gpio: driver for the RPi3 GPIO expander

The Raspberry Pi 3 GPIO expander is controlled by the VC4 firmware over I2C. The firmware mailbox interface allows the ARM core to control the GPIO lines.

Signed-off-by Baruch Siach <[email protected]>

---
v3:
* Rename node name.

v2:
* Rename compatible string to raspberrypi,firmware-gpio

---
 .../bindings/gpio/raspberrypi,firmware-gpio.txt    | 24 ++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/raspberrypi,firmware-gpio.txt

Documentation/devicetree/bindings/gpio/raspberrypi,firmware-gpio.txt new file +9 -0

new file mode 100644
index 000000000000..936dc59eba12
@@ -0,0 +1,24 @@
+Raspberry Pi GPIO expander
+
+The Raspberry Pi 3 GPIO expander is controlled by the VC4 firmware. The
+firmware exposes a mailbox interface that allows the ARM core to control the
+GPIO lines on the expander.
+
+Required properties:
+
+- compatible : Should be "raspberrypi,firmware-gpio"

Quoted 35 lines · Baruch Siach

The Raspberry Pi 3 GPIO expander is controlled by the VC4 firmware over I2C. The firmware mailbox interface allows the ARM core to control the GPIO lines.

Signed-off-by Baruch Siach <[email protected]>

---
v3:
* Rename node name.

v2:
* Rename compatible string to raspberrypi,firmware-gpio

---
 .../bindings/gpio/raspberrypi,firmware-gpio.txt    | 24 ++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/raspberrypi,firmware-gpio.txt

Documentation/devicetree/bindings/gpio/raspberrypi,firmware-gpio.txt new file +13 -0

new file mode 100644
index 000000000000..936dc59eba12
@@ -0,0 +1,24 @@
+Raspberry Pi GPIO expander
+
+The Raspberry Pi 3 GPIO expander is controlled by the VC4 firmware. The
+firmware exposes a mailbox interface that allows the ARM core to control the
+GPIO lines on the expander.
+
+Required properties:
+
+- compatible : Should be "raspberrypi,firmware-gpio"
+- gpio-controller : Marks the device node as a gpio controller
+- #gpio-cells : Should be two.  The first cell is the pin number, and
+  the second cell is used to specify the gpio polarity:
+  0 = active high

Documentation/devicetree/bindings/gpio/raspberrypi,firmware-gpio.txt line 19

Quoted 6 lines

Documentation/devicetree/bindings/gpio/raspberrypi,firmware-gpio.txt new file +6 -0

+  1 = active low
+- firmware : Reference to the RPi firmware device node
+
+Example:
+
+expgpio: gpio-expander {

Still not right. The correct generic node name is "gpio".

Documentation/devicetree/bindings/gpio/raspberrypi,firmware-gpio.txt line 23

Quoted 4 lines

Documentation/devicetree/bindings/gpio/raspberrypi,firmware-gpio.txt new file +4 -0

+	compatible = "raspberrypi,firmware-gpio";
+	gpio-controller;
+	#gpio-cells = <2>;
+	firmware = <&firmware>;

Can you make this a child of the firmware node instead?

Baruch Siach <[email protected]> hat am 16. Januar 2018 um 13:45 geschrieben:

From: Dave Stevenson <[email protected]>

Pi3 and Compute Module 3 have a GPIO expander that the VPU communicates with.
There is a mailbox service that now allows control of this expander, so add a kernel driver that can make use of it.

