Add driver for generic power sequence support for USB deivces which handles below things: - Clock and its frequencies - GPIO for reset and the duration time - GPIO for enable - Regulator for power Signed-off-by: Peter Chen <peter.chen@xxxxxxx> --- drivers/power/pwrseq/Kconfig | 11 ++ drivers/power/pwrseq/Makefile | 1 + drivers/power/pwrseq/pwrseq_usb_generic.c | 202 ++++++++++++++++++++++++++++++ 3 files changed, 214 insertions(+) create mode 100644 drivers/power/pwrseq/pwrseq_usb_generic.c diff --git a/drivers/power/pwrseq/Kconfig b/drivers/power/pwrseq/Kconfig index c7e9271..9749c6d 100644 --- a/drivers/power/pwrseq/Kconfig +++ b/drivers/power/pwrseq/Kconfig @@ -29,4 +29,15 @@ config POWER_SEQ_SIMPLE This driver can also be built as a module. If so, the module will be called pwrseq_simple. +config POWER_SEQ_USB_GENERIC + tristate "Generic power sequence support for USB devices" + default y + depends on OF || COMPILE_TEST + help + This selects generic power sequence support for USB devices. + By default this option is set to y. + + This driver can also be built as a module. If so, the module + will be called pwrseq_usb_generic. + endif diff --git a/drivers/power/pwrseq/Makefile b/drivers/power/pwrseq/Makefile index d475e01..230bb45 100644 --- a/drivers/power/pwrseq/Makefile +++ b/drivers/power/pwrseq/Makefile @@ -1,3 +1,4 @@ obj-$(CONFIG_POWER_SEQ) += core.o obj-$(CONFIG_POWER_SEQ_SIMPLE) += pwrseq_mmc_simple.o obj-$(CONFIG_POWER_SEQ_EMMC) += pwrseq_emmc.o +obj-$(CONFIG_POWER_SEQ_USB_GENERIC) += pwrseq_usb_generic.o diff --git a/drivers/power/pwrseq/pwrseq_usb_generic.c b/drivers/power/pwrseq/pwrseq_usb_generic.c new file mode 100644 index 0000000..6017636 --- /dev/null +++ b/drivers/power/pwrseq/pwrseq_usb_generic.c @@ -0,0 +1,202 @@ +/* + * usb_generic.c The generic power sequence driver for USB device + * + * Copyright (C) 2016 Freescale Semiconductor, Inc. + * Author: Peter Chen <peter.chen@xxxxxxx> + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 of + * the License as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/gpio/consumer.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/module.h> +#include <linux/regulator/consumer.h> +#include <linux/slab.h> +#include <linux/pwrseq.h> + +struct usb_pwrseq_generic { + struct pwrseq pwrseq; + struct gpio_desc *gpiod_reset; + struct gpio_desc *gpiod_enable; + struct clk *clk; + struct regulator *reg_power; +}; + +#define to_pwrseq_generic(p) container_of(p, struct usb_pwrseq_generic, pwrseq) + +static void usb_pwrseq_power_off(struct pwrseq *_pwrseq) +{ + struct usb_pwrseq_generic *pwrseq = to_pwrseq_generic(_pwrseq); + + if (pwrseq->clk) + clk_disable_unprepare(pwrseq->clk); + + if (pwrseq->gpiod_enable) + gpiod_set_value(pwrseq->gpiod_enable, 0); + + if (pwrseq->reg_power) + regulator_disable(pwrseq->reg_power); +} + +static int usb_pwrseq_power_on(struct pwrseq *_pwrseq) +{ + struct usb_pwrseq_generic *pwrseq = to_pwrseq_generic(_pwrseq); + struct gpio_desc *gpiod_reset = pwrseq->gpiod_reset; + struct gpio_desc *gpiod_enable = pwrseq->gpiod_enable; + struct device *dev = _pwrseq->dev; + struct device_node *node = dev->of_node; + u32 duration_us = 50, clk_rate = 0; + int ret; + + if (pwrseq->clk) { + ret = clk_prepare_enable(pwrseq->clk); + if (ret) { + dev_err(dev, + "Can't enable external clock: %d\n", + ret); + return ret; + } + + of_property_read_u32(node, "clock-frequency", &clk_rate); + if (clk_rate) { + ret = clk_set_rate(pwrseq->clk, clk_rate); + if (ret) { + dev_err(dev, "Error setting clock rate\n"); + goto disable_clk; + } + } + } + + if (gpiod_reset) { + of_property_read_u32(node, "reset-duration-us", &duration_us); + gpiod_direction_output(gpiod_reset, 1); + + gpiod_set_value(gpiod_reset, 1); + usleep_range(duration_us, duration_us + 10); + gpiod_set_value(gpiod_reset, 0); + } + + if (gpiod_enable) { + gpiod_direction_output(gpiod_enable, 1); + gpiod_set_value(gpiod_enable, 1); + } + + if (pwrseq->reg_power) { + ret = regulator_enable(pwrseq->reg_power); + if (ret) { + dev_err(dev, "Failed to power regulator, ret=%d\n", + ret); + goto disable_gpio; + } + } + + return 0; + +disable_gpio: + if (gpiod_enable) + gpiod_set_value(gpiod_enable, 0); + +disable_clk: + if (pwrseq->clk) + clk_disable_unprepare(pwrseq->clk); + return ret; +} + +static const struct pwrseq_ops usb_pwrseq_generic_ops = { + .pre_power_on = usb_pwrseq_power_on, + .power_off = usb_pwrseq_power_off, +}; + +static const struct of_device_id usb_pwrseq_generic_of_match[] = { + { .compatible = "usb-pwrseq-generic",}, + {/* sentinel */}, +}; +MODULE_DEVICE_TABLE(of, usb_pwrseq_generic_of_match); + +static int usb_pwrseq_generic_probe(struct platform_device *pdev) +{ + struct usb_pwrseq_generic *pwrseq; + struct device *dev = &pdev->dev; + struct regulator *reg; + int ret; + + pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL); + if (!pwrseq) + return -ENOMEM; + + pwrseq->clk = devm_clk_get(dev, NULL); + if (IS_ERR(pwrseq->clk)) { + dev_dbg(dev, "Can't get clock: %ld\n", + PTR_ERR(pwrseq->clk)); + pwrseq->clk = NULL; + } + + pwrseq->gpiod_reset = devm_gpiod_get_optional(dev, "reset", + GPIOD_ASIS); + ret = PTR_ERR_OR_ZERO(pwrseq->gpiod_reset); + if (ret) { + dev_err(dev, "Failed to get reset gpio, err = %d\n", ret); + return ret; + } + + pwrseq->gpiod_enable = devm_gpiod_get_optional(dev, "enable", + GPIOD_ASIS); + ret = PTR_ERR_OR_ZERO(pwrseq->gpiod_enable); + if (ret) { + dev_err(dev, "Failed to get enable gpio, err = %d\n", ret); + return ret; + } + + reg = devm_regulator_get(dev, "power"); + if (PTR_ERR(reg) == -EPROBE_DEFER) + return -EPROBE_DEFER; + else if (PTR_ERR(reg) == -ENODEV) + /* no power regulator is needed */ + reg = NULL; + else if (IS_ERR(reg)) + return PTR_ERR(reg); + pwrseq->reg_power = reg; + + pwrseq->pwrseq.dev = dev; + pwrseq->pwrseq.ops = &usb_pwrseq_generic_ops; + pwrseq->pwrseq.owner = THIS_MODULE; + platform_set_drvdata(pdev, pwrseq); + + return pwrseq_register(&pwrseq->pwrseq); +} + +static int usb_pwrseq_generic_remove(struct platform_device *pdev) +{ + struct usb_pwrseq_generic *pwrseq = platform_get_drvdata(pdev); + + pwrseq_unregister(&pwrseq->pwrseq); + + return 0; +} + +static struct platform_driver usb_pwrseq_generic_driver = { + .probe = usb_pwrseq_generic_probe, + .remove = usb_pwrseq_generic_remove, + .driver = { + .name = "usb_pwrseq_generic", + .of_match_table = usb_pwrseq_generic_of_match, + }, +}; + +module_platform_driver(usb_pwrseq_generic_driver); +MODULE_LICENSE("GPL v2"); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
