| Message ID | 1479087359-7547-3-git-send-email-peter.chen@nxp.com (mailing list archive) |
|---|---|
| State | Changes Requested, archived |
| Headers | show |
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@nxp.com> > Tested-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name> > Tested-by Joshua Clayton <stillcompiling@gmail.com> > Reviewed-by: Matthias Kaehlcke <mka@chromium.org> > Tested-by: Matthias Kaehlcke <mka@chromium.org> > --- > 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@nxp.com> > +T: git git://git.kernel.org/pub/scm/linux/kernel/git/peter.chen/usb.git > +L: linux-pm@vger.kernel.org > +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@kernel.org> > L: linux-pm@vger.kernel.org > 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@nxp.com> > + * > + * 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@nxp.com> > + * > + * 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@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Nov 14, 2016 at 2:35 AM, Peter Chen <peter.chen@nxp.com> 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. > > Signed-off-by: Peter Chen <peter.chen@nxp.com> > Tested-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name> > Tested-by Joshua Clayton <stillcompiling@gmail.com> > Reviewed-by: Matthias Kaehlcke <mka@chromium.org> > Tested-by: Matthias Kaehlcke <mka@chromium.org> > --- > 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@nxp.com> > +T: git git://git.kernel.org/pub/scm/linux/kernel/git/peter.chen/usb.git > +L: linux-pm@vger.kernel.org > +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@kernel.org> > L: linux-pm@vger.kernel.org > 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@nxp.com> > + * > + * 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/>. The last paragraph is not necessary AFAICS. > + */ > + > +#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); pr_debug() ? > + > + return NULL; > +} > + > +/** > + * of_pwrseq_on: do power sequence on for device node of_pwrseq_on - Carry out power sequence on for device node Argument description should follow this line. > + * > + * 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. That's unclear. What about "Carry out a single device power on. If multiple devices need to be handled, use of_pwrseq_on_list() instead." > + * > + * @np: the device node would like to power on > + * > + * On successful, it returns pwrseq instance, otherwise an error value. "Return a pointer to the power sequence instance on success, or an error code otherwise." > + */ > +struct pwrseq *of_pwrseq_on(struct device_node *np) > +{ > + struct pwrseq *pwrseq; > + int ret; > + > + pwrseq = pwrseq_find_available_instance(np); What does guarantee the integrity of ths list at this point? > + if (!pwrseq) > + return ERR_PTR(-ENONET); ENOENT I suppose? > + > + 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); What happens if two code paths attempt to turn the same power sequence off in parallel? Can it ever happen? If not, then why not? > + > +/** > + * 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. Please format the kerneldoc comment in a usual way. > + */ > +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); Why don't you allocate memory before turning the power sequence on? > + 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); So the caller is supposed to provide a list head of the list to put the power sequence object into on success, right? Can you explain to me what the idea here is, please? Also, what's the protection of the list against concurrent access? > + > +/** > + * 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); This looks horribly inefficient. Is the user expected to create the list from scratch every time things are turned on? OK, let's stop here. I need the above to be clarified first. Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Nov 22, 2016 at 03:23:12AM +0100, Rafael J. Wysocki wrote: > > @@ -0,0 +1,237 @@ > > +/* > > + * core.c power sequence core file > > + * > > + * Copyright (C) 2016 Freescale Semiconductor, Inc. > > + * Author: Peter Chen <peter.chen@nxp.com> > > + * > > + * 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/>. > > The last paragraph is not necessary AFAICS. I just copy it from: https://www.gnu.org/licenses/gpl-howto.en.html If you are concerns about it, I can delete it. > > + > > +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); > > pr_debug() ? If there is no pwrseq instance for that node, the power sequence on routine will return fail, so I think an warning message is useful for user. > > > + > > + return NULL; > > +} > > + > > +/** > > + * of_pwrseq_on: do power sequence on for device node > > of_pwrseq_on - Carry out power sequence on for device node > > Argument description should follow this line. > > > + * > > + * 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. > > That's unclear. > > What about "Carry out a single device power on. If multiple devices > need to be handled, use of_pwrseq_on_list() instead." > > > + * > > + * @np: the device node would like to power on > > + * > > + * On successful, it returns pwrseq instance, otherwise an error value. > > "Return a pointer to the power sequence instance on success, or an > error code otherwise." > Ok, will change. > > + */ > > +struct pwrseq *of_pwrseq_on(struct device_node *np) > > +{ > > + struct pwrseq *pwrseq; > > + int ret; > > + > > + pwrseq = pwrseq_find_available_instance(np); > > What does guarantee the integrity of ths list at this point? Once the use selects the specific pwrseq library, the library will create an empty one instance during the initialization, and it will be called at postcore_initcall, the device driver has not probed yet. > > > + if (!pwrseq) > > + return ERR_PTR(-ENONET); > > ENOENT I suppose? > Good catch, thanks. > > +/** > > + * 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); > > What happens if two code paths attempt to turn the same power sequence > off in parallel? Can it ever happen? If not, then why not? > I don't think the same pwrseq instance off will be called at the same time, the of_pwrseq_off is supposed to be only called at error path during power-on and at device power-off routine, and only the power-on is successful, the device can be created, if the device is not created, its power-off routine is not supposed to be called. > > + > > +/** > > + * 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. > > Please format the kerneldoc comment in a usual way. > Ok. > > + */ > > +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); > > Why don't you allocate memory before turning the power sequence on? > This list is only for power sequence on instance, if I allocate memory before power sequence on, I need to free it if power sequence on is failed. > > + 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); > > So the caller is supposed to provide a list head of the list to put > the power sequence object into on success, right? Yes > > Can you explain to me what the idea here is, please? > Taking USB devices as an example, there is one power sequence on list per bus, and there are several USB devices on the bus. Using a list, we can record which device is powered sequence on, and only powers sequence off which has already powered sequence on at error path, and power sequence off all devices on the bus when the bus (eg, USB HUB) is removed. (eg, when the bus driver is removed) Usually, the power sequence is only needed for hard-wired devices, the power sequence on is carried out during the bus driver probed, and off if carried out during the bus driver is removed, of_pwrseq_on_list/of_powerseq_off_list is not supposed to be called during the other bus driver life cycles. > Also, what's the protection of the list against concurrent access? > I will add comment that the list creator needs to take consideration of concurrent access if exists. > > + > > +/** > > + * 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); > > This looks horribly inefficient. > > Is the user expected to create the list from scratch every time things > are turned on? > Like I explained above, the power sequence is for hard-wired device on board, the list creation and remove are only carried out on driver's probe and remove.
