On Mon, Nov 14, 2016 at 09:35:53AM +0800, Peter Chen wrote: > We have an well-known problem that the device needs to do some power > sequence before it can be recognized by related host, the typical > example like hard-wired mmc devices and usb devices. > > This power sequence is hard to be described at device tree and handled by > related host driver, so we have created a common power sequence > library to cover this requirement. The core code has supplied > some common helpers for host driver, and individual power sequence > libraries handle kinds of power sequence for devices. The pwrseq > librares always need to allocate extra instance for compatible > string match. > > pwrseq_generic is intended for general purpose of power sequence, which > handles gpios and clocks currently, and can cover other controls in > future. The host driver just needs to call of_pwrseq_on/of_pwrseq_off > if only one power sequence is needed, else call of_pwrseq_on_list > /of_pwrseq_off_list instead (eg, USB hub driver). > > For new power sequence library, it can add its compatible string > to pwrseq_of_match_table, then the pwrseq core will match it with > DT's, and choose this library at runtime. > Rafael, would you get any chances to review this version, it makes some changes according to your comments, I hope this patch set could be in v4.10-rc1, thanks. Peter > Signed-off-by: Peter Chen <peter.chen@xxxxxxx> > Tested-by: Maciej S. Szmigiero <mail@xxxxxxxxxxxxxxxxxxxxx> > Tested-by Joshua Clayton <stillcompiling@xxxxxxxxx> > Reviewed-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx> > Tested-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx> > --- > MAINTAINERS | 9 ++ > drivers/power/Kconfig | 1 + > drivers/power/Makefile | 1 + > drivers/power/pwrseq/Kconfig | 21 +++ > drivers/power/pwrseq/Makefile | 2 + > drivers/power/pwrseq/core.c | 237 ++++++++++++++++++++++++++++++++++ > drivers/power/pwrseq/pwrseq_generic.c | 183 ++++++++++++++++++++++++++ > include/linux/power/pwrseq.h | 60 +++++++++ > 8 files changed, 514 insertions(+) > create mode 100644 drivers/power/pwrseq/Kconfig > create mode 100644 drivers/power/pwrseq/Makefile > create mode 100644 drivers/power/pwrseq/core.c > create mode 100644 drivers/power/pwrseq/pwrseq_generic.c > create mode 100644 include/linux/power/pwrseq.h > > diff --git a/MAINTAINERS b/MAINTAINERS > index 3d838cf..066b1e4 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -9621,6 +9621,15 @@ F: include/linux/pm_* > F: include/linux/powercap.h > F: drivers/powercap/ > > +POWER SEQUENCE LIBRARY > +M: Peter Chen <Peter.Chen@xxxxxxx> > +T: git git://git.kernel.org/pub/scm/linux/kernel/git/peter.chen/usb.git > +L: linux-pm@xxxxxxxxxxxxxxx > +S: Maintained > +F: Documentation/devicetree/bindings/power/pwrseq/ > +F: drivers/power/pwrseq/ > +F: include/linux/power/pwrseq.h/ > + > POWER SUPPLY CLASS/SUBSYSTEM and DRIVERS > M: Sebastian Reichel <sre@xxxxxxxxxx> > L: linux-pm@xxxxxxxxxxxxxxx > diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig > index 63454b5..c1bb046 100644 > --- a/drivers/power/Kconfig > +++ b/drivers/power/Kconfig > @@ -1,3 +1,4 @@ > source "drivers/power/avs/Kconfig" > source "drivers/power/reset/Kconfig" > source "drivers/power/supply/Kconfig" > +source "drivers/power/pwrseq/Kconfig" > diff --git a/drivers/power/Makefile b/drivers/power/Makefile > index ff35c71..7db8035 100644 > --- a/drivers/power/Makefile > +++ b/drivers/power/Makefile > @@ -1,3 +1,4 @@ > obj-$(CONFIG_POWER_AVS) += avs/ > obj-$(CONFIG_POWER_RESET) += reset/ > obj-$(CONFIG_POWER_SUPPLY) += supply/ > +obj-$(CONFIG_POWER_SEQUENCE) += pwrseq/ > diff --git a/drivers/power/pwrseq/Kconfig b/drivers/power/pwrseq/Kconfig > new file mode 100644 > index 0000000..88f5597 > --- /dev/null > +++ b/drivers/power/pwrseq/Kconfig > @@ -0,0 +1,21 @@ > +# > +# Power Sequence library > +# > + > +menuconfig POWER_SEQUENCE > + bool "Power sequence control" > + depends on OF > + help > + It is used for drivers which needs to do power sequence > + (eg, turn on clock, toggle reset gpio) before the related > + devices can be found by hardware, eg, USB bus. > + > +if POWER_SEQUENCE > + > +config PWRSEQ_GENERIC > + bool "Generic power sequence control" > + default y > + help > + This is the generic power sequence control library, and is > + supposed to support common power sequence usage. > +endif > diff --git a/drivers/power/pwrseq/Makefile b/drivers/power/pwrseq/Makefile > new file mode 100644 > index 0000000..ad82389 > --- /dev/null > +++ b/drivers/power/pwrseq/Makefile > @@ -0,0 +1,2 @@ > +obj-$(CONFIG_POWER_SEQUENCE) += core.o > +obj-$(CONFIG_PWRSEQ_GENERIC) += pwrseq_generic.o > diff --git a/drivers/power/pwrseq/core.c b/drivers/power/pwrseq/core.c > new file mode 100644 > index 0000000..e3c1fbb > --- /dev/null > +++ b/drivers/power/pwrseq/core.c > @@ -0,0 +1,237 @@ > +/* > + * core.c power sequence core file > + * > + * 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/list.h> > +#include <linux/mutex.h> > +#include <linux/of.h> > +#include <linux/slab.h> > +#include <linux/power/pwrseq.h> > + > +static DEFINE_MUTEX(pwrseq_list_mutex); > +static LIST_HEAD(pwrseq_list); > + > +static int pwrseq_get(struct device_node *np, struct pwrseq *p) > +{ > + if (p && p->get) > + return p->get(np, p); > + > + return -ENOTSUPP; > +} > + > +static int pwrseq_on(struct pwrseq *p) > +{ > + if (p && p->on) > + return p->on(p); > + > + return -ENOTSUPP; > +} > + > +static void pwrseq_off(struct pwrseq *p) > +{ > + if (p && p->off) > + p->off(p); > +} > + > +static void pwrseq_put(struct pwrseq *p) > +{ > + if (p && p->put) > + p->put(p); > +} > + > +static int pwrseq_suspend(struct pwrseq *p) > +{ > + if (p && p->suspend) > + return p->suspend(p); > + > + return 0; > +} > + > +static int pwrseq_resume(struct pwrseq *p) > +{ > + if (p && p->resume) > + return p->resume(p); > + > + return 0; > +} > + > +/** > + * pwrseq_register: add pwrseq instance to global pwrseq list > + * > + * @pwrseq: the pwrseq instance > + */ > +void pwrseq_register(struct pwrseq *pwrseq) > +{ > + mutex_lock(&pwrseq_list_mutex); > + list_add(&pwrseq->node, &pwrseq_list); > + mutex_unlock(&pwrseq_list_mutex); > +} > +EXPORT_SYMBOL_GPL(pwrseq_register); > + > +/** > + * pwrseq_unregister: remove pwrseq instance from global pwrseq list > + * > + * @pwrseq: the pwrseq instance > + */ > +void pwrseq_unregister(struct pwrseq *pwrseq) > +{ > + mutex_lock(&pwrseq_list_mutex); > + list_del(&pwrseq->node); > + mutex_unlock(&pwrseq_list_mutex); > +} > +EXPORT_SYMBOL_GPL(pwrseq_unregister); > + > +static struct pwrseq *pwrseq_find_available_instance(struct device_node *np) > +{ > + struct pwrseq *pwrseq; > + > + list_for_each_entry(pwrseq, &pwrseq_list, node) { > + if (pwrseq->used) > + continue; > + > + /* compare compatible string for pwrseq node */ > + if (of_match_node(pwrseq->pwrseq_of_match_table, np)) { > + pwrseq->used = true; > + return pwrseq; > + } > + > + /* return generic pwrseq instance */ > + if (!strcmp(pwrseq->pwrseq_of_match_table->compatible, > + "generic")) { > + pr_debug("using