dbg(&pdev->dev, "got pwm for backlight\n");
+ dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
+
+ pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
+ if (IS_ERR(pb->pwm)) {
+ dev_err(&pdev->dev, "unable to request legacy PWM\n");
+ ret = PTR_ERR(pb->pwm);
+ goto err_alloc;
+ }
+ }
+
+ dev_dbg(&pdev->dev, "got pwm for backlight\n");
+
+ /*
+ * The DT case will set the pwm_period_ns field to 0 and store the
+ * period, parsed from the DT, in the PWM device. For the non-DT case,
+ * set the period from platform data.
+ */
+ if (data->pwm_period_ns > 0)
+ pwm_set_period(pb->pwm, data->pwm_period_ns);
+
+ pb->period = pwm_get_period(pb->pwm);
+ pb->lth_brightness = data->lth_brightness * (pb->period / max);
memset(&props, 0, sizeof(struct backlight_properties));
props.type = BACKLIGHT_RAW;
@@ -143,7 +256,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
return 0;
err_bl:
- pwm_free(pb->pwm);
+ pwm_put(pb->pwm);
err_alloc:
if (data->exit)
data->exit(&pdev->dev);
@@ -152,16 +265,15 @@ err_alloc:
static int pwm_backlight_remove(struct platform_device *pdev)
{
- struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
struct backlight_device *bl = platform_get_drvdata(pdev);
struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
backlight_device_unregister(bl);
pwm_config(pb->pwm, 0, pb->period);
pwm_disable(pb->pwm);
- pwm_free(pb->pwm);
- if (data->exit)
- data->exit(&pdev->dev);
+ pwm_put(pb->pwm);
+ if (pb->exit)
+ pb->exit(&pdev->dev);
return 0;
}
@@ -195,11 +307,12 @@ static SIMPLE_DEV_PM_OPS(pwm_backlight_pm_ops, pwm_backlight_suspend,
static struct platform_driver pwm_backlight_driver = {
.driver = {
- .name = "pwm-backlight",
- .owner = THIS_MODULE,
+ .name = "pwm-backlight",
+ .owner = THIS_MODULE,
#ifdef CONFIG_PM
- .pm = &pwm_backlight_pm_ops,
+ .pm = &pwm_backlight_pm_ops,
#endif
+ .of_match_table = of_match_ptr(pwm_backlight_of_match),
},
.probe = pwm_backlight_probe,
.remove = pwm_backlight_remove,
generated by cgit v1.2.3-58-ga151 (git 2.39.0) at 2024-12-19 08:50:48 +0000