On Mon, Jul 6, 2015 at 2:54 AM, Lee Jones [off-list ref] wrote:

On Sun, 05 Jul 2015, Jingoo Han wrote:

quoted

On Tuesday, June 30, 2015 3:16 PM, Milo Kim wrote:

quoted

LP855x backlight device can be enabled by external VDD input.
The 'supply' data is used for this purpose.
It's kind of private data which runs internally, so there is no reason to
expose to the platform data.

And LP855x DT property, 'power-supply' is unnecessary.
If a regulator is registered correctly, then lp855x driver can get
regulator resource by using devm_regulator_get().
So devm_regulator_get() is moved from _parse_dt() to _probe().
Ex) The following device tree works without 'power-supply' property.

Even if it's not 'required', I think it would be good to have it in
DT, as it describes the hardware, right?

Yeah. I think it's common practice to specify regulator input in DT.

I'd rather this patch was not merged.

Sean

quoted

quoted

    i2c0: i2c@10002000 {
            (snip)

            backlight@2c {
                    compatible = "ti,lp8556";
                    reg = <0x2c>;

                    bl-name = "lcd-bl";
                    dev-ctrl = /bits/ 8 <0x85>;
                    init-brt = /bits/ 8 <0x10>;
            };
    };

    /* 'power' regulator for LP8556 VDD */
    bl_vdd: fixed-regulator@1 {
            compatible = "regulator-fixed";
            regulator-name = "power";
            regulator-min-microvolt = <3300000>;
            regulator-max-microvolt = <3300000>;

            (snip)
    };

Cc: Sean Paul <redacted>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Lee Jones <redacted>
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Milo Kim <redacted>

Acked-by: Jingoo Han <jingoohan1@gmail.com>

Best regards,
Jingoo Han

quoted

---
 .../devicetree/bindings/video/backlight/lp855x.txt   |  2 --
 drivers/video/backlight/lp855x_bl.c                  | 20 +++++++++-----------
 include/linux/platform_data/lp855x.h                 |  2 --
 3 files changed, 9 insertions(+), 15 deletions(-)

diff --git a/Documentation/devicetree/bindings/video/backlight/lp855x.txt

b/Documentation/devicetree/bindings/video/backlight/lp855x.txt
index 0a3ecbc..96e83a5 100644

--- a/Documentation/devicetree/bindings/video/backlight/lp855x.txt
+++ b/Documentation/devicetree/bindings/video/backlight/lp855x.txt

@@ -12,7 +12,6 @@ Optional properties:
   - pwm-period: PWM period value. Set only PWM input mode used (u32)
   - rom-addr: Register address of ROM area to be updated (u8)
   - rom-val: Register value to be updated (u8)
-  - power-supply: Regulator which controls the 3V rail

 Example:

@@ -57,7 +56,6 @@ Example:
    backlight@2c {
            compatible = "ti,lp8557";
            reg = <0x2c>;
-           power-supply = <&backlight_vdd>;

            dev-ctrl = /bits/ 8 <0x41>;
            init-brt = /bits/ 8 <0x0a>;

diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c
index a26d3bb..277d5ca 100644
--- a/drivers/video/backlight/lp855x_bl.c
+++ b/drivers/video/backlight/lp855x_bl.c

@@ -73,6 +73,7 @@ struct lp855x {
    struct device *dev;
    struct lp855x_platform_data *pdata;
    struct pwm_device *pwm;
+   struct regulator *supply;       /* regulator for VDD input */
 };

 static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)

@@ -384,13 +385,6 @@ static int lp855x_parse_dt(struct lp855x *lp)
            pdata->rom_data = &rom[0];
    }

-   pdata->supply = devm_regulator_get(dev, "power");
-   if (IS_ERR(pdata->supply)) {
-           if (PTR_ERR(pdata->supply) == -EPROBE_DEFER)
-                   return -EPROBE_DEFER;
-           pdata->supply = NULL;
-   }
-
    lp->pdata = pdata;

    return 0;

@@ -431,8 +425,12 @@ static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
    else
            lp->mode = REGISTER_BASED;

-   if (lp->pdata->supply) {
-           ret = regulator_enable(lp->pdata->supply);
+   lp->supply = devm_regulator_get(lp->dev, "power");
+   if (IS_ERR(lp->supply))
+           lp->supply = NULL;
+
+   if (lp->supply) {
+           ret = regulator_enable(lp->supply);
            if (ret < 0) {
                    dev_err(&cl->dev, "failed to enable supply: %d\n", ret);
                    return ret;

@@ -470,8 +468,8 @@ static int lp855x_remove(struct i2c_client *cl)

    lp->bl->props.brightness = 0;
    backlight_update_status(lp->bl);
-   if (lp->pdata->supply)
-           regulator_disable(lp->pdata->supply);
+   if (lp->supply)
+           regulator_disable(lp->supply);
    sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);

    return 0;

diff --git a/include/linux/platform_data/lp855x.h b/include/linux/platform_data/lp855x.h
index 9c7fd1e..1b2ba24 100644
--- a/include/linux/platform_data/lp855x.h
+++ b/include/linux/platform_data/lp855x.h

@@ -136,7 +136,6 @@ struct lp855x_rom_data {
            Only valid when mode is PWM_BASED.
  * @size_program : total size of lp855x_rom_data
  * @rom_data : list of new eeprom/eprom registers
- * @supply : regulator that supplies 3V input
  */
 struct lp855x_platform_data {
    const char *name;

@@ -145,7 +144,6 @@ struct lp855x_platform_data {
    unsigned int period_ns;
    int size_program;
    struct lp855x_rom_data *rom_data;
-   struct regulator *supply;
 };

 #endif

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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