drivers/regulator/vexpress.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License version 2 as
   4  * published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9  * GNU General Public License for more details.
  10  *
  11  * Copyright (C) 2012 ARM Limited
  12  */
  13
  14 #define DRVNAME "vexpress-regulator"
  15 #define pr_fmt(fmt) DRVNAME ": " fmt
  16
  17 #include <linux/device.h>
  18 #include <linux/err.h>
  19 #include <linux/module.h>
  20 #include <linux/of_device.h>
  21 #include <linux/regulator/driver.h>
  22 #include <linux/regulator/machine.h>
  23 #include <linux/regulator/of_regulator.h>
  24 #include <linux/vexpress.h>
  25
  26 struct vexpress_regulator {
  27         struct regulator_desc desc;
  28         struct regulator_dev *regdev;
  29         struct vexpress_config_func *func;
  30 };
  31
  32 static int vexpress_regulator_get_voltage(struct regulator_dev *regdev)
  33 {
  34         struct vexpress_regulator *reg = rdev_get_drvdata(regdev);
  35         u32 uV;
  36         int err = vexpress_config_read(reg->func, 0, &uV);
  37
  38         return err ? err : uV;
  39 }
  40
  41 static int vexpress_regulator_set_voltage(struct regulator_dev *regdev,
  42                 int min_uV, int max_uV, unsigned *selector)
  43 {
  44         struct vexpress_regulator *reg = rdev_get_drvdata(regdev);
  45
  46         return vexpress_config_write(reg->func, 0, min_uV);
  47 }
  48
  49 static struct regulator_ops vexpress_regulator_ops_ro = {
  50         .get_voltage = vexpress_regulator_get_voltage,
  51 };
  52
  53 static struct regulator_ops vexpress_regulator_ops = {
  54         .get_voltage = vexpress_regulator_get_voltage,
  55         .set_voltage = vexpress_regulator_set_voltage,
  56 };
  57
  58 static int vexpress_regulator_probe(struct platform_device *pdev)
  59 {
  60         int err;
  61         struct vexpress_regulator *reg;
  62         struct regulator_init_data *init_data;
  63         struct regulator_config config = { };
  64
  65         reg = devm_kzalloc(&pdev->dev, sizeof(*reg), GFP_KERNEL);
  66         if (!reg) {
  67                 err = -ENOMEM;
  68                 goto error_kzalloc;
  69         }
  70
  71         reg->func = vexpress_config_func_get_by_dev(&pdev->dev);
  72         if (!reg->func) {
  73                 err = -ENXIO;
  74                 goto error_get_func;
  75         }
  76
  77         reg->desc.name = dev_name(&pdev->dev);
  78         reg->desc.type = REGULATOR_VOLTAGE;
  79         reg->desc.owner = THIS_MODULE;
  80         reg->desc.continuous_voltage_range = true;
  81
  82         init_data = of_get_regulator_init_data(&pdev->dev, pdev->dev.of_node);
  83         if (!init_data) {
  84                 err = -EINVAL;
  85                 goto error_get_regulator_init_data;
  86         }
  87
  88         init_data->constraints.apply_uV = 0;
  89         if (init_data->constraints.min_uV && init_data->constraints.max_uV)
  90                 reg->desc.ops = &vexpress_regulator_ops;
  91         else
  92                 reg->desc.ops = &vexpress_regulator_ops_ro;
  93
  94         config.dev = &pdev->dev;
  95         config.init_data = init_data;
  96         config.driver_data = reg;
  97         config.of_node = pdev->dev.of_node;
  98
  99         reg->regdev = regulator_register(&reg->desc, &config);
 100         if (IS_ERR(reg->regdev)) {
 101                 err = PTR_ERR(reg->regdev);
 102                 goto error_regulator_register;
 103         }
 104
 105         platform_set_drvdata(pdev, reg);
 106
 107         return 0;
 108
 109 error_regulator_register:
 110 error_get_regulator_init_data:
 111         vexpress_config_func_put(reg->func);
 112 error_get_func:
 113 error_kzalloc:
 114         return err;
 115 }
 116
 117 static int vexpress_regulator_remove(struct platform_device *pdev)
 118 {
 119         struct vexpress_regulator *reg = platform_get_drvdata(pdev);
 120
 121         vexpress_config_func_put(reg->func);
 122         regulator_unregister(reg->regdev);
 123
 124         return 0;
 125 }
 126
 127 static struct of_device_id vexpress_regulator_of_match[] = {
 128         { .compatible = "arm,vexpress-volt", },
 129         { }
 130 };
 131
 132 static struct platform_driver vexpress_regulator_driver = {
 133         .probe = vexpress_regulator_probe,
 134         .remove = vexpress_regulator_remove,
 135         .driver = {
 136                 .name = DRVNAME,
 137                 .owner = THIS_MODULE,
 138                 .of_match_table = vexpress_regulator_of_match,
 139         },
 140 };
 141
 142 module_platform_driver(vexpress_regulator_driver);
 143
 144 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
 145 MODULE_DESCRIPTION("Versatile Express regulator");
 146 MODULE_LICENSE("GPL");
 147 MODULE_ALIAS("platform:vexpress-regulator");