Hi Baruch,
> Baruch Siach <baruch@xxxxxxxxxx> hat am 11. Januar 2018 um 20:44 geschrieben:
>
>
> From: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
>
> 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 <dave.stevenson@xxxxxxxxxxxxxxx>
> Signed-off-by: Baruch Siach <baruch@xxxxxxxxxx>
> ---
> 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 | 258 ++++++++++++++++++++++++++++++++++++
> 3 files changed, 268 insertions(+)
> create mode 100644 drivers/gpio/gpio-raspberrypi-exp.c
>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index d6a8e851ad13..8df901c75bef 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
> + bool "RaspberryPi 3 Exp GPIO"
How about "RaspberryPi 3 GPIO Expander" ?
Why not tristate? On arm64 it's preferred to have a kernel module.
> + default RASPBERRYPI_FIRMWARE
> + depends on OF_GPIO && RASPBERRYPI_FIRMWARE && \
> + (ARCH_BCM2835 || COMPILE_TEST)
Since this is default on RASPBERRYPI_FIRMWARE, we could remove it from the dependencies.
> + 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..95b1957a69fa
> --- /dev/null
> +++ b/drivers/gpio/gpio-raspberrypi-exp.c
> @@ -0,0 +1,258 @@
> +// 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.
2018?
> + */
> +
> +#include <linux/err.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/dma-mapping.h>
I can't see any DMA handling, so please remove it.
> +#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);
Can't we change this to fit in 2 lines?
> + 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.polarity = rpi_exp_gpio_get_polarity(gc, off);
This could fail, so please check the return code.
> + /* Retain existing setting */
> + 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_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);
see above
> + 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.polarity = rpi_exp_gpio_get_polarity(gc, off);
This could also fail.
> + /* Retain existing setting */
> + 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_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)
> +{
> + int err = 0;
> + 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;
> +
> + err = devm_gpiochip_add_data(dev, &rpi_gpio->gc, rpi_gpio);
> + if (err)
> + return err;
> +
> + platform_set_drvdata(pdev, rpi_gpio);
Since we use devm_gpiochip_add_data, we can drop this.
> +
> + return 0;
> +}
> +
> +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,
Please drop this, too.
Thanks
Stefan
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