* [PATCH 2/2] LEDS: tca6502: add device-tree support for GPIO configuration.
@ 2013-11-01 2:41 NeilBrown
2013-11-07 23:39 ` Bryan Wu
2013-11-18 11:55 ` Mark Rutland
0 siblings, 2 replies; 6+ messages in thread
From: NeilBrown @ 2013-11-01 2:41 UTC (permalink / raw)
To: Bryan Wu, Richard Purdie, Rob Herring, Pawel Moll, Mark Rutland,
Stephen Warren, Ian Campbell, Grant Likely
Cc: linux-leds, linux-kernel, Belisko Marek, Dr. H. Nikolaus Schaller,
devicetree
[-- Attachment #1: Type: text/plain, Size: 2842 bytes --]
The 7 lines driven by the TCA6507 can either drive LEDs or act as output-only
GPIOs.
To make this distinction in devicetree we use the "compatible" property.
If the device attached to a line is "compatible" with "gpio", we treat it
like a GPIO. If it is "compatible" with "led" (or if no "compatible" value
is set) we treat it like an LED.
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/Documentation/devicetree/bindings/leds/tca6507.txt b/Documentation/devicetree/bindings/leds/tca6507.txt
index 80ff3dfb1f32..d7221b84987c 100644
--- a/Documentation/devicetree/bindings/leds/tca6507.txt
+++ b/Documentation/devicetree/bindings/leds/tca6507.txt
@@ -2,6 +2,13 @@ LEDs connected to tca6507
Required properties:
- compatible : should be : "ti,tca6507".
+- #address-cells: must be 1
+- #size-cells: must be 0
+- reg: typically 0x45.
+
+Optional properties:
+- gpio-controller: allows lines to be used as output-only GPIOs.
+- #gpio-cells: if present, must be 0.
Each led is represented as a sub-node of the ti,tca6507 device.
@@ -10,6 +17,7 @@ LED sub-node properties:
- reg : number of LED line (could be from 0 to 6)
- linux,default-trigger : (optional)
see Documentation/devicetree/bindings/leds/common.txt
+- compatible: either "led" (the default) or "gpio".
Examples:
@@ -19,6 +27,9 @@ tca6507@45 {
#size-cells = <0>;
reg = <0x45>;
+ gpio-controller;
+ #gpio-cells = <2>;
+
led0: red-aux@0 {
label = "red:aux";
reg = <0x0>;
@@ -29,5 +40,10 @@ tca6507@45 {
reg = <0x5>;
linux,default-trigger = "default-on";
};
+
+ wifi-reset@6 {
+ reg = <0x6>;
+ compatible = "gpio";
+ };
};
diff --git a/drivers/leds/leds-tca6507.c b/drivers/leds/leds-tca6507.c
index f5063f447463..93a2b1759054 100644
--- a/drivers/leds/leds-tca6507.c
+++ b/drivers/leds/leds-tca6507.c
@@ -638,6 +638,9 @@ static int tca6507_probe_gpios(struct i2c_client *client,
tca->gpio.direction_output = tca6507_gpio_direction_output;
tca->gpio.set = tca6507_gpio_set_value;
tca->gpio.dev = &client->dev;
+#ifdef CONFIG_OF_GPIO
+ tca->gpio.of_node = of_node_get(client->dev.of_node);
+#endif
err = gpiochip_add(&tca->gpio);
if (err) {
tca->gpio.ngpio = 0;
@@ -696,6 +699,8 @@ tca6507_led_dt_init(struct i2c_client *client)
led.default_trigger =
of_get_property(child, "linux,default-trigger", NULL);
led.flags = 0;
+ if (of_property_match_string(child, "compatible", "gpio") >= 0)
+ led.flags |= TCA6507_MAKE_GPIO;
ret = of_property_read_u32(child, "reg", ®);
if (ret != 0 || reg < 0 || reg >= NUM_LEDS)
continue;
@@ -709,6 +714,7 @@ tca6507_led_dt_init(struct i2c_client *client)
pdata->leds.leds = tca_leds;
pdata->leds.num_leds = NUM_LEDS;
+ pdata->gpio_base = -1;
return pdata;
}
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 828 bytes --]
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH 2/2] LEDS: tca6502: add device-tree support for GPIO configuration.
