| Message ID | 1465587597-131467-1-git-send-email-briannorris@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Jun 10, 2016 at 12:39 PM, Brian Norris <briannorris@chromium.org> wrote: > > The LP8556 datasheet describes an EN/VDDIO input, which serves "both as > a chip enable and as a power supply reference for PWM, SDA, and SCL > inputs." The LP8556 that I'm testing doesn't respond properly if I try > to talk I2C to it too quickly after enabling VDDIO, and the LP8555 > datasheet mentions a t_RESPONSE delay of up to 1 millisecond. > > Support this EN/VDDIO by adding a regulator property to the binding; > enabling this regulator at probe time; and sleeping for 1 to 2ms, if the > EN/VDDIO regulator was provided. > > Signed-off-by: Brian Norris <briannorris@chromium.org> > --- > v2: s/TS8555/LP8555/ in comment (typo) > > .../devicetree/bindings/leds/backlight/lp855x.txt | 2 ++ > drivers/video/backlight/lp855x_bl.c | 29 ++++++++++++++++++++++ > 2 files changed, 31 insertions(+) > > diff --git a/Documentation/devicetree/bindings/leds/backlight/lp855x.txt b/Documentation/devicetree/bindings/leds/backlight/lp855x.txt > index 0a3ecbc3a1b9..88f56641fc28 100644 > --- a/Documentation/devicetree/bindings/leds/backlight/lp855x.txt > +++ b/Documentation/devicetree/bindings/leds/backlight/lp855x.txt > @@ -13,6 +13,7 @@ Optional properties: > - 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 > + - enable-supply: Regulator which controls the EN/VDDIO input > > Example: > > @@ -57,6 +58,7 @@ Example: > backlight@2c { > compatible = "ti,lp8557"; > reg = <0x2c>; > + enable-supply = <&backlight_vddio>; > power-supply = <&backlight_vdd>; > > dev-ctrl = /bits/ 8 <0x41>; > diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c > index e5b14f52628f..939f057836e1 100644 > --- a/drivers/video/backlight/lp855x_bl.c > +++ b/drivers/video/backlight/lp855x_bl.c > @@ -13,6 +13,7 @@ > #include <linux/slab.h> > #include <linux/i2c.h> > #include <linux/backlight.h> > +#include <linux/delay.h> > #include <linux/err.h> > #include <linux/of.h> > #include <linux/platform_data/lp855x.h> > @@ -74,6 +75,7 @@ struct lp855x { > struct lp855x_platform_data *pdata; > struct pwm_device *pwm; > struct regulator *supply; /* regulator for VDD input */ > + struct regulator *enable; /* regulator for EN/VDDIO input */ > }; > > static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data) > @@ -433,6 +435,19 @@ static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) > lp->supply = NULL; > } > > + lp->enable = devm_regulator_get_optional(lp->dev, "enable"); > + if (IS_ERR(lp->enable)) { > + ret = PTR_ERR(lp->enable); > + if (ret == -ENODEV) { > + lp->enable = NULL; > + } else { > + if (ret != -EPROBE_DEFER) > + dev_err(lp->dev, "error getting enable regulator: %d\n", > + ret); > + return ret; > + } > + } > + > if (lp->supply) { > ret = regulator_enable(lp->supply); > if (ret < 0) { > @@ -441,6 +456,20 @@ static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) > } > } > > + if (lp->enable) { > + ret = regulator_enable(lp->enable); > + if (ret < 0) { > + dev_err(lp->dev, "failed to enable vddio: %d\n", ret); > + return ret; > + } > + > + /* > + * LP8555 datasheet says t_RESPONSE (time between VDDIO and > + * I2C) is 1ms. > + */ > + usleep_range(1000, 2000); > + } > + > i2c_set_clientdata(cl, lp); > > ret = lp855x_configure(lp); > -- > 2.8.0.rc3.226.g39d4020 > Reviewed-by: Stephen Barber <smbarber@chromium.org> Steve -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 