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Date: Mon, 1 Aug 2022 15:55:04 +0800
From: szuni chen <szunichen@...il.com>
To: Pavel Machek <pavel@....cz>
Cc: ChiaEn Wu <peterwu.pub@...il.com>,
Lee Jones <lee.jones@...aro.org>,
Daniel Thompson <daniel.thompson@...aro.org>,
Jingoo Han <jingoohan1@...il.com>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Matthias Brugger <matthias.bgg@...il.com>,
Sebastian Reichel <sre@...nel.org>,
Chunfeng Yun <chunfeng.yun@...iatek.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Jonathan Cameron <jic23@...nel.org>,
Lars-Peter Clausen <lars@...afoo.de>,
Liam Girdwood <lgirdwood@...il.com>,
Mark Brown <broonie@...nel.org>,
Guenter Roeck <linux@...ck-us.net>,
"Krogerus, Heikki" <heikki.krogerus@...ux.intel.com>,
Helge Deller <deller@....de>,
Andy Shevchenko <andy.shevchenko@...il.com>,
ChiaEn Wu <chiaen_wu@...htek.com>,
Alice Chen <alice_chen@...htek.com>,
ChiYuan Huang <cy_huang@...htek.com>,
dri-devel <dri-devel@...ts.freedesktop.org>,
Linux LED Subsystem <linux-leds@...r.kernel.org>,
devicetree <devicetree@...r.kernel.org>,
linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>,
"moderated list:ARM/Mediatek SoC support"
<linux-mediatek@...ts.infradead.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Linux PM <linux-pm@...r.kernel.org>,
USB <linux-usb@...r.kernel.org>,
linux-iio <linux-iio@...r.kernel.org>,
"open list:FRAMEBUFFER LAYER" <linux-fbdev@...r.kernel.org>
Subject: Re: [PATCH v6 11/13] leds: rgb: mt6370: Add MediaTek MT6370 current
sink type LED Indicator support
Hi Pavel,
Sorry for resending the mail, I add all reviewers this time.
Pavel Machek <pavel@....cz> 於 2022年7月31日 週日 清晨5:39寫道：
>
> Hi!
>
...
>
> > +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.
>
Should we just remove it, or describe Isink4 in another position?
> > +struct mt6370_priv {
> > + /* Per LED access lock */
> > + struct mutex lock;
>
> Do we really need per-led locking?
>
Sorry, maybe the comment is not precise.
The lock is used to prevent LEDs from accessing the HW at the same time.
If I use
/* LED access lock, only one LED can access the HW at the same time */
will it look better?
No, we aren't.
There are six steps tr1, tr2, tf1, tf2, ton, and toff in MT6370 led breath mode.
We parse duration settings from node "hw_pattern" and set them to the registers.
This function is used to generate duration settings from hw_pattern.
The brightness of the six steps mentioned above in breath mode is
limited to the node "brightness".
The target brightness of tr1 and tf1 is 25% of node "brightness", and
they are automatically set by HW.
> > +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.
>
Forgive me, but I would like to know why "keep" / "on" is not preferred.
We think the users might have some conditions that need them.
Best Regards,
Alice
Pavel Machek <pavel@....cz> 於 2022年7月31日 週日 清晨5:39寫道：
>
> 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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