2013-11-01 2:41 [PATCH 2/2] LEDS: tca6502: add device-tree support for GPIO configuration NeilBrown
@ 2013-11-07 23:39 ` Bryan Wu
2013-11-07 23:46 ` NeilBrown
2013-11-07 23:46 ` Bryan Wu
2013-11-18 11:55 ` Mark Rutland
1 sibling, 2 replies; 6+ messages in thread
From: Bryan Wu @ 2013-11-07 23:39 UTC (permalink / raw)
To: NeilBrown
Cc: Richard Purdie, Rob Herring, Pawel Moll, Mark Rutland,
Stephen Warren, Ian Campbell, Grant Likely, Linux LED Subsystem,
lkml, Belisko Marek, Dr. H. Nikolaus Schaller,
devicetree@vger.kernel.org
On Thu, Oct 31, 2013 at 7:41 PM, NeilBrown <neilb@suse.de> wrote:
>
[PATCH 2/2] LEDS: tca6502: add device-tree support for GPIO configuration.
I think it should be tca6507, right? Typo?
For other parts of this patch, I'm OK for them.
And just a quick scan of the leds-tca6507, I found bunch of typos in
the comments:
* An led-tca6507 device must be provided with platform data. This data
* lists for each output: the name, default trigger, and whether the signal
* is being used as a GPiO rather than an led. 'struct led_plaform_data'
Can we unify to use GPIO and gpio?
* is used for this. If 'name' is NULL, the output isn't used. If 'flags'
* is TCA6507_MAKE_CPIO, the output is a GPO.
Here should be TCA6507_MAKE_GPIO and GPIO instead of GPO
* The "struct led_platform_data" can be embedded in a
* "struct tca6507_platform_data" which adds a 'gpio_base' for the GPiOs,
* and a 'setup' callback which is called once the GPiOs are available.
Don't use GPiO, please.
Could you please review the code again and submit a cleanup patch to
fix those typos?
Thanks,
-Bryan
> The 7 lines driven by the TCA6507 can either drive LEDs or act as output-only
> GPIOs.
>
> To make this distinction in devicetree we use the "compatible" property.
>
> If the device attached to a line is "compatible" with "gpio", we treat it
> like a GPIO. If it is "compatible" with "led" (or if no "compatible" value
> is set) we treat it like an LED.
>
> Signed-off-by: NeilBrown <neilb@suse.de>
>
> diff --git a/Documentation/devicetree/bindings/leds/tca6507.txt b/Documentation/devicetree/bindings/leds/tca6507.txt
> index 80ff3dfb1f32..d7221b84987c 100644
> --- a/Documentation/devicetree/bindings/leds/tca6507.txt
> +++ b/Documentation/devicetree/bindings/leds/tca6507.txt
> @@ -2,6 +2,13 @@ LEDs connected to tca6507
>
> Required properties:
> - compatible : should be : "ti,tca6507".
> +- #address-cells: must be 1
> +- #size-cells: must be 0
> +- reg: typically 0x45.
> +
> +Optional properties:
> +- gpio-controller: allows lines to be used as output-only GPIOs.
> +- #gpio-cells: if present, must be 0.
>
> Each led is represented as a sub-node of the ti,tca6507 device.
>
> @@ -10,6 +17,7 @@ LED sub-node properties:
> - reg : number of LED line (could be from 0 to 6)
> - linux,default-trigger : (optional)
> see Documentation/devicetree/bindings/leds/common.txt
> +- compatible: either "led" (the default) or "gpio".
