Lejun Zhu | 61cd482 | 2014-03-30 23:12:00 -0700 | [diff] [blame] | 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/input.h> |
| 21 | #include <linux/platform_device.h> |
| 22 | #include <linux/pnp.h> |
| 23 | |
| 24 | /* |
| 25 | * Definition of buttons on the tablet. The ACPI index of each button |
| 26 | * is defined in section 2.8.7.2 of "Windows ACPI Design Guide for SoC |
| 27 | * Platforms" |
| 28 | */ |
| 29 | #define MAX_NBUTTONS 5 |
| 30 | |
| 31 | struct soc_button_info { |
| 32 | const char *name; |
| 33 | int acpi_index; |
| 34 | unsigned int event_type; |
| 35 | unsigned int event_code; |
| 36 | bool autorepeat; |
| 37 | bool wakeup; |
| 38 | }; |
| 39 | |
| 40 | /* |
| 41 | * Some of the buttons like volume up/down are auto repeat, while others |
| 42 | * are not. To support both, we register two platform devices, and put |
| 43 | * buttons into them based on whether the key should be auto repeat. |
| 44 | */ |
| 45 | #define BUTTON_TYPES 2 |
| 46 | |
| 47 | struct soc_button_data { |
| 48 | struct platform_device *children[BUTTON_TYPES]; |
| 49 | }; |
| 50 | |
| 51 | /* |
| 52 | * Get the Nth GPIO number from the ACPI object. |
| 53 | */ |
| 54 | static int soc_button_lookup_gpio(struct device *dev, int acpi_index) |
| 55 | { |
| 56 | struct gpio_desc *desc; |
| 57 | int gpio; |
| 58 | |
| 59 | desc = gpiod_get_index(dev, KBUILD_MODNAME, acpi_index); |
| 60 | if (IS_ERR(desc)) |
| 61 | return PTR_ERR(desc); |
| 62 | |
| 63 | gpio = desc_to_gpio(desc); |
| 64 | |
| 65 | gpiod_put(desc); |
| 66 | |
| 67 | return gpio; |
| 68 | } |
| 69 | |
| 70 | static struct platform_device * |
| 71 | soc_button_device_create(struct pnp_dev *pdev, |
| 72 | const struct soc_button_info *button_info, |
| 73 | bool autorepeat) |
| 74 | { |
| 75 | const struct soc_button_info *info; |
| 76 | struct platform_device *pd; |
| 77 | struct gpio_keys_button *gpio_keys; |
| 78 | struct gpio_keys_platform_data *gpio_keys_pdata; |
| 79 | int n_buttons = 0; |
| 80 | int gpio; |
| 81 | int error; |
| 82 | |
| 83 | gpio_keys_pdata = devm_kzalloc(&pdev->dev, |
| 84 | sizeof(*gpio_keys_pdata) + |
| 85 | sizeof(*gpio_keys) * MAX_NBUTTONS, |
| 86 | GFP_KERNEL); |
| 87 | gpio_keys = (void *)(gpio_keys_pdata + 1); |
| 88 | |
| 89 | for (info = button_info; info->name; info++) { |
| 90 | if (info->autorepeat != autorepeat) |
| 91 | continue; |
| 92 | |
| 93 | gpio = soc_button_lookup_gpio(&pdev->dev, info->acpi_index); |
| 94 | if (gpio < 0) |
| 95 | continue; |
| 96 | |
| 97 | gpio_keys[n_buttons].type = info->event_type; |
| 98 | gpio_keys[n_buttons].code = info->event_code; |
| 99 | gpio_keys[n_buttons].gpio = gpio; |
| 100 | gpio_keys[n_buttons].active_low = 1; |
| 101 | gpio_keys[n_buttons].desc = info->name; |
| 102 | gpio_keys[n_buttons].wakeup = info->wakeup; |
| 103 | n_buttons++; |
| 104 | } |
| 105 | |
| 106 | if (n_buttons == 0) { |
| 107 | error = -ENODEV; |
| 108 | goto err_free_mem; |
| 109 | } |
| 110 | |
| 111 | gpio_keys_pdata->buttons = gpio_keys; |
| 112 | gpio_keys_pdata->nbuttons = n_buttons; |
| 113 | gpio_keys_pdata->rep = autorepeat; |
| 114 | |
| 115 | pd = platform_device_alloc("gpio-keys", PLATFORM_DEVID_AUTO); |
| 116 | if (!pd) { |
