qcom sdm660 led 分析

msm-pm660l.dtsi相关节点。

qcom,leds@d000 {
			compatible = "qcom,leds-qpnp";
			reg = <0xd000 0x100>;
			label = "rgb";

			red_led: qcom,rgb_0 {
				label = "rgb";
				qcom,id = <3>;
				qcom,mode = "pwm";
				pwms = <&pm660l_pwm_3 0 0>;
				qcom,pwm-us = <2000>;
				qcom,max-current = <12>;
				qcom,default-state = "off";
				linux,name = "red";
				qcom,start-idx = <0>;
				qcom,idx-len = <10>;
				qcom,duty-pcts =
					[00 19 32 4b 64
					64 46 32 19 00];
				qcom,use-blink;
			};

qcom,mode = "pwm";模式为PWM ，另外的两个模式是manual、lpg。一个是手动模式，另一个不太清楚。

qcom,pwm-us = <2000>;表示PWM的一个周期是2s。

qcom,max-current = <12>;最大电流12mA

qcom,duty-pcts =  [00 19 32 4b 64 64 46 32 19 00];亮度值从0到64，再从64到0。实现呼吸灯功能，若想实现闪烁，值改为0与64即可。

LPG模式可选属性

qcom,pause-lo:在周期的低端暂停

qcom,pause-hi:在周期的高端暂停

qcom,ramp-step-ms:每个周期间隔(ms)

qcom,lut-flags:lut配置中使用的标志

Leds-qpnp.c (kernel\msm-4.4\drivers\leds)节点解析文件

static struct platform_driver qpnp_leds_driver = {
	.driver		= {
		.name		= "qcom,leds-qpnp",
		.of_match_table	= spmi_match_table,
	},
	.probe		= qpnp_leds_probe,
	.remove		= qpnp_leds_remove,
};
//进入probe函数
static int qpnp_leds_probe(struct platform_device *pdev)
{
	struct qpnp_led_data *led, *led_array;
	unsigned int base;
	struct device_node *node, *temp;
	int rc, i, num_leds = 0, parsed_leds = 0;
	const char *led_label;
	bool regulator_probe = false;

	node = pdev->dev.of_node;
	if (node == NULL)
		return -ENODEV;

	temp = NULL;
	while ((temp = of_get_next_child(node, temp)))
		num_leds++;

	if (!num_leds)
		return -ECHILD;

	led_array = devm_kcalloc(&pdev->dev, num_leds, sizeof(*led_array),
				GFP_KERNEL);
	if (!led_array)
		return -ENOMEM;

	for_each_child_of_node(node, temp) {
		led = &led_array[parsed_leds];
		led->num_leds = num_leds;
		led->regmap = dev_get_regmap(pdev->dev.parent, NULL);
		if (!led->regmap) {
			dev_err(&pdev->dev, "Couldn't get parent's regmap\n");
			return -EINVAL;
		}
		led->pdev = pdev;

		rc = of_property_read_u32(pdev->dev.of_node, "reg", &base);
		if (rc < 0) {
			dev_err(&pdev->dev,
				"Couldn't find reg in node = %s rc = %d\n",
				pdev->dev.of_node->full_name, rc);
			goto fail_id_check;
		}
		led->base = base;

		rc = of_property_read_string(temp, "label", &led_label);
		if (rc < 0) {
			dev_err(&led->pdev->dev,
				"Failure reading label, rc = %d\n", rc);
			goto fail_id_check;
		}

		rc = of_property_read_string(temp, "linux,name",
			&led->cdev.name);
		if (rc < 0) {
			dev_err(&led->pdev->dev,
				"Failure reading led name, rc = %d\n", rc);
			goto fail_id_check;
		}

		rc = of_property_read_u32(temp, "qcom,max-current",
			&led->max_current);
		if (rc < 0) {
			dev_err(&led->pdev->dev,
				"Failure reading max_current, rc =  %d\n", rc);
			goto fail_id_check;
		}