>
> Examples:
>
> @@ -19,6 +27,9 @@ tca6507@45 {
> #size-cells = <0>;
> reg = <0x45>;
>
> + gpio-controller;
> + #gpio-cells = <2>;
> +
> led0: red-aux@0 {
> label = "red:aux";
> reg = <0x0>;
> @@ -29,5 +40,10 @@ tca6507@45 {
> reg = <0x5>;
> linux,default-trigger = "default-on";
> };
> +
> + wifi-reset@6 {
> + reg = <0x6>;
> + compatible = "gpio";
> + };
> };
>
> diff --git a/drivers/leds/leds-tca6507.c b/drivers/leds/leds-tca6507.c
> index f5063f447463..93a2b1759054 100644
> --- a/drivers/leds/leds-tca6507.c
> +++ b/drivers/leds/leds-tca6507.c
> @@ -638,6 +638,9 @@ static int tca6507_probe_gpios(struct i2c_client *client,
> tca->gpio.direction_output = tca6507_gpio_direction_output;
> tca->gpio.set = tca6507_gpio_set_value;
> tca->gpio.dev = &client->dev;
> +#ifdef CONFIG_OF_GPIO
> + tca->gpio.of_node = of_node_get(client->dev.of_node);
> +#endif
> err = gpiochip_add(&tca->gpio);
> if (err) {
> tca->gpio.ngpio = 0;
> @@ -696,6 +699,8 @@ tca6507_led_dt_init(struct i2c_client *client)
> led.default_trigger =
> of_get_property(child, "linux,default-trigger", NULL);
> led.flags = 0;
> + if (of_property_match_string(child, "compatible", "gpio") >= 0)
> + led.flags |= TCA6507_MAKE_GPIO;
> ret = of_property_read_u32(child, "reg", ®);
> if (ret != 0 || reg < 0 || reg >= NUM_LEDS)
> continue;
> @@ -709,6 +714,7 @@ tca6507_led_dt_init(struct i2c_client *client)
>
> pdata->leds.leds = tca_leds;
> pdata->leds.num_leds = NUM_LEDS;
> + pdata->gpio_base = -1;
>
> return pdata;
> }
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 2/2] LEDS: tca6502: add device-tree support for GPIO configuration.
2013-11-07 23:39 ` Bryan Wu
@ 2013-11-07 23:46 ` NeilBrown
2013-11-07 23:46 ` Bryan Wu
1 sibling, 0 replies; 6+ messages in thread
From: NeilBrown @ 2013-11-07 23:46 UTC (permalink / raw)
To: Bryan Wu
Cc: Richard Purdie, Rob Herring, Pawel Moll, Mark Rutland,
Stephen Warren, Ian Campbell, Grant Likely, Linux LED Subsystem,
lkml, Belisko Marek, Dr. H. Nikolaus Schaller,
devicetree@vger.kernel.org
[-- Attachment #1: Type: text/plain, Size: 1369 bytes --]
On Thu, 7 Nov 2013 15:39:00 -0800 Bryan Wu <cooloney@gmail.com> wrote:
> On Thu, Oct 31, 2013 at 7:41 PM, NeilBrown <neilb@suse.de> wrote:
> >
>
> [PATCH 2/2] LEDS: tca6502: add device-tree support for GPIO configuration.
>
> I think it should be tca6507, right? Typo?
Obviously I'm still dreaming of the Apple IIe. Yes, a typo.
>
> For other parts of this patch, I'm OK for them.
>
> And just a quick scan of the leds-tca6507, I found bunch of typos in
> the comments:
>
> * An led-tca6507 device must be provided with platform data. This data
> * lists for each output: the name, default trigger, and whether the signal
> * is being used as a GPiO rather than an led. 'struct led_plaform_data'
>
> Can we unify to use GPIO and gpio?
>
> * is used for this. If 'name' is NULL, the output isn't used. If 'flags'
> * is TCA6507_MAKE_CPIO, the output is a GPO.
>
> Here should be TCA6507_MAKE_GPIO and GPIO instead of GPO
>
> * The "struct led_platform_data" can be embedded in a
> * "struct tca6507_platform_data" which adds a 'gpio_base' for the GPiOs,
> * and a 'setup' callback which is called once the GPiOs are available.
>
> Don't use GPiO, please.
>
> Could you please review the code again and submit a cleanup patch to
> fix those typos?
Yes, I'll send a patch shortly.
Thanks,
NeilBrown
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 828 bytes --]
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 2/2] LEDS: tca6502: add device-tree support for GPIO configuration.
