drivers/leds/leds-acer-a500.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2
   3 #include <linux/leds.h>
   4 #include <linux/module.h>
   5 #include <linux/platform_device.h>
   6 #include <linux/regmap.h>
   7
   8 #define A500_EC_LED_DELAY_USEC  (100 * 1000)
   9
  10 enum {
  11         REG_RESET_LEDS = 0x40,
  12         REG_POWER_LED_ON = 0x42,
  13         REG_CHARGE_LED_ON = 0x43,
  14         REG_ANDROID_LEDS_OFF = 0x5a,
  15 };
  16
  17 struct a500_led {
  18         struct led_classdev cdev;
  19         const struct reg_sequence *enable_seq;
  20         struct a500_led *other;
  21         struct regmap *rmap;
  22 };
  23
  24 static const struct reg_sequence a500_ec_leds_reset_seq[] = {
  25         REG_SEQ(REG_RESET_LEDS, 0x0, A500_EC_LED_DELAY_USEC),
  26         REG_SEQ(REG_ANDROID_LEDS_OFF, 0x0, A500_EC_LED_DELAY_USEC),
  27 };
  28
  29 static const struct reg_sequence a500_ec_white_led_enable_seq[] = {
  30         REG_SEQ(REG_POWER_LED_ON, 0x0, A500_EC_LED_DELAY_USEC),
  31 };
  32
  33 static const struct reg_sequence a500_ec_orange_led_enable_seq[] = {
  34         REG_SEQ(REG_CHARGE_LED_ON, 0x0, A500_EC_LED_DELAY_USEC),
  35 };
  36
  37 static int a500_ec_led_brightness_set(struct led_classdev *led_cdev,
  38                                       enum led_brightness value)
  39 {
  40         struct a500_led *led = container_of(led_cdev, struct a500_led, cdev);
  41         struct reg_sequence control_seq[2];
  42         unsigned int num_regs = 1;
  43
  44         if (value) {
  45                 control_seq[0] = led->enable_seq[0];
  46         } else {
  47                 /*
  48                  * There is no separate controls which can disable LEDs
  49                  * individually, there is only RESET_LEDS command that turns
  50                  * off both LEDs.
  51                  *
  52                  * RESET_LEDS turns off both LEDs, thus restore other LED if
  53                  * it's turned ON.
  54                  */
  55                 if (led->other->cdev.brightness)
  56                         num_regs = 2;
  57
  58                 control_seq[0] = a500_ec_leds_reset_seq[0];
  59                 control_seq[1] = led->other->enable_seq[0];
  60         }
  61
  62         return regmap_multi_reg_write(led->rmap, control_seq, num_regs);
  63 }
  64
  65 static int a500_ec_leds_probe(struct platform_device *pdev)
  66 {
  67         struct a500_led *white_led, *orange_led;
  68         struct regmap *rmap;
  69         int err;
  70
  71         rmap = dev_get_regmap(pdev->dev.parent, "KB930");
  72         if (!rmap)
  73                 return -EINVAL;
  74
  75         /* reset and turn off LEDs */
  76         regmap_multi_reg_write(rmap, a500_ec_leds_reset_seq, 2);
  77
  78         white_led = devm_kzalloc(&pdev->dev, sizeof(*white_led), GFP_KERNEL);
  79         if (!white_led)
  80                 return -ENOMEM;
  81
  82         white_led->cdev.name = "power:white";
  83         white_led->cdev.brightness_set_blocking = a500_ec_led_brightness_set;
  84         white_led->cdev.flags = LED_CORE_SUSPENDRESUME;
  85         white_led->cdev.max_brightness = 1;
  86         white_led->enable_seq = a500_ec_white_led_enable_seq;
  87         white_led->rmap = rmap;
  88
  89         orange_led = devm_kzalloc(&pdev->dev, sizeof(*orange_led), GFP_KERNEL);
  90         if (!orange_led)
  91                 return -ENOMEM;
  92
  93         orange_led->cdev.name = "power:orange";
  94         orange_led->cdev.brightness_set_blocking = a500_ec_led_brightness_set;
  95         orange_led->cdev.flags = LED_CORE_SUSPENDRESUME;
  96         orange_led->cdev.max_brightness = 1;
  97         orange_led->enable_seq = a500_ec_orange_led_enable_seq;
  98         orange_led->rmap = rmap;
  99
 100         white_led->other = orange_led;
 101         orange_led->other = white_led;
 102
 103         err = devm_led_classdev_register(&pdev->dev, &white_led->cdev);
 104         if (err) {
 105                 dev_err(&pdev->dev, "failed to register white LED\n");
 106                 return err;
 107         }
 108
 109         err = devm_led_classdev_register(&pdev->dev, &orange_led->cdev);
 110         if (err) {
 111                 dev_err(&pdev->dev, "failed to register orange LED\n");
 112                 return err;
 113         }
 114
 115         return 0;
 116 }
 117
 118 static struct platform_driver a500_ec_leds_driver = {
 119         .driver = {
 120                 .name = "acer-a500-iconia-leds",
 121         },
 122         .probe = a500_ec_leds_probe,
 123 };
 124 module_platform_driver(a500_ec_leds_driver);
 125
 126 MODULE_DESCRIPTION("LED driver for Acer Iconia Tab A500 Power Button");
 127 MODULE_AUTHOR("Dmitry Osipenko <digetx@gmail.com>");
 128 MODULE_ALIAS("platform:acer-a500-iconia-leds");
 129 MODULE_LICENSE("GPL");