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Linux/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");
185 

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