2013-11-07 23:39 ` Bryan Wu
2013-11-07 23:46 ` NeilBrown
@ 2013-11-07 23:46 ` Bryan Wu
1 sibling, 0 replies; 6+ messages in thread
From: Bryan Wu @ 2013-11-07 23:46 UTC (permalink / raw)
To: NeilBrown
Cc: Richard Purdie, Rob Herring, Pawel Moll, Mark Rutland,
Stephen Warren, Ian Campbell, Grant Likely, Linux LED Subsystem,
lkml, Belisko Marek, Dr. H. Nikolaus Schaller,
devicetree@vger.kernel.org
On Thu, Nov 7, 2013 at 3:39 PM, Bryan Wu <cooloney@gmail.com> wrote:
> On Thu, Oct 31, 2013 at 7:41 PM, NeilBrown <neilb@suse.de> wrote:
>>
>
> [PATCH 2/2] LEDS: tca6502: add device-tree support for GPIO configuration.
>
> I think it should be tca6507, right? Typo?
>
I fixed this typo and queue up this patch in my devel branch.
-Bryan
> For other parts of this patch, I'm OK for them.
>
> And just a quick scan of the leds-tca6507, I found bunch of typos in
> the comments:
>
> * An led-tca6507 device must be provided with platform data. This data
> * lists for each output: the name, default trigger, and whether the signal
> * is being used as a GPiO rather than an led. 'struct led_plaform_data'
>
> Can we unify to use GPIO and gpio?
>
> * is used for this. If 'name' is NULL, the output isn't used. If 'flags'
> * is TCA6507_MAKE_CPIO, the output is a GPO.
>
> Here should be TCA6507_MAKE_GPIO and GPIO instead of GPO
>
> * The "struct led_platform_data" can be embedded in a
> * "struct tca6507_platform_data" which adds a 'gpio_base' for the GPiOs,
> * and a 'setup' callback which is called once the GPiOs are available.
>
> Don't use GPiO, please.
>
> Could you please review the code again and submit a cleanup patch to
> fix those typos?
>
> Thanks,
> -Bryan
>
>
>> The 7 lines driven by the TCA6507 can either drive LEDs or act as output-only
>> GPIOs.
>>
>> To make this distinction in devicetree we use the "compatible" property.
>>
>> If the device attached to a line is "compatible" with "gpio", we treat it
>> like a GPIO. If it is "compatible" with "led" (or if no "compatible" value
>> is set) we treat it like an LED.
>>
>> Signed-off-by: NeilBrown <neilb@suse.de>
>>
>> diff --git a/Documentation/devicetree/bindings/leds/tca6507.txt b/Documentation/devicetree/bindings/leds/tca6507.txt
>> index 80ff3dfb1f32..d7221b84987c 100644
>> --- a/Documentation/devicetree/bindings/leds/tca6507.txt
>> +++ b/Documentation/devicetree/bindings/leds/tca6507.txt
>> @@ -2,6 +2,13 @@ LEDs connected to tca6507
>>
>> Required properties:
>> - compatible : should be : "ti,tca6507".
>> +- #address-cells: must be 1
>> +- #size-cells: must be 0
>> +- reg: typically 0x45.
>> +
>> +Optional properties:
>> +- gpio-controller: allows lines to be used as output-only GPIOs.
>> +- #gpio-cells: if present, must be 0.
>>
>> Each led is represented as a sub-node of the ti,tca6507 device.
>>
>> @@ -10,6 +17,7 @@ LED sub-node properties:
>> - reg : number of LED line (could be from 0 to 6)
>> - linux,default-trigger : (optional)
>> see Documentation/devicetree/bindings/leds/common.txt
>> +- compatible: either "led" (the default) or "gpio".
