Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751449Ab2KPGiu (ORCPT ); Fri, 16 Nov 2012 01:38:50 -0500 Received: from hqemgate03.nvidia.com ([216.228.121.140]:7603 "EHLO hqemgate03.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751166Ab2KPGir (ORCPT ); Fri, 16 Nov 2012 01:38:47 -0500 X-PGP-Universal: processed; by hqnvupgp05.nvidia.com on Thu, 15 Nov 2012 22:38:46 -0800 From: Alexandre Courbot To: Anton Vorontsov , Stephen Warren , Thierry Reding , Mark Zhang , Grant Likely , Rob Herring , Mark Brown , David Woodhouse , Arnd Bergmann CC: Leela Krishna Amudala , , , , , , Alexandre Courbot , Alexandre Courbot Subject: [PATCH v8 1/3] Runtime Interpreted Power Sequences Date: Fri, 16 Nov 2012 15:38:21 +0900 Message-ID: <1353047903-14363-2-git-send-email-acourbot@nvidia.com> X-Mailer: git-send-email 1.8.0 In-Reply-To: <1353047903-14363-1-git-send-email-acourbot@nvidia.com> References: <1353047903-14363-1-git-send-email-acourbot@nvidia.com> X-NVConfidentiality: public MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 42463 Lines: 1408 Some device drivers (e.g. panel or backlights) need to follow precise sequences for powering on and off, involving GPIOs, regulators, PWMs with a precise powering order and delays to respect between steps. These sequences are device-specific, and do not belong to a particular driver - therefore they have been performed by board-specific hook functions to far. With the advent of the device tree and of ARM kernels that are not board-tied, we cannot rely on these board-specific hooks anymore but need a way to implement these sequences in a portable manner. This patch introduces a simple interpreter that can execute such power sequences encoded either as platform data or within the device tree. Signed-off-by: Alexandre Courbot Reviewed-by: Stephen Warren Reviewed-by: Mark Brown --- .../devicetree/bindings/power/power_seq.txt | 121 +++++++ Documentation/power/power_seq.txt | 253 ++++++++++++++ drivers/power/Kconfig | 1 + drivers/power/Makefile | 1 + drivers/power/power_seq/Kconfig | 2 + drivers/power/power_seq/Makefile | 1 + drivers/power/power_seq/power_seq.c | 376 +++++++++++++++++++++ drivers/power/power_seq/power_seq_delay.c | 65 ++++ drivers/power/power_seq/power_seq_gpio.c | 94 ++++++ drivers/power/power_seq/power_seq_pwm.c | 82 +++++ drivers/power/power_seq/power_seq_regulator.c | 83 +++++ include/linux/power_seq.h | 203 +++++++++++ 12 files changed, 1282 insertions(+) create mode 100644 Documentation/devicetree/bindings/power/power_seq.txt create mode 100644 Documentation/power/power_seq.txt create mode 100644 drivers/power/power_seq/Kconfig create mode 100644 drivers/power/power_seq/Makefile create mode 100644 drivers/power/power_seq/power_seq.c create mode 100644 drivers/power/power_seq/power_seq_delay.c create mode 100644 drivers/power/power_seq/power_seq_gpio.c create mode 100644 drivers/power/power_seq/power_seq_pwm.c create mode 100644 drivers/power/power_seq/power_seq_regulator.c create mode 100644 include/linux/power_seq.h diff --git a/Documentation/devicetree/bindings/power/power_seq.txt b/Documentation/devicetree/bindings/power/power_seq.txt new file mode 100644 index 0000000..7880a6c --- /dev/null +++ b/Documentation/devicetree/bindings/power/power_seq.txt @@ -0,0 +1,121 @@ +Runtime Interpreted Power Sequences +=================================== + +Power sequences are sequential descriptions of actions to be performed on +power-related resources. Having these descriptions in a well-defined data format +allows us to take much of the board- or device- specific power control code out +of the kernel and place it into the device tree instead, making kernels less +board-dependant. + +A device typically makes use of multiple power sequences, for different purposes +such as powering on and off. All the power sequences of a given device are +grouped into a set. In the device tree, this set is a sub-node of the device +node named "power-sequences". + +Power Sequences Structure +------------------------- +Every device that makes use of power sequences must have a "power-sequences" +node into which individual power sequences are declared as sub-nodes. The name +of the node becomes the name of the sequence within the power sequences +framework. + +Similarly, each power sequence declares its steps as sub-nodes of itself. Steps +must be named sequentially, with the first step named step0, the second step1, +etc. Failure to follow this rule will result in a parsing error. + +Power Sequences Steps +--------------------- +Steps of a sequence describe an action to be performed on a resource. They +always include a "type" property which indicates what kind of resource this +step works on. Depending on the resource type, additional properties are defined +to control the action to be performed. + +"delay" type required properties: + - delay: delay to wait (in microseconds) + +"regulator" type required properties: + - id: name of the regulator to