Discussion:
[PATCH v3 4/4] ARM: dts: bcm2837-rpi-3-b: add GPIO expander
(too old to reply)
Baruch Siach
2018-01-16 12:45:10 UTC
Permalink
Add a description of the RPi3 GPIO expander that the VC4 firmware controls.

Signed-off-by: Baruch Siach <***@tkos.co.il>
---
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(+)

diff --git a/arch/arm/boot/dts/bcm2837-rpi-3-b.dts b/arch/arm/boot/dts/bcm2837-rpi-3-b.dts
index b44b3b5af00d..8cd93425ffe3 100644
--- a/arch/arm/boot/dts/bcm2837-rpi-3-b.dts
+++ b/arch/arm/boot/dts/bcm2837-rpi-3-b.dts
@@ -23,6 +23,22 @@
gpios = <&gpio 47 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 */
--
2.15.1
Baruch Siach
2018-01-16 12:45:08 UTC
Permalink
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 <***@tkos.co.il>
---
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

diff --git a/Documentation/devicetree/bindings/gpio/raspberrypi,firmware-gpio.txt b/Documentation/devicetree/bindings/gpio/raspberrypi,firmware-gpio.txt
new file mode 100644
index 000000000000..936dc59eba12
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/raspberrypi,firmware-gpio.txt
@@ -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
+ 1 = active low
+- firmware : Reference to the RPi firmware device node
+
+Example:
+
+expgpio: gpio-expander {
+ compatible = "raspberrypi,firmware-gpio";
+ gpio-controller;
+ #gpio-cells = <2>;
+ firmware = <&firmware>;
+};
--
2.15.1
Baruch Siach
2018-01-29 16:30:20 UTC
Permalink
Hi Rob,

Thanks for reviewing.
Post by 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.
---
* Rename node name.
* 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
diff --git a/Documentation/devicetree/bindings/gpio/raspberrypi,firmware-gpio.txt b/Documentation/devicetree/bindings/gpio/raspberrypi,firmware-gpio.txt
new file mode 100644
index 000000000000..936dc59eba12
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/raspberrypi,firmware-gpio.txt
@@ -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.
+
+
+- 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
+ 0 = active high
+ 1 = active low
+- firmware : Reference to the RPi firmware device node
+
+
+expgpio: gpio-expander {
Still not right. The correct generic node name is "gpio".
I'll fix that.
Post by Baruch Siach
+ compatible = "raspberrypi,firmware-gpio";
+ gpio-controller;
+ #gpio-cells = <2>;
+ firmware = <&firmware>;
Can you make this a child of the firmware node instead?
I guess I can, I'll need to look into it. What is the advantage of that? What
about the existing raspberrypi,bcm2835-power[1] node in bcm2835-rpi.dtsi?
Should it move under the firmware node as well?

[1] Documentation/devicetree/bindings/soc/bcm/raspberrypi,bcm2835-power.txt

baruch
--
http://baruch.siach.name/blog/ ~. .~ Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
- ***@tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -
Baruch Siach
2018-01-16 12:45:07 UTC
Permalink
Add latest firmware property tags from the latest Raspberry Pi downstream
kernel. This is needed for the GPIO tags, so we can control the GPIO
multiplexor lines.

Acked-by: Stefan Wahren <***@i2se.com>
Signed-off-by: Baruch Siach <***@tkos.co.il>
---
v3: Add Stefan's ack

v2: No change
---
include/soc/bcm2835/raspberrypi-firmware.h | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)

diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h
index cb979ad90401..50df5b28d2c9 100644
--- a/include/soc/bcm2835/raspberrypi-firmware.h
+++ b/include/soc/bcm2835/raspberrypi-firmware.h
@@ -63,6 +63,7 @@ enum rpi_firmware_property_tag {
RPI_FIRMWARE_GET_MIN_VOLTAGE = 0x00030008,
RPI_FIRMWARE_GET_TURBO = 0x00030009,
RPI_FIRMWARE_GET_MAX_TEMPERATURE = 0x0003000a,
+ RPI_FIRMWARE_GET_STC = 0x0003000b,
RPI_FIRMWARE_ALLOCATE_MEMORY = 0x0003000c,
RPI_FIRMWARE_LOCK_MEMORY = 0x0003000d,
RPI_FIRMWARE_UNLOCK_MEMORY = 0x0003000e,
@@ -72,12 +73,22 @@ enum rpi_firmware_property_tag {
RPI_FIRMWARE_SET_ENABLE_QPU = 0x00030012,
RPI_FIRMWARE_GET_DISPMANX_RESOURCE_MEM_HANDLE = 0x00030014,
RPI_FIRMWARE_GET_EDID_BLOCK = 0x00030020,
+ RPI_FIRMWARE_GET_CUSTOMER_OTP = 0x00030021,
RPI_FIRMWARE_GET_DOMAIN_STATE = 0x00030030,
RPI_FIRMWARE_SET_CLOCK_STATE = 0x00038001,
RPI_FIRMWARE_SET_CLOCK_RATE = 0x00038002,
RPI_FIRMWARE_SET_VOLTAGE = 0x00038003,
RPI_FIRMWARE_SET_TURBO = 0x00038009,
+ RPI_FIRMWARE_SET_CUSTOMER_OTP = 0x00038021,
RPI_FIRMWARE_SET_DOMAIN_STATE = 0x00038030,
+ RPI_FIRMWARE_GET_GPIO_STATE = 0x00030041,
+ RPI_FIRMWARE_SET_GPIO_STATE = 0x00038041,
+ RPI_FIRMWARE_SET_SDHOST_CLOCK = 0x00038042,
+ RPI_FIRMWARE_GET_GPIO_CONFIG = 0x00030043,
+ RPI_FIRMWARE_SET_GPIO_CONFIG = 0x00038043,
+ RPI_FIRMWARE_GET_PERIPH_REG = 0x00030045,
+ RPI_FIRMWARE_SET_PERIPH_REG = 0x00038045,
+

/* Dispmanx TAGS */
RPI_FIRMWARE_FRAMEBUFFER_ALLOCATE = 0x00040001,
@@ -91,6 +102,8 @@ enum rpi_firmware_property_tag {
RPI_FIRMWARE_FRAMEBUFFER_GET_VIRTUAL_OFFSET = 0x00040009,
RPI_FIRMWARE_FRAMEBUFFER_GET_OVERSCAN = 0x0004000a,
RPI_FIRMWARE_FRAMEBUFFER_GET_PALETTE = 0x0004000b,
+ RPI_FIRMWARE_FRAMEBUFFER_GET_TOUCHBUF = 0x0004000f,
+ RPI_FIRMWARE_FRAMEBUFFER_GET_GPIOVIRTBUF = 0x00040010,
RPI_FIRMWARE_FRAMEBUFFER_RELEASE = 0x00048001,
RPI_FIRMWARE_FRAMEBUFFER_TEST_PHYSICAL_WIDTH_HEIGHT = 0x00044003,
RPI_FIRMWARE_FRAMEBUFFER_TEST_VIRTUAL_WIDTH_HEIGHT = 0x00044004,
@@ -100,6 +113,7 @@ enum rpi_firmware_property_tag {
RPI_FIRMWARE_FRAMEBUFFER_TEST_VIRTUAL_OFFSET = 0x00044009,
RPI_FIRMWARE_FRAMEBUFFER_TEST_OVERSCAN = 0x0004400a,
RPI_FIRMWARE_FRAMEBUFFER_TEST_PALETTE = 0x0004400b,
+ RPI_FIRMWARE_FRAMEBUFFER_TEST_VSYNC = 0x0004400e,
RPI_FIRMWARE_FRAMEBUFFER_SET_PHYSICAL_WIDTH_HEIGHT = 0x00048003,
RPI_FIRMWARE_FRAMEBUFFER_SET_VIRTUAL_WIDTH_HEIGHT = 0x00048004,
RPI_FIRMWARE_FRAMEBUFFER_SET_DEPTH = 0x00048005,
@@ -108,6 +122,10 @@ enum rpi_firmware_property_tag {
RPI_FIRMWARE_FRAMEBUFFER_SET_VIRTUAL_OFFSET = 0x00048009,
RPI_FIRMWARE_FRAMEBUFFER_SET_OVERSCAN = 0x0004800a,
RPI_FIRMWARE_FRAMEBUFFER_SET_PALETTE = 0x0004800b,
+ RPI_FIRMWARE_FRAMEBUFFER_SET_TOUCHBUF = 0x0004801f,
+ RPI_FIRMWARE_FRAMEBUFFER_SET_GPIOVIRTBUF = 0x00048020,
+ RPI_FIRMWARE_FRAMEBUFFER_SET_VSYNC = 0x0004800e,
+ RPI_FIRMWARE_FRAMEBUFFER_SET_BACKLIGHT = 0x0004800f,

