drivers/platform/chrome/cros_kbd_led_backlight.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 // Keyboard backlight LED driver for ChromeOS
   3 //
   4 // Copyright (C) 2012 Google, Inc.
   5
   6 #include <linux/acpi.h>
   7 #include <linux/delay.h>
   8 #include <linux/err.h>
   9 #include <linux/init.h>
  10 #include <linux/kernel.h>
  11 #include <linux/leds.h>
  12 #include <linux/mfd/core.h>
  13 #include <linux/mod_devicetable.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/platform_data/cros_ec_commands.h>
  17 #include <linux/platform_data/cros_ec_proto.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/property.h>
  20 #include <linux/slab.h>
  21
  22 struct keyboard_led {
  23         struct led_classdev cdev;
  24         struct cros_ec_device *ec;
  25 };
  26
  27 /**
  28  * struct keyboard_led_drvdata - keyboard LED driver data.
  29  * @init:                       Init function.
  30  * @brightness_get:             Get LED brightness level.
  31  * @brightness_set:             Set LED brightness level.  Must not sleep.
  32  * @brightness_set_blocking:    Set LED brightness level.  It can block the
  33  *                              caller for the time required for accessing a
  34  *                              LED device register
  35  * @max_brightness:             Maximum brightness.
  36  *
  37  * See struct led_classdev in include/linux/leds.h for more details.
  38  */
  39 struct keyboard_led_drvdata {
  40         int (*init)(struct platform_device *pdev);
  41
  42         enum led_brightness (*brightness_get)(struct led_classdev *led_cdev);
  43
  44         void (*brightness_set)(struct led_classdev *led_cdev,
  45                                enum led_brightness brightness);
  46         int (*brightness_set_blocking)(struct led_classdev *led_cdev,
  47                                        enum led_brightness brightness);
  48
  49         enum led_brightness max_brightness;
  50 };
  51
  52 #define KEYBOARD_BACKLIGHT_MAX 100
  53
  54 #ifdef CONFIG_ACPI
  55
  56 /* Keyboard LED ACPI Device must be defined in firmware */
  57 #define ACPI_KEYBOARD_BACKLIGHT_DEVICE  "\\_SB.KBLT"
  58 #define ACPI_KEYBOARD_BACKLIGHT_READ    ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBQC"
  59 #define ACPI_KEYBOARD_BACKLIGHT_WRITE   ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBCM"
  60
  61 static void keyboard_led_set_brightness_acpi(struct led_classdev *cdev,
  62                                              enum led_brightness brightness)
  63 {
  64         union acpi_object param;
  65         struct acpi_object_list input;
  66         acpi_status status;
  67
  68         param.type = ACPI_TYPE_INTEGER;
  69         param.integer.value = brightness;
  70         input.count = 1;
  71         input.pointer = &param;
  72
  73         status = acpi_evaluate_object(NULL, ACPI_KEYBOARD_BACKLIGHT_WRITE,
  74                                       &input, NULL);
  75         if (ACPI_FAILURE(status))
  76                 dev_err(cdev->dev, "Error setting keyboard LED value: %d\n",
  77                         status);
  78 }
  79
  80 static enum led_brightness
  81 keyboard_led_get_brightness_acpi(struct led_classdev *cdev)
  82 {
  83         unsigned long long brightness;
  84         acpi_status status;
  85
  86         status = acpi_evaluate_integer(NULL, ACPI_KEYBOARD_BACKLIGHT_READ,
  87                                        NULL, &brightness);
  88         if (ACPI_FAILURE(status)) {
  89                 dev_err(cdev->dev, "Error getting keyboard LED value: %d\n",
  90                         status);
  91                 return -EIO;
  92         }
  93
  94         return brightness;
  95 }
  96
  97 static int keyboard_led_init_acpi(struct platform_device *pdev)
  98 {
  99         acpi_handle handle;
 100         acpi_status status;
 101
