text: // SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
  //
  // Copyright (c) 2018 Mellanox Technologies. All rights reserved.
  // Copyright (c) 2018 Vadim Pasternak <vadimp@mellanox.com>
  
  #include <linux/bitops.h>
  #include <linux/device.h>
  #include <linux/io.h>
  #include <linux/leds.h>
  #include <linux/module.h>
  #include <linux/of_device.h>
  #include <linux/platform_data/mlxreg.h>
  #include <linux/platform_device.h>
  #include <linux/regmap.h>
  
  /* Codes for LEDs. */
  #define MLXREG_LED_OFFSET_BLINK_3HZ	0x01 /* Offset from solid: 3Hz blink */
  #define MLXREG_LED_OFFSET_BLINK_6HZ	0x02 /* Offset from solid: 6Hz blink */
  #define MLXREG_LED_IS_OFF		0x00 /* Off */
  #define MLXREG_LED_RED_SOLID		0x05 /* Solid red */
  #define MLXREG_LED_GREEN_SOLID		0x0D /* Solid green */
  #define MLXREG_LED_AMBER_SOLID		0x09 /* Solid amber */
  #define MLXREG_LED_BLINK_3HZ		167 /* ~167 msec off/on - HW support */
  #define MLXREG_LED_BLINK_6HZ		83 /* ~83 msec off/on - HW support */
  #define MLXREG_LED_CAPABILITY_CLEAR	GENMASK(31, 8) /* Clear mask */
  
  /**
   * struct mlxreg_led_data - led control data:
   *
   * @data: led configuration data;
   * @led_cdev: led class data;
   * @base_color: base led color (other colors have constant offset from base);
   * @led_data: led data;
   * @data_parent: pointer to private device control data of parent;
   * @led_cdev_name: class device name
   */
  struct mlxreg_led_data {
  	struct mlxreg_core_data *data;
  	struct led_classdev led_cdev;
  	u8 base_color;
  	void *data_parent;
  	char led_cdev_name[MLXREG_CORE_LABEL_MAX_SIZE];
  };
  
  #define cdev_to_priv(c) container_of(c, struct mlxreg_led_data, led_cdev)
  
  /**
   * struct mlxreg_led_priv_data - platform private data:
   *
   * @pdev: platform device;
   * @pdata: platform data;
   * @access_lock: mutex for attribute IO access;
   */
  struct mlxreg_led_priv_data {
  	struct platform_device *pdev;
  	struct mlxreg_core_platform_data *pdata;
  	struct mutex access_lock; /* protect IO operations */
  };
  
  static int
  mlxreg_led_store_hw(struct mlxreg_led_data *led_data, u8 vset)
  {
  	struct mlxreg_led_priv_data *priv = led_data->data_parent;
  	struct mlxreg_core_platform_data *led_pdata = priv->pdata;
  	struct mlxreg_core_data *data = led_data->data;
  	u32 regval;
  	u32 nib;
  	int ret;
  
  	/*
  	 * Each LED is controlled through low or high nibble of the relevant
  	 * register byte. Register offset is specified by off parameter.
  	 * Parameter vset provides color code: 0x0 for off, 0x5 for solid red,
  	 * 0x6 for 3Hz blink red, 0xd for solid green, 0xe for 3Hz blink
  	 * green.
  	 * Parameter mask specifies which nibble is used for specific LED: mask
  	 * 0xf0 - lower nibble is to be used (bits from 0 to 3), mask 0x0f -
  	 * higher nibble (bits from 4 to 7).
  	 */
  	mutex_lock(&priv->access_lock);
  
  	ret = regmap_read(led_pdata->regmap, data->reg, &regval);
  	if (ret)
  		goto access_error;
  
  	nib = (ror32(data->mask, data->bit) == 0xf0) ? rol32(vset, data->bit) :
  	      rol32(vset, data->bit + 4);
  	regval = (regval & data->mask) | nib;
  
  	ret = regmap_write(led_pdata->regmap, data->reg, regval);
  
  access_error:
  	mutex_unlock(&priv->access_lock);
  
  	return ret;
  }
  
  static enum led_brightness
  mlxreg_led_get_hw(struct mlxreg_led_data *led_data)
  {
  	struct mlxreg_led_priv_data *priv = led_data->data_parent;
  	struct mlxreg_core_platform_data *led_pdata = priv->pdata;
  	struct mlxreg_core_data *data = led_data->data;
  	u32 regval;
  	int err;
  
