| Message ID | 1495068543-6938-3-git-send-email-peter.chen@nxp.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, May 18, 2017 at 08:48:58AM +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. Ping.... > > 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> > --- > Documentation/power/power-sequence/design.rst | 54 +++++ > MAINTAINERS | 9 + > drivers/power/Kconfig | 1 + > drivers/power/Makefile | 1 + > drivers/power/pwrseq/Kconfig | 20 ++ > drivers/power/pwrseq/Makefile | 2 + > drivers/power/pwrseq/core.c | 335 ++++++++++++++++++++++++++ > drivers/power/pwrseq/pwrseq_generic.c | 234 ++++++++++++++++++ > include/linux/power/pwrseq.h | 81 +++++++ > 9 files changed, 737 insertions(+) > create mode 100644 Documentation/power/power-sequence/design.rst > 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/Documentation/power/power-sequence/design.rst b/Documentation/power/power-sequence/design.rst > new file mode 100644 > index 0000000..554608e > --- /dev/null > +++ b/Documentation/power/power-sequence/design.rst > @@ -0,0 +1,54 @@ > +==================================== > +Power Sequence Library > +==================================== > + > +:Date: Feb, 2017 > +:Author: Peter Chen <peter.chen@nxp.com> > + > + > +Introduction > +============ > + > +We have an well-known problem that the device needs to do a power > +sequence before it can be recognized by related host, the typical > +examples are hard-wired mmc devices and usb devices. The host controller > +can't know what kinds of this device is in its bus if the power > +sequence has not done, since the related devices driver's probe calling > +is determined by runtime according to eunumeration results. Besides, > +the devices may have custom power sequence, so the power sequence library > +which is independent with the devices is needed. > + > +Design > +============ > + > +The power sequence library includes the core file and customer power > +sequence library. The core file exports interfaces are called by > +host controller driver for power sequence and customer power sequence > +library files to register its power sequence instance to global > +power sequence list. The custom power sequence library creates power > +sequence instance and implement custom power sequence. > + > +Since the power sequence describes hardware design, the description is > +located at board description file, eg, device tree dts file. And > +a specific power sequence belongs to device, so its description > +is under the device node, please refer to: > +Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt > + > +Custom power sequence library allocates one power sequence instance at > +bootup periods using postcore_initcall, this static allocated instance is > +used to compare with device-tree (DT) node to see if this library can be > +used for the node or not. When the result is matched, the core API will > +try to get resourses (->get, implemented at each library) for power > +sequence, if all resources are got, it will try to allocate another > +instance for next possible request from host driver. > + > +Then, the host controller driver can carry out power sequence on for this > +DT node, the library will do corresponding operations, like open clocks, > +toggle gpio, etc. The power sequence off routine will close and free the > +resources, and is called when the parent is removed. And the power > +sequence suspend and resume routine can be called at host driver's > +suspend and resume routine if needed. > + > +The exported interfaces > +.. kernel-doc:: drivers/power/pwrseq/core.c > + :export: > diff --git a/MAINTAINERS b/MAINTAINERS > index f7d568b..93b07aa 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -10188,6 +10188,15 @@ 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..c6b3569 > --- /dev/null > +++ b/drivers/power/pwrseq/Kconfig > @@ -0,0 +1,20 @@ > +# > +# Power Sequence library > +# > + > +menuconfig POWER_SEQUENCE > + bool "Power sequence control" > + 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" > + depends on OF > + 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..3d19e62 > --- /dev/null > +++ b/drivers/power/pwrseq/core.c > @@ -0,0 +1,335 @@ > +/* > + * 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. > + */ > + > +#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); > +} > + > +/** > + * 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; > + > + mutex_lock(&pwrseq_list_mutex); > + 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; > + mutex_unlock(&pwrseq_list_mutex); > + 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; > + mutex_unlock(&pwrseq_list_mutex); > + return