6/11/2016 4:39 AM, Brian Norris wrote: > The LP8556 datasheet describes an EN/VDDIO input, which serves "both as > a chip enable and as a power supply reference for PWM, SDA, and SCL > inputs." The LP8556 that I'm testing doesn't respond properly if I try > to talk I2C to it too quickly after enabling VDDIO, and the LP8555 > datasheet mentions a t_RESPONSE delay of up to 1 millisecond. > > Support this EN/VDDIO by adding a regulator property to the binding; > enabling this regulator at probe time; and sleeping for 1 to 2ms, if the > EN/VDDIO regulator was provided. > > Signed-off-by: Brian Norris <briannorris@chromium.org> Acked-by: Milo Kim <milo.kim@ti.com> Thanks! > --- > v2: s/TS8555/LP8555/ in comment (typo) > > .../devicetree/bindings/leds/backlight/lp855x.txt | 2 ++ > drivers/video/backlight/lp855x_bl.c | 29 ++++++++++++++++++++++ > 2 files changed, 31 insertions(+) > > diff --git a/Documentation/devicetree/bindings/leds/backlight/lp855x.txt b/Documentation/devicetree/bindings/leds/backlight/lp855x.txt > index 0a3ecbc3a1b9..88f56641fc28 100644 > --- a/Documentation/devicetree/bindings/leds/backlight/lp855x.txt > +++ b/Documentation/devicetree/bindings/leds/backlight/lp855x.txt > @@ -13,6 +13,7 @@ Optional properties: > - 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 > + - enable-supply: Regulator which controls the EN/VDDIO input > > Example: > > @@ -57,6 +58,7 @@ Example: > backlight@2c { > compatible = "ti,lp8557"; > reg = <0x2c>; > + enable-supply = <&backlight_vddio>; > power-supply = <&backlight_vdd>; > > dev-ctrl = /bits/ 8 <0x41>; > diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c > index e5b14f52628f..939f057836e1 100644 > --- a/drivers/video/backlight/lp855x_bl.c > +++ b/drivers/video/backlight/lp855x_bl.c > @@ -13,6 +13,7 @@ > #include <linux/slab.h> > #include <linux/i2c.h> > #include <linux/backlight.h> > +#include <linux/delay.h> > #include <linux/err.h> > #include <linux/of.h> > #include <linux/platform_data/lp855x.h> > @@ -74,6 +75,7 @@ struct lp855x { > struct lp855x_platform_data *pdata; > struct pwm_device *pwm; > struct regulator *supply; /* regulator for VDD input */ > + struct regulator *enable; /* regulator for EN/VDDIO input */ > }; > > static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data) > @@ -433,6 +435,19 @@ static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) > lp->supply = NULL; > } > > + lp->enable = devm_regulator_get_optional(lp->dev, "enable"); > + if (IS_ERR(lp->enable)) { > + ret = PTR_ERR(lp->enable); > + if (ret == -ENODEV) { > + lp->enable = NULL; > + } else { > + if (ret != -EPROBE_DEFER) > + dev_err(lp->dev, "error getting enable regulator: %d\n", > + ret); > + return ret; > + } > + } > + > if (lp->supply) { > ret = regulator_enable(lp->supply); > if (ret < 0) { > @@ -441,6 +456,20 @@ static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) > } > } > > + if (lp->enable) { > + ret = regulator_enable(lp->enable); > + if (ret < 0) { > + dev_err(lp->dev, "failed to enable vddio: %d\n", ret); > + return ret; > + } > + > + /* > + * LP8555 datasheet says t_RESPONSE (time between VDDIO and > + * I2C) is 1ms. > + */ > + usleep_range(1000, 2000); > + } > + > i2c_set_clientdata(cl, lp); > > ret = lp855x_configure(lp); > -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Jun 10, 2016 at 12:39:57PM -0700, Brian Norris wrote: > The LP8556 datasheet describes an EN/VDDIO input, which serves "both as > a chip enable and as a power supply reference for PWM, SDA, and