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[PATCH] Make EN2 pin optional in the TRF7970A driver

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  [PATCH] Make EN2 pin optional in the TRF7970A driver Heiko Schocher <hs@denx.de> - 2017-02-07 06:30 +0100
    Re: [PATCH] Make EN2 pin optional in the TRF7970A driver Rob Herring <robh@kernel.org> - 2017-02-10 17:00 +0100
      Re: [PATCH] Make EN2 pin optional in the TRF7970A driver Heiko Schocher <hs@denx.de> - 2017-02-13 07:40 +0100

#1575391 — [PATCH] Make EN2 pin optional in the TRF7970A driver

From: Guan Ben <ben.guan@cn.bosch.com>

Make the EN2 pin optional. This is useful for boards,
which have this pin fix wired, for example to ground.

Signed-off-by: Guan Ben <ben.guan@cn.bosch.com>
Signed-off-by: Mark Jonas <mark.jonas@de.bosch.com>
Signed-off-by: Heiko Schocher <hs@denx.de>

---

 .../devicetree/bindings/net/nfc/trf7970a.txt       |  4 ++--
 drivers/nfc/trf7970a.c                             | 26 ++++++++++++----------
 2 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/nfc/trf7970a.txt b/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
index 32b35a0..5889a3d 100644
--- a/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
+++ b/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
@@ -5,8 +5,8 @@ Required properties:
 - spi-max-frequency: Maximum SPI frequency (<= 2000000).
 - interrupt-parent: phandle of parent interrupt handler.
 - interrupts: A single interrupt specifier.
-- ti,enable-gpios: Two GPIO entries used for 'EN' and 'EN2' pins on the
-  TRF7970A.
+- ti,enable-gpios: One or two GPIO entries used for 'EN' and 'EN2' pins on the
+  TRF7970A. EN2 is optional.
 - vin-supply: Regulator for supply voltage to VIN pin
 
 Optional SoC Specific Properties:
diff --git a/drivers/nfc/trf7970a.c b/drivers/nfc/trf7970a.c
index 26c9dbb..75079fb 100644
--- a/drivers/nfc/trf7970a.c
+++ b/drivers/nfc/trf7970a.c
@@ -1885,8 +1885,10 @@ static int trf7970a_power_up(struct trf7970a *trf)
 	usleep_range(5000, 6000);
 
 	if (!(trf->quirks & TRF7970A_QUIRK_EN2_MUST_STAY_LOW)) {
-		gpio_set_value(trf->en2_gpio, 1);
-		usleep_range(1000, 2000);
+		if (gpio_is_valid(trf->en2_gpio)) {
+			gpio_set_value(trf->en2_gpio, 1);
+			usleep_range(1000, 2000);
+		}
 	}
 
 	gpio_set_value(trf->en_gpio, 1);
@@ -1914,7 +1916,8 @@ static int trf7970a_power_down(struct trf7970a *trf)
 	}
 
 	gpio_set_value(trf->en_gpio, 0);
-	gpio_set_value(trf->en2_gpio, 0);
+	if (gpio_is_valid(trf->en2_gpio))
+		gpio_set_value(trf->en2_gpio, 0);
 
 	ret = regulator_disable(trf->regulator);
 	if (ret)
@@ -2032,15 +2035,14 @@ static int trf7970a_probe(struct spi_device *spi)
 
 	trf->en2_gpio = of_get_named_gpio(np, "ti,enable-gpios", 1);
 	if (!gpio_is_valid(trf->en2_gpio)) {
-		dev_err(trf->dev, "No EN2 GPIO property\n");
-		return trf->en2_gpio;
-	}
-
-	ret = devm_gpio_request_one(trf->dev, trf->en2_gpio,
-			GPIOF_DIR_OUT | GPIOF_INIT_LOW, "trf7970a EN2");
-	if (ret) {
-		dev_err(trf->dev, "Can't request EN2 GPIO: %d\n", ret);
-		return ret;
+		dev_info(trf->dev, "No EN2 GPIO property\n");
+	} else {
+		ret = devm_gpio_request_one(trf->dev, trf->en2_gpio,
+				GPIOF_DIR_OUT | GPIOF_INIT_LOW, "trf7970a EN2");
+		if (ret) {
+			dev_err(trf->dev, "Can't request EN2 GPIO: %d\n", ret);
+			return ret;
+		}
 	}
 