		rc = of_property_read_u32(temp, "qcom,id", &led->id);
		if (rc < 0) {
			dev_err(&led->pdev->dev,
				"Failure reading led id, rc =  %d\n", rc);
			goto fail_id_check;
		}

		rc = qpnp_get_common_configs(led, temp);
		if (rc) {
			dev_err(&led->pdev->dev, "Failure reading common led configuration, rc = %d\n",
				rc);
			goto fail_id_check;
		}

		led->cdev.brightness_set    = qpnp_led_set;
		led->cdev.brightness_get    = qpnp_led_get;

		if (strcmp(led_label, "wled") == 0) {
			rc = qpnp_get_config_wled(led, temp);
			if (rc < 0) {
				dev_err(&led->pdev->dev,
					"Unable to read wled config data\n");
				goto fail_id_check;
			}
		} else if (strcmp(led_label, "flash") == 0) {
			if (!of_find_property(node, "flash-boost-supply", NULL))
				regulator_probe = true;
			rc = qpnp_get_config_flash(led, temp, ®ulator_probe);
			if (rc < 0) {
				dev_err(&led->pdev->dev,
					"Unable to read flash config data\n");
				goto fail_id_check;
			}
		} else if (strcmp(led_label, "rgb") == 0) {
			rc = qpnp_get_config_rgb(led, temp);
			if (rc < 0) {
				dev_err(&led->pdev->dev,
					"Unable to read rgb config data\n");
				goto fail_id_check;
			}
		} else if (strcmp(led_label, "mpp") == 0) {
			rc = qpnp_get_config_mpp(led, temp);
			if (rc < 0) {
				dev_err(&led->pdev->dev,
						"Unable to read mpp config data\n");
				goto fail_id_check;
			}
		} else if (strcmp(led_label, "gpio") == 0) {
			rc = qpnp_get_config_gpio(led, temp);
			if (rc < 0) {
				dev_err(&led->pdev->dev,
						"Unable to read gpio config data\n");
				goto fail_id_check;
			}
		} else if (strcmp(led_label, "kpdbl") == 0) {
			bitmap_zero(kpdbl_leds_in_use, NUM_KPDBL_LEDS);
			is_kpdbl_master_turn_on = false;
			rc = qpnp_get_config_kpdbl(led, temp);
			if (rc < 0) {
				dev_err(&led->pdev->dev,
					"Unable to read kpdbl config data\n");
				goto fail_id_check;
			}
		} else {
			dev_err(&led->pdev->dev, "No LED matching label\n");
			rc = -EINVAL;
			goto fail_id_check;
		}

		if (led->id != QPNP_ID_FLASH1_LED0 &&
					led->id != QPNP_ID_FLASH1_LED1)
			mutex_init(&led->lock);

		led->in_order_command_processing = of_property_read_bool
				(temp, "qcom,in-order-command-processing");

		if (led->in_order_command_processing) {
			/*
			 * the command order from user space needs to be
			 * maintained use ordered workqueue to prevent
			 * concurrency
			 */
			led->workqueue = alloc_ordered_workqueue
							("led_workqueue", 0);
			if (!led->workqueue) {
				rc = -ENOMEM;
				goto fail_id_check;
			}
		}

		INIT_WORK(&led->work, qpnp_led_work);

		rc =  qpnp_led_initialize(led);
		if (rc < 0)
			goto fail_id_check;

		rc = qpnp_led_set_max_brightness(led);
		if (rc < 0)
			goto fail_id_check;

		rc = led_classdev_register(&pdev->dev, &led->cdev);
		if (rc) {
			dev_err(&pdev->dev,
				"unable to register led %d,rc=%d\n",
						 led->id, rc);
			goto fail_id_check;
		}

		if (led->id == QPNP_ID_FLASH1_LED0 ||
			led->id == QPNP_ID_FLASH1_LED1) {
			rc = sysfs_create_group(&led->cdev.dev->kobj,
							&led_attr_group);
			if (rc)
				goto fail_id_check;