On Tue, Nov 22, 2016 at 4:53 AM, Peter Chen <hzpeterchen@gmail.com> wrote: > On Tue, Nov 22, 2016 at 03:23:12AM +0100, Rafael J. Wysocki wrote: >> > @@ -0,0 +1,237 @@ >> > +/* >> > + * core.c power sequence core file >> > + * >> > + * Copyright (C) 2016 Freescale Semiconductor, Inc. >> > + * Author: Peter Chen <peter.chen@nxp.com> >> > + * >> > + * 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/>. >> >> The last paragraph is not necessary AFAICS. > > I just copy it from: > > https://www.gnu.org/licenses/gpl-howto.en.html > > If you are concerns about it, I can delete it. It is redundant, so yes, please. >> > + >> > +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); >> >> pr_debug() ? > > If there is no pwrseq instance for that node, the power sequence on routine will > return fail, so I think an warning message is useful for user. Useful in what way? How is the user supposed to know what happened from this message? >> >> > + >> > + return NULL; >> > +} >> > + >> > +/** >> > + * of_pwrseq_on: do power sequence on for device node >> >> of_pwrseq_on - Carry out power sequence on for device node >> >> Argument description should follow this line. >> >> > + * >> > + * 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. >> >> That's unclear. >> >> What about "Carry out a single device power on. If multiple devices >> need to be handled, use of_pwrseq_on_list() instead." >> >> > + * >> > + * @np: the device node would like to power on >> > + * >> > + * On successful, it returns pwrseq instance, otherwise an error value. >> >> "Return a pointer to the power sequence instance on success, or an >> error code otherwise." >> > > Ok, will change. > >> > + */ >> > +struct pwrseq *of_pwrseq_on(struct device_node *np) >> > +{ >> > + struct pwrseq *pwrseq; >> > + int ret; >> > + >> > + pwrseq = pwrseq_find_available_instance(np); >> >> What does guarantee the integrity of ths list at this point? > > Once the use selects the specific pwrseq library, the library will > create an empty one instance during the initialization, and it > will be called at postcore_initcall, the device driver has not > probed yet. Which doesn't matter really, because the list is global and some other driver using it might have been probed already. You have a mutex here and it is used for add/remove. Why isn't it used for list browsing? > >> >> > + if (!pwrseq) >> > + return ERR_PTR(-ENONET); >> >> ENOENT I suppose? >> > > Good catch, thanks. > >> > +/** >> > + * 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); >> >> What happens if two code paths attempt to turn the same power sequence >> off in parallel? Can it ever happen? If not, then why not? >> > > I don't think the same pwrseq instance off will be called at the same > time, the of_pwrseq_off is supposed to be only called at error path > during power-on and at device power-off routine, and only the power-on is > successful, the device can be created, if the device is not created, > its power-off routine is not supposed to be called. > >> > + >> > +/** >> > + * 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. >> >> Please format the kerneldoc comment in a usual way. >> > > Ok. > >> > + */ >> > +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); >> >> Why don't you allocate memory before turning the power sequence on? >> > > This list is only for power sequence on instance, if I allocate memory before > power sequence on, I need to free it if power sequence on is failed. So why is that a problem? >> > + 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); >> >> So the caller is supposed to provide a list head of the list to put >> the power sequence object into on success, right? > > Yes > >> >> Can you explain to me what the idea here is, please? >> > > Taking USB devices as an example, there is one power sequence on list > per bus, and there are several USB devices on the bus. Using a list, > we can record which device is powered sequence on, and only powers > sequence off which has already powered sequence on at error path, and > power sequence off all devices on the bus when the bus (eg, USB HUB) > is removed. (eg, when the bus driver is removed) Well, I'm not sure I understand this correctly. What about system suspend/resume and such, for instance? > Usually, the power sequence is only needed for hard-wired devices, > the power sequence on is carried out during the bus driver probed, > and off if carried out during the bus driver is removed, > of_pwrseq_on_list/of_powerseq_off_list is not supposed to be > called during the other bus driver life cycles. > >> Also, what's the protection of the list against concurrent access? >> > > I will add comment that the list creator needs to take consideration > of concurrent access if exists. > >> > + >> > +/** >> > + * 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); >> >> This looks horribly inefficient. >> >> Is the user expected to create the list from scratch every time things >> are turned on? >> > > Like I explained above, the power sequence is for hard-wired device on > board, the list creation and remove are only carried out on driver's > probe and remove. Which driver exactly are you referring to? Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Dec 01, 2016 at 10:57:24PM +0100, Rafael J. Wysocki wrote: > On Tue, Nov 22, 2016 at 4:53 AM, Peter Chen <hzpeterchen@gmail.com> wrote: > > On Tue, Nov 22, 2016 at 03:23:12AM +0100, Rafael J. Wysocki wrote: > >> > @@ -0,0 +1,237 @@ > >> > +/* > >> > + * core.c power sequence core file > >> > + * > >> > + * Copyright (C) 2016 Freescale Semiconductor, Inc. > >> > + * Author: Peter Chen <peter.chen@nxp.com> > >> > + * > >> > + * 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/>. > >> > >> The last paragraph is not necessary AFAICS. > > > > I just copy it from: > > > > https://www.gnu.org/licenses/gpl-howto.en.html > > > > If you are concerns about it, I can delete it. > > It is redundant, so yes, please. ok. > > >> > + > >> > +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); > >> > >> pr_debug() ? > > > > If there is no pwrseq instance for that node, the power sequence on routine will > > return fail, so I think an warning message is useful for user. > > Useful in what way? How is the user supposed to know what happened > from this message? Ok, I will change it to debug message. > >> > + */ > >> > +struct pwrseq *of_pwrseq_on(struct device_node *np) > >> > +{ > >> > + struct pwrseq *pwrseq; > >> > + int ret; > >> > + > >> > + pwrseq = pwrseq_find_available_instance(np); > >> > >> What does guarantee the integrity of ths list at this point? > > > > Once the use selects the specific pwrseq library, the library will > > create an empty one instance during the initialization, and it > > will be called at postcore_initcall, the device driver has not > > probed yet. > > Which doesn't matter really, because the list is global and some other > driver using it might have been probed already. > > You have a mutex here and it is used for add/remove. Why isn't it > used for list browsing? I will add mutex for it, thanks. > > > >> > + */ > >> > +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); > >> > >> Why don't you allocate memory before turning the power sequence on? > >> > > > > This list is only for power sequence on instance, if I allocate memory before > > power sequence on, I need to free it if power sequence on is failed. > > So why is that a problem? > Not any problems, I will follow your comments. > >> > + 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); > >> > >> So the caller is supposed to provide a list head of the list to put > >> the power sequence object into on success, right? > > > > Yes > > > >> > >> Can you explain to me what the idea here is, please? > >> > > > > Taking USB devices as an example, there is one power sequence on list > > per bus, and there are several USB devices on the bus. Using a list, > > we can record which device is powered sequence on, and only powers > > sequence off which has already powered sequence on at error path, and > > power sequence off all devices on the bus when the bus (eg, USB HUB) > > is removed. (eg, when the bus driver is removed) > > Well, I'm not sure I understand this correctly. > > What about system suspend/resume and such, for instance? Thanks, yes, we need to consider PM. The initial idea for this library is only for power on/off. It does not take power management into consideration. As an enhancement, we need to consider PM, and implement pwrseq_suspend/resume accordingly (will consider concurrent issue). I will add related APIs at pwrseq_generic.c at next version, and only call clock operations at it (reset gpio is not needed for PM). > > > Usually, the power sequence is only needed for hard-wired devices, > > the power sequence on is carried out during the bus driver probed, > > and off if carried out during the bus driver is removed, > > of_pwrseq_on_list/of_powerseq_off_list is not supposed to be > > called during the other bus driver life cycles. > > > >> Also, what's the protection of the list against concurrent access? > >> > > > > I will add comment that the list creator needs to take consideration > > of concurrent access if exists. > > > >> > + > >> > +/** > >> > + * 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); > >> > >> This looks horribly inefficient. > >> > >> Is the user expected to create the list from scratch every time things > >> are turned on? > >> > > > > Like I explained above, the power sequence is for hard-wired device on > > board, the list creation and remove are only carried out on driver's > > probe and remove. > > Which driver exactly are you referring to? > For system PM, the list is still existed. It calls of_pwrseq_suspend/resume accordingly. The first user for this pwrseq library is USB HUB. (drivers/usb/core/hub.c).
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@nxp.com> +T: git git://git.kernel.org/pub/scm/linux/kernel/git/peter.chen/usb.git +L: linux-pm@vger.kernel.org +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@kernel.org> L: linux-pm@vger.kernel.org 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@nxp.com> + * + * 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@nxp.com> + * + * 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 */