Signed-off-by Dave Stevenson <[email protected]>

Signed-off-by Baruch Siach <[email protected]>

---
v3:
* Tweak Kconfig driver prompt
* Make GPIO_RASPBERRYPI_EXP tristate
* Make COMPILE_TEST independent of RASPBERRYPI_FIRMWARE
* Remove redundant DMA header
* Use less code lines for dev_err()
* Check rpi_exp_gpio_get_polarity() return value
* Remove redundant platform_set_drvdata() call

v2:
* Rename driver to gpio-raspberrypi-exp
* Populate the gpiochip parent device pointer
* Use macro for the mailbox base GPIO number
* Drop linux/gpio.h and GPIOF_DIR_*
* Check and print firmware error value
* Use devm_gpiochip_add_data(); drop .remove
* A few more minor tweaks

---
 drivers/gpio/Kconfig                |   9 ++
 drivers/gpio/Makefile               |   1 +
 drivers/gpio/gpio-raspberrypi-exp.c | 253 ++++++++++++++++++++++++++++++++++++
 3 files changed, 263 insertions(+)
 create mode 100644 drivers/gpio/gpio-raspberrypi-exp.c

...

drivers/gpio/gpio-raspberrypi-exp.c new file +41 -0

+
+static int rpi_exp_gpio_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct device_node *fw_node;
+	struct rpi_firmware *fw;
+	struct rpi_exp_gpio *rpi_gpio;
+
+	fw_node = of_parse_phandle(np, "firmware", 0);
+	if (!fw_node) {
+		dev_err(dev, "Missing firmware node\n");
+		return -ENOENT;
+	}
+
+	fw = rpi_firmware_get(fw_node);
+	if (!fw)
+		return -EPROBE_DEFER;
+
+	rpi_gpio = devm_kzalloc(dev, sizeof(*rpi_gpio), GFP_KERNEL);
+	if (!rpi_gpio)
+		return -ENOMEM;
+
+	rpi_gpio->fw = fw;
+	rpi_gpio->gc.parent = dev;
+	rpi_gpio->gc.label = MODULE_NAME;
+	rpi_gpio->gc.owner = THIS_MODULE;
+	rpi_gpio->gc.of_node = np;
+	rpi_gpio->gc.base = -1;
+	rpi_gpio->gc.ngpio = NUM_GPIO;
+
+	rpi_gpio->gc.direction_input = rpi_exp_gpio_dir_in;
+	rpi_gpio->gc.direction_output = rpi_exp_gpio_dir_out;
+	rpi_gpio->gc.get_direction = rpi_exp_gpio_get_direction;
+	rpi_gpio->gc.get = rpi_exp_gpio_get;
+	rpi_gpio->gc.set = rpi_exp_gpio_set;
+	rpi_gpio->gc.can_sleep = true;
+
+	return devm_gpiochip_add_data(dev, &rpi_gpio->gc, rpi_gpio);
+}
+

drivers/gpio/gpio-raspberrypi-exp.c new file +10 -0

+		.of_match_table	= of_match_ptr(rpi_exp_gpio_ids),
+	},
+	.probe	= rpi_exp_gpio_probe,
+};
+module_platform_driver(rpi_exp_gpio_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Dave Stevenson <[email protected]>");
+MODULE_DESCRIPTION("Raspberry Pi 3 expander GPIO driver");
+MODULE_ALIAS("platform:rpi-exp-gpio");

Signature · 7 lines

2.15.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel at lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Add a description of the RPi3 GPIO expander that the VC4 firmware controls.

Signed-off-by Baruch Siach <[email protected]>

---
v3:
* List GPIO names one per line.

v2:
* Move GPIO expander node out of the soc container
* Rename compatible string
* Add gpio-line-names property

---
  arch/arm/boot/dts/bcm2837-rpi-3-b.dts | 16 ++++++++++++++++
  1 file changed, 16 insertions(+)

arch/arm/boot/dts/bcm2837-rpi-3-b.dts +0 -0

index b44b3b5af00d..8cd93425ffe3 100644

arch/arm/boot/dts/bcm2837-rpi-3-b.dts +16 -0

+
+	expgpio: gpio-expander {
+		compatible = "raspberrypi,firmware-gpio";
+		gpio-controller;
+		#gpio-cells = <2>;
+		firmware = <&firmware>;
+		gpio-line-names = "BT_ON",
+				  "WL_ON",
+				  "STATUS_LED",
+				  "LAN_RUN",
+				  "HPD_N",
+				  "CAM_GPIO0",
+				  "CAM_GPIO1",
+				  "PWR_LOW_N";
+		status = "okay";
+	};
  };
 
  /* uart0 communicates with the BT module */

Hi Linus,
hi Eric,

Am 16.01.2018 um 13:45 schrieb Baruch Siach:

Quoted 23 lines

Add a description of the RPi3 GPIO expander that the VC4 firmware controls.

