Re: [PATCH v6 3/5] backlight: lm3533: Support initialization from Device Tree

From: Lee Jones
Date: Wed Feb 08 2017 - 07:55:11 EST


Cc'ing Daniel Thompson, the new Maintainer.

On Mon, 30 Jan 2017, Bjorn Andersson wrote:

> From: Bjorn Andersson <bjorn.andersson@xxxxxxxxxxxxxx>
>
> Implement support for initialization of the lm3533 backlight from Device
> Tree.
>
> Acked-by: Jingoo Han <jingoohan1@xxxxxxxxx>
> Acked-by: Pavel Machek <pavel@xxxxxx>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxxxxxx>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
> ---
>
> Note that this patch can be merged independently of the other patches in the
> series.
>
> Changes since v5:
> - None
>
> Changes since v4:
> - Acks from Pavel and Jingoo
>
> Changes since v3:
> - Moved backlight DT parsing from mfd driver
> - Gave driver its own compatible
>
> drivers/video/backlight/lm3533_bl.c | 98 +++++++++++++++++++++++++++++++++++--
> 1 file changed, 95 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/video/backlight/lm3533_bl.c b/drivers/video/backlight/lm3533_bl.c
> index 0e2337f367b6..2f132199e604 100644
> --- a/drivers/video/backlight/lm3533_bl.c
> +++ b/drivers/video/backlight/lm3533_bl.c
> @@ -22,6 +22,7 @@
>
>
> #define LM3533_HVCTRLBANK_COUNT 2
> +#define LM3533_BL_DEFAULT_BRIGHTNESS 200
> #define LM3533_BL_MAX_BRIGHTNESS 255
>
> #define LM3533_REG_CTRLBANK_AB_BCONF 0x1a
> @@ -269,6 +270,86 @@ static int lm3533_bl_setup(struct lm3533_bl *bl,
> return lm3533_ctrlbank_set_pwm(&bl->cb, pdata->pwm);
> }
>
> +static int lm3533_of_parse_pwm_zones(struct device_node *node)
> +{
> + const char *propname = "ti,pwm-zones";
> + u32 zones[5];
> + int count;
> + int ret;
> + int i;
> +
> + count = of_property_count_u32_elems(node, propname);
> + if (count == -EINVAL)
> + return 0;
> + if (count <= 0)
> + return count;
> + if (count >= ARRAY_SIZE(zones))
> + return -EINVAL;
> +
> + ret = of_property_read_u32_array(node, propname, zones, count);
> + if (ret < 0)
> + return ret;
> +
> + /* Enable pwm input, and enable the selected zones */
> + ret = BIT(0);
> + for (i = 0; i < count; i++)
> + ret |= BIT(zones[i] + 1);
> +
> + return ret;
> +}
> +
> +static struct lm3533_bl_platform_data *lm3533_bl_of_parse(struct device *dev,
> + int *id)
> +{
> + struct lm3533_bl_platform_data *bl_pdata;
> + struct device_node *node = dev->of_node;
> + int ret;
> + u32 reg;
> + u32 val;
> +
> + bl_pdata = devm_kzalloc(dev, sizeof(*bl_pdata), GFP_KERNEL);
> + if (!bl_pdata)
> + return NULL;
> +
> + ret = of_property_read_u32(node, "reg", &reg);
> + if (ret < 0) {
> + dev_err(dev, "invalid reg property\n");
> + return NULL;
> + }
> + *id = reg;
> +
> + ret = of_property_read_string(node, "label",
> + (const char **)&bl_pdata->name);
> + if (ret < 0) {
> + dev_err(dev, "unable to parse label\n");
> + return NULL;
> + }
> +
> + ret = of_property_read_u32(node, "led-max-microamp", &val);
> + if (ret < 0) {
> + dev_err(dev, "unable to parse led-max-microamp\n");
> + return NULL;
> + }
> + bl_pdata->max_current = val;
> +
> + val = LM3533_BL_DEFAULT_BRIGHTNESS;
> + ret = of_property_read_u32(node, "default-brightness", &val);
> + if (ret < 0 && ret != -EINVAL) {
> + dev_err(dev, "unable to parse default-brightness\n");
> + return NULL;
> + }
> + bl_pdata->default_brightness = val;
> +
> + ret = lm3533_of_parse_pwm_zones(node);
> + if (ret < 0) {
> + dev_err(dev, "failed to parse ti,pwm-zones\n");
> + return NULL;
> + }
> + bl_pdata->pwm = ret;
> +
> + return bl_pdata;
> +}
> +
> static int lm3533_bl_probe(struct platform_device *pdev)
> {
> struct lm3533 *lm3533;
> @@ -277,6 +358,7 @@ static int lm3533_bl_probe(struct platform_device *pdev)
> struct backlight_device *bd;
> struct backlight_properties props;
> int ret;
> + int id;
>
> dev_dbg(&pdev->dev, "%s\n", __func__);
>
> @@ -284,14 +366,17 @@ static int lm3533_bl_probe(struct platform_device *pdev)
> if (!lm3533)
> return -EINVAL;
>
> + id = pdev->id;
> pdata = dev_get_platdata(&pdev->dev);
> + if (!pdata)
> + pdata = lm3533_bl_of_parse(&pdev->dev, &id);
> if (!pdata) {
> dev_err(&pdev->dev, "no platform data\n");
> return -EINVAL;
> }
>
> - if (pdev->id < 0 || pdev->id >= LM3533_HVCTRLBANK_COUNT) {
> - dev_err(&pdev->dev, "illegal backlight id %d\n", pdev->id);
> + if (id < 0 || id >= LM3533_HVCTRLBANK_COUNT) {
> + dev_err(&pdev->dev, "illegal backlight id %d\n", id);
> return -EINVAL;
> }
>
> @@ -300,7 +385,7 @@ static int lm3533_bl_probe(struct platform_device *pdev)
> return -ENOMEM;
>
> bl->lm3533 = lm3533;
> - bl->id = pdev->id;
> + bl->id = id;
>
> bl->cb.lm3533 = lm3533;
> bl->cb.id = lm3533_bl_get_ctrlbank_id(bl);
> @@ -394,10 +479,17 @@ static void lm3533_bl_shutdown(struct platform_device *pdev)
> lm3533_ctrlbank_disable(&bl->cb);
> }
>
> +static const struct of_device_id lm3533_bl_of_match[] = {
> + { .compatible = "ti,lm3533-backlight", },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, lm3533_bl_of_match);
> +
> static struct platform_driver lm3533_bl_driver = {
> .driver = {
> .name = "lm3533-backlight",
> .pm = &lm3533_bl_pm_ops,
> + .of_match_table = lm3533_bl_of_match,
> },
> .probe = lm3533_bl_probe,
> .remove = lm3533_bl_remove,

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org â Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog