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    SubjectRe: [PATCH v1 1/2] leds: rt4505: Add support for Richtek RT4505 flash led controller
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    Hi Pavel, ChiYuan,

    On 10/27/20 9:29 AM, Pavel Machek wrote:
    > Hi!
    >
    >> From: ChiYuan Huang <cy_huang@richtek.com>
    >>
    >> Add support for RT4505 flash led controller. It can support up to 1.5A
    >> flash current with hardware timeout and low input voltage
    >> protection.
    >
    > Please use upper-case "LED" everywhere.
    >
    > This should be 2nd in the series, after DT changes.
    >
    >> Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
    >> ---
    >> drivers/leds/Kconfig | 11 ++
    >> drivers/leds/Makefile | 1 +
    >> drivers/leds/leds-rt4505.c | 397 +++++++++++++++++++++++++++++++++++++++++++++
    >> 3 files changed, 409 insertions(+)
    >> create mode 100644 drivers/leds/leds-rt4505.c
    [...]
    >> +static int rt4505_torch_brightness_set(struct led_classdev *lcdev, enum led_brightness level)
    >> +{
    >
    > 80 columns, where easy.
    >
    >> + struct rt4505_priv *priv = container_of(lcdev, struct rt4505_priv, flash.led_cdev);
    >> + u32 val = 0;
    >> + int ret;
    >> +
    >> + mutex_lock(&priv->lock);
    >> +
    >> + if (level != LED_OFF) {
    >> + ret = regmap_update_bits(priv->regmap, RT4505_REG_ILED, RT4505_ITORCH_MASK,
    >> + (level - 1) << RT4505_ITORCH_SHIFT);
    >> + if (ret)
    >> + goto unlock;
    >> +
    >> + val = RT4505_TORCH_SET;
    >> + }
    >> +
    >> + ret = regmap_update_bits(priv->regmap, RT4505_REG_ENABLE, RT4505_ENABLE_MASK, val);
    >> +
    >> +unlock:
    >> + mutex_unlock(&priv->lock);
    >> + return ret;
    >> +}
    >
    > Why is the locking needed? What will the /sys/class/leds interface
    > look like on system with your flash?

    The locking is needed since this can be called via led_set_brightness()
    from any place in the kernel, and especially from triggers.

    --
    Best regards,
    Jacek Anaszewski

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