drivers/leds/leds-acer-a500.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002
0003 #include <linux/leds.h>
0004 #include <linux/module.h>
0005 #include <linux/platform_device.h>
0006 #include <linux/regmap.h>
0007
0008 #define A500_EC_LED_DELAY_USEC  (100 * 1000)
0009
0010 enum {
0011     REG_RESET_LEDS = 0x40,
0012     REG_POWER_LED_ON = 0x42,
0013     REG_CHARGE_LED_ON = 0x43,
0014     REG_ANDROID_LEDS_OFF = 0x5a,
0015 };
0016
0017 struct a500_led {
0018     struct led_classdev cdev;
0019     const struct reg_sequence *enable_seq;
0020     struct a500_led *other;
0021     struct regmap *rmap;
0022 };
0023
0024 static const struct reg_sequence a500_ec_leds_reset_seq[] = {
0025     REG_SEQ(REG_RESET_LEDS, 0x0, A500_EC_LED_DELAY_USEC),
0026     REG_SEQ(REG_ANDROID_LEDS_OFF, 0x0, A500_EC_LED_DELAY_USEC),
0027 };
0028
0029 static const struct reg_sequence a500_ec_white_led_enable_seq[] = {
0030     REG_SEQ(REG_POWER_LED_ON, 0x0, A500_EC_LED_DELAY_USEC),
0031 };
0032
0033 static const struct reg_sequence a500_ec_orange_led_enable_seq[] = {
0034     REG_SEQ(REG_CHARGE_LED_ON, 0x0, A500_EC_LED_DELAY_USEC),
0035 };
0036
0037 static int a500_ec_led_brightness_set(struct led_classdev *led_cdev,
0038                       enum led_brightness value)
0039 {
0040     struct a500_led *led = container_of(led_cdev, struct a500_led, cdev);
0041     struct reg_sequence control_seq[2];
0042     unsigned int num_regs = 1;
0043
0044     if (value) {
0045         control_seq[0] = led->enable_seq[0];
0046     } else {
0047         /*
0048          * There is no separate controls which can disable LEDs
0049          * individually, there is only RESET_LEDS command that turns
0050          * off both LEDs.
0051          *
0052          * RESET_LEDS turns off both LEDs, thus restore other LED if
0053          * it's turned ON.
0054          */
0055         if (led->other->cdev.brightness)
0056             num_regs = 2;
0057
0058         control_seq[0] = a500_ec_leds_reset_seq[0];
0059         control_seq[1] = led->other->enable_seq[0];
0060     }
0061
0062     return regmap_multi_reg_write(led->rmap, control_seq, num_regs);
0063 }
0064
0065 static int a500_ec_leds_probe(struct platform_device *pdev)
0066 {
0067     struct a500_led *white_led, *orange_led;
0068     struct regmap *rmap;
0069     int err;
0070
0071     rmap = dev_get_regmap(pdev->dev.parent, "KB930");
0072     if (!rmap)
0073         return -EINVAL;
0074
0075     /* reset and turn off LEDs */
0076     regmap_multi_reg_write(rmap, a500_ec_leds_reset_seq, 2);
0077
0078     white_led = devm_kzalloc(&pdev->dev, sizeof(*white_led), GFP_KERNEL);
0079     if (!white_led)
0080         return -ENOMEM;
0081
0082     white_led->cdev.name = "power:white";
0083     white_led->cdev.brightness_set_blocking = a500_ec_led_brightness_set;
0084     white_led->cdev.flags = LED_CORE_SUSPENDRESUME;
0085     white_led->cdev.max_brightness = 1;
0086     white_led->enable_seq = a500_ec_white_led_enable_seq;
0087     white_led->rmap = rmap;
0088
0089     orange_led = devm_kzalloc(&pdev->dev, sizeof(*orange_led), GFP_KERNEL);
0090     if (!orange_led)
0091         return -ENOMEM;
0092
0093     orange_led->cdev.name = "power:orange";
0094     orange_led->cdev.brightness_set_blocking = a500_ec_led_brightness_set;
0095     orange_led->cdev.flags = LED_CORE_SUSPENDRESUME;
0096     orange_led->cdev.max_brightness = 1;
0097     orange_led->enable_seq = a500_ec_orange_led_enable_seq;
0098     orange_led->rmap = rmap;
0099
0100     white_led->other = orange_led;
0101     orange_led->other = white_led;
0102
0103     err = devm_led_classdev_register(&pdev->dev, &white_led->cdev);
0104     if (err) {
0105         dev_err(&pdev->dev, "failed to register white LED\n");
0106         return err;
0107     }
0108
0109     err = devm_led_classdev_register(&pdev->dev, &orange_led->cdev);
0110     if (err) {
0111         dev_err(&pdev->dev, "failed to register orange LED\n");
0112         return err;
0113     }
0114
0115     return 0;
0116 }
0117
0118 static struct platform_driver a500_ec_leds_driver = {
0119     .driver = {
0120         .name = "acer-a500-iconia-leds",
0121     },
0122     .probe = a500_ec_leds_probe,
0123 };
0124 module_platform_driver(a500_ec_leds_driver);
0125
0126 MODULE_DESCRIPTION("LED driver for Acer Iconia Tab A500 Power Button");
0127 MODULE_AUTHOR("Dmitry Osipenko <digetx@gmail.com>");
0128 MODULE_ALIAS("platform:acer-a500-iconia-leds");
0129 MODULE_LICENSE("GPL");