RPI_FIRMWARE_VCHIQ_INIT = 0x00048010,
--
2.15.1
Baruch Siach
2018-01-16 12:45:09 UTC
Permalink
From: Dave Stevenson <***@raspberrypi.org>

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 <***@raspberrypi.org>
Signed-off-by: Baruch Siach <***@tkos.co.il>
---
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

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index d6a8e851ad13..2d67b65bfec3 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -128,6 +128,15 @@ config GPIO_AXP209
help
Say yes to enable GPIO support for the AXP209 PMIC

+config GPIO_RASPBERRYPI_EXP
+ tristate "Raspberry Pi 3 GPIO Expander"
+ default RASPBERRYPI_FIRMWARE
+ depends on OF_GPIO
+ depends on (ARCH_BCM2835 && RASPBERRYPI_FIRMWARE) || COMPILE_TEST
+ help
+ Turn on GPIO support for the expander on Raspberry Pi 3 boards, using
+ the firmware mailbox to communicate with VideoCore on BCM283x chips.
+
config GPIO_BCM_KONA
bool "Broadcom Kona GPIO"
depends on OF_GPIO && (ARCH_BCM_MOBILE || COMPILE_TEST)
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 4bc24febb889..71021b0e71da 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -33,6 +33,7 @@ obj-$(CONFIG_GPIO_ARIZONA) += gpio-arizona.o
obj-$(CONFIG_GPIO_ATH79) += gpio-ath79.o
obj-$(CONFIG_GPIO_ASPEED) += gpio-aspeed.o
obj-$(CONFIG_GPIO_AXP209) += gpio-axp209.o
+obj-$(CONFIG_GPIO_RASPBERRYPI_EXP) += gpio-raspberrypi-exp.o
obj-$(CONFIG_GPIO_BCM_KONA) += gpio-bcm-kona.o
obj-$(CONFIG_GPIO_BD9571MWV) += gpio-bd9571mwv.o
obj-$(CONFIG_GPIO_BRCMSTB) += gpio-brcmstb.o
diff --git a/drivers/gpio/gpio-raspberrypi-exp.c b/drivers/gpio/gpio-raspberrypi-exp.c
new file mode 100644
index 000000000000..cf0fd6401c40
--- /dev/null
+++ b/drivers/gpio/gpio-raspberrypi-exp.c
@@ -0,0 +1,253 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Raspberry Pi 3 expander GPIO driver
+ *
+ * Uses the firmware mailbox service to communicate with the
+ * GPIO expander on the VPU.
+ *
+ * Copyright (C) 2017 Raspberry Pi Trading Ltd.
+ */
+
+#include <linux/err.h>
+#include <linux/gpio/driver.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <soc/bcm2835/raspberrypi-firmware.h>
+
+#define MODULE_NAME "raspberrypi-exp-gpio"
+#define NUM_GPIO 8
+
+#define RPI_EXP_GPIO_BASE 128
+
+#define RPI_EXP_GPIO_DIR_IN 0
+#define RPI_EXP_GPIO_DIR_OUT 1
+
+struct rpi_exp_gpio {
+ struct gpio_chip gc;
+ struct rpi_firmware *fw;
+};
+
+/* VC4 firmware mailbox interface data structures */
+
+struct gpio_set_config {
+ u32 gpio;
+ u32 direction;
+ u32 polarity;
+ u32 term_en;
+ u32 term_pull_up;
+ u32 state;
+};
+
+struct gpio_get_config {
+ u32 gpio;
+ u32 direction;
+ u32 polarity;
+ u32 term_en;
+ u32 term_pull_up;
+};
+
+struct gpio_get_set_state {
+ u32 gpio;
+ u32 state;
+};
+
+static int rpi_exp_gpio_get_polarity(struct gpio_chip *gc, unsigned int off)
+{
+ struct rpi_exp_gpio *gpio;
+ struct gpio_get_config get;
+ int ret;
+
+ gpio = gpiochip_get_data(gc);
+
+ get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
+
+ ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG,
+ &get, sizeof(get));
+ if (ret || get.gpio != 0) {
+ dev_err(gc->parent, "Failed to get GPIO %u config (%d %x)\n",
+ off, ret, get.gpio);
+ return ret ? ret : -EIO;
+ }
+ return get.polarity;
+}
+
+static int rpi_exp_gpio_dir_in(struct gpio_chip *gc, unsigned int off)