		}

		if (led->id == QPNP_ID_LED_MPP) {
			if (!led->mpp_cfg->pwm_cfg)
				break;
			if (led->mpp_cfg->pwm_cfg->mode == PWM_MODE) {
				rc = sysfs_create_group(&led->cdev.dev->kobj,
					&pwm_attr_group);
				if (rc)
					goto fail_id_check;
			}
			if (led->mpp_cfg->pwm_cfg->use_blink) {
				rc = sysfs_create_group(&led->cdev.dev->kobj,
					&blink_attr_group);
				if (rc)
					goto fail_id_check;

				rc = sysfs_create_group(&led->cdev.dev->kobj,
					&lpg_attr_group);
				if (rc)
					goto fail_id_check;
			} else if (led->mpp_cfg->pwm_cfg->mode == LPG_MODE) {
				rc = sysfs_create_group(&led->cdev.dev->kobj,
					&lpg_attr_group);
				if (rc)
					goto fail_id_check;
			}
		} else if ((led->id == QPNP_ID_RGB_RED) ||
			(led->id == QPNP_ID_RGB_GREEN) ||
			(led->id == QPNP_ID_RGB_BLUE)) {
			if (led->rgb_cfg->pwm_cfg->mode == PWM_MODE) {
				rc = sysfs_create_group(&led->cdev.dev->kobj,
					&pwm_attr_group);
				if (rc)
					goto fail_id_check;
			}
			if (led->rgb_cfg->pwm_cfg->use_blink) {
				rc = sysfs_create_group(&led->cdev.dev->kobj,
					&blink_attr_group);
				if (rc)
					goto fail_id_check;

				rc = sysfs_create_group(&led->cdev.dev->kobj,
					&lpg_attr_group);
				if (rc)
					goto fail_id_check;
			} else if (led->rgb_cfg->pwm_cfg->mode == LPG_MODE) {
				rc = sysfs_create_group(&led->cdev.dev->kobj,
					&lpg_attr_group);
				if (rc)
					goto fail_id_check;
			}
		} else if (led->id == QPNP_ID_KPDBL) {
			if (led->kpdbl_cfg->pwm_cfg->mode == PWM_MODE) {
				rc = sysfs_create_group(&led->cdev.dev->kobj,
					&pwm_attr_group);
				if (rc)
					goto fail_id_check;
			}
			if (led->kpdbl_cfg->pwm_cfg->use_blink) {
				rc = sysfs_create_group(&led->cdev.dev->kobj,
					&blink_attr_group);
				if (rc)
					goto fail_id_check;

				rc = sysfs_create_group(&led->cdev.dev->kobj,
					&lpg_attr_group);
				if (rc)
					goto fail_id_check;
			} else if (led->kpdbl_cfg->pwm_cfg->mode == LPG_MODE) {
				rc = sysfs_create_group(&led->cdev.dev->kobj,
					&lpg_attr_group);
				if (rc)
					goto fail_id_check;
			}
		}

		/* configure default state */
		if (led->default_on) {
			led->cdev.brightness = led->cdev.max_brightness;
			__qpnp_led_work(led, led->cdev.brightness);
			if (led->turn_off_delay_ms > 0)
				qpnp_led_turn_off(led);
		} else
			led->cdev.brightness = LED_OFF;

		parsed_leds++;
	}
	dev_set_drvdata(&pdev->dev, led_array);
	return 0;

fail_id_check:
	for (i = 0; i < parsed_leds; i++) {
		if (led_array[i].id != QPNP_ID_FLASH1_LED0 &&
				led_array[i].id != QPNP_ID_FLASH1_LED1)
			mutex_destroy(&led_array[i].lock);
		if (led_array[i].in_order_command_processing)
			destroy_workqueue(led_array[i].workqueue);
		led_classdev_unregister(&led_array[i].cdev);
	}

	return rc;
}

led->cdev.brightness_set    = qpnp_led_set;这里和led_class联系起来了。

static void qpnp_led_set(struct led_classdev *led_cdev,
				enum led_brightness value)
{
	struct qpnp_led_data *led;

	led = container_of(led_cdev, struct qpnp_led_data, cdev);
	if (value < LED_OFF) {
		dev_err(&led->pdev->dev, "Invalid brightness value\n");
		return;
	}

	if (value > led->cdev.max_brightness)
		value = led->cdev.max_brightness;

	led->cdev.brightness = value;
	if (led->in_order_command_processing)
		queue_work(led->workqueue, &led->work);
	else
		schedule_work(&led->work);
}