>>
>> Examples:
>>
>> @@ -19,6 +27,9 @@ tca6507@45 {
>> #size-cells = <0>;
>> reg = <0x45>;
>>
>> + gpio-controller;
>> + #gpio-cells = <2>;
>> +
>> led0: red-aux@0 {
>> label = "red:aux";
>> reg = <0x0>;
>> @@ -29,5 +40,10 @@ tca6507@45 {
>> reg = <0x5>;
>> linux,default-trigger = "default-on";
>> };
>> +
>> + wifi-reset@6 {
>> + reg = <0x6>;
>> + compatible = "gpio";
>> + };
>> };
>>
>> diff --git a/drivers/leds/leds-tca6507.c b/drivers/leds/leds-tca6507.c
>> index f5063f447463..93a2b1759054 100644
>> --- a/drivers/leds/leds-tca6507.c
>> +++ b/drivers/leds/leds-tca6507.c
>> @@ -638,6 +638,9 @@ static int tca6507_probe_gpios(struct i2c_client *client,
>> tca->gpio.direction_output = tca6507_gpio_direction_output;
>> tca->gpio.set = tca6507_gpio_set_value;
>> tca->gpio.dev = &client->dev;
>> +#ifdef CONFIG_OF_GPIO
>> + tca->gpio.of_node = of_node_get(client->dev.of_node);
>> +#endif
>> err = gpiochip_add(&tca->gpio);
>> if (err) {
>> tca->gpio.ngpio = 0;
>> @@ -696,6 +699,8 @@ tca6507_led_dt_init(struct i2c_client *client)
>> led.default_trigger =
>> of_get_property(child, "linux,default-trigger", NULL);
>> led.flags = 0;
>> + if (of_property_match_string(child, "compatible", "gpio") >= 0)
>> + led.flags |= TCA6507_MAKE_GPIO;
>> ret = of_property_read_u32(child, "reg", ®);
>> if (ret != 0 || reg < 0 || reg >= NUM_LEDS)
>> continue;
>> @@ -709,6 +714,7 @@ tca6507_led_dt_init(struct i2c_client *client)
>>
>> pdata->leds.leds = tca_leds;
>> pdata->leds.num_leds = NUM_LEDS;
>> + pdata->gpio_base = -1;
>>
>> return pdata;
>> }
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 2/2] LEDS: tca6502: add device-tree support for GPIO configuration.
2013-11-01 2:41 [PATCH 2/2] LEDS: tca6502: add device-tree support for GPIO configuration NeilBrown
2013-11-07 23:39 ` Bryan Wu
@ 2013-11-18 11:55 ` Mark Rutland
2013-11-18 22:50 ` NeilBrown
1 sibling, 1 reply; 6+ messages in thread
From: Mark Rutland @ 2013-11-18 11:55 UTC (permalink / raw)
To: NeilBrown
Cc: Bryan Wu, Richard Purdie, rob.herring@calxeda.com, Pawel Moll,
Stephen Warren, Ian Campbell, grant.likely@linaro.org,
linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org,
Belisko Marek, Dr. H. Nikolaus Schaller,
devicetree@vger.kernel.org
On Fri, Nov 01, 2013 at 02:41:20AM +0000, NeilBrown wrote:
>
> The 7 lines driven by the TCA6507 can either drive LEDs or act as output-only
> GPIOs.
>
> To make this distinction in devicetree we use the "compatible" property.
>
> If the device attached to a line is "compatible" with "gpio", we treat it
> like a GPIO. If it is "compatible" with "led" (or if no "compatible" value
> is set) we treat it like an LED.
I'm nto sure I understand the purpose of this.
Are these lines all GPIOs, some of which happen to by attached to LEDs?
If so, why is handlnig the device as a gpio-controller and using the
gpio-leds binding not sufficient?
THanksm
Mark.
>
> Signed-off-by: NeilBrown <neilb@suse.de>
>
> diff --git a/Documentation/devicetree/bindings/leds/tca6507.txt b/Documentation/devicetree/bindings/leds/tca6507.txt
> index 80ff3dfb1f32..d7221b84987c 100644
> --- a/Documentation/devicetree/bindings/leds/tca6507.txt
> +++ b/Documentation/devicetree/bindings/leds/tca6507.txt
> @@ -2,6 +2,13 @@ LEDs connected to tca6507
>
> Required properties:
> - compatible : should be : "ti,tca6507".
> +- #address-cells: must be 1
> +- #size-cells: must be 0
> +- reg: typically 0x45.
> +
> +Optional properties:
> +- gpio-controller: allows lines to be used as output-only GPIOs.
> +- #gpio-cells: if present, must be 0.
>
> Each led is represented as a sub-node of the ti,tca6507 device.
>
> @@ -10,6 +17,7 @@ LED sub-node properties:
> - reg : number of LED line (could be from 0 to 6)
> - linux,default-trigger : (optional)
> see Documentation/devicetree/bindings/leds/common.txt
> +- compatible: either "led" (the default) or "gpio".
