| Message ID | 1448025892-20899-5-git-send-email-hdegoede@redhat.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On Fri, Nov 20, 2015 at 02:24:49PM +0100, Hans de Goede wrote: > From: Sander Vermin <sander@vermin.nl> > > On some devices the wake and enable pins of the pixcir touchscreen > controller are connected to gpios and these must be controlled by the > driver for the device to operate properly. > > Signed-off-by: Sander Vermin <sander@vermin.nl> > Signed-off-by: Hans de Goede <hdegoede@redhat.com> > --- > Changes in v2 (Hans de Goede): > -Split the changes for dealing with inverted / swapped axis out into a > separate patch > -Remove a bunch of dev_info calls to make the driver less chatty > -Use devm_gpiod_get_optional as these new gpios are optional > -Only msleep after setting enable high if we have an enable pin > --- > .../bindings/input/touchscreen/pixcir_i2c_ts.txt | 2 + > drivers/input/touchscreen/pixcir_i2c_ts.c | 46 ++++++++++++++++++++++ > 2 files changed, 48 insertions(+) > > diff --git a/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt b/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt > index 8eb240a..72ca5ec 100644 > --- a/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt > +++ b/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt > @@ -10,6 +10,8 @@ Required properties: > > Optional properties: > - reset-gpio: GPIO connected to the RESET line of the chip > +- enable-gpios: GPIO connected to the ENABLE line of the chip > +- wake-gpios: GPIO connected to the WAKE line of the chip > > Example: > > diff --git a/drivers/input/touchscreen/pixcir_i2c_ts.c b/drivers/input/touchscreen/pixcir_i2c_ts.c > index 211408c..b75ef65 100644 > --- a/drivers/input/touchscreen/pixcir_i2c_ts.c > +++ b/drivers/input/touchscreen/pixcir_i2c_ts.c > @@ -38,6 +38,8 @@ struct pixcir_i2c_ts_data { > struct input_dev *input; > struct gpio_desc *gpio_attb; > struct gpio_desc *gpio_reset; > + struct gpio_desc *gpio_enable; > + struct gpio_desc *gpio_wake; > const struct pixcir_i2c_chip_data *chip; > int max_fingers; /* Max fingers supported in this instance */ > bool running; > @@ -208,6 +210,11 @@ static int pixcir_set_power_mode(struct pixcir_i2c_ts_data *ts, > struct device *dev = &ts->client->dev; > int ret; > > + if (mode == PIXCIR_POWER_ACTIVE || mode == PIXCIR_POWER_IDLE) { > + if (!IS_ERR_OR_NULL(ts->gpio_wake)) > + gpiod_set_value_cansleep(ts->gpio_wake, 1); > + } > + > ret = i2c_smbus_read_byte_data(ts->client, PIXCIR_REG_POWER_MODE); > if (ret < 0) { > dev_err(dev, "%s: can't read reg 0x%x : %d\n", > @@ -228,6 +235,11 @@ static int pixcir_set_power_mode(struct pixcir_i2c_ts_data *ts, > return ret; > } > > + if (mode == PIXCIR_POWER_HALT) { > + if (!IS_ERR_OR_NULL(ts->gpio_wake)) > + gpiod_set_value_cansleep(ts->gpio_wake, 0); > + } > + > return 0; > } > > @@ -302,6 +314,11 @@ static int pixcir_start(struct pixcir_i2c_ts_data *ts) > struct device *dev = &ts->client->dev; > int error; > > + if (!IS_ERR_OR_NULL(ts->gpio_enable)) { > + gpiod_set_value_cansleep(ts->gpio_enable, 1); > + msleep(100); > + } > + > /* LEVEL_TOUCH interrupt with active low polarity */ > error = pixcir_set_int_mode(ts, PIXCIR_INT_LEVEL_TOUCH, 0); > if (error) { > @@ -343,6 +360,9 @@ static int pixcir_stop(struct pixcir_i2c_ts_data *ts) > /* Wait till running ISR is complete */ > synchronize_irq(ts->client->irq); > > + if (!IS_ERR_OR_NULL(ts->gpio_enable)) > + gpiod_set_value_cansleep(ts->gpio_enable, 0); > + > return 0; > } > > @@ -534,6 +554,24 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client, > return error; > } > > + tsdata->gpio_wake = devm_gpiod_get_optional(dev, "wake", > + GPIOD_OUT_HIGH); > + if (IS_ERR(tsdata->gpio_wake)) { > + error = PTR_ERR(tsdata->gpio_wake); > + if (error != -EPROBE_DEFER) > + dev_err(dev, "Failed to get wake gpio: %d\n", error); > + return error; > + } > + > + tsdata->gpio_enable = devm_gpiod_get_optional(dev, "enable", > + GPIOD_OUT_HIGH); > + if (IS_ERR(tsdata->gpio_enable)) { > + error = PTR_ERR(tsdata->gpio_enable); > + if (error != -EPROBE_DEFER) > + dev_err(dev, "Failed to get enable gpio: %d\n", error); > + return error; > + } > + > error = devm_request_threaded_irq(dev, client->irq, NULL, pixcir_ts_isr, > IRQF_TRIGGER_FALLING | IRQF_ONESHOT, > client->name, tsdata); > @@ -542,6 +580,14 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client, > return error; > } > > + if (!IS_ERR_OR_NULL(tsdata->gpio_wake)) > + gpiod_set_value_cansleep(tsdata->gpio_wake, 1); > + > + if (!IS_ERR_OR_NULL(tsdata->gpio_enable)) { > + gpiod_set_value_cansleep(tsdata->gpio_enable, 1); > + msleep(100); > + } Actually, another question: why do we need this calls to activate wake and enable gpios here if we request them as active? Thanks. > + > pixcir_reset(tsdata); > > /* Always be in IDLE mode to save power, device supports auto wake */ > -- > 2.5.0 >
Hi, On 20-11-15 19:54, Dmitry Torokhov wrote: > On Fri, Nov 20, 2015 at 02:24:49PM +0100, Hans de Goede wrote: >> From: Sander Vermin <sander@vermin.nl> >> >> On some devices the wake and enable pins of the pixcir touchscreen >> controller are connected to gpios and these must be controlled by the >> driver for the device to operate properly. >> >> Signed-off-by: Sander Vermin <sander@vermin.nl> >> Signed-off-by: Hans de Goede <hdegoede@redhat.com> >> --- >> Changes in v2 (Hans de Goede): >> -Split the changes for dealing with inverted / swapped axis out into a >> separate patch >> -Remove a bunch of dev_info calls to make the driver less chatty >> -Use devm_gpiod_get_optional as these new gpios are optional >> -Only msleep after setting enable high if we have an enable pin >> --- >> .../bindings/input/touchscreen/pixcir_i2c_ts.txt | 2 + >> drivers/input/touchscreen/pixcir_i2c_ts.c | 46 ++++++++++++++++++++++ >> 2 files changed, 48 insertions(+) >> >> diff --git a/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt b/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt >> index 8eb240a..72ca5ec 100644 >> --- a/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt >> +++ b/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt >> @@ -10,6 +10,8 @@ Required properties: >> >> Optional properties: >> - reset-gpio: GPIO connected to the RESET line of the chip >> +- enable-gpios: GPIO connected to