| 117 | error = -ENOMEM; |
| 118 | goto err_free_mem; |
| 119 | } |
| 120 | |
| 121 | error = platform_device_add_data(pd, gpio_keys_pdata, |
| 122 | sizeof(*gpio_keys_pdata)); |
| 123 | if (error) |
| 124 | goto err_free_pdev; |
| 125 | |
| 126 | error = platform_device_add(pd); |
| 127 | if (error) |
| 128 | goto err_free_pdev; |
| 129 | |
| 130 | return pd; |
| 131 | |
| 132 | err_free_pdev: |
| 133 | platform_device_put(pd); |
| 134 | err_free_mem: |
| 135 | devm_kfree(&pdev->dev, gpio_keys_pdata); |
| 136 | return ERR_PTR(error); |
| 137 | } |
| 138 | |
| 139 | static void soc_button_remove(struct pnp_dev *pdev) |
| 140 | { |
| 141 | struct soc_button_data *priv = pnp_get_drvdata(pdev); |
| 142 | int i; |
| 143 | |
| 144 | for (i = 0; i < BUTTON_TYPES; i++) |
| 145 | if (priv->children[i]) |
| 146 | platform_device_unregister(priv->children[i]); |
| 147 | } |
| 148 | |
| 149 | static int soc_button_pnp_probe(struct pnp_dev *pdev, |
| 150 | const struct pnp_device_id *id) |
| 151 | { |
| 152 | const struct soc_button_info *button_info = (void *)id->driver_data; |
| 153 | struct soc_button_data *priv; |
| 154 | struct platform_device *pd; |
| 155 | int i; |
| 156 | int error; |
| 157 | |
| 158 | priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); |
| 159 | if (!priv) |
| 160 | return -ENOMEM; |
| 161 | |
| 162 | pnp_set_drvdata(pdev, priv); |
| 163 | |
| 164 | for (i = 0; i < BUTTON_TYPES; i++) { |
| 165 | pd = soc_button_device_create(pdev, button_info, i == 0); |
| 166 | if (IS_ERR(pd)) { |
| 167 | error = PTR_ERR(pd); |
| 168 | if (error != -ENODEV) { |
| 169 | soc_button_remove(pdev); |
| 170 | return error; |
| 171 | } |
| 172 | } |
| 173 | |
| 174 | priv->children[i] = pd; |
| 175 | } |
| 176 | |
| 177 | if (!priv->children[0] && !priv->children[1]) |
| 178 | return -ENODEV; |
| 179 | |
| 180 | return 0; |
| 181 | } |
| 182 | |
| 183 | static struct soc_button_info soc_button_PNP0C40[] = { |
| 184 | { "power", 0, EV_KEY, KEY_POWER, false, true }, |
| 185 | { "home", 1, EV_KEY, KEY_HOME, false, true }, |
| 186 | { "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false }, |
| 187 | { "volume_down", 3, EV_KEY, KEY_VOLUMEDOWN, true, false }, |
| 188 | { "rotation_lock", 4, EV_SW, SW_ROTATE_LOCK, false, false }, |
| 189 | { } |
| 190 | }; |
| 191 | |
| 192 | static const struct pnp_device_id soc_button_pnp_match[] = { |
| 193 | { .id = "PNP0C40", .driver_data = (long)soc_button_PNP0C40 }, |
| 194 | { .id = "" } |
| 195 | }; |
| 196 | MODULE_DEVICE_TABLE(pnp, soc_button_pnp_match); |
| 197 | |
| 198 | static struct pnp_driver soc_button_pnp_driver = { |
| 199 | .name = KBUILD_MODNAME, |
| 200 | .id_table = soc_button_pnp_match, |
| 201 | .probe = soc_button_pnp_probe, |
| 202 | .remove = soc_button_remove, |
| 203 | }; |
| 204 | |
| 205 | static int __init soc_button_init(void) |
| 206 | { |
| 207 | return pnp_register_driver(&soc_button_pnp_driver); |
| 208 | } |
| 209 | |
| 210 | static void __exit soc_button_exit(void) |
| 211 | { |
| 212 | pnp_unregister_driver(&soc_button_pnp_driver); |
| 213 | } |
| 214 | |
| 215 | module_init(soc_button_init); |
| 216 | module_exit(soc_button_exit); |
| 217 | |
| 218 | MODULE_LICENSE("GPL"); |