 102         /* Look for the keyboard LED ACPI Device */
 103         status = acpi_get_handle(ACPI_ROOT_OBJECT,
 104                                  ACPI_KEYBOARD_BACKLIGHT_DEVICE,
 105                                  &handle);
 106         if (ACPI_FAILURE(status)) {
 107                 dev_err(&pdev->dev, "Unable to find ACPI device %s: %d\n",
 108                         ACPI_KEYBOARD_BACKLIGHT_DEVICE, status);
 109                 return -ENXIO;
 110         }
 111
 112         return 0;
 113 }
 114
 115 static const struct keyboard_led_drvdata keyboard_led_drvdata_acpi = {
 116         .init = keyboard_led_init_acpi,
 117         .brightness_set = keyboard_led_set_brightness_acpi,
 118         .brightness_get = keyboard_led_get_brightness_acpi,
 119         .max_brightness = KEYBOARD_BACKLIGHT_MAX,
 120 };
 121
 122 #endif /* CONFIG_ACPI */
 123
 124 #if IS_ENABLED(CONFIG_CROS_EC)
 125
 126 static int
 127 keyboard_led_set_brightness_ec_pwm(struct led_classdev *cdev,
 128                                    enum led_brightness brightness)
 129 {
 130         struct {
 131                 struct cros_ec_command msg;
 132                 struct ec_params_pwm_set_keyboard_backlight params;
 133         } __packed buf;
 134         struct ec_params_pwm_set_keyboard_backlight *params = &buf.params;
 135         struct cros_ec_command *msg = &buf.msg;
 136         struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev);
 137
 138         memset(&buf, 0, sizeof(buf));
 139
 140         msg->command = EC_CMD_PWM_SET_KEYBOARD_BACKLIGHT;
 141         msg->outsize = sizeof(*params);
 142
 143         params->percent = brightness;
 144
 145         return cros_ec_cmd_xfer_status(keyboard_led->ec, msg);
 146 }
 147
 148 static enum led_brightness
 149 keyboard_led_get_brightness_ec_pwm(struct led_classdev *cdev)
 150 {
 151         struct {
 152                 struct cros_ec_command msg;
 153                 struct ec_response_pwm_get_keyboard_backlight resp;
 154         } __packed buf;
 155         struct ec_response_pwm_get_keyboard_backlight *resp = &buf.resp;
 156         struct cros_ec_command *msg = &buf.msg;
 157         struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev);
 158         int ret;
 159
 160         memset(&buf, 0, sizeof(buf));
 161
 162         msg->command = EC_CMD_PWM_GET_KEYBOARD_BACKLIGHT;
 163         msg->insize = sizeof(*resp);
 164
 165         ret = cros_ec_cmd_xfer_status(keyboard_led->ec, msg);
 166         if (ret < 0)
 167                 return ret;
 168
 169         return resp->percent;
 170 }
 171
 172 static int keyboard_led_init_ec_pwm(struct platform_device *pdev)
 173 {
 174         struct keyboard_led *keyboard_led = platform_get_drvdata(pdev);
 175
 176         keyboard_led->ec = dev_get_drvdata(pdev->dev.parent);
 177         if (!keyboard_led->ec) {
 178                 dev_err(&pdev->dev, "no parent EC device\n");
 179                 return -EINVAL;
 180         }
 181
 182         return 0;
 183 }
 184
 185 static const __maybe_unused struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {
 186         .init = keyboard_led_init_ec_pwm,
 187         .brightness_set_blocking = keyboard_led_set_brightness_ec_pwm,
 188         .brightness_get = keyboard_led_get_brightness_ec_pwm,
 189         .max_brightness = KEYBOARD_BACKLIGHT_MAX,
 190 };
 191
 192 #else /* IS_ENABLED(CONFIG_CROS_EC) */
 193
 194 static const __maybe_unused struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {};
 195
 196 #endif /* IS_ENABLED(CONFIG_CROS_EC) */
 197
 198 #if IS_ENABLED(CONFIG_MFD_CROS_EC_DEV)
 199 static int keyboard_led_init_ec_pwm_mfd(struct platform_device *pdev)
 200 {
 201         struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent);
 202         struct cros_ec_device *cros_ec = ec_dev->ec_dev;
 203         struct keyboard_led *keyboard_led = platform_get_drvdata(pdev);
 204
