Make use of the power sequences specified in the device tree or platform data, if any.
Signed-off-by: Alexandre Courbot <[email protected]> --- .../bindings/video/backlight/pwm-backlight.txt | 55 +++++- drivers/video/backlight/Kconfig | 1 + drivers/video/backlight/pwm_bl.c | 213 +++++++++++++++------ include/linux/pwm_backlight.h | 18 +- 4 files changed, 225 insertions(+), 62 deletions(-) diff --git a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt index 1e4fc72..59abeba 100644 --- a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt +++ b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt @@ -2,7 +2,6 @@ pwm-backlight bindings Required properties: - compatible: "pwm-backlight" - - pwms: OF device-tree PWM specification (see PWM binding[0]) - brightness-levels: Array of distinct brightness levels. Typically these are in the range from 0 to 255, but any range starting at 0 will do. The actual brightness level (PWM duty cycle) will be interpolated @@ -10,10 +9,22 @@ Required properties: last value in the array represents a 100% duty cycle (brightest). - default-brightness-level: the default brightness level (index into the array defined by the "brightness-levels" property) + - pwms: OF device-tree PWM specification (see PWM binding[0]). Exactly one PWM + must be specified + - pwm-names: a list of names for the PWM devices specified in the + "pwms" property (see PWM binding[0]) + - power-on-sequence: Power sequence that will bring the backlight on. This + sequence must reference the PWM specified in the pwms property by its + name. It can also reference extra GPIOs or regulators, and introduce + delays between sequence steps + - power-off-sequence: Power sequence that will bring the backlight off. This + sequence must reference the PWM specified in the pwms property by its + name. It can also reference extra GPIOs or regulators, and introduce + delays between sequence steps Optional properties: - - pwm-names: a list of names for the PWM devices specified in the - "pwms" property (see PWM binding[0]) + - *-supply: regulators used within a power sequence + - *-gpio: GPIOs used within a power sequence [0]: Documentation/devicetree/bindings/pwm/pwm.txt @@ -21,8 +32,42 @@ Example: backlight { compatible = "pwm-backlight"; - pwms = <&pwm 0 5000000>; - brightness-levels = <0 4 8 16 32 64 128 255>; default-brightness-level = <6>; + + pwms = <&pwm 0 5000000>; + pwm-names = "backlight"; + power-supply = <&backlight_reg>; + enable-gpio = <&gpio 6 0>; + + power-on-sequence { + regulator@0 { + id = "power"; + enable; + post-delay = <10>; + }; + pwm@1 { + id = "backlight"; + enable; + }; + gpio@2 { + id = "enable-gpio"; + enable; + }; + }; + power-off-sequence { + gpio@0 { + id = "enable-gpio"; + disable; + }; + pwm@1 { + id = "backlight"; + disable; + }; + regulator@2 { + id = "power"; + disable; + pre-delay = <10>; + }; + }; }; diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig index cf28276..6fb8aa3 100644 --- a/drivers/video/backlight/Kconfig +++ b/drivers/video/backlight/Kconfig @@ -246,6 +246,7 @@ config BACKLIGHT_CARILLO_RANCH config BACKLIGHT_PWM tristate "Generic PWM based Backlight Driver" depends on PWM + select POWER_SEQ 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 995f016..6e3a49e 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -27,6 +27,12 @@ struct pwm_bl_data { unsigned int period; unsigned int lth_brightness; unsigned int *levels; + bool enabled; + power_seq_resources resources; + power_seq *power_on_seq; + power_seq *power_off_seq; + + /* Legacy callbacks */ int (*notify)(struct device *, int brightness); void (*notify_after)(struct device *, @@ -35,6 +41,34 @@ struct pwm_bl_data { void (*exit)(struct device *); }; +static void pwm_backlight_on(struct backlight_device *bl) +{ + struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev); + int ret; + + if (pb->enabled) + return; + + if ((ret = power_seq_run(pb->dev, pb->power_on_seq)) < 