Re: [PATCH v3 1/2] leds: mt6360: Add LED driver for MT6360

On Mon, Sep 7, 2020 at 1:31 PM Gene Chen [off-list ref] wrote:

From: Gene Chen <redacted>

Add MT6360 LED driver include 2-channel Flash LED with torch/strobe mode,
and 4-channel RGB LED support Register/Flash/Breath Mode

I'm wondering why you don't use struct led_classdev_flash.

...

+//
+// Copyright (C) 2020 MediaTek Inc.
+//

Do you really need these two // lines?

...

+enum {
+       MT6360_LED_ISNK1 = 0,
+       MT6360_LED_ISNK2,
+       MT6360_LED_ISNK3,
+       MT6360_LED_ISNK4,
+       MT6360_LED_FLASH1,
+       MT6360_LED_FLASH2,

+       MT6360_MAX_LEDS,

No comma for terminator entry.

+};

...

+#define MT6360_ISNK_MASK               0x1F

GENMASK()

...

+#define MT6360_ITORCH_MIN              25000
+#define MT6360_ITORCH_STEP             12500
+#define MT6360_ITORCH_MAX              400000
+#define MT6360_ISTRB_MIN               50000
+#define MT6360_ISTRB_STEP              12500
+#define MT6360_ISTRB_MAX               1500000
+#define MT6360_STRBTO_MIN              64000
+#define MT6360_STRBTO_STEP             32000
+#define MT6360_STRBTO_MAX              2432000

Add unit suffixes, please.

...

+#define FLED_TORCH_FLAG_MASK           0x0c

+#define FLED_STROBE_FLAG_MASK          0x03

GENMASK()

...

+       dev_dbg(lcdev->dev, "[%d] brightness %d\n", led->led_no, level);

Not production noise.

...

+       ret = regmap_update_bits(priv->regmap, MT6360_REG_RGBEN, enable_mask, val);
+       if (ret)
+               return ret;
+
+       return 0;

return regmap...

+       u32 val = (level) ? MT6360_FLCSEN_MASK(led->led_no) : 0;

Why parens?

...

+       dev_dbg(lcdev->dev, "[%d] brightness %d\n", led->led_no, level);

Noise.

...

+       if (priv->fled_strobe_used) {
+               dev_warn(lcdev->dev, "Please disable strobe first [%d]\n", priv->fled_strobe_used);
+               return -EINVAL;

Hmm... Shouldn't be guaranteed by some framework?

...

+               curr = prev & (~BIT(led->led_no));

Too many parens.

...

+static int mt6360_strobe_brightness_set(struct led_classdev_flash *fl_cdev, u32 brightness)
+{
+       struct mt6360_led *led = container_of(fl_cdev, struct mt6360_led, flash);
+       struct led_classdev *lcdev = &fl_cdev->led_cdev;
+

+       dev_dbg(lcdev->dev, "[%d] strobe brightness %d\n", led->led_no, brightness);

Noise. Point of this entire function?

+       return 0;
+}

...

+       dev_dbg(lcdev->dev, "[%d] strobe state %d\n", led->led_no, state);

Noise.

If you wish to do it right, add trace events to the framework.

...

+       if (priv->fled_torch_used) {

+               dev_warn(lcdev->dev, "Please disable torch first [0x%x]\n", priv->fled_torch_used);

Again, why the warning? Can this be a part of the framework?

+               return -EINVAL;
+       }

...

+               curr = prev & (~BIT(led->led_no));

Too many parens.

...

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

These delays must be explained.

...

+       if (led->led_no == MT6360_LED_FLASH1) {
+               strobe_timeout_mask = MT6360_FLED1STRBTO_MASK;
+               fled_short_mask = MT6360_FLED1SHORT_MASK;

+

Redundant blank line.

+       } else {
+               strobe_timeout_mask = MT6360_FLED2STRBTO_MASK;
+               fled_short_mask = MT6360_FLED2SHORT_MASK;
+       }

...