  	/*
  	 * Each LED is controlled through low or high nibble of the relevant
  	 * register byte. Register offset is specified by off parameter.
  	 * Parameter vset provides color code: 0x0 for off, 0x5 for solid red,
  	 * 0x6 for 3Hz blink red, 0xd for solid green, 0xe for 3Hz blink
  	 * green.
  	 * Parameter mask specifies which nibble is used for specific LED: mask
  	 * 0xf0 - lower nibble is to be used (bits from 0 to 3), mask 0x0f -
  	 * higher nibble (bits from 4 to 7).
  	 */
  	err = regmap_read(led_pdata->regmap, data->reg, &regval);
  	if (err < 0) {
  		dev_warn(led_data->led_cdev.dev, "Failed to get current brightness, error: %d\n",
  			 err);
  		/* Assume the LED is OFF */
  		return LED_OFF;
  	}
  
  	regval = regval & ~data->mask;
  	regval = (ror32(data->mask, data->bit) == 0xf0) ? ror32(regval,
  		 data->bit) : ror32(regval, data->bit + 4);
  	if (regval >= led_data->base_color &&
  	    regval <= (led_data->base_color + MLXREG_LED_OFFSET_BLINK_6HZ))
  		return LED_FULL;
  
  	return LED_OFF;
  }
  
  static int
  mlxreg_led_brightness_set(struct led_classdev *cled, enum led_brightness value)
  {
  	struct mlxreg_led_data *led_data = cdev_to_priv(cled);
  
  	if (value)
  		return mlxreg_led_store_hw(led_data, led_data->base_color);
  	else
  		return mlxreg_led_store_hw(led_data, MLXREG_LED_IS_OFF);
  }
  
  static enum led_brightness
  mlxreg_led_brightness_get(struct led_classdev *cled)
  {
  	struct mlxreg_led_data *led_data = cdev_to_priv(cled);
  
  	return mlxreg_led_get_hw(led_data);
  }
  
  static int
  mlxreg_led_blink_set(struct led_classdev *cled, unsigned long *delay_on,
  		     unsigned long *delay_off)
  {
  	struct mlxreg_led_data *led_data = cdev_to_priv(cled);
  	int err;
  
  	/*
  	 * HW supports two types of blinking: full (6Hz) and half (3Hz).
  	 * For delay on/off zero LED is setting to solid color. For others
  	 * combination blinking is to be controlled by the software timer.
  	 */
  	if (!(*delay_on == 0 && *delay_off == 0) &&
  	    !(*delay_on == MLXREG_LED_BLINK_3HZ &&
  	      *delay_off == MLXREG_LED_BLINK_3HZ) &&
  	    !(*delay_on == MLXREG_LED_BLINK_6HZ &&
  	      *delay_off == MLXREG_LED_BLINK_6HZ))
  		return -EINVAL;
  
  	if (*delay_on == MLXREG_LED_BLINK_6HZ)
  		err = mlxreg_led_store_hw(led_data, led_data->base_color +
  					  MLXREG_LED_OFFSET_BLINK_6HZ);
  	else if (*delay_on == MLXREG_LED_BLINK_3HZ)
  		err = mlxreg_led_store_hw(led_data, led_data->base_color +
  					  MLXREG_LED_OFFSET_BLINK_3HZ);
  	else
  		err = mlxreg_led_store_hw(led_data, led_data->base_color);
  
  	return err;
  }
  
  static int mlxreg_led_config(struct mlxreg_led_priv_data *priv)
  {
  	struct mlxreg_core_platform_data *led_pdata = priv->pdata;
  	struct mlxreg_core_data *data = led_pdata->data;
  	struct mlxreg_led_data *led_data;
  	struct led_classdev *led_cdev;
  	enum led_brightness brightness;
  	u32 regval;
  	int i;
  	int err;
  