+{
+ struct rpi_exp_gpio *gpio;
+ struct gpio_set_config set_in;
+ int ret;
+
+ gpio = gpiochip_get_data(gc);
+
+ set_in.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
+ set_in.direction = RPI_EXP_GPIO_DIR_IN;
+ set_in.term_en = 0; /* termination disabled */
+ set_in.term_pull_up = 0; /* n/a as termination disabled */
+ set_in.state = 0; /* n/a as configured as an input */
+
+ ret = rpi_exp_gpio_get_polarity(gc, off);
+ if (ret < 0)
+ return ret;
+ set_in.polarity = ret; /* Retain existing setting */
+
+ ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_CONFIG,
+ &set_in, sizeof(set_in));
+ if (ret || set_in.gpio != 0) {
+ dev_err(gc->parent, "Failed to set GPIO %u to input (%d %x)\n",
+ off, ret, set_in.gpio);
+ return ret ? ret : -EIO;
+ }
+ return 0;
+}
+
+static int rpi_exp_gpio_dir_out(struct gpio_chip *gc, unsigned int off, int val)
+{
+ struct rpi_exp_gpio *gpio;
+ struct gpio_set_config set_out;
+ int ret;
+
+ gpio = gpiochip_get_data(gc);
+
+ set_out.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
+ set_out.direction = RPI_EXP_GPIO_DIR_OUT;
+ set_out.term_en = 0; /* n/a as an output */
+ set_out.term_pull_up = 0; /* n/a as termination disabled */
+ set_out.state = val; /* Output state */
+
+ ret = rpi_exp_gpio_get_polarity(gc, off);
+ if (ret < 0)
+ return ret;
+ set_out.polarity = ret; /* Retain existing setting */
+
+ ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_CONFIG,
+ &set_out, sizeof(set_out));
+ if (ret || set_out.gpio != 0) {
+ dev_err(gc->parent, "Failed to set GPIO %u to output (%d %x)\n",
+ off, ret, set_out.gpio);
+ return ret ? ret : -EIO;
+ }
+ return 0;
+}
+
+static int rpi_exp_gpio_get_direction(struct gpio_chip *gc, unsigned int off)
+{
+ struct rpi_exp_gpio *gpio;
+ struct gpio_get_config get;
+ int ret;
+
+ gpio = gpiochip_get_data(gc);
+
+ get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
+
+ ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG,
+ &get, sizeof(get));
+ if (ret || get.gpio != 0) {
+ dev_err(gc->parent,
+ "Failed to get GPIO %u config (%d %x)\n", off, ret,
+ get.gpio);
+ return ret ? ret : -EIO;
+ }
+ return !get.direction;
+}
+
+static int rpi_exp_gpio_get(struct gpio_chip *gc, unsigned int off)
+{
+ struct rpi_exp_gpio *gpio;
+ struct gpio_get_set_state get;
+ int ret;
+
+ gpio = gpiochip_get_data(gc);
+
+ get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
+ get.state = 0; /* storage for returned value */
+
+ ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_STATE,
+ &get, sizeof(get));
+ if (ret || get.gpio != 0) {
+ dev_err(gc->parent,
+ "Failed to get GPIO %u state (%d %x)\n", off, ret,
+ get.gpio);
+ return ret ? ret : -EIO;
+ }
+ return !!get.state;
+}
+
+static void rpi_exp_gpio_set(struct gpio_chip *gc, unsigned int off, int val)
+{
+ struct rpi_exp_gpio *gpio;
+ struct gpio_get_set_state set;
+ int ret;
+
+ gpio = gpiochip_get_data(gc);
+
+ set.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
+ set.state = val; /* Output state */
+
+ ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_STATE,
+ &set, sizeof(set));
+ if (ret || set.gpio != 0)
+ dev_err(gc->parent,
+ "Failed to set GPIO %u state (%d %x)\n", off, ret,
+ set.gpio);
+}
+
+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);
+}
+