+static int mt6360_flash_external_strobe_set(struct v4l2_flash *v4l2_flash, bool enable)
+{
+       struct led_classdev_flash *flash = v4l2_flash->fled_cdev;
+       struct mt6360_led *led = container_of(flash, struct mt6360_led, flash);
+       struct mt6360_priv *priv = led->priv;

+       u32 enable_mask = MT6360_FLCSEN_MASK(led->led_no);

enable_mask -> mask
  u32 value = enable ? mask : 0;

+       int ret;
+
+       ret = regmap_update_bits(priv->regmap, MT6360_REG_FLEDEN, enable_mask,

+                                enable ? enable_mask : 0);

  ret =  ... mask, value);

+       if (ret)
+               return ret;
+
+       if (enable)
+               priv->fled_strobe_used |= BIT(led->led_no);
+       else
+               priv->fled_strobe_used &= (~BIT(led->led_no));

Too many parens.

+
+       return 0;
+}

...

+       s->val = s->max = (s->min) + (lcdev->max_brightness - 1) * s->step;

Ditto.

...

+static void clamp_align(u32 *v, u32 min, u32 max, u32 step)

Can we keep a similar API, i.e. return a new value rather than update old?

+{

+       *v = clamp_val(*v, min, max);

I would rather use a temporary variable (and it actually will be
required with above).

+       if (step > 1)
+               *v = (*v - min) / step * step + min;

Sounds like open coded rounddown().

+}

...

+       lcdev->max_brightness = (val - MT6360_ITORCH_MIN) / MT6360_ITORCH_STEP + 1;

DIV_ROUND_UP(val - MT6360_ITORCH_MIN, MT6360_ITORCH_STEP) ?

...

+static int mt6360_init_common_properties(struct mt6360_led *led, struct led_init_data *init_data)
+{
+       const char *str;
+
+       if (!fwnode_property_read_string(init_data->fwnode, "default-state", &str)) {
+               if (!strcmp(str, "on"))
+                       led->default_state = STATE_ON;
+               else if (!strcmp(str, "keep"))
+                       led->default_state = STATE_KEEP;

+               else

I wouldn't allow some garbage to be off.

+                       led->default_state = STATE_OFF;
+       }

What about

static const char * const states = { "on", "keep", "off" };

int ret;

ret = match_string(states, ARRAY_SIZE(states), str);
if (ret)
 ...

default_state = ret;

?

+       return 0;
+}

...

+static int mt6360_led_probe(struct platform_device *pdev)
+{
+       struct mt6360_priv *priv;
+       struct fwnode_handle *child;
+       int i, ret;
+

+       priv->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+       if (!priv->regmap) {
+               dev_err(&pdev->dev, "Failed to get parent regmap\n");
+               return -ENODEV;
+       }

...

+out:

out_flash_leds_release: ?

+       for (i = MT6360_LED_FLASH1; i <= MT6360_LED_FLASH2; i++) {
+               struct mt6360_led *led = priv->leds[i];
+
+               if (led && led->v4l2_flash)
+                       v4l2_flash_release(led->v4l2_flash);
+
+       }

...

+static int mt6360_led_remove(struct platform_device *pdev)
+{
+       struct mt6360_priv *priv = platform_get_drvdata(pdev);
+       int i;
+
+       for (i = MT6360_LED_FLASH1; i <= MT6360_LED_FLASH2; i++) {
+               struct mt6360_led *led = priv->leds[i];
+
+               if (led && led->v4l2_flash)
+                       v4l2_flash_release(led->v4l2_flash);
+
+       }

Looks like a code duplication.

+
+       return 0;
+}
+
+static const struct of_device_id __maybe_unused mt6360_led_of_id[] = {
+       { .compatible = "mediatek,mt6360-led", },

+       {},

No need comma.

+};

-- 
With Best Regards,
Andy Shevchenko