345 lines
9.0 KiB
C
345 lines
9.0 KiB
C
/*
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* fixed.c
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*
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* Copyright 2008 Wolfson Microelectronics PLC.
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*
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* Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
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*
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* Copyright (c) 2009 Nokia Corporation
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* Roger Quadros <ext-roger.quadros@nokia.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This is useful for systems with mixed controllable and
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* non-controllable regulators, as well as for allowing testing on
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* systems with no controllable regulators.
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*/
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#include <linux/err.h>
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#include <linux/mutex.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/regulator/driver.h>
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#include <linux/regulator/fixed.h>
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#include <linux/gpio.h>
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#include <linux/delay.h>
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#include <linux/slab.h>
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#include <linux/of.h>
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#include <linux/of_gpio.h>
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#include <linux/regulator/of_regulator.h>
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#include <linux/regulator/machine.h>
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struct fixed_voltage_data {
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struct regulator_desc desc;
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struct regulator_dev *dev;
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int microvolts;
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int gpio;
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unsigned startup_delay;
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bool enable_high;
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bool is_enabled;
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};
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/**
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* of_get_fixed_voltage_config - extract fixed_voltage_config structure info
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* @dev: device requesting for fixed_voltage_config
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*
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* Populates fixed_voltage_config structure by extracting data from device
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* tree node, returns a pointer to the populated structure of NULL if memory
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* alloc fails.
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*/
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static struct fixed_voltage_config *
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of_get_fixed_voltage_config(struct device *dev)
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{
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struct fixed_voltage_config *config;
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struct device_node *np = dev->of_node;
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const __be32 *delay;
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struct regulator_init_data *init_data;
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config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
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GFP_KERNEL);
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if (!config)
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return ERR_PTR(-ENOMEM);
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config->init_data = of_get_regulator_init_data(dev, dev->of_node);
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if (!config->init_data)
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return ERR_PTR(-EINVAL);
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init_data = config->init_data;
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init_data->constraints.apply_uV = 0;
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config->supply_name = init_data->constraints.name;
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if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
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config->microvolts = init_data->constraints.min_uV;
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} else {
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dev_err(dev,
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"Fixed regulator specified with variable voltages\n");
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return ERR_PTR(-EINVAL);
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}
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if (init_data->constraints.boot_on)
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config->enabled_at_boot = true;
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config->gpio = of_get_named_gpio(np, "gpio", 0);
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/*
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* of_get_named_gpio() currently returns ENODEV rather than
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* EPROBE_DEFER. This code attempts to be compatible with both
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* for now; the ENODEV check can be removed once the API is fixed.
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* of_get_named_gpio() doesn't differentiate between a missing
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* property (which would be fine here, since the GPIO is optional)
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* and some other error. Patches have been posted for both issues.
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* Once they are check in, we should replace this with:
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* if (config->gpio < 0 && config->gpio != -ENOENT)
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*/
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if ((config->gpio == -ENODEV) || (config->gpio == -EPROBE_DEFER))
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return ERR_PTR(-EPROBE_DEFER);
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delay = of_get_property(np, "startup-delay-us", NULL);
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if (delay)
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config->startup_delay = be32_to_cpu(*delay);
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if (of_find_property(np, "enable-active-high", NULL))
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config->enable_high = true;
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if (of_find_property(np, "parent-supply", NULL))
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init_data->supply_regulator = "parent";
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return config;
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}
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static int fixed_voltage_is_enabled(struct regulator_dev *dev)
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{
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struct fixed_voltage_data *data = rdev_get_drvdata(dev);
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return data->is_enabled;
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}
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static int fixed_voltage_enable(struct regulator_dev *dev)
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{
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struct fixed_voltage_data *data = rdev_get_drvdata(dev);
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if (gpio_is_valid(data->gpio)) {
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gpio_set_value_cansleep(data->gpio, data->enable_high);
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data->is_enabled = true;
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}
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return 0;
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}
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static int fixed_voltage_disable(struct regulator_dev *dev)
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{
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struct fixed_voltage_data *data = rdev_get_drvdata(dev);
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if (gpio_is_valid(data->gpio)) {
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gpio_set_value_cansleep(data->gpio, !data->enable_high);
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data->is_enabled = false;
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}
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return 0;
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}
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static int fixed_voltage_enable_time(struct regulator_dev *dev)
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{
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struct fixed_voltage_data *data = rdev_get_drvdata(dev);
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return data->startup_delay;
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}
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static int fixed_voltage_get_voltage(struct regulator_dev *dev)
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{
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struct fixed_voltage_data *data = rdev_get_drvdata(dev);
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if (data->microvolts)
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return data->microvolts;
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else
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return -EINVAL;
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}
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static int fixed_voltage_list_voltage(struct regulator_dev *dev,
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unsigned selector)
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{
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struct fixed_voltage_data *data = rdev_get_drvdata(dev);
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if (selector != 0)
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return -EINVAL;
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return data->microvolts;
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}
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static struct regulator_ops fixed_voltage_ops = {
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.is_enabled = fixed_voltage_is_enabled,
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.enable = fixed_voltage_enable,
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.disable = fixed_voltage_disable,