use. + - enable / disable: one of these two empty properties must be present to + enable or disable the resource + +"pwm" type required properties: + - id: name of the PWM to use. + - enable / disable: one of these two empty properties must be present to + enable or disable the resource + +"gpio" type required properties: + - gpio: phandle of the GPIO to use. + - value: value this GPIO should take. Must be 0 or 1. + +Example +------- +Here are example sequences declared within a backlight device that use all the +supported resources types: + + backlight { + compatible = "pwm-backlight"; + ... + + /* resources used by the power sequences */ + pwms = <&pwm 2 5000000>; + pwm-names = "backlight"; + power-supply = <&backlight_reg>; + + power-sequences { + power-on { + step0 { + type = "regulator"; + id = "power"; + enable; + }; + step1 { + type = "delay"; + delay = <10000>; + }; + step2 { + type = "pwm"; + id = "backlight"; + enable; + }; + step3 { + type = "gpio"; + gpio = <&gpio 28 0>; + value = <1>; + }; + }; + + power-off { + step0 { + type = "gpio"; + gpio = <&gpio 28 0>; + value = <0>; + }; + step1 { + type = "pwm"; + id = "backlight"; + disable; + }; + step2 { + type = "delay"; + delay = <10000>; + }; + step3 { + type = "regulator"; + id = "power"; + disable; + }; + }; + }; + }; + +The first part lists the PWM and regulator resources used by the sequences. +These resources will be requested on behalf of the backlight device when the +sequences are built and are declared according to their own bindings (for +instance, regulators and pwms are resolved by name - note though that name +declaration is done differently by the two frameworks). + +After the resources declaration, two sequences follow for powering the backlight +on and off. Their names are specified by the pwm-backlight device bindings. Once +the sequences are built by calling devm_of_parse_power_seq_set() on the +backlight device, they can be added to a set using +power_seq_set_add_sequences(). diff --git a/Documentation/power/power_seq.txt b/Documentation/power/power_seq.txt new file mode 100644 index 0000000..8be0570 --- /dev/null +++ b/Documentation/power/power_seq.txt @@ -0,0 +1,253 @@ +Runtime Interpreted Power Sequences +=================================== + +Problem +------- +Very commonly, boards need the help of out-of-driver code to turn some of their +devices on and off. For instance, SoC boards might use a GPIO (abstracted to a +regulator or not) to control the power supply of a backlight. The GPIO that +should be used, however, as well as the exact power sequence that may also +involve other resources, is board-dependent and thus unknown to the driver. + +This was previously addressed by having hooks in the device's platform data that +are called whenever the state of the device might need a power status change. +This approach, however, introduces board-dependant code into the kernel and is +not compatible with the device tree. + +The Runtime Interpreted Power Sequences (or power sequences for short) aim at +turning this code into platform data or device tree nodes. Power sequences are +described using a simple format and run by a lightweight interpreter whenever +needed. This allows device drivers to work without power callbacks and makes the +kernel less board-dependant. + +What are Power Sequences? +------------------------- +A power sequence is an array of sequential steps describing an action to be +performed on a resource. The supported resources and actions operations are: +- delay (just wait for a given number of microseconds) +- GPIO (set to 0 or 1) +- regulator (enable or disable) +- PWM (enable or disable) + +When a power sequence is run, its steps is executed one after the other until +one step fails or the end of the sequence is reached. + +Power sequences are named, and grouped into "sets" which contain all the +sequences of a device as well as the resources they use. + +Power sequences can be declared as platform data or in the device tree. + +Platform Data Format +-------------------- +All relevant data structures for declaring power sequences are located in +include/linux/power_seq.h. + +The platform data for a device may include an instance of platform_power_seq_set +which references all the power sequences used for a device. The power sequences +reference resources in their steps, and setup the union member that corresponds +to the resource's type. Resources, similarly, have a union which relevant member +depends on their type. + +Note that the only "platform data" per se here is platform_power_seq_set. Other +structures (power_seq and power_seq_resource) will be used at runtime and thus +*must* survive initialization, so do not declare them with the __initdata +attribute. + +The following example should make it clear how the platform data for power +sequences is defined. It declares two power sequences named "power-on" and +"power-off" for a backlight device. The "power-on" sequence enables