generic pwrseq instance for %s\n", > + np->full_name); > + pwrseq->used = true; > + return pwrseq; > + } > + } > + pr_warn("Can't find any pwrseq instances for %s\n", np->full_name); > + > + return NULL; > +} > + > +/** > + * of_pwrseq_on: do power sequence on for device node > + * > + * This API is used to power on single device, if the host > + * controller only needs to handle one child device (this device > + * node points to), use this API. If multiply devices are needed > + * to handle on bus, use of_pwrseq_on_list. > + * > + * @np: the device node would like to power on > + * > + * On successful, it returns pwrseq instance, otherwise an error value. > + */ > +struct pwrseq *of_pwrseq_on(struct device_node *np) > +{ > + struct pwrseq *pwrseq; > + int ret; > + > + pwrseq = pwrseq_find_available_instance(np); > + if (!pwrseq) > + return ERR_PTR(-ENONET); > + > + ret = pwrseq_get(np, pwrseq); > + if (ret) { > + /* Mark current pwrseq as unused */ > + pwrseq->used = false; > + return ERR_PTR(ret); > + } > + > + ret = pwrseq_on(pwrseq); > + if (ret) > + goto pwr_put; > + > + return pwrseq; > + > +pwr_put: > + pwrseq_put(pwrseq); > + return ERR_PTR(ret); > +} > +EXPORT_SYMBOL_GPL(of_pwrseq_on); > + > +/** > + * of_pwrseq_off: do power sequence off for this pwrseq instance > + * > + * This API is used to power off single device, it is the opposite > + * operation for of_pwrseq_on. > + * > + * @pwrseq: the pwrseq instance which related device would like to be off > + */ > +void of_pwrseq_off(struct pwrseq *pwrseq) > +{ > + pwrseq_off(pwrseq); > + pwrseq_put(pwrseq); > +} > +EXPORT_SYMBOL_GPL(of_pwrseq_off); > + > +/** > + * of_pwrseq_on_list: do power sequence on for list > + * > + * This API is used to power on multiple devices at single bus. > + * If there are several devices on bus (eg, USB bus), uses this > + * this API. Otherwise, use of_pwrseq_on. After the device > + * is powered on successfully, it will be added to pwrseq list for > + * this bus. > + * > + * @np: the device node would like to power on > + * @head: the list head for pwrseq list on this bus > + * > + * On successful, it returns 0, otherwise an error value. > + */ > +int of_pwrseq_on_list(struct device_node *np, struct list_head *head) > +{ > + struct pwrseq *pwrseq; > + struct pwrseq_list_per_dev *pwrseq_list_node; > + > + pwrseq = of_pwrseq_on(np); > + if (IS_ERR(pwrseq)) > + return PTR_ERR(pwrseq); > + > + pwrseq_list_node = kzalloc(sizeof(*pwrseq_list_node), GFP_KERNEL); > + if (!pwrseq_list_node) { > + of_pwrseq_off(pwrseq); > + return -ENOMEM; > + } > + pwrseq_list_node->pwrseq = pwrseq; > + list_add(&pwrseq_list_node->list, head); > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(of_pwrseq_on_list); > + > +/** > + * of_pwrseq_off_list: do power sequence off for the list > + * > + * This API is used to power off all devices on this bus, it is > + * the opposite operation for of_pwrseq_on_list. > + * > + * @head: the list head for pwrseq instance list on this bus > + */ > +void of_pwrseq_off_list(struct list_head *head) > +{ > + struct pwrseq *pwrseq; > + struct pwrseq_list_per_dev *pwrseq_list_node, *tmp_node; > + > + list_for_each_entry_safe(pwrseq_list_node, tmp_node, head, list) { > + pwrseq = pwrseq_list_node->pwrseq; > + of_pwrseq_off(pwrseq); > + list_del(&pwrseq_list_node->list); > + kfree(pwrseq_list_node); > + } > +} > +EXPORT_SYMBOL_GPL(of_pwrseq_off_list); > diff --git a/drivers/power/pwrseq/pwrseq_generic.c b/drivers/power/pwrseq/pwrseq_generic.c > new file mode 100644 > index 0000000..d7a77f2 > --- /dev/null > +++ b/drivers/power/pwrseq/pwrseq_generic.c > @@ -0,0 +1,183 @@ > +/* > + * pwrseq_generic.c Generic power sequence handling > + * > + * 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/gpio.h> > +#include <linux/gpio/consumer.h> > +#include <linux/of.h> > +#include <linux/of_gpio.h> > +#include <linux/slab.h> > + > +#include <linux/power/pwrseq.h> > + > +struct pwrseq_generic { > + struct pwrseq pwrseq; > + struct gpio_desc *gpiod_reset; > + struct clk *clks[PWRSEQ_MAX_CLKS]; > + u32 duration_us; > +}; > + > +#define to_generic_pwrseq(p) container_of(p, struct pwrseq_generic, pwrseq) > + > +static int pwrseq_generic_alloc_instance(void); > +static const struct of_device_id generic_id_table[] = { > + { .compatible = "generic",}, > + { /* sentinel */ } > +}; > + > +static void pwrseq_generic_put(struct pwrseq *pwrseq) > +{ > + struct pwrseq_generic *pwrseq_gen = to_generic_pwrseq(pwrseq); > + int clk; > + > + if (pwrseq_gen->gpiod_reset) > + gpiod_put(pwrseq_gen->gpiod_reset); > + > + for (clk = 0; clk < PWRSEQ_MAX_CLKS; clk++) > + clk_put(pwrseq_gen->clks[clk]); > + > + pwrseq_unregister(&pwrseq_gen->pwrseq); > + kfree(pwrseq_gen); > +} > + > +static void pwrseq_generic_off(struct pwrseq *pwrseq) > +{ > + struct pwrseq_generic *pwrseq_gen = to_generic_pwrseq(pwrseq); > + int clk; > + > + for (clk = PWRSEQ_MAX_CLKS - 1; clk >= 0; clk--) > + clk_disable_unprepare(pwrseq_gen->clks[clk]); > +} > + > +static int pwrseq_generic_on(struct pwrseq *pwrseq) > +{ > + struct pwrseq_generic *pwrseq_gen = to_generic_pwrseq(pwrseq); > + int clk, ret = 0; > + struct gpio_desc *gpiod_reset = pwrseq_gen->gpiod_reset; > + > + for (clk = 0; clk < PWRSEQ_MAX_CLKS && pwrseq_gen->clks[clk]; clk++) { > + ret = clk_prepare_enable(pwrseq_gen->clks[clk]); > + if (ret) { > + pr_err("Can't enable clock, ret=%d\n", ret); > + goto err_disable_clks; > + } > + } > + > + if (gpiod_reset) { > + u32 duration_us = pwrseq_gen->duration_us; > + > + if (duration_us <= 10) > + udelay(10); > + else > + usleep_range(duration_us, duration_us + 100); > + gpiod_set_value(gpiod_reset, 0); > + } > + > + return ret; > + > +err_disable_clks: > + while (--clk >= 0) > + clk_disable_unprepare(pwrseq_gen->clks[clk]); > + > + return ret; > +} > + > +static int pwrseq_generic_get(struct device_node *np, struct pwrseq *pwrseq) > +{ > + struct pwrseq_generic *pwrseq_gen = to_generic_pwrseq(pwrseq); > + enum of_gpio_flags flags; > + int reset_gpio, clk, ret = 0; > + > + for (clk = 0; clk < PWRSEQ_MAX_CLKS; clk++) { > + pwrseq_gen->clks[clk] = of_clk_get(np, clk); > + if (IS_ERR(pwrseq_gen->clks[clk])) { > + ret = PTR_ERR(pwrseq_gen->clks[clk]); > + if (ret != -ENOENT) > + goto err_put_clks; > + pwrseq_gen->clks[clk] = NULL; > + break; > + } > + } > + > + reset_gpio = of_get_named_gpio_flags(np, "reset-gpios", 0, &flags); > + if (gpio_is_valid(reset_gpio)) { > + unsigned long gpio_flags; > + > + if (flags & OF_GPIO_ACTIVE_LOW) > + gpio_flags = GPIOF_ACTIVE_LOW | GPIOF_OUT_INIT_LOW; > + else > + gpio_flags = GPIOF_OUT_INIT_HIGH; > + > + ret = gpio_request_one(reset_gpio, gpio_flags, > + "pwrseq-reset-gpios"); > + if (ret) > + goto err_put_clks; > + > + pwrseq_gen->gpiod_reset = gpio_to_desc(reset_gpio); > + of_property_read_u32(np, "reset-duration-us", > + &pwrseq_gen->duration_us); > + } else if (reset_gpio == -ENOENT) { > + ; /* no such gpio */ > + } else { > + ret = reset_gpio; > + pr_err("Failed to get reset gpio on %s, err = %d\n", > + np->full_name, reset_gpio); > + goto