 	if (of_property_read_bool(np, "en2-rf-quirk"))
-- 
2.7.4

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#1578571

On Tue, Feb 07, 2017 at 06:22:04AM +0100, Heiko Schocher wrote:
> From: Guan Ben <ben.guan@cn.bosch.com>
> 
> Make the EN2 pin optional. This is useful for boards,
> which have this pin fix wired, for example to ground.
> 
> Signed-off-by: Guan Ben <ben.guan@cn.bosch.com>
> Signed-off-by: Mark Jonas <mark.jonas@de.bosch.com>
> Signed-off-by: Heiko Schocher <hs@denx.de>
> 
> ---
> 
>  .../devicetree/bindings/net/nfc/trf7970a.txt       |  4 ++--
>  drivers/nfc/trf7970a.c                             | 26 ++++++++++++----------
>  2 files changed, 16 insertions(+), 14 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/net/nfc/trf7970a.txt b/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
> index 32b35a0..5889a3d 100644
> --- a/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
> +++ b/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
> @@ -5,8 +5,8 @@ Required properties:
>  - spi-max-frequency: Maximum SPI frequency (<= 2000000).
>  - interrupt-parent: phandle of parent interrupt handler.
>  - interrupts: A single interrupt specifier.
> -- ti,enable-gpios: Two GPIO entries used for 'EN' and 'EN2' pins on the
> -  TRF7970A.
> +- ti,enable-gpios: One or two GPIO entries used for 'EN' and 'EN2' pins on the
> +  TRF7970A. EN2 is optional.

Could EN ever be optional/fixed? If so, perhaps deprecate this property 
and do 2 properties, one for each pin.

Rob

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#1579463

Hello Rob,

Am 10.02.2017 um 16:51 schrieb Rob Herring:
> On Tue, Feb 07, 2017 at 06:22:04AM +0100, Heiko Schocher wrote:
>> From: Guan Ben <ben.guan@cn.bosch.com>
>>
>> Make the EN2 pin optional. This is useful for boards,
>> which have this pin fix wired, for example to ground.
>>
>> Signed-off-by: Guan Ben <ben.guan@cn.bosch.com>
>> Signed-off-by: Mark Jonas <mark.jonas@de.bosch.com>
>> Signed-off-by: Heiko Schocher <hs@denx.de>
>>
>> ---
>>
>>   .../devicetree/bindings/net/nfc/trf7970a.txt       |  4 ++--
>>   drivers/nfc/trf7970a.c                             | 26 ++++++++++++----------
>>   2 files changed, 16 insertions(+), 14 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/net/nfc/trf7970a.txt b/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
>> index 32b35a0..5889a3d 100644
>> --- a/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
>> +++ b/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
>> @@ -5,8 +5,8 @@ Required properties:
>>   - spi-max-frequency: Maximum SPI frequency (<= 2000000).
>>   - interrupt-parent: phandle of parent interrupt handler.
>>   - interrupts: A single interrupt specifier.
>> -- ti,enable-gpios: Two GPIO entries used for 'EN' and 'EN2' pins on the
>> -  TRF7970A.
>> +- ti,enable-gpios: One or two GPIO entries used for 'EN' and 'EN2' pins on the
>> +  TRF7970A. EN2 is optional.
>
> Could EN ever be optional/fixed? If so, perhaps deprecate this property
> and do 2 properties, one for each pin.

The hardware I have has the EN2 pin fix connected to ground. Looking
into http://www.ti.com/lit/ds/slos743k/slos743k.pdf page 19 table 6-3
and 6-4 the EN2 pin is a don;t core if EN = 1. If EN = 0 EN2 pin
selects between Power Down and Sleep Mode ... I see no reason why
this is not possible/allowed ...

Hmm.. I do not like the idea of deprecating the "ti,enable-gpios"
property into 2 seperate properties ... but if this would be a reason
for not accepting this patch, I can do this ... How should I name
the 2 new properties?

"ti,pin-enable"  and "ti,pin-enable2" ?

bye,
Heiko
-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

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