设置了灯的亮度值，并在 结尾开启了一个work队列，也就是INIT_WORK(&led->work, qpnp_led_work);最后调用到下面函数

static int qpnp_rgb_set(struct qpnp_led_data *led)
{
	int rc;
	int duty_us, duty_ns, period_us;

	if (led->cdev.brightness) {
		if (!led->rgb_cfg->pwm_cfg->blinking)
			led->rgb_cfg->pwm_cfg->mode =
				led->rgb_cfg->pwm_cfg->default_mode;
		if (led->rgb_cfg->pwm_cfg->mode == PWM_MODE) {
			rc = pwm_change_mode(led->rgb_cfg->pwm_cfg->pwm_dev,
					PM_PWM_MODE_PWM);
			if (rc < 0) {
				dev_err(&led->pdev->dev,
					"Failed to set PWM mode, rc = %d\n",
					rc);
				return rc;
			}
			period_us = led->rgb_cfg->pwm_cfg->pwm_period_us;
			if (period_us > INT_MAX / NSEC_PER_USEC) {
				duty_us = (period_us * led->cdev.brightness) /
					LED_FULL;
				rc = pwm_config_us(
					led->rgb_cfg->pwm_cfg->pwm_dev,
					duty_us,
					period_us);
			} else {
				duty_ns = ((period_us * NSEC_PER_USEC) /
					LED_FULL) * led->cdev.brightness;
				rc = pwm_config(
					led->rgb_cfg->pwm_cfg->pwm_dev,
					duty_ns,
					period_us * NSEC_PER_USEC);
			}
			if (rc < 0) {
				dev_err(&led->pdev->dev,
					"pwm config failed\n");
				return rc;
			}
		}
		rc = qpnp_led_masked_write(led,
			RGB_LED_EN_CTL(led->base),
			led->rgb_cfg->enable, led->rgb_cfg->enable);
		if (rc) {
			dev_err(&led->pdev->dev,
				"Failed to write led enable reg\n");
			return rc;
		}
		if (!led->rgb_cfg->pwm_cfg->pwm_enabled) {
			pwm_enable(led->rgb_cfg->pwm_cfg->pwm_dev);
			led->rgb_cfg->pwm_cfg->pwm_enabled = 1;
		}
	} else {
		led->rgb_cfg->pwm_cfg->mode =
			led->rgb_cfg->pwm_cfg->default_mode;
		if (led->rgb_cfg->pwm_cfg->pwm_enabled) {
			pwm_disable(led->rgb_cfg->pwm_cfg->pwm_dev);
			led->rgb_cfg->pwm_cfg->pwm_enabled = 0;
		}
		rc = qpnp_led_masked_write(led,
			RGB_LED_EN_CTL(led->base),
			led->rgb_cfg->enable, RGB_LED_DISABLE);
		if (rc) {
			dev_err(&led->pdev->dev,
				"Failed to write led enable reg\n");
			return rc;
		}
	}

	led->rgb_cfg->pwm_cfg->blinking = false;
	qpnp_dump_regs(led, rgb_pwm_debug_regs, ARRAY_SIZE(rgb_pwm_debug_regs));

	return 0;
}

qpnp_led_masked_write，这个函数的作用就是把相应的信息写入到寄存器中 ，使能led。

中间部分的配置，根据led_label=rgb进入qpnp_get_config_rgb()开始配置led。

static int qpnp_get_config_rgb(struct qpnp_led_data *led,
				struct device_node *node)
{
	int rc;
	u8 led_mode;
	const char *mode;

	led->rgb_cfg = devm_kzalloc(&led->pdev->dev,
				sizeof(struct rgb_config_data), GFP_KERNEL);
	if (!led->rgb_cfg)
		return -ENOMEM;

