diff options
| -rw-r--r-- | doc/device-tree-bindings/pwm/cros-ec-pwm.txt | 23 | ||||
| -rw-r--r-- | drivers/misc/cros_ec.c | 17 | ||||
| -rw-r--r-- | drivers/pwm/Kconfig | 9 | ||||
| -rw-r--r-- | drivers/pwm/Makefile | 1 | ||||
| -rw-r--r-- | drivers/pwm/cros_ec_pwm.c | 84 | ||||
| -rw-r--r-- | include/cros_ec.h | 13 |
6 files changed, 147 insertions, 0 deletions
diff --git a/doc/device-tree-bindings/pwm/cros-ec-pwm.txt b/doc/device-tree-bindings/pwm/cros-ec-pwm.txt new file mode 100644 index 0000000000..f198d08891 --- /dev/null +++ b/doc/device-tree-bindings/pwm/cros-ec-pwm.txt @@ -0,0 +1,23 @@ +PWM controlled by ChromeOS EC + +Google's ChromeOS EC PWM is a simple PWM attached to the Embedded Controller +(EC) and controlled via a host-command interface. + +An EC PWM node should be only found as a sub-node of the EC node (see +doc/device-tree-bindings/misc/cros-ec.txt). + +Required properties: +- compatible: Must contain "google,cros-ec-pwm" +- #pwm-cells: Should be 1. The cell specifies the PWM index. + +Example: + cros-ec@0 { + compatible = "google,cros-ec-spi"; + + ... + + cros_ec_pwm: ec-pwm { + compatible = "google,cros-ec-pwm"; + #pwm-cells = <1>; + }; + }; diff --git a/drivers/misc/cros_ec.c b/drivers/misc/cros_ec.c index ebfa7c41c2..7904d5cc72 100644 --- a/drivers/misc/cros_ec.c +++ b/drivers/misc/cros_ec.c @@ -1170,6 +1170,23 @@ int cros_ec_battery_cutoff(struct udevice *dev, uint8_t flags) return 0; } +int cros_ec_set_pwm_duty(struct udevice *dev, uint8_t index, uint16_t duty) +{ + struct ec_params_pwm_set_duty p; + int ret; + + p.duty = duty; + p.pwm_type = EC_PWM_TYPE_GENERIC; + p.index = index; + + ret = ec_command(dev, EC_CMD_PWM_SET_DUTY, 0, &p, sizeof(p), + NULL, 0); + if (ret < 0) + return ret; + + return 0; +} + int cros_ec_set_ldo(struct udevice *dev, uint8_t index, uint8_t state) { struct ec_params_ldo_set params; diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index ccf81abbe9..cf7f4c6840 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -9,6 +9,15 @@ config DM_PWM frequency/period can be controlled along with the proportion of that time that the signal is high. +config PWM_CROS_EC + bool "Enable support for the Chrome OS EC PWM" + depends on DM_PWM + help + This PWM is found on several Chrome OS devices and controlled by + the Chrome OS embedded controller. It may be used to control the + screen brightness and/or the keyboard backlight depending on the + device. + config PWM_EXYNOS bool "Enable support for the Exynos PWM" depends on DM_PWM diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index 0b9d2698a3..10d244bfb7 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -10,6 +10,7 @@ obj-$(CONFIG_DM_PWM) += pwm-uclass.o +obj-$(CONFIG_PWM_CROS_EC) += cros_ec_pwm.o obj-$(CONFIG_PWM_EXYNOS) += exynos_pwm.o obj-$(CONFIG_PWM_IMX) += pwm-imx.o pwm-imx-util.o obj-$(CONFIG_PWM_MESON) += pwm-meson.o diff --git a/drivers/pwm/cros_ec_pwm.c b/drivers/pwm/cros_ec_pwm.c new file mode 100644 index 0000000000..44f4105dfd --- /dev/null +++ b/drivers/pwm/cros_ec_pwm.c @@ -0,0 +1,84 @@ +// SPDX-License-Identifier: GPL-2.0+ + +#include <common.h> +#include <cros_ec.h> +#include <dm.h> +#include <errno.h> +#include <log.h> +#include <pwm.h> + +struct cros_ec_pwm_priv { + bool enabled; + uint duty; +}; + +static int cros_ec_pwm_set_config(struct udevice *dev, uint channel, + uint period_ns, uint duty_ns) +{ + struct cros_ec_pwm_priv *priv = dev_get_priv(dev); + uint duty; + int ret; + + debug("%s: period_ns=%u, duty_ns=%u asked\n", __func__, + period_ns, duty_ns); + + /* No way to set the period, only a relative duty cycle */ + duty = EC_PWM_MAX_DUTY * duty_ns / period_ns; + if (duty > EC_PWM_MAX_DUTY) + duty = EC_PWM_MAX_DUTY; + + if (!priv->enabled) { + priv->duty = duty; + debug("%s: duty=%#x to-be-set\n", __func__, duty); + return 0; + } + + ret = cros_ec_set_pwm_duty(dev->parent, channel, duty); + if (ret) { + debug("%s: duty=%#x failed\n", __func__, duty); + return ret; + } + + priv->duty = duty; + debug("%s: duty=%#x set\n", __func__, duty); + + return 0; +} + +static int cros_ec_pwm_set_enable(struct udevice *dev, uint channel, + bool enable) +{ + struct cros_ec_pwm_priv *priv = dev_get_priv(dev); + int ret; + + ret = cros_ec_set_pwm_duty(dev->parent, channel, + enable ? priv->duty : 0); + if (ret) { + debug("%s: enable=%d failed\n", __func__, enable); + return ret; + } + + priv->enabled = enable; + debug("%s: enable=%d (duty=%#x) set\n", __func__, + enable, priv->duty); + + return 0; +} + +static const struct pwm_ops cros_ec_pwm_ops = { + .set_config = cros_ec_pwm_set_config, + .set_enable = cros_ec_pwm_set_enable, +}; + +static const struct udevice_id cros_ec_pwm_ids[] = { + { .compatible = "google,cros-ec-pwm" }, + { } +}; + +U_BOOT_DRIVER(cros_ec_pwm) = { + .name = "cros_ec_pwm", + .id = UCLASS_PWM, + .of_match = cros_ec_pwm_ids, + .ops = &cros_ec_pwm_ops, + .priv_auto_alloc_size = sizeof(struct cros_ec_pwm_priv), +}; diff --git a/include/cros_ec.h b/include/cros_ec.h index eddc23d48f..9396b4d246 100644 --- a/include/cros_ec.h +++ b/include/cros_ec.h @@ -513,6 +513,19 @@ int cros_ec_efs_verify(struct udevice *dev, enum ec_flash_region region); int cros_ec_battery_cutoff(struct udevice *dev, uint8_t flags); /** + * cros_ec_set_pwm_duty() - Set duty cycle of a generic pwm + * + * Note that duty value needs to be passed to the EC as a 16 bit number + * for increased precision. + * + * @param dev CROS-EC device + * @param index Index of the pwm + * @param duty Desired duty cycle, in 0..EC_PWM_MAX_DUTY range. + * @return 0 if OK, -ve on error + */ +int cros_ec_set_pwm_duty(struct udevice *dev, uint8_t index, uint16_t duty); + +/** * cros_ec_read_limit_power() - Check if power is limited by batter/charger * * Sometimes the battery is low and / or the device is connected to a charger |