  	for (i = 0; i < led_pdata->counter; i++, data++) {
  		led_data = devm_kzalloc(&priv->pdev->dev, sizeof(*led_data),
  					GFP_KERNEL);
  		if (!led_data)
  			return -ENOMEM;
  
  		if (data->capability) {
  			err = regmap_read(led_pdata->regmap, data->capability,
  					  &regval);
  			if (err) {
  				dev_err(&priv->pdev->dev, "Failed to query capability register\n");
  				return err;
  			}
  			if (!(regval & data->bit))
  				continue;
  			/*
  			 * Field "bit" can contain one capability bit in 0 byte
  			 * and offset bit in 1-3 bytes. Clear capability bit and
  			 * keep only offset bit.
  			 */
  			data->bit &= MLXREG_LED_CAPABILITY_CLEAR;
  		}
  
  		led_cdev = &led_data->led_cdev;
  		led_data->data_parent = priv;
  		if (strstr(data->label, "red") ||
  		    strstr(data->label, "orange")) {
  			brightness = LED_OFF;
  			led_data->base_color = MLXREG_LED_RED_SOLID;
  		} else if (strstr(data->label, "amber")) {
  			brightness = LED_OFF;
  			led_data->base_color = MLXREG_LED_AMBER_SOLID;
  		} else {
  			brightness = LED_OFF;
  			led_data->base_color = MLXREG_LED_GREEN_SOLID;
  		}
  		snprintf(led_data->led_cdev_name, sizeof(led_data->led_cdev_name),
  			 "mlxreg:%s", data->label);
  		led_cdev->name = led_data->led_cdev_name;
  		led_cdev->brightness = brightness;
  		led_cdev->max_brightness = LED_ON;
  		led_cdev->brightness_set_blocking =
  						mlxreg_led_brightness_set;
  		led_cdev->brightness_get = mlxreg_led_brightness_get;
  		led_cdev->blink_set = mlxreg_led_blink_set;
  		led_cdev->flags = LED_CORE_SUSPENDRESUME;
  		led_data->data = data;
  		err = devm_led_classdev_register(&priv->pdev->dev, led_cdev);
  		if (err)
  			return err;
  
  		if (led_cdev->brightness)
  			mlxreg_led_brightness_set(led_cdev,
  						  led_cdev->brightness);
  		dev_info(led_cdev->dev, "label: %s, mask: 0x%02x, offset:0x%02x\n",
  			 data->label, data->mask, data->reg);
  	}
  
  	return 0;
  }
  
  static int mlxreg_led_probe(struct platform_device *pdev)
  {
  	struct mlxreg_core_platform_data *led_pdata;
  	struct mlxreg_led_priv_data *priv;
  
  	led_pdata = dev_get_platdata(&pdev->dev);
  	if (!led_pdata) {
  		dev_err(&pdev->dev, "Failed to get platform data.\n");
  		return -EINVAL;
  	}
  
  	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
  	if (!priv)
  		return -ENOMEM;
  
  	mutex_init(&priv->access_lock);
  	priv->pdev = pdev;
  	priv->pdata = led_pdata;
  
  	return mlxreg_led_config(priv);
  }
  
  static int mlxreg_led_remove(struct platform_device *pdev)
  {
  	struct mlxreg_led_priv_data *priv = dev_get_drvdata(&pdev->dev);
  
  	mutex_destroy(&priv->access_lock);
  
  	return 0;
  }
  
  static struct platform_driver mlxreg_led_driver = {
  	.driver = {
  	    .name = "leds-mlxreg",
  	},
  	.probe = mlxreg_led_probe,
  	.remove = mlxreg_led_remove,
  };
  
  module_platform_driver(mlxreg_led_driver);
  
  MODULE_AUTHOR("Vadim Pasternak <vadimp@mellanox.com>");
  MODULE_DESCRIPTION("Mellanox LED regmap driver");
  MODULE_LICENSE("Dual BSD/GPL");
  MODULE_ALIAS("platform:leds-mlxreg");
  