	if (led->id == QPNP_ID_RGB_RED)
		led->rgb_cfg->enable = RGB_LED_ENABLE_RED;
	else if (led->id == QPNP_ID_RGB_GREEN)
		led->rgb_cfg->enable = RGB_LED_ENABLE_GREEN;
	else if (led->id == QPNP_ID_RGB_BLUE)
		led->rgb_cfg->enable = RGB_LED_ENABLE_BLUE;
	else
		return -EINVAL;

	rc = of_property_read_string(node, "qcom,mode", &mode);
	if (!rc) {
		led_mode = qpnp_led_get_mode(mode);
		if ((led_mode == MANUAL_MODE) || (led_mode == -EINVAL)) {
			dev_err(&led->pdev->dev, "Selected mode not supported for rgb\n");
			return -EINVAL;
		}
		led->rgb_cfg->pwm_cfg = devm_kzalloc(&led->pdev->dev,
					sizeof(struct pwm_config_data),
					GFP_KERNEL);
		if (!led->rgb_cfg->pwm_cfg) {
			dev_err(&led->pdev->dev,
				"Unable to allocate memory\n");
			return -ENOMEM;
		}
		led->rgb_cfg->pwm_cfg->mode = led_mode;
		led->rgb_cfg->pwm_cfg->default_mode = led_mode;
	} else {
		return rc;
	}

	rc = qpnp_get_config_pwm(led->rgb_cfg->pwm_cfg, led->pdev, node);
	if (rc < 0) {
		if (led->rgb_cfg->pwm_cfg->pwm_dev)
			pwm_put(led->rgb_cfg->pwm_cfg->pwm_dev);
		return rc;
	}

	return 0;
}

先解析出led的模式，有三种模式。

static int qpnp_led_get_mode(const char *mode)
{
	if (strcmp(mode, "manual") == 0)
		return MANUAL_MODE;
	else if (strcmp(mode, "pwm") == 0)
		return PWM_MODE;
	else if (strcmp(mode, "lpg") == 0)
		return LPG_MODE;
	else
		return -EINVAL;
};

随后解析出PWM的配置

static int qpnp_get_config_pwm(struct pwm_config_data *pwm_cfg,
				struct platform_device *pdev,
				struct device_node *node)
{
	struct property *prop;
	int rc, i, lut_max_size;
	u32 val;
	u8 *temp_cfg;
	const char *led_label;

	pwm_cfg->pwm_dev = of_pwm_get(node, NULL);

	if (IS_ERR(pwm_cfg->pwm_dev)) {
		rc = PTR_ERR(pwm_cfg->pwm_dev);
		dev_err(&pdev->dev, "Cannot get PWM device rc:(%d)\n", rc);
		pwm_cfg->pwm_dev = NULL;
		return rc;
	}

	if (pwm_cfg->mode != MANUAL_MODE) {
		rc = of_property_read_u32(node, "qcom,pwm-us", &val);
		if (!rc)
			pwm_cfg->pwm_period_us = val;
		else
			return rc;
	}

	pwm_cfg->use_blink =
		of_property_read_bool(node, "qcom,use-blink");

	if (pwm_cfg->mode == LPG_MODE || pwm_cfg->use_blink) {
		pwm_cfg->duty_cycles =
			devm_kzalloc(&pdev->dev,
			sizeof(struct pwm_duty_cycles), GFP_KERNEL);
		if (!pwm_cfg->duty_cycles) {
			dev_err(&pdev->dev, "Unable to allocate memory\n");
			rc = -ENOMEM;
			goto bad_lpg_params;
		}

		prop = of_find_property(node, "qcom,duty-pcts",
			&pwm_cfg->duty_cycles->num_duty_pcts);
		if (!prop) {
			dev_err(&pdev->dev, "Looking up property node qcom,duty-pcts failed\n");
			rc =  -ENODEV;
			goto bad_lpg_params;
		} else if (!pwm_cfg->duty_cycles->num_duty_pcts) {
			dev_err(&pdev->dev, "Invalid length of duty pcts\n");
			rc =  -EINVAL;
			goto bad_lpg_params;
		}