err_put_clks; > + } > + > + /* allocate new one for later pwrseq instance request */ > + ret = pwrseq_generic_alloc_instance(); > + if (ret) > + goto err_put_gpio; > + > + return 0; > + > +err_put_gpio: > + if (pwrseq_gen->gpiod_reset) > + gpiod_put(pwrseq_gen->gpiod_reset); > +err_put_clks: > + while (--clk >= 0) > + clk_put(pwrseq_gen->clks[clk]); > + return ret; > +} > + > +static int pwrseq_generic_alloc_instance(void) > +{ > + struct pwrseq_generic *pwrseq_gen; > + > + pwrseq_gen = kzalloc(sizeof(*pwrseq_gen), GFP_KERNEL); > + if (!pwrseq_gen) > + return -ENOMEM; > + > + pwrseq_gen->pwrseq.pwrseq_of_match_table = generic_id_table; > + pwrseq_gen->pwrseq.get = pwrseq_generic_get; > + pwrseq_gen->pwrseq.on = pwrseq_generic_on; > + pwrseq_gen->pwrseq.off = pwrseq_generic_off; > + pwrseq_gen->pwrseq.put = pwrseq_generic_put; > + > + pwrseq_register(&pwrseq_gen->pwrseq); > + return 0; > +} > + > +static int __init pwrseq_generic_register(void) > +{ > + return pwrseq_generic_alloc_instance(); > +} > +postcore_initcall(pwrseq_generic_register) > diff --git a/include/linux/power/pwrseq.h b/include/linux/power/pwrseq.h > new file mode 100644 > index 0000000..598301a > --- /dev/null > +++ b/include/linux/power/pwrseq.h > @@ -0,0 +1,60 @@ > +#ifndef __LINUX_PWRSEQ_H > +#define __LINUX_PWRSEQ_H > + > +#include <linux/of.h> > + > +#define PWRSEQ_MAX_CLKS 3 > + > +/** > + * struct pwrseq - the power sequence structure > + * @pwrseq_of_match_table: the OF device id table this pwrseq library supports > + * @node: the list pointer to be added to pwrseq list > + * @get: the API is used to get pwrseq instance from the device node > + * @on: do power on for this pwrseq instance > + * @off: do power off for this pwrseq instance > + * @put: release the resources on this pwrseq instance > + * @suspend: do suspend operation on this pwrseq instance > + * @resume: do resume operation on this pwrseq instance > + * @used: this pwrseq instance is used by device > + */ > +struct pwrseq { > + const struct of_device_id *pwrseq_of_match_table; > + struct list_head node; > + int (*get)(struct device_node *np, struct pwrseq *p); > + int (*on)(struct pwrseq *p); > + void (*off)(struct pwrseq *p); > + void (*put)(struct pwrseq *p); > + int (*suspend)(struct pwrseq *p); > + int (*resume)(struct pwrseq *p); > + bool used; > +}; > + > +/* used for power sequence instance list in one driver */ > +struct pwrseq_list_per_dev { > + struct pwrseq *pwrseq; > + struct list_head list; > +}; > + > +#if IS_ENABLED(CONFIG_POWER_SEQUENCE) > +void pwrseq_register(struct pwrseq *pwrseq); > +void pwrseq_unregister(struct pwrseq *pwrseq); > +struct pwrseq *of_pwrseq_on(struct device_node *np); > +void of_pwrseq_off(struct pwrseq *pwrseq); > +int of_pwrseq_on_list(struct device_node *np, struct list_head *head); > +void of_pwrseq_off_list(struct list_head *head); > +#else > +static inline void pwrseq_register(struct pwrseq *pwrseq) {} > +static inline void pwrseq_unregister(struct pwrseq *pwrseq) {} > +static inline struct pwrseq *of_pwrseq_on(struct device_node *np) > +{ > + return NULL; > +} > +void of_pwrseq_off(struct pwrseq *pwrseq) {} > +int of_pwrseq_on_list(struct device_node *np, struct list_head *head) > +{ > + return 0; > +} > +void of_pwrseq_off_list(struct list_head *head) {} > +#endif /* CONFIG_POWER_SEQUENCE */ > + > +#endif /* __LINUX_PWRSEQ_H */ > -- > 2.7.4 > > -- > 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 -- Best Regards, Peter Chen -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
