1 /* 2 * Supports for the button array on SoC tablets originally running 3 * Windows 8. 4 * 5 * (C) Copyright 2014 Intel Corporation 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; version 2 10 * of the License. 11 */ 12 13 #include <linux/module.h> 14 #include <linux/input.h> 15 #include <linux/init.h> 16 #include <linux/kernel.h> 17 #include <linux/acpi.h> 18 #include <linux/gpio/consumer.h> 19 #include <linux/gpio_keys.h> 20 #include <linux/platform_device.h> 21 22 /* 23 * Definition of buttons on the tablet. The ACPI index of each button 24 * is defined in section 2.8.7.2 of "Windows ACPI Design Guide for SoC 25 * Platforms" 26 */ 27 #define MAX_NBUTTONS 5 28 29 struct soc_button_info { 30 const char *name; 31 int acpi_index; 32 unsigned int event_type; 33 unsigned int event_code; 34 bool autorepeat; 35 bool wakeup; 36 }; 37 38 /* 39 * Some of the buttons like volume up/down are auto repeat, while others 40 * are not. To support both, we register two platform devices, and put 41 * buttons into them based on whether the key should be auto repeat. 42 */ 43 #define BUTTON_TYPES 2 44 45 struct soc_button_data { 46 struct platform_device *children[BUTTON_TYPES]; 47 }; 48 49 /* 50 * Get the Nth GPIO number from the ACPI object. 51 */ 52 static int soc_button_lookup_gpio(struct device *dev, int acpi_index) 53 { 54 struct gpio_desc *desc; 55 int gpio; 56 57 desc = gpiod_get_index(dev, KBUILD_MODNAME, acpi_index, GPIOD_ASIS); 58 if (IS_ERR(desc)) 59 return PTR_ERR(desc); 60 61 gpio = desc_to_gpio(desc); 62 63 gpiod_put(desc); 64 65 return gpio; 66 } 67 68 static struct platform_device * 69 soc_button_device_create(struct platform_device *pdev, 70 const struct soc_button_info *button_info, 71 bool autorepeat) 72 { 73 const struct soc_button_info *info; 74 struct platform_device *pd; 75 struct gpio_keys_button *gpio_keys; 76 struct gpio_keys_platform_data *gpio_keys_pdata; 77 int n_buttons = 0; 78 int gpio; 79 int error; 80 81 gpio_keys_pdata = devm_kzalloc(&pdev->dev, 82 sizeof(*gpio_keys_pdata) + 83 sizeof(*gpio_keys) * MAX_NBUTTONS, 84 GFP_KERNEL); 85 if (!gpio_keys_pdata) 86 return ERR_PTR(-ENOMEM); 87 88 gpio_keys = (void *)(gpio_keys_pdata + 1); 89 90 for (info = button_info; info->name; info++) { 91 if (info->autorepeat != autorepeat) 92 continue; 93 94 gpio = soc_button_lookup_gpio(&pdev->dev, info->acpi_index); 95 if (gpio < 0) 96 continue; 97 98 gpio_keys[n_buttons].type = info->event_type; 99 gpio_keys[n_buttons].code = info->event_code; 100 gpio_keys[n_buttons].gpio = gpio; 101 gpio_keys[n_buttons].active_low = 1; 102 gpio_keys[n_buttons].desc = info->name; 103 gpio_keys[n_buttons].wakeup = info->wakeup; 104 n_buttons++; 105 } 106 107 if (n_buttons == 0) { 108 error = -ENODEV; 109 goto err_free_mem; 110 } 111 112 gpio_keys_pdata->buttons = gpio_keys; 113 gpio_keys_pdata->nbuttons = n_buttons; 114 gpio_keys_pdata->rep = autorepeat; 115 116 pd = platform_device_alloc("gpio-keys", PLATFORM_DEVID_AUTO); 117 if (!pd) { 118 error = -ENOMEM; 119 goto err_free_mem; 120 } 121 122 error = platform_device_add_data(pd, gpio_keys_pdata, 123 sizeof(*gpio_keys_pdata)); 124 if (error) 125 goto err_free_pdev; 126 127 error = platform_device_add(pd); 128 if (error) 129 goto err_free_pdev; 130 131 return pd; 132 133 err_free_pdev: 134 platform_device_put(pd); 135 err_free_mem: 136 devm_kfree(&pdev->dev, gpio_keys_pdata); 137 return ERR_PTR(error); 138 } 139 140 static int soc_button_remove(struct platform_device *pdev) 141 { 142 struct soc_button_data *priv = platform_get_drvdata(pdev); 143 144 int i; 145 146 for (i = 0; i < BUTTON_TYPES; i++) 147 if (priv->children[i]) 148 platform_device_unregister(priv->children[i]); 149 150 return 0; 151 } 152 153 static int soc_button_probe(struct platform_device *pdev) 154 { 155 struct device *dev = &pdev->dev; 156 const struct acpi_device_id *id; 157 struct soc_button_info *button_info; 158 struct soc_button_data *priv; 159 struct platform_device *pd; 160 int i; 161 int error; 162 163 id = acpi_match_device(dev->driver->acpi_match_table, dev); 164 if (!id) 165 return -ENODEV; 166 167 button_info = (struct soc_button_info *)id->driver_data; 168 169 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 170 if (!priv) 171 return -ENOMEM; 172 173 platform_set_drvdata(pdev, priv); 174 175 for (i = 0; i < BUTTON_TYPES; i++) { 176 pd = soc_button_device_create(pdev, button_info, i == 0); 177 if (IS_ERR(pd)) { 178 error = PTR_ERR(pd); 179 if (error != -ENODEV) { 180 soc_button_remove(pdev); 181 return error; 182 } 183 continue; 184 } 185 186 priv->children[i] = pd; 187 } 188 189 if (!priv->children[0] && !priv->children[1]) 190 return -ENODEV; 191 192 return 0; 193 } 194 195 static struct soc_button_info soc_button_PNP0C40[] = { 196 { "power", 0, EV_KEY, KEY_POWER, false, true }, 197 { "home", 1, EV_KEY, KEY_LEFTMETA, false, true }, 198 { "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false }, 199 { "volume_down", 3, EV_KEY, KEY_VOLUMEDOWN, true, false }, 200 { "rotation_lock", 4, EV_SW, SW_ROTATE_LOCK, false, false }, 201 { } 202 }; 203 204 static const struct acpi_device_id soc_button_acpi_match[] = { 205 { "PNP0C40", (unsigned long)soc_button_PNP0C40 }, 206 { } 207 }; 208 209 MODULE_DEVICE_TABLE(acpi, soc_button_acpi_match); 210 211 static struct platform_driver soc_button_driver = { 212 .probe = soc_button_probe, 213 .remove = soc_button_remove, 214 .driver = { 215 .name = KBUILD_MODNAME, 216 .acpi_match_table = ACPI_PTR(soc_button_acpi_match), 217 }, 218 }; 219 module_platform_driver(soc_button_driver); 220 221 MODULE_LICENSE("GPL"); 222