SCL > inputs." The LP8556 that I'm testing doesn't respond properly if I try > to talk I2C to it too quickly after enabling VDDIO, and the LP8555 > datasheet mentions a t_RESPONSE delay of up to 1 millisecond. > > Support this EN/VDDIO by adding a regulator property to the binding; > enabling this regulator at probe time; and sleeping for 1 to 2ms, if the > EN/VDDIO regulator was provided. > > Signed-off-by: Brian Norris <briannorris@chromium.org> > --- > v2: s/TS8555/LP8555/ in comment (typo) > > .../devicetree/bindings/leds/backlight/lp855x.txt | 2 ++ I would have picked 'vddio' as the name, but it's fine. Acked-by: Rob Herring <robh@kernel.org> > drivers/video/backlight/lp855x_bl.c | 29 ++++++++++++++++++++++ > 2 files changed, 31 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, 10 Jun 2016, Brian Norris wrote: > The LP8556 datasheet describes an EN/VDDIO input, which serves "both as > a chip enable and as a power supply reference for PWM, SDA, and SCL > inputs." The LP8556 that I'm testing doesn't respond properly if I try > to talk I2C to it too quickly after enabling VDDIO, and the LP8555 > datasheet mentions a t_RESPONSE delay of up to 1 millisecond. > > Support this EN/VDDIO by adding a regulator property to the binding; > enabling this regulator at probe time; and sleeping for 1 to 2ms, if the > EN/VDDIO regulator was provided. > > Signed-off-by: Brian Norris <briannorris@chromium.org> > --- > v2: s/TS8555/LP8555/ in comment (typo) > > .../devicetree/bindings/leds/backlight/lp855x.txt | 2 ++ > drivers/video/backlight/lp855x_bl.c | 29 ++++++++++++++++++++++ > 2 files changed, 31 insertions(+) Collected Acks and applied, thanks. > diff --git a/Documentation/devicetree/bindings/leds/backlight/lp855x.txt b/Documentation/devicetree/bindings/leds/backlight/lp855x.txt > index 0a3ecbc3a1b9..88f56641fc28 100644 > --- a/Documentation/devicetree/bindings/leds/backlight/lp855x.txt > +++ b/Documentation/devicetree/bindings/leds/backlight/lp855x.txt > @@ -13,6 +13,7 @@ Optional properties: > - 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 > + - enable-supply: Regulator which controls the EN/VDDIO input > > Example: > > @@ -57,6 +58,7 @@ Example: > backlight@2c { > compatible = "ti,lp8557"; > reg = <0x2c>; > + enable-supply = <&backlight_vddio>; > power-supply = <&backlight_vdd>; > > dev-ctrl = /bits/ 8 <0x41>; > diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c > index e5b14f52628f..939f057836e1 100644 > --- a/drivers/video/backlight/lp855x_bl.c > +++ b/drivers/video/backlight/lp855x_bl.c > @@ -13,6 +13,7 @@ > #include <linux/slab.h> > #include <linux/i2c.h> > #include <linux/backlight.h> > +#include <linux/delay.h> > #include <linux/err.h> > #include <linux/of.h> > #include <linux/platform_data/lp855x.h> > @@ -74,6 +75,7 @@ struct lp855x { > struct lp855x_platform_data *pdata; > struct pwm_device *pwm; > struct regulator *supply; /* regulator for VDD input */ > + struct regulator *enable; /* regulator for EN/VDDIO input */ > }; > > static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data) > @@ -433,6 +435,19 @@ static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) > lp->supply = NULL; > } > > + lp->enable = devm_regulator_get_optional(lp->dev, "enable"); > + if (IS_ERR(lp->enable)) { > + ret = PTR_ERR(lp->enable); > + if (ret == -ENODEV) { > + lp->enable = NULL; > + } else { > + if (ret != -EPROBE_DEFER) > + dev_err(lp->dev, "error getting enable regulator: %d\n", > + ret); > + return ret; > + } > + } > + > if (lp->supply) { > ret = regulator_enable(lp->supply); > if (ret < 0) { > @@ -441,6 +456,20 @@ static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) > } > } > > + if (lp->enable) { > + ret = regulator_enable(lp->enable); > + if (ret < 0) { > + dev_err(lp->dev, "failed to enable vddio: %d\n", ret); > + return ret; > + } > + > + /* > + * LP8555 datasheet says t_RESPONSE (time between VDDIO and > + * I2C) is 1ms. > + */ > + usleep_range(1000, 2000); > + } > + > i2c_set_clientdata(cl, lp); > > ret = lp855x_configure(lp);
diff --git a/Documentation/devicetree/bindings/leds/backlight/lp855x.txt b/Documentation/devicetree/bindings/leds/backlight/lp855x.txt index 0a3ecbc3a1b9..88f56641fc28 100644 --- a/Documentation/devicetree/bindings/leds/backlight/lp855x.txt +++ b/Documentation/devicetree/bindings/leds/backlight/lp855x.txt @@ -13,6 +13,7 @@ Optional properties: - 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 + - enable-supply: Regulator which controls the EN/VDDIO input Example: @@ -57,6 +58,7 @@ Example: backlight@2c { compatible = "ti,lp8557"; reg = <0x2c>; + enable-supply = <&backlight_vddio>; power-supply = <&backlight_vdd>; dev-ctrl = /bits/ 8 <0x41>; diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c index e5b14f52628f..939f057836e1 100644 --- a/drivers/video/backlight/lp855x_bl.c +++ b/drivers/video/backlight/lp855x_bl.c @@ -13,6 +13,7 @@ #include <linux/slab.h> #include <linux/i2c.h> #include <linux/backlight.h> +#include <linux/delay.h> #include <linux/err.h> #include <linux/of.h> #include <linux/platform_data/lp855x.h> @@ -74,6 +75,7 @@ struct lp855x { struct lp855x_platform_data *pdata; struct pwm_device *pwm; struct regulator *supply; /* regulator for VDD input */ + struct regulator *enable; /* regulator for EN/VDDIO input */ }; static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data) @@ -433,6 +435,19 @@ static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) lp->supply = NULL; } + lp->enable = devm_regulator_get_optional(lp->dev, "enable"); + if (IS_ERR(lp->enable)) { + ret = PTR_ERR(lp->enable); + if (ret == -ENODEV) { + lp->enable = NULL; + } else { + if (ret != -EPROBE_DEFER) + dev_err(lp->dev, "error getting enable regulator: %d\n", + ret); + return ret; + } + } + if (lp->supply) { ret = regulator_enable(lp->supply); if (ret < 0) { @@ -441,6 +456,20 @@ static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) } } + if (lp->enable) { + ret = regulator_enable(lp->enable); + if (ret < 0) { + dev_err(lp->dev, "failed to enable vddio: %d\n", ret); + return ret; + } + + /* + * LP8555 datasheet says t_RESPONSE (time between VDDIO and + * I2C) is 1ms. + */ + usleep_range(1000, 2000); + } + i2c_set_clientdata(cl, lp); ret = lp855x_configure(lp);
The LP8556 datasheet describes an EN/VDDIO input, which serves "both as a chip enable and as a power supply reference for PWM, SDA, and SCL inputs." The LP8556 that I'm testing doesn't respond properly if I try to talk I2C to it too quickly after enabling VDDIO, and the LP8555 datasheet mentions a t_RESPONSE delay of up to 1 millisecond. Support this EN/VDDIO by adding a regulator property to the binding; enabling this regulator at probe time; and sleeping for 1 to 2ms, if the EN/VDDIO regulator was provided. Signed-off-by: Brian Norris <briannorris@chromium.org> --- v2: s/TS8555/LP8555/ in comment (typo) .../devicetree/bindings/leds/backlight/lp855x.txt | 2 ++ drivers/video/backlight/lp855x_bl.c | 29 ++++++++++++++++++++++ 2 files changed, 31 insertions(+)