pwrseq; > + } > + } > + mutex_unlock(&pwrseq_list_mutex); > + pr_debug("Can't find any pwrseq instances for %s\n", np->full_name); > + > + return NULL; > +} > + > +/** > + * of_pwrseq_on - Carry out power sequence on for device node > + * > + * @np: the device node would like to power on > + * > + * Carry out a single device power on. If multiple devices > + * need to be handled, use of_pwrseq_on_list() instead. > + * > + * 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); > + if (!pwrseq) > + return ERR_PTR(-ENOENT); > + > + 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 - Carry out power sequence off for this pwrseq instance > + * > + * @pwrseq: the pwrseq instance which related device would like to be off > + * > + * This API is used to power off single device, it is the opposite > + * operation for of_pwrseq_on. > + */ > +void of_pwrseq_off(struct pwrseq *pwrseq) > +{ > + pwrseq_off(pwrseq); > + pwrseq_put(pwrseq); > +} > +EXPORT_SYMBOL_GPL(of_pwrseq_off); > + > +/** > + * of_pwrseq_on_list - Carry out power sequence on for list > + * > + * @np: the device node would like to power on > + * @head: the list head for pwrseq list on this bus > + * > + * 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 instead. After the device > + * is powered on successfully, it will be added to pwrseq list for > + * this bus. The caller needs to use mutex_lock for concurrent. > + * > + * Return 0 on success, or an error value otherwise. > + */ > +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_list_node = kzalloc(sizeof(*pwrseq_list_node), GFP_KERNEL); > + if (!pwrseq_list_node) > + return -ENOMEM; > + > + pwrseq = of_pwrseq_on(np); > + if (IS_ERR(pwrseq)) { > + kfree(pwrseq_list_node); > + return PTR_ERR(pwrseq); > + } > + > + 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 - Carry out power sequence off for the list > + * > + * @head: the list head for pwrseq instance list on this bus > + * > + * This API is used to power off all devices on this bus, it is > + * the opposite operation for of_pwrseq_on_list. > + * The caller needs to use mutex_lock for concurrent. > + */ > +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); > + > +/** > + * pwrseq_suspend - Carry out power sequence suspend for this pwrseq instance > + * > + * @pwrseq: the pwrseq instance > + * > + * This API is used to do suspend operation on pwrseq instance. > + * > + * Return 0 on success, or an error value otherwise. > + */ > +int pwrseq_suspend(struct pwrseq *p) > +{ > + int ret = 0; > + > + if (p && p->suspend) > + ret = p->suspend(p); > + else > + return ret; > + > + if (!ret) > + p->suspended = true; > + else > + pr_err("%s failed\n", __func__); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(pwrseq_suspend); > + > +/** > + * pwrseq_resume - Carry out power sequence resume for this pwrseq instance > + * > + * @pwrseq: the pwrseq instance > + * > + * This API is used to do resume operation on pwrseq instance. > + * > + * Return 0 on success, or an error value otherwise. > + */ > +int pwrseq_resume(struct pwrseq *p) > +{ > + int ret = 0; > + > + if (p && p->resume) > + ret = p->resume(p); > + else > + return ret; > + > + if (!ret) > + p->suspended = false; > + else > + pr_err("%s failed\n", __func__); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(pwrseq_resume); > + > +/** > + * pwrseq_suspend_list - Carry out power sequence suspend for list > + * > + * @head: the list head for pwrseq instance list on this bus > + * > + * This API is used to do suspend on all power sequence instances on this bus. > + * The caller needs to use mutex_lock for concurrent. > + */ > +int pwrseq_suspend_list(struct list_head *head) > +{ > + struct pwrseq *pwrseq; > + struct pwrseq_list_per_dev *pwrseq_list_node; > + int ret = 0; > + > + list_for_each_entry(pwrseq_list_node, head, list) { > + ret = pwrseq_suspend(pwrseq_list_node->pwrseq); > + if (ret) > + break; > + } > + > + if (ret) { > + list_for_each_entry(pwrseq_list_node, head, list) { > + pwrseq = pwrseq_list_node->pwrseq; > + if (pwrseq->suspended) > + pwrseq_resume(pwrseq); > + } > + } > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(pwrseq_suspend_list); > + > +/** > + * pwrseq_resume_list - Carry out power sequence resume for the list > + * > + * @head: the list head for pwrseq instance list on this bus > + * > + * This API is used to do resume on all power sequence instances on this bus. > + * The caller needs to use mutex_lock for concurrent. > + */ > +int pwrseq_resume_list(struct list_head *head) > +{ > + struct pwrseq_list_per_dev *pwrseq_list_node; > + int ret = 