On Fri, 2017-01-06 at 15:48 -0500, Olimpiu Dejeu wrote:
> backlight: Add support for Arctic Sand LED backlight driver chips
> This driver provides support for the Arctic Sand arc2c0608 chip,
> and provides a framework to support future devices.
style trivia:
> diff --git a/drivers/video/backlight/arcxcnn_bl.c b/drivers/video/backlight/arcxcnn_bl.c
[]
> +static int arcxcnn_bl_update_status(struct backlight_device *bl)
> +{
> + struct arcxcnn *lp = bl_get_data(bl);
> + u32 brightness = bl->props.brightness;
> +
> + if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
> + brightness = 0;
> +
> + arcxcnn_set_brightness(lp, brightness);
> +
> + /* set power-on/off/save modes */
> + if (bl->props.power == 0)
> + /* take out of standby */
> + arcxcnn_update_bit(lp, ARCXCNN_CMD, ARCXCNN_CMD_STDBY, 0);
> + else
> + /* place in low-power standby mode */
> + arcxcnn_update_bit(lp, ARCXCNN_CMD,
> + ARCXCNN_CMD_STDBY, ARCXCNN_CMD_STDBY);
This is generally smaller code using a temporary and
a single call instead of two calls like:
int cmd;
...
if (bl->props.power == 0)
cmd = 0; /* take out of standby */
else
cmd = ARCXCNN_CMD_STDBY;
arcxcnn_update_bit(lp, ARCXCNN_CMD, ARCXCNN_CMD_STDBY, cmd);
or maybe
arcxcnn_update_bit(lp, ARCXCNN_CMD, ARCXCNN_CMD_STDBY,
bl->props.power == 0 ? 0 : ARCXCNN_CMD_STDBY);
> +static int arcxcnn_backlight_register(struct arcxcnn *lp)
> +{
> + struct backlight_properties *props;
> + const char *name = lp->pdata->name ? : "arctic_bl";
> +
> + props = devm_kzalloc(lp->dev, sizeof(*props), GFP_KERNEL);
> + if (!props)
> + return -ENOMEM;
> +
> + memset(props, 0, sizeof(props));
props has already been zeroed by devm_kzalloc and doesn't
need to be memset to 0 again.
> + props->type = BACKLIGHT_PLATFORM;
> + props->max_brightness = MAX_BRIGHTNESS;
> +
> + if (lp->pdata->initial_brightness > props->max_brightness)
> + lp->pdata->initial_brightness = props->max_brightness;
> +
> + props->brightness = lp->pdata->initial_brightness;
> +
> + lp->bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp,
> + &arcxcnn_bl_ops, props);
> +
This blank line above is generally not needed.
> + if (IS_ERR(lp->bl))
> + return PTR_ERR(lp->bl);
the typical style is:
rtn = foo(...)
if (rtn < 0)
error_handler...
> +static void arcxcnn_parse_dt(struct arcxcnn *lp)
> +{
> + struct device *dev = lp->dev;
> + struct device_node *node = dev->of_node;
> + u32 prog_val, num_entry, entry, sources[ARCXCNN_LEDEN_BITS];
> + int ret;
[]
> + ret = of_property_count_u32_elems(node, "led-sources");
> + if (ret < 0) {
> + lp->pdata->leden = ARCXCNN_LEDEN_MASK; /* all on is default */
> + } else {
> + num_entry = ret;
> + if (num_entry > ARCXCNN_LEDEN_BITS)
> + num_entry = ARCXCNN_LEDEN_BITS;
> +
> + ret = of_property_read_u32_array(node, "led-sources", sources,
> + num_entry);
> + if (ret < 0) {
> + dev_err(dev, "led-sources node is invalid.\n");
> + } else {
> + u8 onbit;
> +
> + lp->pdata->leden = 0;
> +
> + /* for each enable in source, set bit in led enable */
> + for (entry = 0; entry < num_entry; entry++) {
> + onbit = 1 << sources[entry];
> + lp->pdata->leden |= onbit;
> + }
> + }
> + }
> +}
The cascading indentation can be avoided by using return;
as necessary
ret = of_property_count_u32_elems(node, "led-sources");
if (ret < 0) {
lp->pdata->leden = ARCXCNN_LEDEN_MASK; /* all on is default */
return;
}
num_entry = min(ret, ARCXCNN_LEDEN_BITS);
ret = of_property_read_u32_array(node, "led-sources", sources, num_entry);
if (ret < 0) {
dev_err(dev, "led-sources node is invalid\n");
return;
}
lp->pdata->leden = 0;
/* for each enable in source, set bit in led enable */
for (entry = 0; entry < num_entry; entry++) {
u8 onbit = 1 << sources[entry];
lp->pdata->leden |= onbit;
}
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