linux-kernel - Re: [PATCH v5 12/13] leds: flashlight: mt6370: Add MediaTek MT6370 flashlight support

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Date:   Fri, 15 Jul 2022 20:13:49 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     ChiaEn Wu <peterwu.pub@...il.com>
Cc:     Lee Jones <lee.jones@...aro.org>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        Jingoo Han <jingoohan1@...il.com>, Pavel Machek <pavel@....cz>,
        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>,
        ChiaEn Wu <chiaen_wu@...htek.com>,
        Alice Chen <alice_chen@...htek.com>,
        cy_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>,
        szuni chen <szunichen@...il.com>
Subject: Re: [PATCH v5 12/13] leds: flashlight: mt6370: Add MediaTek MT6370
 flashlight support

On Fri, Jul 15, 2022 at 1:29 PM ChiaEn Wu <peterwu.pub@...il.com> wrote:

> The MediaTek MT6370 is a highly-integrated smart power management IC,
> whichincludes a single cell Li-Ion/Li-Polymer switching battery

which includes

> 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.
>
> The Flash LED in MT6370 has 2 channel and support torch/strobe mode.

channels

> The commit add the support of MT6370 FLASH LED.

Add the

...

> +#define MT6370_FLCSEN_MASK_ALL         (BIT(0) | BIT(1))

GENMASK()

...

> +               for (i = 0; i < MT6370_MAX_LEDS; i++) {
> +                       ret = regmap_update_bits(priv->regmap,
> +                                               MT6370_REG_FLEDISTRB(i),
> +                                               MT6370_ISTROBE_MASK, flevel[i]);
> +                       if (ret)
> +                               return ret;
> +               }
> +       } else {

> +               ret = regmap_update_bits(priv->regmap,
> +                                        MT6370_REG_FLEDISTRB(led->led_no),
> +                                        MT6370_ISTROBE_MASK, val);
> +       }
> +       return ret;

    return regmap_update_bits(...);
  }

  return 0;

...

> +       /*
> +        * If the flash need to be on,

needs

> +        * config the flash current ramping up to the setting value.
> +        * Else, always recover back to the minimum one.
> +        */

...

> +       /* For the flash turn on/off, need to wait HW ramping up/down time

to turn

> +        * 5ms/500us to prevent the unexpected problem.
> +        */

Wrong multi-line comment style.

> +

No need for a blank line.

> +       if (!prev && curr)
> +               usleep_range(5000, 6000);
> +       else if (prev && !curr)
> +               udelay(500);

...

> +static int mt6370_led_register(struct device *parent, struct mt6370_led *led,
> +                               struct led_init_data *init_data)
> +{
> +       struct v4l2_flash_config v4l2_config = {0};
> +       int ret;
> +
> +       ret = devm_led_classdev_flash_register_ext(parent, &led->flash,
> +                                                  init_data);
> +       if (ret) {
> +               dev_err(parent, "Couldn't register flash %d\n", led->led_no);
> +               return ret;

return dev_err_probe() here and everywhere where it is about probe stage.

> +       }
> +
> +       mt6370_init_v4l2_flash_config(led, &v4l2_config);
> +       led->v4l2_flash = v4l2_flash_init(parent, init_data->fwnode,
> +                                         &led->flash, &v4l2_flash_ops,
> +                                         &v4l2_config);
> +       if (IS_ERR(led->v4l2_flash)) {
> +               dev_err(parent, "Failed to register %d v4l2 sd\n", led->led_no);
> +               return PTR_ERR(led->v4l2_flash);
> +       }
> +
> +       return 0;
> +}

...

> +       num = fwnode_property_count_u32(init_data->fwnode, "led-sources");
> +       if (num < 1 || num > MT6370_MAX_LEDS) {
> +               dev_err(priv->dev,
> +                       "Not specified or wrong number of led-sources\n");
> +               return -EINVAL;

Ditto.

> +       }

...

> +       ret = fwnode_property_read_u32(init_data->fwnode, "led-max-microamp",
> +                                      &val);

One line?

...

> +               val = clamp_align(val, MT6370_STRBTO_MIN_US, MT6370_STRBTO_MAX_US,
> +                                 MT6370_STRBTO_STEP_US);

I would name it mt6370_clamp() to avoid potential collision in the
global namespace in the future.

-- 
With Best Regards,
Andy Shevchenko