linux-kernel - Re: [PATCH v8 1/2] leds: flash: add driver to support flash LED module in QCOM PMICs

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Date:   Tue, 28 Mar 2023 16:02:15 +0800
From:   Fenglin Wu <quic_fenglinw@...cinc.com>
To:     Pavel Machek <pavel@....cz>
CC:     <linux-arm-msm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <lee@...nel.org>, <krzysztof.kozlowski@...aro.org>,
        <linux-leds@...r.kernel.org>, <quic_collinsd@...cinc.com>,
        <quic_subbaram@...cinc.com>, Luca Weiss <luca.weiss@...rphone.com>
Subject: Re: [PATCH v8 1/2] leds: flash: add driver to support flash LED
 module in QCOM PMICs



On 3/26/2023 1:33 AM, Pavel Machek wrote:
> Hi!
> 
>> Add initial driver to support flash LED module found in Qualcomm
>> Technologies, Inc. PMICs. The flash module can have 3 or 4 channels
>> and each channel can be controlled indepedently and support full scale
>> current up to 1.5 A. It also supports connecting two channels together
>> to supply one LED component with full scale current up to 2 A. In that
>> case, the current will be split on each channel symmetrically and the
>> channels will be enabled and disabled at the same time.
> 
> 
>> +static int qcom_flash_strobe_set(struct led_classdev_flash *fled_cdev, bool state)
>> +{
>> +	struct qcom_flash_led *led = flcdev_to_qcom_fled(fled_cdev);
>> +	int rc;
>> +
>> +	rc = set_flash_current(led, led->flash_current_ma, FLASH_MODE);
>> +	if (rc)
>> +		return rc;
>> +
>> +	rc = set_flash_timeout(led, led->flash_timeout_ms);
>> +	if (rc)
>> +		return rc;
>> +
>> +	rc = set_flash_module_en(led, state);
>> +	if (rc)
>> +		return rc;
>> +
>> +	return set_flash_strobe(led, SW_STROBE, state);
>> +}
> 
> Should we disable the module before setting the current? It might be
> already active due to torch mode...
> 
The module enabling status should be kept as it is because it may be 
still controlling other LED channels, I can strobe off the LED before 
setting the current to cover such case. I will update it as a following 
patch.

> 
>> +		return -EINVAL;
>> +	}
>> +
>> +	flash_data->v4l2_flash = devm_kcalloc(dev, count,
>> +			sizeof(*flash_data->v4l2_flash), GFP_KERNEL);
>> +	if (!flash_data->v4l2_flash)
>> +		return -ENOMEM;
>> +
>> +	device_for_each_child_node(dev, child) {
>> +		led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
>> +		if (!led) {
>> +			rc = -ENOMEM;
>> +			goto release;
>> +		}
>> +
>> +		led->flash_data = flash_data;
>> +		rc = qcom_flash_register_led_device(dev, child, led);
>> +		if (rc < 0)
>> +			goto release;
>> +
>> +		flash_data->leds_count++;
>> +	}
> 
> Do you need to do of_node_put in error path
I will update this as well.

> 
> BR,
> 							Pavel