the "power" +regulator of the device, waits for 10ms, and then enables PWM "backlight" and +set GPIO 28 to 1. "power-off" does the opposite. + +struct power_seq_resource reg_res = { + .type = POWER_SEQ_REGULATOR, + .regulator.id = "power", +}; + +struct power_seq_resource gpio_res = { + .type = POWER_SEQ_GPIO, + .gpio.gpio = 28, +}; + +struct power_seq_resource pwm_res = { + .type = POWER_SEQ_PWM, + .pwm.id = "backlight", +}; + +struct power_seq_resource delay_res = { + .type = POWER_SEQ_DELAY, +}; + +struct power_seq power_on_seq = { + .id = "power-on", + .num_steps = 4, + .steps = { + { + .resource = ®_res, + .regulator.enable = true, + }, { + .resource = &delay_res, + .delay.delay = 10000, + }, { + .resource = &pwm_res, + .pwm.enable = true, + }, { + .resource = &gpio_res, + .gpio.value = 1, + }, + }, +}; + +struct power_seq power_off_seq = { + .id = "power-off", + .num_steps = 4, + .steps = { + { + .resource = &gpio_res, + .gpio.value = 0, + }, { + .resource = &pwm_res, + .pwm.enable = false, + }, { + .resource = &delay_res, + .delay.delay = 10000, + }, { + .resource = ®_res, + .regulator.enable = false, + }, + }, +}; + +struct platform_power_seq_set backlight_power_seqs __initdata = { + .num_seqs = 2, + .seqs = { + &power_on_seq, + &power_off_seq, + }, +}; + +"backlight_power_seqs" can then be passed to power_seq_set_add_sequences() in +order to add the sequences to a set and allocate all the necessary resources. +More on this later in this document. + +Device Tree +----------- +Power sequences can also be encoded as device tree nodes. The following +properties and nodes are equivalent to the platform data defined previously: + +pwms = <&pwm 2 5000000>; +pwm-names = "backlight"; +power-supply = <&vdd_bl_reg>; + +power-sequences { + power-on { + step0 { + type = "regulator"; + id = "power"; + enable; + }; + step1 { + type = "delay"; + delay = <10000>; + }; + step2 { + type = "pwm"; + id = "backlight"; + enable; + }; + step3 { + type = "gpio"; + gpio = <&gpio 28 0>; + value = <1>; + }; + }; + + power-off { + step0 { + type = "gpio"; + gpio = <&gpio 28 0>; + value = <0>; + }; + step1 { + type = "pwm"; + id = "backlight"; + disable; + }; + step2 { + type = "delay"; + delay = <10000>; + }; + step3 { + type = "regulator"; + id = "power"; + disable; + }; + }; +}; + +See Documentation/devicetree/bindings/power/power_seq.txt for the complete +syntax of the DT bindings. + +Use by Drivers and Resources Management +--------------------------------------- +Power sequences make use of resources that must be properly allocated and +managed. The power_seq_set structure manages the sequences and resources for a +particular device. A driver willing to use power sequences will thus declare one +instance of power_seq_set per device and initialize it at probe time: + +struct my_device_data { + struct device *dev; + ... + struct power_set_set power_seqs; + ... +}; + +power_seq_set_init(&my_device->power_seqs, my_device->dev); + +The power_seq_set_add_sequence() and power_seq_set_add_sequences() functions are +then used to add one or several sequences to a set. These functions will also +allocate all the resources used by the sequence(s) and make sure they are ready +to be run. All resources are allocated through devm and will thus be freed when +the set's device is removed. + + int power_seq_set_add_sequence(struct power_seq_set *set, + struct power_seq *seq); + int power_seq_set_add_sequences(struct power_seq_set *set, + struct platform_power_seq_set *seqs); + +Power sequences added to a set can then be resolved by their name using +power_seq_lookup(): + + struct power_seq *power_seq_lookup(struct power_seq_set *seqs, + const char *id); + +power_seq_lookup() returns a ready-to-run pointer to the power sequence which +name matches the id parameter. + +A retrieved power sequence can then be executed by power_seq_run: + + int power_seq_run(struct power_seq *seq); + +It returns 0 if the sequence has successfully been run, or an error code if a +problem occurred. + +Sometimes, you may want to browse the list of resources allocated for the +sequences of a device, for instance to ensure that a resource of a given type is +present. The power_seq_for_each_resource() macro does this: + + power_seq_for_each_resource(pos, seqs) + +Here "pos" will be a pointer to a struct power_seq_resource. This structure +contains the type of the resource, the information used for identifying it, and +the resolved resource itself. + +Finally, users of the device tree can obtain a platform_power_seq_set structure +built from the device's node using devm_of_parse_power_seq_set: + + struct platform_power_seq_set *devm_of_parse_power_seq_set(struct device *dev); + +The power sequences must be declared under a "power-sequences" node directly +declared under the device's node. Detailed syntax contained in Documentation/devicetree/bindings/power/power_seq.txt. As the function name +states, all memory is allocated through devm. The