0) + dev_err(&bl->dev, "cannot run power on sequence\n"); + + pb->enabled = true; +} + +static void pwm_backlight_off(struct backlight_device *bl) +{ + struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev); + int ret; + + if (!pb->enabled) + return; + + if ((ret = power_seq_run(pb->dev, pb->power_off_seq)) < 0) + dev_err(&bl->dev, "cannot run power off sequence\n"); + + pb->enabled = false; +} + static int pwm_backlight_update_status(struct backlight_device *bl) { struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev); @@ -51,8 +85,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl) brightness = pb->notify(pb->dev, brightness); if (brightness == 0) { - pwm_config(pb->pwm, 0, pb->period); - pwm_disable(pb->pwm); + pwm_backlight_off(bl); } else { int duty_cycle; @@ -66,7 +99,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl) 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); + pwm_backlight_on(bl); } if (pb->notify_after) @@ -145,12 +178,16 @@ static int pwm_backlight_parse_dt(struct device *dev, 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. - */ + data->power_on_seq = of_parse_power_seq(dev, of_find_node_by_name(node, + "power-on-sequence")); + if (IS_ERR(data->power_on_seq)) + return PTR_ERR(data->power_on_seq); + data->power_off_seq = of_parse_power_seq(dev, of_find_node_by_name(node, + "power-off-sequence")); + if (IS_ERR(data->power_off_seq)) + return PTR_ERR(data->power_off_seq); + data->use_power_sequences = true; return 0; } @@ -168,73 +205,141 @@ static int pwm_backlight_parse_dt(struct device *dev, } #endif +/** + * Construct the power sequences corresponding to the legacy platform data. + */ +static int pwm_backlight_legacy_probe(struct platform_device *pdev, + struct pwm_bl_data *pb) +{ + struct platform_pwm_backlight_data *data = pdev->dev.platform_data; + struct device *dev = &pdev->dev; + struct power_seq_resource *res; + struct power_seq_step *step; + + pb->pwm = pwm_get(dev, NULL); + if (IS_ERR(pb->pwm)) { + dev_warn(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(dev, "unable to request legacy PWM\n"); + return PTR_ERR(pb->pwm); + } + pwm_set_period(pb->pwm, data->pwm_period_ns); + } + + pb->notify = data->notify; + pb->notify_after = data->notify_after; + pb->check_fb = data->check_fb; + pb->exit = data->exit; + pb->dev = dev; + + /* Now build the resources and sequences corresponding to this PWM */ + res = devm_kzalloc(dev, sizeof(*res), GFP_KERNEL); + if (!res) return -ENOMEM; + res->type = POWER_SEQ_PWM; + res->id = "pwm-backlight"; + res->pwm = pb->pwm; + list_add(&res->list, &pb->resources); + + /* allocate both power on and off sequences at the same time */ + step = devm_kzalloc(dev, sizeof(*step) * 4, GFP_KERNEL); + if (!step) return -ENOMEM; + step->resource = res; + memcpy(&step[2], &step[0], sizeof(*step)); + step[0].params.enable = 1; + pb->power_on_seq = &step[0]; + pb->power_off_seq = &step[2]; + + return 0; +} + static int pwm_backlight_probe(struct platform_device *pdev) { struct platform_pwm_backlight_data *data = pdev->dev.platform_data; struct platform_pwm_backlight_data defdata; + struct power_seq_resource *res; struct backlight_properties props; struct backlight_device *bl; struct pwm_bl_data *pb; unsigned int max; int ret; + pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL); + if (!pb) { + dev_err(&pdev->dev, "no memory for state\n"); + return -ENOMEM; + } + + INIT_LIST_HEAD(&pb->resources); + + /* using new interface or device tree */ if (!data) { + /* build platform data from device tree */ ret = pwm_backlight_parse_dt(&pdev->dev, &defdata); - if (ret < 0) { + if (ret == -EPROBE_DEFER) { + return ret; + } else if (ret < 0) { dev_err(&pdev->dev, "failed to find platform data\n"); return ret; } - data = &defdata; } - if (data->init) { - ret = data->init(&pdev->dev); + if (!data->use_power_sequences) { + /* using legacy interface */ + ret = pwm_backlight_legacy_probe(pdev, pb); if (ret < 0) return ret; + } else { + /* build sequences and allocate resources from platform data */ + if (data->power_on_seq) { + pb->power_on_seq = power_seq_build(&pdev->dev, + &pb->resources, + data->power_on_seq); + if (IS_ERR(pb->power_on_seq)) + return PTR_ERR(pb->power_on_seq); + } + if (data->power_off_seq) { + pb->power_off_seq = power_seq_build(&pdev->dev, + &pb->resources, + data->power_off_seq); + if (IS_ERR(pb->power_off_seq)) + return PTR_ERR(pb->power_off_seq); + } + + /* we must have exactly one PWM for this driver */ + list_for_each_entry(res, &pb->resources, list) { + if (res->type != POWER_SEQ_PWM) + continue; + if (pb->pwm) { + dev_err(&pdev->dev, "more than one PWM used\n"); + return -EINVAL; + } + /* keep the pwm at hand */ + pb->pwm = res->pwm; + } } - pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL); - if (!pb) { - dev_err(&pdev->dev, "no memory for state\n"); - ret = -ENOMEM; - goto err_alloc; + /* from here we should have a PWM */ + if (!pb->pwm) { + dev_err(&pdev->dev, "no PWM defined!\n"); + return -EINVAL; + } + + if (data->init) { + ret = data->init(&pdev->dev); + if (ret < 0) + goto err; } if (data->levels) { max = data->levels[data->max_brightness]; pb->levels = data->levels; - } else + } else { max = data->max_brightness; - - pb->notify = data->notify; - pb->notify_after = data->notify_after; - pb->check_fb = data->check_fb; - pb->exit = data->exit; - pb->dev = &pdev->dev; - - pb->pwm = pwm_get(&pdev->dev, NULL); - if (IS_ERR(pb->pwm)) { - 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); @@ -246,20 +351,20 @@ static int pwm_backlight_probe(struct platform_device *pdev) if (IS_ERR(bl)) { dev_err(&pdev->dev, "failed to register backlight\n"); ret = PTR_ERR(bl); - goto err_bl; + goto err; } bl->props.brightness = data->dft_brightness; backlight_update_status(bl); platform_set_drvdata(pdev, bl); + return 0; -err_bl: - pwm_put(pb->pwm); -err_alloc: +err: if (data->exit) data->exit(&pdev->dev); + power_seq_free_resources(&pb->resources); return ret; } @@ -269,9 +374,9 @@ static int pwm_backlight_remove(struct platform_device *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_put(pb->pwm); + pwm_backlight_off(bl); + power_seq_free_resources(&pb->resources); + if (pb->exit) pb->exit(&pdev->dev); return 0; @@ -285,8 +390,7 @@ static int pwm_backlight_suspend(struct device *dev) if (pb->notify) pb->notify(pb->dev, 0); - pwm_config(pb->pwm, 0, pb->period); - pwm_disable(pb->pwm); + pwm_backlight_off(bl); if (pb->notify_after) pb->notify_after(pb->dev, 0); return 0; @@ -323,4 +427,3 @@ module_platform_driver(pwm_backlight_driver); MODULE_DESCRIPTION("PWM based Backlight Driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:pwm-backlight"); - diff --git a/include/linux/pwm_backlight.h b/include/linux/pwm_backlight.h index 56f4a86..3e8bd2c 100644 --- a/include/linux/pwm_backlight.h +++ b/include/linux/pwm_backlight.h @@ -5,14 +5,28 @@ #define __LINUX_PWM_BACKLIGHT_H #include <linux/backlight.h> +#include <linux/power_seq.h> struct platform_pwm_backlight_data { - int pwm_id; unsigned int max_brightness; unsigned int dft_brightness; unsigned int lth_brightness; - unsigned int pwm_period_ns; unsigned int *levels; + /* Set this to true otherwise the legacy interface will be used */ + bool use_power_sequences; + /* + * New interface - arrays of steps terminated by a STOP instance, or + * NULL if unused. + */ + struct platform_power_seq_step *power_on_seq; + struct platform_power_seq_step *power_off_seq; + /* + * Legacy interface - single PWM and callback methods to control + * the power sequence. pwm_id and pwm_period_ns need only be specified + * if get_pwm(dev, NULL) will return NULL. + */ + int pwm_id; + unsigned int pwm_period_ns; int (*init)(struct device *dev); int (*notify)(struct device *dev, int brightness); void (*notify_after)(struct device *dev, int brightness); -- 1.7.11.3 -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
