Hi Andy,
Thanks for your reply! I have some questions want to ask you below.

Andy Shevchenko [off-list ref] 於 2022年7月5日 週二 清晨5:14寫道：

On Mon, Jul 4, 2022 at 7:43 AM ChiaEn Wu [off-list ref] wrote:

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From: ChiaEn Wu <redacted>

Add Mediatek MT6370 Backlight support.

...

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+         This driver can also be built as a module. If so the module

If so,

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+         will be called "mt6370-backlight.ko".

No ".ko" part.

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+#include <linux/gpio/driver.h>

Can you elaborate on this?

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+#include <linux/kernel.h>
+#include <linux/log2.h>
+#include <linux/minmax.h>
+#include <linux/module.h>

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+#include <linux/of.h>

Can you elaborate on this?

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+#include <linux/platform_device.h>
+#include <linux/regmap.h>

Missed mod_devicetable.h.

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+               brightness_val[0] = (brightness - 1) & MT6370_BL_DIM2_MASK;
+               brightness_val[1] = (brightness - 1)
+                                   >> fls(MT6370_BL_DIM2_MASK);

Bad indentation. One line?

Well... if indent to one line, it will be over 80 characters(or called columns?)
From my understanding, it is not allowed, right??

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+       if (priv->enable_gpio)

Dup check.

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+               gpiod_set_value(priv->enable_gpio, brightness ? 1 : 0);

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+       brightness = brightness_val[1] << fls(MT6370_BL_DIM2_MASK);
+       brightness += (brightness_val[0] & MT6370_BL_DIM2_MASK);

Too many parentheses.

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+               /*
+                * prop_val =  1      -->  1 steps --> 0x00
+                * prop_val =  2 ~  4 -->  4 steps --> 0x01
+                * prop_val =  5 ~ 16 --> 16 steps --> 0x10
+                * prop_val = 17 ~ 64 --> 64 steps --> 0x11
+                */
+               prop_val = (ilog2(roundup_pow_of_two(prop_val)) + 1) >> 1;

Isn't something closer to get_order() or fls()?

I will revise it to "(get_order(prop_va * PAGE_SIZE) + 1) / 2" and
this change is meet your expectations??

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+       props->max_brightness = min_t(u32, brightness,
+                                     MT6370_BL_MAX_BRIGHTNESS);

One line?

 Ditto, it will be over 80 characters...

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+       val = 0;

Do you need this here?

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+       prop_val = 0;

Useless.

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+       ret = device_property_read_u8(dev, "mediatek,bled-channel-use",
+                                     &prop_val);
+       if (ret) {
+               dev_err(dev, "mediatek,bled-channel-use DT property missing\n");
+               return ret;
+       }
+
+       if (!prop_val || prop_val > MT6370_BL_MAX_CH) {
+               dev_err(dev,
+                       "No channel specified or over than upper bound (%d)\n",
+                       prop_val);
+               return -EINVAL;
+       }

...

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+static int mt6370_bl_probe(struct platform_device *pdev)
+{
+       struct mt6370_priv *priv;
+       struct backlight_properties props = {
+               .type = BACKLIGHT_RAW,
+               .scale = BACKLIGHT_SCALE_LINEAR,
+       };
+       int ret;

  struct device *dev = &pdev->dev;

will save you a few LoCs.

--
With Best Regards,
Andy Shevchenko

Best regards,
ChiaEn Wu