linux-kernel - Re: [PATCH v6 11/13] leds: rgb: mt6370: Add MediaTek MT6370 current sink type LED Indicator support

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Message-ID: <20220730213913.GJ23307@duo.ucw.cz>
Date:   Sat, 30 Jul 2022 23:39:13 +0200
From:   Pavel Machek <pavel@....cz>
To:     ChiaEn Wu <peterwu.pub@...il.com>
Cc:     lee.jones@...aro.org, daniel.thompson@...aro.org,
        jingoohan1@...il.com, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, matthias.bgg@...il.com,
        sre@...nel.org, chunfeng.yun@...iatek.com,
        gregkh@...uxfoundation.org, jic23@...nel.org, lars@...afoo.de,
        lgirdwood@...il.com, broonie@...nel.org, linux@...ck-us.net,
        heikki.krogerus@...ux.intel.com, deller@....de,
        andy.shevchenko@...il.com, chiaen_wu@...htek.com,
        alice_chen@...htek.com, cy_huang@...htek.com,
        dri-devel@...ts.freedesktop.org, linux-leds@...r.kernel.org,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org, linux-usb@...r.kernel.org,
        linux-iio@...r.kernel.org, linux-fbdev@...r.kernel.org,
        szunichen@...il.com
Subject: Re: [PATCH v6 11/13] leds: rgb: mt6370: Add MediaTek MT6370 current
 sink type LED Indicator support

Hi!

> From: ChiYuan Huang <cy_huang@...htek.com>
> 
> The MediaTek MT6370 is a highly-integrated smart power management IC,
> which includes a single cell Li-Ion/Li-Polymer switching battery
> charger, a USB Type-C & Power Delivery (PD) controller, dual
> Flash LED current sources, a RGB LED driver, a backlight WLED driver,
> a display bias driver and a general LDO for portable devices.
> 
> In MediaTek MT6370, there are four channel current-sink RGB LEDs that
> support hardware pattern for constant current, PWM, and breath mode.
> Isink4 channel can also be used as a CHG_VIN power good indicator.
>

> +config LEDS_MT6370_RGB
> +	tristate "LED Support for MediaTek MT6370 PMIC"
> +	depends on MFD_MT6370
> +	select LINEAR_RANGE
> +	help
> +	  Say Y here to enable support for MT6370_RGB LED device.
> +	  In MT6370, there are four channel current-sink LED drivers that
> +	  support hardware pattern for constant current, PWM, and breath mode.


> +	  Isink4 channel can also be used as a CHG_VIN power good  indicator.

That does not really belong here.

> +struct mt6370_priv {
> +	/* Per LED access lock */
> +	struct mutex lock;

Do we really need per-led locking?

> +static int mt6370_gen_breath_pattern(struct mt6370_priv *priv,
> +				     struct led_pattern *pattern, u32 len,
> +				     u8 *pattern_val, u32 val_len)
> +{
> +	enum mt6370_led_ranges sel_range;
> +	struct led_pattern *curr;
> +	unsigned int sel;
> +	u8 val[P_MAX_PATTERNS / 2] = {};
> +	int i;
> +
> +	if (len < P_MAX_PATTERNS && val_len < P_MAX_PATTERNS / 2)
> +		return -EINVAL;
> +
> +	/*
> +	 * Pattern list
> +	 * tr1:	byte 0, b'[7: 4]
> +	 * tr2:	byte 0, b'[3: 0]
> +	 * tf1:	byte 1, b'[7: 4]
> +	 * tf2:	byte 1, b'[3: 0]
> +	 * ton:	byte 2, b'[7: 4]
> +	 * toff: byte 2, b'[3: 0]
> +	 */
> +	for (i = 0; i < P_MAX_PATTERNS; i++) {
> +		curr = pattern + i;
> +
> +		sel_range = i == P_LED_TOFF ? R_LED_TOFF : R_LED_TRFON;
> +
> +		linear_range_get_selector_within(priv->ranges + sel_range,
> +						 curr->delta_t, &sel);
> +
> +		val[i / 2] |= sel << (4 * ((i + 1) % 2));
> +	}
> +
> +	memcpy(pattern_val, val, 3);
> +
> +	return 0;
> +}

I wonder how this works... you are not creating private sysfs
interface, are you?

> +static int mt6370_init_led_properties(struct mt6370_led *led,
> +				      struct led_init_data *init_data)
> +{
> +	struct mt6370_priv *priv = led->priv;
> +	struct device *dev = priv->dev;
> +	struct led_classdev *lcdev;
> +	struct fwnode_handle *child;
> +	enum mt6370_led_ranges sel_range;
> +	u32 max_uA, max_level;
> +	const char * const states[] = { "off", "keep", "on" };

We'd really preffer not to add "keep" / "on" support unless you need
it.

> +			if (ret)
> +				return dev_err_probe(dev, ret,
> +						     "led %d, no color specified\n",
> +						     led->index);

led->LED.

> +		if (num_color < 2)
> +			return dev_err_probe(dev, -EINVAL,
> +					     "Multicolor must include
> 2 or more led channel\n");

"LED channels".

> +static int mt6370_isnk_init_default_state(struct mt6370_led *led)
> +{
> +	struct mt6370_priv *priv = led->priv;
> +	unsigned int enable, level;
> +	int ret;
> +
> +	ret = mt6370_get_led_brightness(priv, led->index, &level);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_field_read(priv->fields[F_RGB_EN], &enable);
> +	if (ret)
> +		return ret;
> +
> +	if (!(enable & MT6370_CHEN_BIT(led->index)))
> +		level = LED_OFF;

Just use 0 instead of LED_OFF.

Best regards,
							Pavel

-- 
People of Russia, stop Putin before his war on Ukraine escalates.

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