the ENABLE line of the chip >> +- wake-gpios: GPIO connected to the WAKE line of the chip >> >> Example: >> >> diff --git a/drivers/input/touchscreen/pixcir_i2c_ts.c b/drivers/input/touchscreen/pixcir_i2c_ts.c >> index 211408c..b75ef65 100644 >> --- a/drivers/input/touchscreen/pixcir_i2c_ts.c >> +++ b/drivers/input/touchscreen/pixcir_i2c_ts.c >> @@ -38,6 +38,8 @@ struct pixcir_i2c_ts_data { >> struct input_dev *input; >> struct gpio_desc *gpio_attb; >> struct gpio_desc *gpio_reset; >> + struct gpio_desc *gpio_enable; >> + struct gpio_desc *gpio_wake; >> const struct pixcir_i2c_chip_data *chip; >> int max_fingers; /* Max fingers supported in this instance */ >> bool running; >> @@ -208,6 +210,11 @@ static int pixcir_set_power_mode(struct pixcir_i2c_ts_data *ts, >> struct device *dev = &ts->client->dev; >> int ret; >> >> + if (mode == PIXCIR_POWER_ACTIVE || mode == PIXCIR_POWER_IDLE) { >> + if (!IS_ERR_OR_NULL(ts->gpio_wake)) >> + gpiod_set_value_cansleep(ts->gpio_wake, 1); >> + } >> + >> ret = i2c_smbus_read_byte_data(ts->client, PIXCIR_REG_POWER_MODE); >> if (ret < 0) { >> dev_err(dev, "%s: can't read reg 0x%x : %d\n", >> @@ -228,6 +235,11 @@ static int pixcir_set_power_mode(struct pixcir_i2c_ts_data *ts, >> return ret; >> } >> >> + if (mode == PIXCIR_POWER_HALT) { >> + if (!IS_ERR_OR_NULL(ts->gpio_wake)) >> + gpiod_set_value_cansleep(ts->gpio_wake, 0); >> + } >> + >> return 0; >> } >> >> @@ -302,6 +314,11 @@ static int pixcir_start(struct pixcir_i2c_ts_data *ts) >> struct device *dev = &ts->client->dev; >> int error; >> >> + if (!IS_ERR_OR_NULL(ts->gpio_enable)) { >> + gpiod_set_value_cansleep(ts->gpio_enable, 1); >> + msleep(100); >> + } >> + >> /* LEVEL_TOUCH interrupt with active low polarity */ >> error = pixcir_set_int_mode(ts, PIXCIR_INT_LEVEL_TOUCH, 0); >> if (error) { >> @@ -343,6 +360,9 @@ static int pixcir_stop(struct pixcir_i2c_ts_data *ts) >> /* Wait till running ISR is complete */ >> synchronize_irq(ts->client->irq); >> >> + if (!IS_ERR_OR_NULL(ts->gpio_enable)) >> + gpiod_set_value_cansleep(ts->gpio_enable, 0); >> + >> return 0; >> } >> >> @@ -534,6 +554,24 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client, >> return error; >> } >> >> + tsdata->gpio_wake = devm_gpiod_get_optional(dev, "wake", >> + GPIOD_OUT_HIGH); >> + if (IS_ERR(tsdata->gpio_wake)) { >> + error = PTR_ERR(tsdata->gpio_wake); >> + if (error != -EPROBE_DEFER) >> + dev_err(dev, "Failed to get wake gpio: %d\n", error); >> + return error; >> + } >> + >> + tsdata->gpio_enable = devm_gpiod_get_optional(dev, "enable", >> + GPIOD_OUT_HIGH); >> + if (IS_ERR(tsdata->gpio_enable)) { >> + error = PTR_ERR(tsdata->gpio_enable); >> + if (error != -EPROBE_DEFER) >> + dev_err(dev, "Failed to get enable gpio: %d\n", error); >> + return error; >> + } >> + >> error = devm_request_threaded_irq(dev, client->irq, NULL, pixcir_ts_isr, >> IRQF_TRIGGER_FALLING | IRQF_ONESHOT, >> client->name, tsdata); >> @@ -542,6 +580,14 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client, >> return error; >> } >> >> + if (!IS_ERR_OR_NULL(tsdata->gpio_wake)) >> + gpiod_set_value_cansleep(tsdata->gpio_wake, 1); >> + >> + if (!IS_ERR_OR_NULL(tsdata->gpio_enable)) { >> + gpiod_set_value_cansleep(tsdata->gpio_enable, 1); >> + msleep(100); >> + } > > Actually, another question: why do we need this calls to activate wake > and enable gpios here if we request them as active? Hmm, interesting point. I will re-test with just the msleep there. For v2 what do you want to do with the if tests, keep as "if (!IS_ERR_OR_NULL(...))" or change them to just "if (...)" ? Regards, Hans > > Thanks. > >> + >> pixcir_reset(tsdata); >> >> /* Always be in IDLE mode to save power, device supports auto wake */ >> -- >> 2.5.0 >> > -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Nov 20, 2015 at 08:19:52PM +0100, Hans de Goede wrote: > Hi, > > On 20-11-15 19:54, Dmitry Torokhov wrote: > >On Fri, Nov 20, 2015 at 02:24:49PM +0100, Hans de Goede wrote: > >>From: Sander Vermin <sander@vermin.nl> > >> > >>On some devices the wake and enable pins of the pixcir touchscreen > >>controller are connected to gpios and these must be controlled by the > >>driver for the device to operate properly. > >> > >>Signed-off-by: Sander Vermin <sander@vermin.nl> > >>Signed-off-by: Hans de Goede <hdegoede@redhat.com> > >>--- > >>Changes in v2 (Hans de Goede): > >>-Split the changes for dealing with inverted / swapped axis out into a > >> separate patch > >>-Remove a bunch of dev_info calls to make the driver less chatty > >>-Use devm_gpiod_get_optional as these new gpios are optional > >>-Only msleep after setting enable high if we have an enable pin > >>--- > >> .../bindings/input/touchscreen/pixcir_i2c_ts.txt | 2 + > >> drivers/input/touchscreen/pixcir_i2c_ts.c | 46 ++++++++++++++++++++++ > >> 2 files changed, 48 insertions(+) > >> > >>diff --git a/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt b/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt > >>index 8eb240a..72ca5ec 100644 > >>--- a/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt > >>+++ b/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt > >>@@ -10,6 +10,8 @@ Required properties: > >> > >> Optional properties: > >> - reset-gpio: GPIO connected to the RESET line of the chip > >>+- enable-gpios: GPIO connected to the ENABLE line of the chip > >>+- wake-gpios: GPIO connected to the WAKE line of the chip > >> > >> Example: > >> > >>diff --git a/drivers/input/touchscreen/pixcir_i2c_ts.c b/drivers/input/touchscreen/pixcir_i2c_ts.c > >>index 211408c..b75ef65 100644 > >>--- a/drivers/input/touchscreen/pixcir_i2c_ts.c > >>+++ b/drivers/input/touchscreen/pixcir_i2c_ts.c > >>@@ -38,6 +38,8 @@ struct pixcir_i2c_ts_data { > >> struct input_dev *input; > >> struct gpio_desc *gpio_attb; > >> struct gpio_desc *gpio_reset; > >>+ struct gpio_desc *gpio_enable; > >>+ struct gpio_desc *gpio_wake; > >> const struct pixcir_i2c_chip_data *chip; > >> int max_fingers; /* Max fingers supported in this instance */ > >> bool running; > >>@@ -208,6 +210,11 @@ static int pixcir_set_power_mode(struct pixcir_i2c_ts_data *ts, > >> struct device *dev = &ts->client->dev; > >> int ret; > >> > >>+ if (mode == PIXCIR_POWER_ACTIVE || mode == PIXCIR_POWER_IDLE) { > >>+ if (!IS_ERR_OR_NULL(ts->gpio_wake)) > >>+ gpiod_set_value_cansleep(ts->gpio_wake, 1); > >>+ } > >>+ > >> ret = i2c_smbus_read_byte_data(ts->client, PIXCIR_REG_POWER_MODE); > >> if (ret < 0) { > >> dev_err(dev, "%s: can't read reg 0x%x : %d\n", > >>@@ -228,6 +235,11 @@ static int pixcir_set_power_mode(struct pixcir_i2c_ts_data *ts, > >> return ret; > >> } > >> > >>+ if (mode == PIXCIR_POWER_HALT) { > >>+ if (!IS_ERR_OR_NULL(ts->gpio_wake)) > >>+ gpiod_set_value_cansleep(ts->gpio_wake, 0); > >>+ } > >>+ > >> return 0; > >> } > >> > >>@@ -302,6 +314,11 @@ static int pixcir_start(struct pixcir_i2c_ts_data *ts) > >> struct device *dev = &ts->client->dev; > >> int error; > >> > >>+ if (!IS_ERR_OR_NULL(ts->gpio_enable)) { > >>+ gpiod_set_value_cansleep(ts->gpio_enable, 1); > >>+ msleep(100); > >>+ } > >>+ > >> /* LEVEL_TOUCH interrupt with active low polarity */ > >> error = pixcir_set_int_mode(ts, PIXCIR_INT_LEVEL_TOUCH, 0); > >> if (error) { > >>@@ -343,6 +360,9 @@ static int pixcir_stop(struct pixcir_i2c_ts_data *ts) > >> /* Wait till running ISR is complete */ > >> synchronize_irq(ts->client->irq); > >> > >>+ if (!IS_ERR_OR_NULL(ts->gpio_enable)) > >>+ gpiod_set_value_cansleep(ts->gpio_enable, 0); > >>+ > >> return 0; > >> } > >> > >>@@ -534,6 +554,24 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client, > >> return error; > >> } > >> > >>+ tsdata->gpio_wake = devm_gpiod_get_optional(dev, "wake", > >>+ GPIOD_OUT_HIGH); > >>+ if (IS_ERR(tsdata->gpio_wake)) { > >>+ error = PTR_ERR(tsdata->gpio_wake); > >>+ if (error != -EPROBE_DEFER) > >>+ dev_err(dev, "Failed to get wake gpio: %d\n", error); > >>+ return error; > >>+ } > >>+ > >>+ tsdata->gpio_enable = devm_gpiod_get_optional(dev, "enable", > >>+ GPIOD_OUT_HIGH); > >>+ if (IS_ERR(tsdata->gpio_enable)) { > >>+ error = PTR_ERR(tsdata->gpio_enable); > >>+ if (error != -EPROBE_DEFER) > >>+ dev_err(dev, "Failed to get enable gpio: %d\n", error); > >>+ return error; > >>+ } > >>+ > >> error = devm_request_threaded_irq(dev, client->irq, NULL, pixcir_ts_isr, > >> IRQF_TRIGGER_FALLING | IRQF_ONESHOT, > >> client->name, tsdata); > >>@@ -542,6 +580,14 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client, > >> return error; > >> } > >> > >>+ if (!IS_ERR_OR_NULL(tsdata->gpio_wake)) > >>+ gpiod_set_value_cansleep(tsdata->gpio_wake, 1); > >>+ > >>+ if (!IS_ERR_OR_NULL(tsdata->gpio_enable)) { > >>+ gpiod_set_value_cansleep(tsdata->gpio_enable, 1); > >>+ msleep(100); > >>+ } > > > >Actually, another question: why do we need this calls to activate wake > >and enable gpios here if we request them as active? > > Hmm, interesting point. I will re-test with just the msleep there. For v2 > what do you want to do with the if tests, keep as "if (!IS_ERR_OR_NULL(...))" > or change them to just "if (...)" ? Would prefer plain "if (gpio)" where makes sense. Thanks!