+static const struct of_device_id rpi_exp_gpio_ids[] = {
+ { .compatible = "raspberrypi,firmware-gpio" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, rpi_exp_gpio_ids);
+
+static struct platform_driver rpi_exp_gpio_driver = {
+ .driver = {
+ .name = MODULE_NAME,
+ .owner = THIS_MODULE,
+ .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 <***@raspberrypi.org>");
+MODULE_DESCRIPTION("Raspberry Pi 3 expander GPIO driver");
+MODULE_ALIAS("platform:rpi-exp-gpio");
--
2.15.1
Stefan Wahren
2018-01-19 18:50:07 UTC
Permalink
Hi Baruch,
Post by Baruch Siach
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.
---
* 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
* 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
...
+
+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);
+}
+
+static const struct of_device_id rpi_exp_gpio_ids[] = {
+ { .compatible = "raspberrypi,firmware-gpio" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, rpi_exp_gpio_ids);
+
+static struct platform_driver rpi_exp_gpio_driver = {
+ .driver = {
+ .name = MODULE_NAME,
+ .owner = THIS_MODULE,
i assume you got the kbuild test robot mail about this. So please remove this and you can add my
Post by Baruch Siach
+ .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_DESCRIPTION("Raspberry Pi 3 expander GPIO driver");
+MODULE_ALIAS("platform:rpi-exp-gpio");
--
2.15.1
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linux-arm-kernel mailing list
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Stefan Wahren
2018-01-17 08:30:09 UTC
Permalink
Hi Linus,
hi Eric,
Post by Baruch Siach
Add a description of the RPi3 GPIO expander that the VC4 firmware controls.
---
* List GPIO names one per line.
* 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(+)
diff --git a/arch/arm/boot/dts/bcm2837-rpi-3-b.dts b/arch/arm/boot/dts/bcm2837-rpi-3-b.dts
index b44b3b5af00d..8cd93425ffe3 100644
--- a/arch/arm/boot/dts/bcm2837-rpi-3-b.dts
+++ b/arch/arm/boot/dts/bcm2837-rpi-3-b.dts
@@ -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?
Post by Baruch Siach
+
+ 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 */
Linus Walleij
2018-01-17 09:39:06 UTC
Permalink
Post by Stefan Wahren
Hi Linus,
hi Eric,
Post by Baruch Siach
Add a description of the RPi3 GPIO expander that the VC4 firmware controls.
---
* List GPIO names one per line.
* 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(+)
diff --git a/arch/arm/boot/dts/bcm2837-rpi-3-b.dts
b/arch/arm/boot/dts/bcm2837-rpi-3-b.dts
index b44b3b5af00d..8cd93425ffe3 100644
--- a/arch/arm/boot/dts/bcm2837-rpi-3-b.dts
+++ b/arch/arm/boot/dts/bcm2837-rpi-3-b.dts
@@ -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?
All DTS patches shall be merged through ARM SoC so the conflict should
be resolved by whoever sends the pull requests to ARM SoC before
sending the pull request.

I think these patches will be for the next kernel anyways, unless Torvalds
think we should have an -rc9 this time (because of all the meltdowns and
spectres etc you know).

Yours,
Linus Walleij
Stefan Wahren
2018-01-19 18:52:28 UTC
Permalink
Post by Baruch Siach
Add a description of the RPi3 GPIO expander that the VC4 firmware controls.
Acked-by: Stefan Wahren <***@i2se.com>
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