returned +platform_power_seq_set can be freed after being added to a set, but the +sequences themselves must be preserved until they are freed by devm. \ No newline at end of file diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig index 49a8939..f20d449 100644 --- a/drivers/power/Kconfig +++ b/drivers/power/Kconfig @@ -338,3 +338,4 @@ config AB8500_BATTERY_THERM_ON_BATCTRL endif # POWER_SUPPLY source "drivers/power/avs/Kconfig" +source "drivers/power/power_seq/Kconfig" diff --git a/drivers/power/Makefile b/drivers/power/Makefile index b949cf8..883ad4d 100644 --- a/drivers/power/Makefile +++ b/drivers/power/Makefile @@ -49,3 +49,4 @@ obj-$(CONFIG_CHARGER_MAX8997) += max8997_charger.o obj-$(CONFIG_CHARGER_MAX8998) += max8998_charger.o obj-$(CONFIG_POWER_AVS) += avs/ obj-$(CONFIG_CHARGER_SMB347) += smb347-charger.o +obj-$(CONFIG_POWER_SEQ) += power_seq/ diff --git a/drivers/power/power_seq/Kconfig b/drivers/power/power_seq/Kconfig new file mode 100644 index 0000000..3bff26e --- /dev/null +++ b/drivers/power/power_seq/Kconfig @@ -0,0 +1,2 @@ +config POWER_SEQ + bool diff --git a/drivers/power/power_seq/Makefile b/drivers/power/power_seq/Makefile new file mode 100644 index 0000000..f77a359 --- /dev/null +++ b/drivers/power/power_seq/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_POWER_SEQ) += power_seq.o diff --git a/drivers/power/power_seq/power_seq.c b/drivers/power/power_seq/power_seq.c new file mode 100644 index 0000000..255b1a0 --- /dev/null +++ b/drivers/power/power_seq/power_seq.c @@ -0,0 +1,376 @@ +/* + * power_seq.c - power sequence interpreter for platform devices and device tree + * + * Author: Alexandre Courbot + * + * Copyright (c) 2012 NVIDIA Corporation. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * 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. + * + */ + +#include +#include +#include +#include + +#include + +#define power_seq_err(seq, step_nbr, format, ...) \ + dev_err(seq->set->dev, "%s[%d]: " format, seq->id, step_nbr, \ + ##__VA_ARGS__); + +/** + * struct power_seq_res_ops - operators for power sequences resources + * @name: Name of the resource type. Set to null when a resource + * type support is not compiled in + * @of_parse: Parse a step for this kind of resource from a device + * tree node. The result of parsing must be written into + * step step_nbr of seq + * @step_run: Run a step for this kind of resource + * @res_compare: Return true if the resource used by the resource is the + * same as the one referenced by the step, false otherwise. + * @res_alloc: Resolve and allocate a resource. Return error code if + * the resource cannot be allocated, 0 otherwise + */ +struct power_seq_res_ops { + const char *name; + int (*of_parse)(struct device_node *node, struct power_seq *seq, + unsigned int step_nbr, struct power_seq_resource *res); + int (*step_run)(struct power_seq_step *step); + bool (*res_compare)(struct power_seq_resource *res, + struct power_seq_resource *res2); + int (*res_alloc)(struct device *dev, + struct power_seq_resource *res); +}; + +static const struct power_seq_res_ops power_seq_ops[POWER_SEQ_NUM_TYPES]; + +#ifdef CONFIG_OF +static int of_power_seq_parse_enable_properties(struct device_node *node, + struct power_seq *seq, + unsigned int step_nbr, + bool *enable) +{ + if (of_find_property(node, "enable", NULL)) { + *enable = true; + } else if (of_find_property(node, "disable", NULL)) { + *enable = false; + } else { + power_seq_err(seq, step_nbr, + "missing enable or disable property\n"); + return -EINVAL; + } + + return 0; +} + +static int of_power_seq_parse_step(struct device *dev, + struct device_node *node, + struct power_seq *seq, + unsigned int step_nbr, + struct list_head *resources) +{ + struct power_seq_step *step = &seq->steps[step_nbr]; + struct power_seq_resource res, *res2; + const char *type; + int i, err; + + err = of_property_read_string(node, "type", &type); + if (err < 0) { + power_seq_err(seq, step_nbr, "cannot read type property\n"); + return err; + } + for (i = 0; i < POWER_SEQ_NUM_TYPES; i++) { + if (power_seq_ops[i].name == NULL) + continue; + if (!strcmp(type, power_seq_ops[i].name)) + break; + } + if (i >= POWER_SEQ_NUM_TYPES) { + power_seq_err(seq, step_nbr, "unknown type %s\n", type); + return -EINVAL; + } + memset(&res, 0, sizeof(res)); + res.type = i; + err = power_seq_ops[res.type].of_parse(node, seq, step_nbr, &res); + if (err < 0) + return err; + + /* Use the same instance of the resource if met before */ + list_for_each_entry(res2, resources, list) { + if (res.type == res2->type && + power_seq_ops[res.type].res_compare(&res, res2)) + break; + } + /* Resource never met before, create it */ + if (&res2->list == resources) { + res2 = devm_kzalloc(dev, sizeof(*res2), GFP_KERNEL); + if (!res2) + return -ENOMEM; + memcpy(res2, &res, sizeof(res)); + list_add_tail(&res2->list, resources); + } + step->resource = res2; + + return 0; +} + +static struct power_seq *of_parse_power_seq(struct device *dev, + struct device_node *node, + struct list_head *resources) +{ + struct device_node *child = NULL; + struct power_seq *pseq; + int num_steps, sz; + int err; + + if (!node) + return ERR_PTR(-EINVAL); + + num_steps = of_get_child_count(node); + sz = sizeof(*pseq) + sizeof(pseq->steps[0]) * num_steps; + pseq = devm_kzalloc(dev, sz, GFP_KERNEL); + if (!pseq) + return ERR_PTR(-ENOMEM); + pseq->id = node->name; + pseq->num_steps = num_steps; + + for_each_child_of_node(node, child) { + unsigned int pos; + + /* Check that the name's format is correct and within bounds */ + if (strncmp("step", child->name, 4)) { + err = -EINVAL; + goto parse_error; + } + + err = kstrtouint(child->name + 4, 10, &pos); + if (err < 0) + goto parse_error; + + /* Invalid step index or step already parsed? */ + if (pos >= num_steps || pseq->steps[pos].resource != NULL) { + err = -EINVAL; + goto parse_error; + } + + err = of_power_seq_parse_step(dev, child, pseq, pos, resources); + if (err) + return ERR_PTR(err); + } + + return pseq; + +parse_error: + dev_err(dev, "%s: invalid power step name %s!\n", pseq->id, + child->name); + return ERR_PTR(err); +} + +/** + * devm_of_parse_power_seq_set - build a power_seq_set from the device tree + * @dev: Device to parse the power sequences of + * + * Sequences must be contained into a subnode named "power-sequences" of the + * device root node. + * + * Memory for the sequence is allocated using devm_kzalloc on dev. The returned + * platform_power_seq_set can be freed by devm_kfree after the sequences have + * been added, but the sequences themselves must be preserved. + * + * Returns the built set on success, or an error code in case of failure. + */ +struct platform_power_seq_set *devm_of_parse_power_seq_set(struct device *dev) +{ + struct platform_power_seq_set *set; + struct device_node *root = dev->of_node; + struct device_node *seq; + struct list_head resources; + int n, sz; + + if (!root) + return NULL; + + root = of_find_node_by_name(root, "power-sequences"); + if (!root) + return NULL; + + n = of_get_child_count(root); + sz = sizeof(*set) + sizeof(struct power_seq *) * n; + set = devm_kzalloc(dev, sz, GFP_KERNEL); + if (!set) + return ERR_PTR(-ENOMEM); + set->num_seqs = n; + + n = 0; + INIT_LIST_HEAD(&resources); + for_each_child_of_node(root, seq) { + struct power_seq *pseq; + + pseq = of_parse_power_seq(dev, seq, &resources); + if (IS_ERR(pseq)) + return (void *)pseq; + + set->seqs[n++] = pseq; + } + + return set; +} +EXPORT_SYMBOL_GPL(devm_of_parse_power_seq_set); +#endif /* CONFIG_OF */ + +/** + * power_seq_set_init - initialize a power_seq_set + * @set: Set to initialize + * @dev: Device this set is going to belong to + */ +void power_seq_set_init(struct power_seq_set *set, struct device *dev) +{ + set->dev = dev; + INIT_LIST_HEAD(&set->resources); + INIT_LIST_HEAD(&set->seqs); +} +EXPORT_SYMBOL_GPL(power_seq_set_init); + +/** + * power_seq_add_sequence - add a power sequence to a set + * @set: Set to add the sequence to + * @seq: Sequence to add + * + * This step will check that all the resources used by the sequence are + * allocated. If they are not, an attempt to allocate them is made. This + * operation can fail and and return an error code. + * + * Returns 0 on success, error code if a resource initialization failed. + */ +int power_seq_add_sequence(struct power_seq_set *set, struct power_seq *seq) +{ + struct power_seq_resource *res; + int i, err; + + for (i = 0; i < seq->num_steps; i++) { + struct power_seq_step *step = &seq->steps[i]; + struct power_seq_resource *step_res = step->resource; + list_for_each_entry(res, &set->resources, list) { + if (res == step_res) + break; + } + /* resource not allocated yet, allocate and add it */ + if (&res->list == &set->resources) { + err = power_seq_ops[step_res->type].res_alloc(set->dev, + step_res); + if (err) + return err; + list_add_tail(&step->resource->list, &set->resources); + } + } + + list_add_tail(&seq->list, &set->seqs); + seq->set = set; + + return 0; +} +EXPORT_SYMBOL_GPL(power_seq_add_sequence); + +/** + * power_seq_add_sequences - add power sequences defined as platform data + * @set: Set to add the sequences to + * @seqs: Sequences to add + * + * See power_seq_add_sequence for more details. + * + * Returns 0 on success, error code if a resource initialization failed. + */ +int power_seq_set_add_sequences(struct power_seq_set *set, + struct platform_power_seq_set *seqs) +{ + int i, ret; + + for (i = 0; i < seqs->num_seqs; i++) { + ret = power_seq_add_sequence(set, seqs->seqs[i]); + if (ret < 0) + return ret; + } + + return 0; +} +EXPORT_SYMBOL_GPL(power_seq_set_add_sequences); + +/** + * power_seq_lookup - Lookup a power sequence by name from a set + * @seqs: The set to look in + * @id: Name to look after + * + * Returns a matching power sequence if it exists, NULL if it does not. + */ +struct power_seq *power_seq_lookup(struct power_seq_set *set, const char *id) +{ + struct power_seq *seq; + + list_for_each_entry(seq, &set->seqs, list) { + if (!strcmp(seq->id, id)) + return seq; + } + + return NULL; +} +EXPORT_SYMBOL_GPL(power_seq_lookup); + +/** + * power_seq_run() - run a power sequence + * @seq: The power sequence to run + * + * Returns 0 on success, error code in case of failure. + */ +int power_seq_run(struct power_seq *seq) +{ + unsigned int i; + int err; + + if (!seq) + return 0; + + if (!seq->set) { + pr_err("cannot run a sequence not added to a set"); + return -EINVAL; + } + + for (i = 0; i < seq->num_steps; i++) { + unsigned int type = seq->steps[i].resource->type; + + err = power_seq_ops[type].step_run(&seq->steps[i]); + if (err) { + power_seq_err(seq, i, + "error %d while running power sequence step\n", + err); + return err; + } + } + + return 0; +} +EXPORT_SYMBOL_GPL(power_seq_run); + +#include "power_seq_delay.c" +#include "power_seq_regulator.c" +#include "power_seq_pwm.c" +#include "power_seq_gpio.c" + +static const struct power_seq_res_ops power_seq_ops[POWER_SEQ_NUM_TYPES] = { + [POWER_SEQ_DELAY] = POWER_SEQ_DELAY_TYPE, + [POWER_SEQ_REGULATOR] = POWER_SEQ_REGULATOR_TYPE, + [POWER_SEQ_PWM] = POWER_SEQ_PWM_TYPE, + [POWER_SEQ_GPIO] = POWER_SEQ_GPIO_TYPE, +}; + +MODULE_AUTHOR("Alexandre Courbot "); +MODULE_DESCRIPTION("Runtime Interpreted Power Sequences"); +MODULE_LICENSE("GPL v2"); diff --git a/drivers/power/power_seq/power_seq_delay.c b/drivers/power/power_seq/power_seq_delay.c new file mode 100644 index 0000000..5bb0a46 --- /dev/null +++ b/drivers/power/power_seq/power_seq_delay.c @@ -0,0 +1,65 @@ +/* + * Copyright (c) 2012 NVIDIA Corporation. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * 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. + * + */ + +#include + +#ifdef CONFIG_OF +static int of_power_seq_parse_delay(struct device_node *node, + struct power_seq *seq, + unsigned int step_nbr, + struct power_seq_resource *res) +{ + struct power_seq_step *step = &seq->steps[step_nbr]; + int err; + + err = of_property_read_u32(node, "delay", + &step->delay.delay); + if (err < 0) + power_seq_err(seq, step_nbr, "error reading delay property\n"); + + return err; +} +#else +#define of_power_seq_parse_delay NULL +#endif + +static bool power_seq_res_compare_delay(struct power_seq_resource *res, + struct power_seq_resource *res2) +{ + /* Delay resources are just here to hold the type of steps, so they are + * all equivalent. */ + return true; +} + +static int power_seq_res_alloc_delay(struct device *dev, + struct power_seq_resource *res) +{ + return 0; +} + +static int power_seq_step_run_delay(struct power_seq_step *step) +{ + usleep_range(step->delay.delay, + step->delay.delay + 1000); + + return 0; +} + +#define POWER_SEQ_DELAY_TYPE { \ + .name = "delay", \ + .of_parse = of_power_seq_parse_delay, \ + .step_run = power_seq_step_run_delay, \ + .res_compare = power_seq_res_compare_delay, \ + .res_alloc = power_seq_res_alloc_delay, \ +} diff --git a/drivers/power/power_seq/power_seq_gpio.c b/drivers/power/power_seq/power_seq_gpio.c new file mode 100644 index 0000000..028a4cc --- /dev/null +++ b/drivers/power/power_seq/power_seq_gpio.c @@ -0,0 +1,94 @@ +/* + * Copyright (c) 2012 NVIDIA Corporation. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * 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. + * + */ + +#include +#include + +#ifdef CONFIG_OF +static int of_power_seq_parse_gpio(struct device_node *node, + struct power_seq *seq, + unsigned int step_nbr, + struct power_seq_resource *res) +{ + struct power_seq_step *step = &seq->steps[step_nbr]; + int gpio; + int err; + + gpio = of_get_named_gpio(node, "gpio", 0); + if (gpio < 0) { + power_seq_err(seq, step_nbr, "error reading gpio property\n"); + return gpio; + } + res->gpio.gpio = gpio; + + err = of_property_read_u32(node, "value", &step->gpio.value); + if (err < 0) { + power_seq_err(seq, step_nbr, "error reading value property\n"); + } else if (step->gpio.value < 0 || step->gpio.value > 1) { + power_seq_err(seq, step_nbr, + "value out of range (must be 0 or 1)\n"); + err = -EINVAL; + } + + return err; +} +#else +#define of_power_seq_parse_gpio NULL +#endif + +static bool power_seq_res_compare_gpio(struct power_seq_resource *res, + struct power_seq_resource *res2) +{ + return res->gpio.gpio == res2->gpio.gpio; +} + +static int power_seq_res_alloc_gpio(struct device *dev, + struct power_seq_resource *res) +{ + int err; + + err = devm_gpio_request(dev, res->gpio.gpio, dev_name(dev)); + if (err) { + dev_err(dev, "cannot get gpio %d\n", res->gpio.gpio); + return err; + } + + return 0; +} + +static int power_seq_step_run_gpio(struct power_seq_step *step) +{ + struct power_seq_resource *res = step->resource; + + /* set the GPIO direction at first use */ + if (!res->gpio.is_set) { + int err = gpio_direction_output(res->gpio.gpio, + step->gpio.value); + if (err) + return err; + res->gpio.is_set = true; + } else { + gpio_set_value_cansleep(res->gpio.gpio, step->gpio.value); + } + + return 0; +} + +#define POWER_SEQ_GPIO_TYPE { \ + .name = "gpio", \ + .of_parse = of_power_seq_parse_gpio, \ + .step_run = power_seq_step_run_gpio, \ + .res_compare = power_seq_res_compare_gpio, \ + .res_alloc = power_seq_res_alloc_gpio, \ +} diff --git a/drivers/power/power_seq/power_seq_pwm.c b/drivers/power/power_seq/power_seq_pwm.c new file mode 100644 index 0000000..e61acdd --- /dev/null +++ b/drivers/power/power_seq/power_seq_pwm.c @@ -0,0 +1,82 @@ +/* + * Copyright (c) 2012 NVIDIA Corporation. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * 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. + * + */ + +#ifdef CONFIG_PWM + +#include + +#ifdef CONFIG_OF +static int of_power_seq_parse_pwm(struct device_node *node, + struct power_seq *seq, + unsigned int step_nbr, + struct power_seq_resource *res) +{ + struct power_seq_step *step = &seq->steps[step_nbr]; + int err; + + err = of_property_read_string(node, "id", &res->pwm.id); + if (err) { + power_seq_err(seq, step_nbr, "error reading id property\n"); + return err; + } + + err = of_power_seq_parse_enable_properties(node, seq, step_nbr, + &step->pwm.enable); + return err; +} +#else +#define of_power_seq_parse_pwm NULL +#endif + +static bool power_seq_res_compare_pwm(struct power_seq_resource *res, + struct power_seq_resource *res2) +{ + return !strcmp(res->pwm.id, res2->pwm.id); +} + +static int power_seq_res_alloc_pwm(struct device *dev, + struct power_seq_resource *res) +{ + res->pwm.pwm = devm_pwm_get(dev, res->pwm.id); + if (IS_ERR(res->pwm.pwm)) { + dev_err(dev, "cannot get pwm \"%s\"\n", res->pwm.id); + return PTR_ERR(res->pwm.pwm); + } + + return 0; +} + +static int power_seq_step_run_pwm(struct power_seq_step *step) +{ + if (step->pwm.enable) { + return pwm_enable(step->resource->pwm.pwm); + } else { + pwm_disable(step->resource->pwm.pwm); + return 0; + } +} + +#define POWER_SEQ_PWM_TYPE { \ + .name = "pwm", \ + .of_parse = of_power_seq_parse_pwm, \ + .step_run = power_seq_step_run_pwm, \ + .res_compare = power_seq_res_compare_pwm, \ + .res_alloc = power_seq_res_alloc_pwm, \ +} + +#else + +#define POWER_SEQ_PWM_TYPE {} + +#endif diff --git a/drivers/power/power_seq/power_seq_regulator.c b/drivers/power/power_seq/power_seq_regulator.c new file mode 100644 index 0000000..2025155 --- /dev/null +++ b/drivers/power/power_seq/power_seq_regulator.c @@ -0,0 +1,83 @@ +/* + * Copyright (c) 2012 NVIDIA Corporation. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * 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. + * + */ + +#ifdef CONFIG_REGULATOR + +#include + +#ifdef CONFIG_OF +static int of_power_seq_parse_regulator(struct device_node *node, + struct power_seq *seq, + unsigned int step_nbr, + struct power_seq_resource *res) +{ + struct power_seq_step *step = &seq->steps[step_nbr]; + int err; + + err = of_property_read_string(node, "id", + &res->regulator.id); + if (err) { + power_seq_err(seq, step_nbr, "error reading id property\n"); + return err; + } + + err = of_power_seq_parse_enable_properties(node, seq, step_nbr, + &step->regulator.enable); + return err; +} +#else +#define of_power_seq_parse_regulator NULL +#endif + +static bool +power_seq_res_compare_regulator(struct power_seq_resource *res, + struct power_seq_resource *res2) +{ + return !strcmp(res->regulator.id, res2->regulator.id); +} + +static int power_seq_res_alloc_regulator(struct device *dev, + struct power_seq_resource *res) +{ + res->regulator.regulator = devm_regulator_get(dev, res->regulator.id); + if (IS_ERR(res->regulator.regulator)) { + dev_err(dev, "cannot get regulator \"%s\"\n", + res->regulator.id); + return PTR_ERR(res->regulator.regulator); + } + + return 0; +} + +static int power_seq_step_run_regulator(struct power_seq_step *step) +{ + if (step->regulator.enable) + return regulator_enable(step->resource->regulator.regulator); + else + return regulator_disable(step->resource->regulator.regulator); +} + +#define POWER_SEQ_REGULATOR_TYPE { \ + .name = "regulator", \ + .of_parse = of_power_seq_parse_regulator, \ + .step_run = power_seq_step_run_regulator, \ + .res_compare = power_seq_res_compare_regulator, \ + .res_alloc = power_seq_res_alloc_regulator, \ +} + +#else + +#define POWER_SEQ_REGULATOR_TYPE {} + +#endif diff --git a/include/linux/power_seq.h b/include/linux/power_seq.h new file mode 100644 index 0000000..21b95b6 --- /dev/null +++ b/include/linux/power_seq.h @@ -0,0 +1,203 @@ +/* + * power_seq.h + * + * Simple interpreter for power sequences defined as platform data or device + * tree properties. + * + * Power sequences are designed to replace the callbacks typically used in + * board-specific files that implement board- or device- specific power + * sequences (such as those of backlights). A power sequence is an array of + * steps referencing resources (regulators, GPIOs, PWMs, ...) with an action to + * perform on them. By having the power sequences interpreted, it becomes + * possible to describe them in the device tree and thus to remove + * board-specific files from the kernel. + * + * See Documentation/power/power_seqs.txt for detailed information. + * + * Author: Alexandre Courbot + * + * Copyright (c) 2012 NVIDIA Corporation. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * 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. + * + */ + +#ifndef __LINUX_POWER_SEQ_H +#define __LINUX_POWER_SEQ_H + +#include +#include + +struct device; +struct regulator; +struct pwm_device; + +/** + * The different kinds of resources that can be controlled by the sequences + */ +enum power_seq_res_type { + POWER_SEQ_DELAY, + POWER_SEQ_REGULATOR, + POWER_SEQ_PWM, + POWER_SEQ_GPIO, + POWER_SEQ_NUM_TYPES, +}; + +/** + * struct power_seq_regulator_resource + * @id: name of the regulator + * @regulator: resolved regulator. Written during resource resolution. + */ +struct power_seq_regulator_resource { + const char *id; + struct regulator *regulator; +}; + +/** + * struct power_seq_pwm_resource + * @id: name of the PWM + * @regulator: resolved PWM. Written during resource resolution. + */ +struct power_seq_pwm_resource { + const char *id; + struct pwm_device *pwm; +}; + +/** + * struct power_seq_gpio_resource + * @gpio: number of the GPIO + * @is_set: track GPIO state to set its direction at first use + */ +struct power_seq_gpio_resource { + int gpio; + bool is_set; +}; + +/** + * struct power_seq_resource - resource used by power sequences + * @type: type of the resource. This decides which member of the union is + * used for this resource + * @list: link resources together in power_seq_set + * @regulator: used if @type == POWER_SEQ_REGULATOR + * @pwm: used if @type == POWER_SEQ_PWM + * @gpio: used if @type == POWER_SEQ_GPIO + */ +struct power_seq_resource { + enum power_seq_res_type type; + struct list_head list; + union { + struct power_seq_regulator_resource regulator; + struct power_seq_pwm_resource pwm; + struct power_seq_gpio_resource gpio; + }; +}; +#define power_seq_for_each_resource(pos, set) \ + list_for_each_entry(pos, &(set)->resources, list) + +/** + * struct power_seq_delay_step - action data for delay steps + * @delay: amount of time to wait, in microseconds + */ +struct power_seq_delay_step { + unsigned int delay; +}; + +/** + * struct power_seq_regulator_step - platform data for regulator steps + * @enable: whether to enable or disable the regulator during this step + */ +struct power_seq_regulator_step { + bool enable; +}; + +/** + * struct power_seq_pwm_step - action data for PWM steps + * @enable: whether to enable or disable the PWM during this step + */ +struct power_seq_pwm_step { + bool enable; +}; + +/** + * struct power_seq_gpio_step - action data for GPIO steps + * @enable: whether to enable or disable the GPIO during this step + */ +struct power_seq_gpio_step { + int value; +}; + +/** + * struct power_seq_step - data for power sequences steps + * @resource: resource used by this step + * @delay: used if resource->type == POWER_SEQ_DELAY + * @regulator: used if resource->type == POWER_SEQ_REGULATOR + * @pwm: used if resource->type == POWER_SEQ_PWN + * @gpio: used if resource->type == POWER_SEQ_GPIO + */ +struct power_seq_step { + struct power_seq_resource *resource; + union { + struct power_seq_delay_step delay; + struct power_seq_regulator_step regulator; + struct power_seq_pwm_step pwm; + struct power_seq_gpio_step gpio; + }; +}; + +struct power_seq_set; + +/** + * struct power_seq - single power sequence + * @id: name of this sequence + * @list: link sequences together in power_seq_set. Leave as-is + * @set: set this sequence belongs to. Written when added to a set + * @num_steps: number of steps in the sequence + * @steps: array of steps that make the sequence + */ +struct power_seq { + const char *id; + struct list_head list; + struct power_seq_set *set; + unsigned int num_steps; + struct power_seq_step steps[]; +}; + +/** + * struct power_seq_set - power sequences and resources used by a device + * @dev: device this set belongs to + * @resources: list of resources used by power sequences + * @seqs: list of power sequences + */ +struct power_seq_set { + struct device *dev; + struct list_head resources; + struct list_head seqs; +}; + +/** + * struct platform_power_seq_set - define power sequences as platform data + * @num_seqs: number of sequences defined + * @seqs: array of num_seqs power sequences + */ +struct platform_power_seq_set { + unsigned int num_seqs; + struct power_seq *seqs[]; +}; + +struct platform_power_seq_set *devm_of_parse_power_seq_set(struct device *dev); +void power_seq_set_init(struct power_seq_set *set, struct device *dev); +int power_seq_set_add_sequence(struct power_seq_set *set, + struct power_seq *seq); +int power_seq_set_add_sequences(struct power_seq_set *set, + struct platform_power_seq_set *seqs); +struct power_seq *power_seq_lookup(struct power_seq_set *seqs, const char *id); +int power_seq_run(struct power_seq *seq); + +#endif -- 1.8.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/