diff --git a/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt b/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt index 8eb240a..72ca5ec 100644 --- a/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt +++ b/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt @@ -10,6 +10,8 @@ Required properties: Optional properties: - reset-gpio: GPIO connected to the RESET line of the chip +- enable-gpios: GPIO connected to the ENABLE line of the chip +- wake-gpios: GPIO connected to the WAKE line of the chip Example: diff --git a/drivers/input/touchscreen/pixcir_i2c_ts.c b/drivers/input/touchscreen/pixcir_i2c_ts.c index 211408c..b75ef65 100644 --- a/drivers/input/touchscreen/pixcir_i2c_ts.c +++ b/drivers/input/touchscreen/pixcir_i2c_ts.c @@ -38,6 +38,8 @@ struct pixcir_i2c_ts_data { struct input_dev *input; struct gpio_desc *gpio_attb; struct gpio_desc *gpio_reset; + struct gpio_desc *gpio_enable; + struct gpio_desc *gpio_wake; const struct pixcir_i2c_chip_data *chip; int max_fingers; /* Max fingers supported in this instance */ bool running; @@ -208,6 +210,11 @@ static int pixcir_set_power_mode(struct pixcir_i2c_ts_data *ts, struct device *dev = &ts->client->dev; int ret; + if (mode == PIXCIR_POWER_ACTIVE || mode == PIXCIR_POWER_IDLE) { + if (!IS_ERR_OR_NULL(ts->gpio_wake)) + gpiod_set_value_cansleep(ts->gpio_wake, 1); + } + ret = i2c_smbus_read_byte_data(ts->client, PIXCIR_REG_POWER_MODE); if (ret < 0) { dev_err(dev, "%s: can't read reg 0x%x : %d\n", @@ -228,6 +235,11 @@ static int pixcir_set_power_mode(struct pixcir_i2c_ts_data *ts, return ret; } + if (mode == PIXCIR_POWER_HALT) { + if (!IS_ERR_OR_NULL(ts->gpio_wake)) + gpiod_set_value_cansleep(ts->gpio_wake, 0); + } + return 0; } @@ -302,6 +314,11 @@ static int pixcir_start(struct pixcir_i2c_ts_data *ts) struct device *dev = &ts->client->dev; int error; + if (!IS_ERR_OR_NULL(ts->gpio_enable)) { + gpiod_set_value_cansleep(ts->gpio_enable, 1); + msleep(100); + } + /* LEVEL_TOUCH interrupt with active low polarity */ error = pixcir_set_int_mode(ts, PIXCIR_INT_LEVEL_TOUCH, 0); if (error) { @@ -343,6 +360,9 @@ static int pixcir_stop(struct pixcir_i2c_ts_data *ts) /* Wait till running ISR is complete */ synchronize_irq(ts->client->irq); + if (!IS_ERR_OR_NULL(ts->gpio_enable)) + gpiod_set_value_cansleep(ts->gpio_enable, 0); + return 0; } @@ -534,6 +554,24 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client, return error; } + tsdata->gpio_wake = devm_gpiod_get_optional(dev, "wake", + GPIOD_OUT_HIGH); + if (IS_ERR(tsdata->gpio_wake)) { + error = PTR_ERR(tsdata->gpio_wake); + if (error != -EPROBE_DEFER) + dev_err(dev, "Failed to get wake gpio: %d\n", error); + return error; + } + + tsdata->gpio_enable = devm_gpiod_get_optional(dev, "enable", + GPIOD_OUT_HIGH); + if (IS_ERR(tsdata->gpio_enable)) { + error = PTR_ERR(tsdata->gpio_enable); + if (error != -EPROBE_DEFER) + dev_err(dev, "Failed to get enable gpio: %d\n", error); + return error; + } + error = devm_request_threaded_irq(dev, client->irq, NULL, pixcir_ts_isr, IRQF_TRIGGER_FALLING | IRQF_ONESHOT, client->name, tsdata); @@ -542,6 +580,14 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client, return error; } + if (!IS_ERR_OR_NULL(tsdata->gpio_wake)) + gpiod_set_value_cansleep(tsdata->gpio_wake, 1); + + if (!IS_ERR_OR_NULL(tsdata->gpio_enable)) { + gpiod_set_value_cansleep(tsdata->gpio_enable, 1); + msleep(100); + } + pixcir_reset(tsdata); /* Always be in IDLE mode to save power, device supports auto wake */