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