Signed-off-by Baruch Siach <[email protected]>

---
v3:
* List GPIO names one per line.

v2:
* Move GPIO expander node out of the soc container
* Rename compatible string
* Add gpio-line-names property

---
  arch/arm/boot/dts/bcm2837-rpi-3-b.dts | 16 ++++++++++++++++
  1 file changed, 16 insertions(+)

arch/arm/boot/dts/bcm2837-rpi-3-b.dts +0 -0

index b44b3b5af00d..8cd93425ffe3 100644

arch/arm/boot/dts/bcm2837-rpi-3-b.dts line 25

Quoted 3 lines

arch/arm/boot/dts/bcm2837-rpi-3-b.dts +0 -0

@@ -23,6 +23,22 @@
                        gpios = <&gpio 47 0>;
                };
        };

i noticed that this patch conflicts with my patch ("ARM: dts: bcm283x: Use GPIO polarity defines consistently") in linux-next.

How should we proceed?

Baruch Siach <[email protected]> hat am 16. Januar 2018 um 13:45 geschrieben:

Add a description of the RPi3 GPIO expander that the VC4 firmware controls.

Signed-off-by Baruch Siach <[email protected]>

The Raspberry Pi 3 has a GPIO expander that controls, among others, the activity LED, and the camera connector GPIOs. The GPIO expander on an I2C bus that is not directly controlled from the ARM core. The VC4 firmware controls the I2C bus, and allows the ARM core to set/get GPIO settings over its mailbox interface.

This series adds support for the RPi3 expander.

The driver is ported from the downstream kernel at
https://github.com/raspberrypi/linux/, branch rpi-4.9.y.

Changes in v3:

* Kconfig tweaks
* Check rpi_exp_gpio_get_polarity() return value
* Redundant header removal
* Redundant platform_set_drvdata() call removal
* Small coding style changes

Quoted 11 lines · Baruch Siach

The Raspberry Pi 3 has a GPIO expander that controls, among others, the activity LED, and the camera connector GPIOs. The GPIO expander on an I2C bus that is not directly controlled from the ARM core. The VC4 firmware controls the I2C bus, and allows the ARM core to set/get GPIO settings over its mailbox interface.

This series adds support for the RPi3 expander.

The driver is ported from the downstream kernel at
https://github.com/raspberrypi/linux/, branch rpi-4.9.y.

Quoted 7 lines

Changes in v3:

* Kconfig tweaks
* Check rpi_exp_gpio_get_polarity() return value
* Redundant header removal
* Redundant platform_set_drvdata() call removal
* Small coding style changes

All is looking pretty good. I see Rob had some last minute comments, but please rebase and repost post v4.16-rc1 so we can get this merged, we need to get this upstream.

Quoted 21 lines · Linus Walleij

Quoted 18 lines · Baruch Siach

The Raspberry Pi 3 has a GPIO expander that controls, among others, the activity LED, and the camera connector GPIOs. The GPIO expander on an I2C bus that is not directly controlled from the ARM core. The VC4 firmware controls the I2C bus, and allows the ARM core to set/get GPIO settings over its mailbox interface.

This series adds support for the RPi3 expander.

The driver is ported from the downstream kernel at
https://github.com/raspberrypi/linux/, branch rpi-4.9.y.

Changes in v3:

* Kconfig tweaks
* Check rpi_exp_gpio_get_polarity() return value
* Redundant header removal
* Redundant platform_set_drvdata() call removal
* Small coding style changes

Quoted 3 lines

All is looking pretty good. I see Rob had some last minute comments, but please rebase and repost post v4.16-rc1 so we can get this merged, we need to get this upstream.