0; > + > + list_for_each_entry(pwrseq_list_node, head, list) { > + ret = pwrseq_resume(pwrseq_list_node->pwrseq); > + if (ret) > + break; > + } > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(pwrseq_resume_list); > diff --git a/drivers/power/pwrseq/pwrseq_generic.c b/drivers/power/pwrseq/pwrseq_generic.c > new file mode 100644 > index 0000000..4e7c090 > --- /dev/null > +++ b/drivers/power/pwrseq/pwrseq_generic.c > @@ -0,0 +1,234 @@ > +/* > + * 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. > + */ > + > +#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; > + bool suspended; > +}; > + > +#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 int pwrseq_generic_suspend(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]); > + > + pwrseq_gen->suspended = true; > + return 0; > +} > + > +static int pwrseq_generic_resume(struct pwrseq *pwrseq) > +{ > + struct pwrseq_generic *pwrseq_gen = to_generic_pwrseq(pwrseq); > + int clk, ret = 0; > + > + 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; > + } > + } > + > + pwrseq_gen->suspended = false; > + return ret; > + > +err_disable_clks: > + while (--clk >= 0) > + clk_disable_unprepare(pwrseq_gen->clks[clk]); > + > + return ret; > +} > + > +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; > + > + if (pwrseq_gen->suspended) > + return; > + > + 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; > +} > + > +/** > + * pwrseq_generic_alloc_instance - power sequence instance allocation > + * > + * This function is used to allocate one generic power sequence instance, > + * it is called when the system boots up and after one power sequence > + * instance is got successfully. > + * > + * Return zero on success or an error code otherwise. > + */ > +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_gen->pwrseq.suspend = pwrseq_generic_suspend; > + pwrseq_gen->pwrseq.resume = pwrseq_generic_resume; > + > + pwrseq_register(&pwrseq_gen->pwrseq); > + return 0; > +} > + > +/* Allocate one pwrseq instance during boots up */ > +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..cbc344c > --- /dev/null > +++ b/include/linux/power/pwrseq.h > @@ -0,0 +1,81 @@ > +#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; > + bool suspended; > +}; > + > +/* 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); > +int pwrseq_suspend(struct pwrseq *p); > +int pwrseq_resume(struct pwrseq *p); > +int pwrseq_suspend_list(struct list_head *head); > +int pwrseq_resume_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; > +} > +static void of_pwrseq_off(struct pwrseq *pwrseq) {} > +static int of_pwrseq_on_list(struct device_node *np, struct list_head *head) > +{ > + return 0; > +} > +static void of_pwrseq_off_list(struct list_head *head) {} > +static int pwrseq_suspend(struct pwrseq *p) > +{ > + return 0; > +} > +static int pwrseq_resume(struct pwrseq *p) > +{ > + return 0; > +} > +static int pwrseq_suspend_list(struct list_head *head) > +{ > + return 0; > +} > +static int pwrseq_resume_list(struct list_head *head) > +{ > + return 0; > +} > +#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
diff --git a/Documentation/power/power-sequence/design.rst b/Documentation/power/power-sequence/design.rst new file mode 100644 index 0000000..554608e --- /dev/null +++ b/Documentation/power/power-sequence/design.rst @@ -0,0 +1,54 @@ +==================================== +Power Sequence Library +==================================== + +:Date: Feb, 2017 +:Author: Peter Chen <peter.chen@nxp.com> + + +Introduction +============ + +We have an well-known problem that the device needs to do a power +sequence before it can be recognized by related host, the typical +examples are hard-wired mmc devices and usb devices. The host controller +can't know what kinds of this device is in its bus if the power +sequence has not done, since the related devices driver's probe calling +is determined by runtime according to eunumeration results. Besides, +the devices may have custom power sequence, so the power sequence library +which is independent with the devices is needed. + +Design +============ + +The power sequence library includes the core file and customer power +sequence library. The core file exports interfaces are called by +host controller driver for power sequence and customer power sequence +library files to register its power sequence instance to global +power sequence list. The custom power sequence library creates power +sequence instance and implement custom power sequence. + +Since the power sequence describes hardware design, the description is +located at board description file, eg, device tree dts file. And +a specific power sequence belongs to device, so its description +is under the device node, please refer to: +Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt + +Custom power sequence library allocates one power sequence instance at +bootup periods using postcore_initcall, this static allocated instance is +used to compare with device-tree (DT) node to see if this library can be +used for the node or not. When the result is matched, the core API will +try to get resourses (->get, implemented at each library) for power +sequence, if all resources are got, it will try to allocate another +instance for next possible request from host driver. + +Then, the host controller driver can carry out power sequence on for this +DT node, the library will do corresponding operations, like open clocks, +toggle gpio, etc. The power sequence off routine will close and free the +resources, and is called when the parent is removed. And the power +sequence suspend and resume routine can be called at host driver's +suspend and resume routine if needed. + +The exported interfaces +.. kernel-doc:: drivers/power/pwrseq/core.c + :export: diff --git a/MAINTAINERS b/MAINTAINERS index f7d568b..93b07aa 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -10188,6 +10188,15 @@ 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..c6b3569 --- /dev/null +++ b/drivers/power/pwrseq/Kconfig @@ -0,0 +1,20 @@ +# +# Power Sequence library +# + +menuconfig POWER_SEQUENCE + bool "Power sequence control" + 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" + depends on OF + 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..3d19e62 --- /dev/null +++ b/drivers/power/pwrseq/core.c @@ -0,0 +1,335 @@ +/* + * 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. + */ + +#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); +} + +/** + * 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; + + mutex_lock(&pwrseq_list_mutex); + 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; + mutex_unlock(&pwrseq_list_mutex); + 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; + mutex_unlock(&pwrseq_list_mutex); + return pwrseq; + } + } + mutex_unlock(&pwrseq_list_mutex); + pr_debug("Can't find any pwrseq instances for %s\n", np->full_name); + + return NULL; +} + +/** + * of_pwrseq_on - Carry out power sequence on for device node + * + * @np: the device node would like to power on + * + * Carry out a single device power on. If multiple devices + * need to be handled, use of_pwrseq_on_list() instead. + * + * 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); + if (!pwrseq) + return ERR_PTR(-ENOENT); + + 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 - Carry out power sequence off for this pwrseq instance + * + * @pwrseq: the pwrseq instance which related device would like to be off + * + * This API is used to power off single device, it is the opposite + * operation for of_pwrseq_on. + */ +void of_pwrseq_off(struct pwrseq *pwrseq) +{ + pwrseq_off(pwrseq); + pwrseq_put(pwrseq); +} +EXPORT_SYMBOL_GPL(of_pwrseq_off); + +/** + * of_pwrseq_on_list - Carry out power sequence on for list + * + * @np: the device node would like to power on + * @head: the list head for pwrseq list on this bus + * + * 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 instead. After the device + * is powered on successfully, it will be added to pwrseq list for + * this bus. The caller needs to use mutex_lock for concurrent. + * + * Return 0 on success, or an error value otherwise. + */ +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_list_node = kzalloc(sizeof(*pwrseq_list_node), GFP_KERNEL); + if (!pwrseq_list_node) + return -ENOMEM; + + pwrseq = of_pwrseq_on(np); + if (IS_ERR(pwrseq)) { + kfree(pwrseq_list_node); + return PTR_ERR(pwrseq); + } + + 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 - Carry out power sequence off for the list + * + * @head: the list head for pwrseq instance list on this bus + * + * This API is used to power off all devices on this bus, it is + * the opposite operation for of_pwrseq_on_list. + * The caller needs to use mutex_lock for concurrent. + */ +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); + +/** + * pwrseq_suspend - Carry out power sequence suspend for this pwrseq instance + * + * @pwrseq: the pwrseq instance + * + * This API is used to do suspend operation on pwrseq instance. + * + * Return 0 on success, or an error value otherwise. + */ +int pwrseq_suspend(struct pwrseq *p) +{ + int ret = 0; + + if (p && p->suspend) + ret = p->suspend(p); + else + return ret; + + if (!ret) + p->suspended = true; + else + pr_err("%s