>
> Examples:
>
> @@ -19,6 +27,9 @@ tca6507@45 {
> #size-cells = <0>;
> reg = <0x45>;
>
> + gpio-controller;
> + #gpio-cells = <2>;
> +
> led0: red-aux@0 {
> label = "red:aux";
> reg = <0x0>;
> @@ -29,5 +40,10 @@ tca6507@45 {
> reg = <0x5>;
> linux,default-trigger = "default-on";
> };
> +
> + wifi-reset@6 {
> + reg = <0x6>;
> + compatible = "gpio";
> + };
> };
>
> diff --git a/drivers/leds/leds-tca6507.c b/drivers/leds/leds-tca6507.c
> index f5063f447463..93a2b1759054 100644
> --- a/drivers/leds/leds-tca6507.c
> +++ b/drivers/leds/leds-tca6507.c
> @@ -638,6 +638,9 @@ static int tca6507_probe_gpios(struct i2c_client *client,
> tca->gpio.direction_output = tca6507_gpio_direction_output;
> tca->gpio.set = tca6507_gpio_set_value;
> tca->gpio.dev = &client->dev;
> +#ifdef CONFIG_OF_GPIO
> + tca->gpio.of_node = of_node_get(client->dev.of_node);
> +#endif
> err = gpiochip_add(&tca->gpio);
> if (err) {
> tca->gpio.ngpio = 0;
> @@ -696,6 +699,8 @@ tca6507_led_dt_init(struct i2c_client *client)
> led.default_trigger =
> of_get_property(child, "linux,default-trigger", NULL);
> led.flags = 0;
> + if (of_property_match_string(child, "compatible", "gpio") >= 0)
> + led.flags |= TCA6507_MAKE_GPIO;
> ret = of_property_read_u32(child, "reg", ®);
> if (ret != 0 || reg < 0 || reg >= NUM_LEDS)
> continue;
> @@ -709,6 +714,7 @@ tca6507_led_dt_init(struct i2c_client *client)
>
> pdata->leds.leds = tca_leds;
> pdata->leds.num_leds = NUM_LEDS;
> + pdata->gpio_base = -1;
>
> return pdata;
> }
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 2/2] LEDS: tca6502: add device-tree support for GPIO configuration.
2013-11-18 11:55 ` Mark Rutland
@ 2013-11-18 22:50 ` NeilBrown
0 siblings, 0 replies; 6+ messages in thread
From: NeilBrown @ 2013-11-18 22:50 UTC (permalink / raw)
To: Mark Rutland
Cc: Bryan Wu, Richard Purdie, rob.herring@calxeda.com, Pawel Moll,
Stephen Warren, Ian Campbell, grant.likely@linaro.org,
linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org,
Belisko Marek, Dr. H. Nikolaus Schaller,
devicetree@vger.kernel.org
[-- Attachment #1: Type: text/plain, Size: 4652 bytes --]
On Mon, 18 Nov 2013 11:55:12 +0000 Mark Rutland <mark.rutland@arm.com> wrote:
> On Fri, Nov 01, 2013 at 02:41:20AM +0000, NeilBrown wrote:
> >
> > The 7 lines driven by the TCA6507 can either drive LEDs or act as output-only
> > GPIOs.
> >
> > To make this distinction in devicetree we use the "compatible" property.
> >
> > If the device attached to a line is "compatible" with "gpio", we treat it
> > like a GPIO. If it is "compatible" with "led" (or if no "compatible" value
> > is set) we treat it like an LED.
>
> I'm nto sure I understand the purpose of this.
>
> Are these lines all GPIOs, some of which happen to by attached to LEDs?
>
> If so, why is handlnig the device as a gpio-controller and using the
> gpio-leds binding not sufficient?
No, all the lines are designed to drives LEDs but can happen to be wired up
like GPIOs. This configuration is explicitly described in the data sheets
for the chip, and is actually used in my board.
The 7 pins either float or sink current. They can switch between the two
modes in various ways under hardware control with a PWM which can have a
varying duty cycle.
So they are very suitable for driving LEDs as the PWM can adjust the apparent
brightness and the varying duty cycle can effect a 'blink' pattern.
But the pins can also be fixed in one state of the other - either never on or
always on. Floating or constantly sinking current.
This mode combined with a pull-up resistor makes an effective output-only
GPIO. The same action that would turn the LED on, will pull the GPIO low.