 205         keyboard_led->ec = cros_ec;
 206
 207         return 0;
 208 }
 209
 210 static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm_mfd = {
 211         .init = keyboard_led_init_ec_pwm_mfd,
 212         .brightness_set_blocking = keyboard_led_set_brightness_ec_pwm,
 213         .brightness_get = keyboard_led_get_brightness_ec_pwm,
 214         .max_brightness = KEYBOARD_BACKLIGHT_MAX,
 215 };
 216
 217 #else /* IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) */
 218
 219 static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm_mfd = {};
 220
 221 #endif /* IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) */
 222
 223 static int keyboard_led_is_mfd_device(struct platform_device *pdev)
 224 {
 225         return IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) && mfd_get_cell(pdev);
 226 }
 227
 228 static int keyboard_led_probe(struct platform_device *pdev)
 229 {
 230         const struct keyboard_led_drvdata *drvdata;
 231         struct keyboard_led *keyboard_led;
 232         int error;
 233
 234         if (keyboard_led_is_mfd_device(pdev))
 235                 drvdata = &keyboard_led_drvdata_ec_pwm_mfd;
 236         else
 237                 drvdata = device_get_match_data(&pdev->dev);
 238         if (!drvdata)
 239                 return -EINVAL;
 240
 241         keyboard_led = devm_kzalloc(&pdev->dev, sizeof(*keyboard_led), GFP_KERNEL);
 242         if (!keyboard_led)
 243                 return -ENOMEM;
 244         platform_set_drvdata(pdev, keyboard_led);
 245
 246         if (drvdata->init) {
 247                 error = drvdata->init(pdev);
 248                 if (error)
 249                         return error;
 250         }
 251
 252         keyboard_led->cdev.name = "chromeos::kbd_backlight";
 253         keyboard_led->cdev.flags |= LED_CORE_SUSPENDRESUME | LED_REJECT_NAME_CONFLICT;
 254         keyboard_led->cdev.max_brightness = drvdata->max_brightness;
 255         keyboard_led->cdev.brightness_set = drvdata->brightness_set;
 256         keyboard_led->cdev.brightness_set_blocking = drvdata->brightness_set_blocking;
 257         keyboard_led->cdev.brightness_get = drvdata->brightness_get;
 258
 259         error = devm_led_classdev_register(&pdev->dev, &keyboard_led->cdev);
 260         if (error == -EEXIST) /* Already bound via other mechanism */
 261                 return -ENODEV;
 262         if (error)
 263                 return error;
 264
 265         return 0;
 266 }
 267
 268 #ifdef CONFIG_ACPI
 269 static const struct acpi_device_id keyboard_led_acpi_match[] = {
 270         { "GOOG0002", (kernel_ulong_t)&keyboard_led_drvdata_acpi },
 271         { }
 272 };
 273 MODULE_DEVICE_TABLE(acpi, keyboard_led_acpi_match);
 274 #endif
 275
 276 #ifdef CONFIG_OF
 277 static const struct of_device_id keyboard_led_of_match[] = {
 278         {
 279                 .compatible = "google,cros-kbd-led-backlight",
 280                 .data = &keyboard_led_drvdata_ec_pwm,
 281         },
 282         {}
 283 };
 284 MODULE_DEVICE_TABLE(of, keyboard_led_of_match);
 285 #endif
 286
 287 static const struct platform_device_id keyboard_led_id[] = {
 288         { "cros-keyboard-leds", 0 },
 289         {}
 290 };
 291 MODULE_DEVICE_TABLE(platform, keyboard_led_id);
 292
 293 static struct platform_driver keyboard_led_driver = {
 294         .driver         = {
 295                 .name   = "cros-keyboard-leds",
 296                 .acpi_match_table = ACPI_PTR(keyboard_led_acpi_match),
 297                 .of_match_table = of_match_ptr(keyboard_led_of_match),
 298         },
 299         .probe          = keyboard_led_probe,
 300         .id_table       = keyboard_led_id,
 301 };
 302 module_platform_driver(keyboard_led_driver);
 303
 304 MODULE_AUTHOR("Simon Que <sque@chromium.org>");
 305 MODULE_DESCRIPTION("ChromeOS Keyboard backlight LED Driver");
 306 MODULE_LICENSE("GPL");