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