net/rfkill/rfkill-gpio.c

   1 /*
   2  * Copyright (c) 2011, NVIDIA Corporation.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  17  */
  18
  19 #include <linux/gpio.h>
  20 #include <linux/init.h>
  21 #include <linux/kernel.h>
  22 #include <linux/module.h>
  23 #include <linux/rfkill.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/clk.h>
  26 #include <linux/slab.h>
  27 #include <linux/acpi.h>
  28 #include <linux/gpio/consumer.h>
  29
  30 struct rfkill_gpio_data {
  31         const char              *name;
  32         enum rfkill_type        type;
  33         struct gpio_desc        *reset_gpio;
  34         struct gpio_desc        *shutdown_gpio;
  35
  36         struct rfkill           *rfkill_dev;
  37         struct clk              *clk;
  38
  39         bool                    clk_enabled;
  40 };
  41
  42 static int rfkill_gpio_set_power(void *data, bool blocked)
  43 {
  44         struct rfkill_gpio_data *rfkill = data;
  45
  46         if (!blocked && !IS_ERR(rfkill->clk) && !rfkill->clk_enabled)
  47                 clk_enable(rfkill->clk);
  48
  49         gpiod_set_value_cansleep(rfkill->shutdown_gpio, !blocked);
  50         gpiod_set_value_cansleep(rfkill->reset_gpio, !blocked);
  51
  52         if (blocked && !IS_ERR(rfkill->clk) && rfkill->clk_enabled)
  53                 clk_disable(rfkill->clk);
  54
  55         rfkill->clk_enabled = !blocked;
  56
  57         return 0;
  58 }
  59
  60 static const struct rfkill_ops rfkill_gpio_ops = {
  61         .set_block = rfkill_gpio_set_power,
  62 };
  63
  64 static const struct acpi_gpio_params reset_gpios = { 0, 0, false };
  65 static const struct acpi_gpio_params shutdown_gpios = { 1, 0, false };
  66
  67 static const struct acpi_gpio_mapping acpi_rfkill_default_gpios[] = {
  68         { "reset-gpios", &reset_gpios, 1 },
  69         { "shutdown-gpios", &shutdown_gpios, 1 },
  70         { },
  71 };
  72
  73 static int rfkill_gpio_acpi_probe(struct device *dev,
  74                                   struct rfkill_gpio_data *rfkill)
  75 {
  76         const struct acpi_device_id *id;
  77
  78         id = acpi_match_device(dev->driver->acpi_match_table, dev);
  79         if (!id)
  80                 return -ENODEV;
  81
  82         rfkill->type = (unsigned)id->driver_data;
  83
  84         return acpi_dev_add_driver_gpios(ACPI_COMPANION(dev),
  85                                          acpi_rfkill_default_gpios);
  86 }
  87
  88 static int rfkill_gpio_probe(struct platform_device *pdev)
  89 {
  90         struct rfkill_gpio_data *rfkill;
  91         struct gpio_desc *gpio;
  92         const char *type_name;
  93         int ret;
  94
  95         rfkill = devm_kzalloc(&pdev->dev, sizeof(*rfkill), GFP_KERNEL);
  96         if (!rfkill)
  97                 return -ENOMEM;
  98
  99         device_property_read_string(&pdev->dev, "name", &rfkill->name);
 100         device_property_read_string(&pdev->dev, "type", &type_name);
 101
 102         if (!rfkill->name)
 103                 rfkill->name = dev_name(&pdev->dev);
 104
 105         rfkill->type = rfkill_find_type(type_name);
 106
 107         if (ACPI_HANDLE(&pdev->dev)) {
 108                 ret = rfkill_gpio_acpi_probe(&pdev->dev, rfkill);
 109                 if (ret)
 110                         return ret;
 111         }
 112
 113         rfkill->clk = devm_clk_get(&pdev->dev, NULL);
 114
 115         gpio = devm_gpiod_get_optional(&pdev->dev, "reset", GPIOD_OUT_LOW);
 116         if (IS_ERR(gpio))
 117                 return PTR_ERR(gpio);
 118
 119         rfkill->reset_gpio = gpio;
 120
 121         gpio = devm_gpiod_get_optional(&pdev->dev, "shutdown", GPIOD_OUT_LOW);
 122         if (IS_ERR(gpio))
 123                 return PTR_ERR(gpio);
 124
 125         rfkill->shutdown_gpio = gpio;
 126
 127         /* Make sure at-least one GPIO is defined for this instance */
 128         if (!rfkill->reset_gpio && !rfkill->shutdown_gpio) {
 129                 dev_err(&pdev->dev, "invalid platform data\n");
 130                 return -EINVAL;
 131         }
 132
 133         rfkill->rfkill_dev = rfkill_alloc(rfkill->name, &pdev->dev,
 134                                           rfkill->type, &rfkill_gpio_ops,
 135                                           rfkill);
 136         if (!rfkill->rfkill_dev)
 137                 return -ENOMEM;
 138
 139         ret = rfkill_register(rfkill->rfkill_dev);
 140         if (ret < 0)
 141                 return ret;
 142
 143         platform_set_drvdata(pdev, rfkill);
 144
 145         dev_info(&pdev->dev, "%s device registered.\n", rfkill->name);
 146
 147         return 0;
 148 }
 149
 150 static int rfkill_gpio_remove(struct platform_device *pdev)
 151 {
 152         struct rfkill_gpio_data *rfkill = platform_get_drvdata(pdev);
 153
 154         rfkill_unregister(rfkill->rfkill_dev);
 155         rfkill_destroy(rfkill->rfkill_dev);
 156
 157         acpi_dev_remove_driver_gpios(ACPI_COMPANION(&pdev->dev));
 158
 159         return 0;
 160 }
 161
 162 #ifdef CONFIG_ACPI
 163 static const struct acpi_device_id rfkill_acpi_match[] = {
 164         { "BCM4752", RFKILL_TYPE_GPS },
 165         { "LNV4752", RFKILL_TYPE_GPS },
 166         { },
 167 };
 168 MODULE_DEVICE_TABLE(acpi, rfkill_acpi_match);
 169 #endif
 170
 171 static struct platform_driver rfkill_gpio_driver = {
 172         .probe = rfkill_gpio_probe,
 173         .remove = rfkill_gpio_remove,
 174         .driver = {
 175                 .name = "rfkill_gpio",
 176                 .acpi_match_table = ACPI_PTR(rfkill_acpi_match),
 177         },
 178 };
 179
 180 module_platform_driver(rfkill_gpio_driver);
 181
 182 MODULE_DESCRIPTION("gpio rfkill");
 183 MODULE_AUTHOR("NVIDIA");
 184 MODULE_LICENSE("GPL");