I was about to send v4 when I saw your email. I based v4 on current LinusT's tree as of e237f98a9c. I guess that affected files will not change before v4.16-rc1, but I can wait a few more days for -rc1.

Hi Linus,

Quoted 20 lines · Linus Walleij

Quoted 18 lines · Baruch Siach

The Raspberry Pi 3 has a GPIO expander that controls, among others, the activity LED, and the camera connector GPIOs. The GPIO expander on an I2C bus that is not directly controlled from the ARM core. The VC4 firmware controls the I2C bus, and allows the ARM core to set/get GPIO settings over its mailbox interface.

This series adds support for the RPi3 expander.

The driver is ported from the downstream kernel at
https://github.com/raspberrypi/linux/, branch rpi-4.9.y.

Changes in v3:

* Kconfig tweaks
* Check rpi_exp_gpio_get_polarity() return value
* Redundant header removal
* Redundant platform_set_drvdata() call removal
* Small coding style changes

Quoted 3 lines

All is looking pretty good. I see Rob had some last minute comments, but please rebase and repost post v4.16-rc1 so we can get this merged, we need to get this upstream.

I was about to send v4 when I saw your email. I based v4 on current LinusT's tree as of e237f98a9c. I guess that affected files will not change before v4.16-rc1, but I can wait a few more days for -rc1.

baruch

Am 06.02.2018 um 17:27 schrieb Baruch Siach:

Quoted 24 lines · Linus Walleij

Quoted 23 lines · Baruch Siach

Quoted 12 lines

The Raspberry Pi 3 has a GPIO expander that controls, among others, the activity LED, and the camera connector GPIOs. The GPIO expander on an I2C bus that is not directly controlled from the ARM core. The VC4 firmware controls the I2C bus, and allows the ARM core to set/get GPIO settings over its mailbox interface.

This series adds support for the RPi3 expander.

The driver is ported from the downstream kernel at
https://github.com/raspberrypi/linux/, branch rpi-4.9.y.

Quoted 7 lines

Changes in v3:

* Kconfig tweaks
* Check rpi_exp_gpio_get_polarity() return value
* Redundant header removal
* Redundant platform_set_drvdata() call removal
* Small coding style changes

All is looking pretty good. I see Rob had some last minute comments, but please rebase and repost post v4.16-rc1 so we can get this merged, we need to get this upstream.

Quoted 3 lines

I was about to send v4 when I saw your email. I based v4 on current LinusT's tree as of e237f98a9c. I guess that affected files will not change before v4.16-rc1, but I can wait a few more days for -rc1.

please also address the owner issue in the driver, which was reported by kbuild test robot.

Hi Stefan,

Quoted 25 lines · Stefan Wahren

Am 06.02.2018 um 17:27 schrieb Baruch Siach:

Quoted 24 lines · Linus Walleij

Quoted 23 lines · Baruch Siach

Quoted 12 lines

The Raspberry Pi 3 has a GPIO expander that controls, among others, the activity LED, and the camera connector GPIOs. The GPIO expander on an I2C bus that is not directly controlled from the ARM core. The VC4 firmware controls the I2C bus, and allows the ARM core to set/get GPIO settings over its mailbox interface.

This series adds support for the RPi3 expander.

The driver is ported from the downstream kernel at
https://github.com/raspberrypi/linux/, branch rpi-4.9.y.

Quoted 7 lines

Changes in v3:

* Kconfig tweaks
* Check rpi_exp_gpio_get_polarity() return value
* Redundant header removal
* Redundant platform_set_drvdata() call removal
* Small coding style changes

All is looking pretty good. I see Rob had some last minute comments, but please rebase and repost post v4.16-rc1 so we can get this merged, we need to get this upstream.

Quoted 5 lines

Quoted 3 lines

I was about to send v4 when I saw your email. I based v4 on current LinusT's tree as of e237f98a9c. I guess that affected files will not change before v4.16-rc1, but I can wait a few more days for -rc1.

please also address the owner issue in the driver, which was reported by kbuild test robot.

I removed the .owner platform_driver field set from v4. The owner field in gpio_chip is still set.

baruch