		rc = of_property_read_string(node, "label", &led_label);

		if (rc < 0) {
			dev_err(&pdev->dev,
				"Failure reading label, rc = %d\n", rc);
			return rc;
		}

		if (strcmp(led_label, "kpdbl") == 0)
			lut_max_size = PWM_GPLED_LUT_MAX_SIZE;
		else
			lut_max_size = PWM_LUT_MAX_SIZE;

		pwm_cfg->duty_cycles->duty_pcts =
			devm_kzalloc(&pdev->dev,
			sizeof(int) * lut_max_size,
			GFP_KERNEL);
		if (!pwm_cfg->duty_cycles->duty_pcts) {
			dev_err(&pdev->dev, "Unable to allocate memory\n");
			rc = -ENOMEM;
			goto bad_lpg_params;
		}

		pwm_cfg->old_duty_pcts =
			devm_kzalloc(&pdev->dev,
			sizeof(int) * lut_max_size,
			GFP_KERNEL);
		if (!pwm_cfg->old_duty_pcts) {
			dev_err(&pdev->dev, "Unable to allocate memory\n");
			rc = -ENOMEM;
			goto bad_lpg_params;
		}

		temp_cfg = devm_kzalloc(&pdev->dev,
				pwm_cfg->duty_cycles->num_duty_pcts *
				sizeof(u8), GFP_KERNEL);
		if (!temp_cfg) {
			dev_err(&pdev->dev, "Failed to allocate memory for duty pcts\n");
			rc = -ENOMEM;
			goto bad_lpg_params;
		}

		memcpy(temp_cfg, prop->value,
			pwm_cfg->duty_cycles->num_duty_pcts);

		for (i = 0; i < pwm_cfg->duty_cycles->num_duty_pcts; i++)
			pwm_cfg->duty_cycles->duty_pcts[i] =
				(int) temp_cfg[i];

		rc = of_property_read_u32(node, "qcom,start-idx", &val);
		if (!rc) {
			pwm_cfg->lut_params.start_idx = val;
			pwm_cfg->duty_cycles->start_idx = val;
		} else
			goto bad_lpg_params;

		pwm_cfg->lut_params.lut_pause_hi = 0;
		rc = of_property_read_u32(node, "qcom,pause-hi", &val);
		if (!rc)
			pwm_cfg->lut_params.lut_pause_hi = val;
		else if (rc != -EINVAL)
			goto bad_lpg_params;

		pwm_cfg->lut_params.lut_pause_lo = 0;
		rc = of_property_read_u32(node, "qcom,pause-lo", &val);
		if (!rc)
			pwm_cfg->lut_params.lut_pause_lo = val;
		else if (rc != -EINVAL)
			goto bad_lpg_params;

		pwm_cfg->lut_params.ramp_step_ms =
				QPNP_LUT_RAMP_STEP_DEFAULT;
		rc = of_property_read_u32(node, "qcom,ramp-step-ms", &val);
		if (!rc)
			pwm_cfg->lut_params.ramp_step_ms = val;
		else if (rc != -EINVAL)
			goto bad_lpg_params;

		pwm_cfg->lut_params.flags = QPNP_LED_PWM_FLAGS;
		rc = of_property_read_u32(node, "qcom,lut-flags", &val);
		if (!rc)
			pwm_cfg->lut_params.flags = (u8) val;
		else if (rc != -EINVAL)
			goto bad_lpg_params;

		pwm_cfg->lut_params.idx_len =
			pwm_cfg->duty_cycles->num_duty_pcts;
	}
	return 0;

bad_lpg_params:
	pwm_cfg->use_blink = false;
	if (pwm_cfg->mode == PWM_MODE) {
		dev_err(&pdev->dev, "LPG parameters not set for blink mode, defaulting to PWM mode\n");
		return 0;
	}
	return rc;
};

配置完后就能通过brightness_set调用qpnp_led_set了。