The action that would turn the LED off, will allow the GPIO to go high.
So the device connected to each pin can be treated as an LED or as a GPIO.
I hope that clarifies the situation.
Thanks,
NeilBrown
>
> THanksm
> Mark.
>
> >
> > Signed-off-by: NeilBrown <neilb@suse.de>
> >
> > diff --git a/Documentation/devicetree/bindings/leds/tca6507.txt b/Documentation/devicetree/bindings/leds/tca6507.txt
> > index 80ff3dfb1f32..d7221b84987c 100644
> > --- a/Documentation/devicetree/bindings/leds/tca6507.txt
> > +++ b/Documentation/devicetree/bindings/leds/tca6507.txt
> > @@ -2,6 +2,13 @@ LEDs connected to tca6507
> >
> > Required properties:
> > - compatible : should be : "ti,tca6507".
> > +- #address-cells: must be 1
> > +- #size-cells: must be 0
> > +- reg: typically 0x45.
> > +
> > +Optional properties:
> > +- gpio-controller: allows lines to be used as output-only GPIOs.
> > +- #gpio-cells: if present, must be 0.
> >
> > Each led is represented as a sub-node of the ti,tca6507 device.
> >
> > @@ -10,6 +17,7 @@ LED sub-node properties:
> > - reg : number of LED line (could be from 0 to 6)
> > - linux,default-trigger : (optional)
> > see Documentation/devicetree/bindings/leds/common.txt
> > +- compatible: either "led" (the default) or "gpio".
> >
> > Examples:
> >
> > @@ -19,6 +27,9 @@ tca6507@45 {
> > #size-cells = <0>;
> > reg = <0x45>;
> >
> > + gpio-controller;
> > + #gpio-cells = <2>;
> > +
> > led0: red-aux@0 {
> > label = "red:aux";
> > reg = <0x0>;
> > @@ -29,5 +40,10 @@ tca6507@45 {
> > reg = <0x5>;
> > linux,default-trigger = "default-on";
> > };
> > +
> > + wifi-reset@6 {
> > + reg = <0x6>;
> > + compatible = "gpio";
> > + };
> > };
> >
> > diff --git a/drivers/leds/leds-tca6507.c b/drivers/leds/leds-tca6507.c
> > index f5063f447463..93a2b1759054 100644
> > --- a/drivers/leds/leds-tca6507.c
> > +++ b/drivers/leds/leds-tca6507.c
> > @@ -638,6 +638,9 @@ static int tca6507_probe_gpios(struct i2c_client *client,
> > tca->gpio.direction_output = tca6507_gpio_direction_output;
> > tca->gpio.set = tca6507_gpio_set_value;
> > tca->gpio.dev = &client->dev;
> > +#ifdef CONFIG_OF_GPIO
> > + tca->gpio.of_node = of_node_get(client->dev.of_node);
> > +#endif
> > err = gpiochip_add(&tca->gpio);
> > if (err) {
> > tca->gpio.ngpio = 0;
> > @@ -696,6 +699,8 @@ tca6507_led_dt_init(struct i2c_client *client)
> > led.default_trigger =
> > of_get_property(child, "linux,default-trigger", NULL);
> > led.flags = 0;
> > + if (of_property_match_string(child, "compatible", "gpio") >= 0)
> > + led.flags |= TCA6507_MAKE_GPIO;
> > ret = of_property_read_u32(child, "reg", ®);
> > if (ret != 0 || reg < 0 || reg >= NUM_LEDS)
> > continue;
> > @@ -709,6 +714,7 @@ tca6507_led_dt_init(struct i2c_client *client)
> >
> > pdata->leds.leds = tca_leds;
> > pdata->leds.num_leds = NUM_LEDS;
> > + pdata->gpio_base = -1;
> >
> > return pdata;
> > }
>
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 828 bytes --]
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2013-11-18 22:50 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-11-01 2:41 [PATCH 2/2] LEDS: tca6502: add device-tree support for GPIO configuration NeilBrown
2013-11-07 23:39 ` Bryan Wu
2013-11-07 23:46 ` NeilBrown
2013-11-07 23:46 ` Bryan Wu
2013-11-18 11:55 ` Mark Rutland
2013-11-18 22:50 ` NeilBrown
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).