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.enable_time = fixed_voltage_enable_time,
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.get_voltage = fixed_voltage_get_voltage,
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.list_voltage = fixed_voltage_list_voltage,
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};
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static int __devinit reg_fixed_voltage_probe(struct platform_device *pdev)
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{
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struct fixed_voltage_config *config;
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struct fixed_voltage_data *drvdata;
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int ret;
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if (pdev->dev.of_node) {
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config = of_get_fixed_voltage_config(&pdev->dev);
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if (IS_ERR(config))
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return PTR_ERR(config);
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} else {
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config = pdev->dev.platform_data;
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}
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if (!config)
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return -ENOMEM;
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drvdata = kzalloc(sizeof(struct fixed_voltage_data), GFP_KERNEL);
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if (drvdata == NULL) {
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dev_err(&pdev->dev, "Failed to allocate device data\n");
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ret = -ENOMEM;
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goto err;
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}
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drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
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if (drvdata->desc.name == NULL) {
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dev_err(&pdev->dev, "Failed to allocate supply name\n");
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ret = -ENOMEM;
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goto err;
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}
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drvdata->desc.type = REGULATOR_VOLTAGE;
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drvdata->desc.owner = THIS_MODULE;
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drvdata->desc.ops = &fixed_voltage_ops;
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if (config->microvolts)
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drvdata->desc.n_voltages = 1;
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drvdata->microvolts = config->microvolts;
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drvdata->gpio = config->gpio;
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drvdata->startup_delay = config->startup_delay;
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if (gpio_is_valid(config->gpio)) {
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drvdata->enable_high = config->enable_high;
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/* FIXME: Remove below print warning
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*
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* config->gpio must be set to -EINVAL by platform code if
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* GPIO control is not required. However, early adopters
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* not requiring GPIO control may forget to initialize
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* config->gpio to -EINVAL. This will cause GPIO 0 to be used
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* for GPIO control.
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*
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* This warning will be removed once there are a couple of users
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* for this driver.
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*/
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if (!config->gpio)
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dev_warn(&pdev->dev,
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"using GPIO 0 for regulator enable control\n");
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ret = gpio_request(config->gpio, config->supply_name);
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if (ret) {
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dev_err(&pdev->dev,
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"Could not obtain regulator enable GPIO %d: %d\n",
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config->gpio, ret);
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goto err_name;
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}
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/* set output direction without changing state
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* to prevent glitch
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*/
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drvdata->is_enabled = config->enabled_at_boot;
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ret = drvdata->is_enabled ?
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config->enable_high : !config->enable_high;
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ret = gpio_direction_output(config->gpio, ret);
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if (ret) {
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dev_err(&pdev->dev,
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"Could not configure regulator enable GPIO %d direction: %d\n",
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config->gpio, ret);
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goto err_gpio;
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}
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} else {
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/* Regulator without GPIO control is considered
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* always enabled
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*/
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drvdata->is_enabled = true;
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}
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drvdata->dev = regulator_register(&drvdata->desc, &pdev->dev,
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config->init_data, drvdata,
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pdev->dev.of_node);
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if (IS_ERR(drvdata->dev)) {
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ret = PTR_ERR(drvdata->dev);
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dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
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goto err_gpio;
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}
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platform_set_drvdata(pdev, drvdata);
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dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
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drvdata->microvolts);
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return 0;
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err_gpio:
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if (gpio_is_valid(config->gpio))
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gpio_free(config->gpio);
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err_name:
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kfree(drvdata->desc.name);
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err:
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kfree(drvdata);
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return ret;
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}
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static int __devexit reg_fixed_voltage_remove(struct platform_device *pdev)
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{
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struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev);
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regulator_unregister(drvdata->dev);
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if (gpio_is_valid(drvdata->gpio))
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gpio_free(drvdata->gpio);
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kfree(drvdata->desc.name);
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kfree(drvdata);
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return 0;
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}
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#if defined(CONFIG_OF)
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static const struct of_device_id fixed_of_match[] __devinitconst = {
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{ .compatible = "regulator-fixed", },
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{},
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};
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MODULE_DEVICE_TABLE(of, fixed_of_match);
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#else
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#define fixed_of_match NULL
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#endif
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static struct platform_driver regulator_fixed_voltage_driver = {
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.probe = reg_fixed_voltage_probe,
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.remove = __devexit_p(reg_fixed_voltage_remove),
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.driver = {
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.name = "reg-fixed-voltage",
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.owner = THIS_MODULE,
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.of_match_table = fixed_of_match,
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},
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};
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static int __init regulator_fixed_voltage_init(void)
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{
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return platform_driver_register(®ulator_fixed_voltage_driver);
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}
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subsys_initcall(regulator_fixed_voltage_init);
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static void __exit regulator_fixed_voltage_exit(void)
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{
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platform_driver_unregister(®ulator_fixed_voltage_driver);
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}
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module_exit(regulator_fixed_voltage_exit);
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MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
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MODULE_DESCRIPTION("Fixed voltage regulator");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:reg-fixed-voltage");
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