failed\n", __func__); + + return ret; +} +EXPORT_SYMBOL_GPL(pwrseq_suspend); + +/** + * pwrseq_resume - Carry out power sequence resume for this pwrseq instance + * + * @pwrseq: the pwrseq instance + * + * This API is used to do resume operation on pwrseq instance. + * + * Return 0 on success, or an error value otherwise. + */ +int pwrseq_resume(struct pwrseq *p) +{ + int ret = 0; + + if (p && p->resume) + ret = p->resume(p); + else + return ret; + + if (!ret) + p->suspended = false; + else + pr_err("%s failed\n", __func__); + + return ret; +} +EXPORT_SYMBOL_GPL(pwrseq_resume); + +/** + * pwrseq_suspend_list - Carry out power sequence suspend for list + * + * @head: the list head for pwrseq instance list on this bus + * + * This API is used to do suspend on all power sequence instances on this bus. + * The caller needs to use mutex_lock for concurrent. + */ +int pwrseq_suspend_list(struct list_head *head) +{ + struct pwrseq *pwrseq; + struct pwrseq_list_per_dev *pwrseq_list_node; + int ret = 0; + + list_for_each_entry(pwrseq_list_node, head, list) { + ret = pwrseq_suspend(pwrseq_list_node->pwrseq); + if (ret) + break; + } + + if (ret) { + list_for_each_entry(pwrseq_list_node, head, list) { + pwrseq = pwrseq_list_node->pwrseq; + if (pwrseq->suspended) + pwrseq_resume(pwrseq); + } + } + + return ret; +} +EXPORT_SYMBOL_GPL(pwrseq_suspend_list); + +/** + * pwrseq_resume_list - Carry out power sequence resume for the list + * + * @head: the list head for pwrseq instance list on this bus + * + * This API is used to do resume on all power sequence instances on this bus. + * The caller needs to use mutex_lock for concurrent. + */ +int pwrseq_resume_list(struct list_head *head) +{ + struct pwrseq_list_per_dev *pwrseq_list_node; + int ret = 0; + + list_for_each_entry(pwrseq_list_node, head, list) { + ret = pwrseq_resume(pwrseq_list_node->pwrseq); + if (ret) + break; + } + + return ret; +} +EXPORT_SYMBOL_GPL(pwrseq_resume_list); diff --git a/drivers/power/pwrseq/pwrseq_generic.c b/drivers/power/pwrseq/pwrseq_generic.c new file mode 100644 index 0000000..4e7c090 --- /dev/null +++ b/drivers/power/pwrseq/pwrseq_generic.c @@ -0,0 +1,234 @@ +/* + * 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. + */ + +#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; + bool suspended; +}; + +#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 int pwrseq_generic_suspend(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]); + + pwrseq_gen->suspended = true; + return 0; +} + +static int pwrseq_generic_resume(struct pwrseq *pwrseq) +{ + struct pwrseq_generic *pwrseq_gen = to_generic_pwrseq(pwrseq); + int clk, ret = 0; + + 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; + } + } + + pwrseq_gen->suspended = false; + return ret; + +err_disable_clks: + while (--clk >= 0) + clk_disable_unprepare(pwrseq_gen->clks[clk]); + + return ret; +} + +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; + + if (pwrseq_gen->suspended) + return; + + 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; +} + +/** + * pwrseq_generic_alloc_instance - power sequence instance allocation + * + * This function is used to allocate one generic power sequence instance, + * it is called when the system boots up and after one power sequence + * instance is got successfully. + * + * Return zero on success or an error code otherwise. + */ +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_gen->pwrseq.suspend = pwrseq_generic_suspend; + pwrseq_gen->pwrseq.resume = pwrseq_generic_resume; + + pwrseq_register(&pwrseq_gen->pwrseq); + return 0; +} + +/* Allocate one pwrseq instance during boots up */ +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..cbc344c --- /dev/null +++ b/include/linux/power/pwrseq.h @@ -0,0 +1,81 @@ +#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; + bool suspended; +}; + +/* 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); +int pwrseq_suspend(struct pwrseq *p); +int pwrseq_resume(struct pwrseq *p); +int pwrseq_suspend_list(struct list_head *head); +int pwrseq_resume_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; +} +static void of_pwrseq_off(struct pwrseq *pwrseq) {} +static int of_pwrseq_on_list(struct device_node *np, struct list_head *head) +{ + return 0; +} +static void of_pwrseq_off_list(struct list_head *head) {} +static int pwrseq_suspend(struct pwrseq *p) +{ + return 0; +} +static int pwrseq_resume(struct pwrseq *p) +{ + return 0; +} +static int pwrseq_suspend_list(struct list_head *head) +{ + return 0; +} +static int pwrseq_resume_list(struct list_head *head) +{ + return 0; +} +#endif /* CONFIG_POWER_SEQUENCE */ + +#endif /* __LINUX_PWRSEQ_H */