[PATCH 1/6] bcm2835-gpio-exp: Driver for GPIO expander via mailbox service
Stefan Wahren
stefan.wahren at i2se.com
Sat Mar 18 06:23:23 PDT 2017
> Michael Zoran <mzoran at crowfest.net> hat am 17. März 2017 um 16:22 geschrieben:
>
>
> From: Dave Stevenson <dave.stevenson at 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.
>
> Pwr_led node added to device-tree for Pi3.
Looks like debris
>
> Signed-off-by: Dave Stevenson <dave.stevenson at raspberrypi.org>
>
> Stripped off changes to Makefile and Kconfig
> Also stripped off changes to raspberrypi-firmware.h
> Moved to drivers/staging/vc04_services/bcm2835-firmware-gpio
>
> Signed-off-by: Michael Zoran <mzoran at crowfest.net>
> ---
> .../bcm2835-firmware-gpio/gpio-bcm-exp.c | 256 +++++++++++++++++++++
> 1 file changed, 256 insertions(+)
> create mode 100644 drivers/staging/vc04_services/bcm2835-firmware-gpio/gpio-bcm-exp.c
>
> diff --git a/drivers/staging/vc04_services/bcm2835-firmware-gpio/gpio-bcm-exp.c b/drivers/staging/vc04_services/bcm2835-firmware-gpio/gpio-bcm-exp.c
> new file mode 100644
> index 000000000000..681a91492d4c
> --- /dev/null
> +++ b/drivers/staging/vc04_services/bcm2835-firmware-gpio/gpio-bcm-exp.c
> @@ -0,0 +1,256 @@
> +/*
> + * Broadcom expander GPIO driver
> + *
> + * Uses the firmware mailbox service to communicate with the
> + * GPIO expander on the VPU.
> + *
> + * Copyright (C) 2017 Raspberry Pi Trading Ltd.
> + *
> + * Author: Dave Stevenson <dave.stevenson at raspberrypi.org>
> + * Based on gpio-bcm-virt.c by Dom Cobley <popcornmix at gmail.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + */
> +
> +#include <linux/err.h>
> +#include <linux/gpio.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/dma-mapping.h>
> +#include <soc/bcm2835/raspberrypi-firmware.h>
> +
> +#define MODULE_NAME "brcmexp-gpio"
> +#define NUM_GPIO 8
> +
> +struct brcmexp_gpio {
> + struct gpio_chip gc;
> + struct device *dev;
> + struct rpi_firmware *fw;
> +};
> +
> +struct gpio_set_config {
> + u32 gpio, direction, polarity, term_en, term_pull_up, state;
Please one line per member
> +};
> +
> +struct gpio_get_config {
> + u32 gpio, direction, polarity, term_en, term_pull_up;
ditto
> +};
> +
> +struct gpio_get_set_state {
> + u32 gpio, state;
ditto
> +};
> +
> +static int brcmexp_gpio_get_polarity(struct gpio_chip *gc, unsigned int off)
> +{
> + struct brcmexp_gpio *gpio;
> + struct gpio_get_config get;
> + int ret;
> +
> + gpio = container_of(gc, struct brcmexp_gpio, gc);
> +
> + get.gpio = off + gpio->gc.base; /* GPIO to update */
> +
> + ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG,
> + &get, sizeof(get));
This define comes from patch 2 which should breaks the build after apply only this patch :-(
> + if (ret) {
> + dev_err(gpio->dev,
> + "Failed to get GPIO %u config (%d)\n", off, ret);
> + return ret;
> + }
> + return get.polarity;
> +}
> +
> +static int brcmexp_gpio_dir_in(struct gpio_chip *gc, unsigned int off)
> +{
> + struct brcmexp_gpio *gpio;
> + struct gpio_set_config set_in;
> + int ret;
> +
> + gpio = container_of(gc, struct brcmexp_gpio, gc);
> +
> + set_in.gpio = off + gpio->gc.base; /* GPIO to update */
> + set_in.direction = 0; /* Input */
I think a self explaining define would be better.
> + set_in.polarity = brcmexp_gpio_get_polarity(gc, off);
> + /* 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) {
> + dev_err(gpio->dev,
> + "Failed to set GPIO %u to input (%d)\n",
> + off, ret);
> + return ret;
> + }
> + return 0;
> +}
> +
> +static int brcmexp_gpio_dir_out(struct gpio_chip *gc, unsigned int off, int val)
> +{
> + struct brcmexp_gpio *gpio;
> + struct gpio_set_config set_out;
> + int ret;
> +
> + gpio = container_of(gc, struct brcmexp_gpio, gc);
> +
> + set_out.gpio = off + gpio->gc.base; /* GPIO to update */
> + set_out.direction = 1; /* Output */
> + set_out.polarity = brcmexp_gpio_get_polarity(gc, off);
> + /* 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) {
> + dev_err(gpio->dev,
> + "Failed to set GPIO %u to output (%d)\n", off, ret);
> + return ret;
> + }
> + return 0;
> +}
> +
> +static int brcmexp_gpio_get_direction(struct gpio_chip *gc, unsigned int off)
> +{
> + struct brcmexp_gpio *gpio;
> + struct gpio_get_config get;
> + int ret;
> +
> + gpio = container_of(gc, struct brcmexp_gpio, gc);
> +
> + get.gpio = off + gpio->gc.base; /* GPIO to update */
> +
> + ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG,
> + &get, sizeof(get));
> + if (ret) {
> + dev_err(gpio->dev,
> + "Failed to get GPIO %u config (%d)\n", off, ret);
> + return ret;
> + }
> + return get.direction ? GPIOF_DIR_OUT : GPIOF_DIR_IN;
> +}
> +
> +static int brcmexp_gpio_get(struct gpio_chip *gc, unsigned int off)
> +{
> + struct brcmexp_gpio *gpio;
> + struct gpio_get_set_state get;
> + int ret;
> +
> + gpio = container_of(gc, struct brcmexp_gpio, gc);
> +
> + get.gpio = off + gpio->gc.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) {
> + dev_err(gpio->dev,
> + "Failed to get GPIO %u state (%d)\n", off, ret);
> + return ret;
> + }
> + return !!get.state;
> +}
> +
> +static void brcmexp_gpio_set(struct gpio_chip *gc, unsigned int off, int val)
> +{
> + struct brcmexp_gpio *gpio;
> + struct gpio_get_set_state set;
> + int ret;
> +
> + gpio = container_of(gc, struct brcmexp_gpio, gc);
> +
> + off += gpio->gc.base;
> +
> + set.gpio = off + gpio->gc.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)
> + dev_err(gpio->dev,
> + "Failed to set GPIO %u state (%d)\n", off, ret);
> +}
> +
> +static int brcmexp_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 brcmexp_gpio *ucb;
The variable name isn't good.
> +
> + 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;
> +
> + ucb = devm_kzalloc(dev, sizeof(*ucb), GFP_KERNEL);
> + if (!ucb)
> + return -EINVAL;
ENOMEM ?
> +
> + ucb->fw = fw;
> + ucb->dev = dev;
> + ucb->gc.label = MODULE_NAME;
> + ucb->gc.owner = THIS_MODULE;
> + ucb->gc.of_node = np;
> + ucb->gc.base = 128;
> + ucb->gc.ngpio = NUM_GPIO;
> +
> + ucb->gc.direction_input = brcmexp_gpio_dir_in;
> + ucb->gc.direction_output = brcmexp_gpio_dir_out;
> + ucb->gc.get_direction = brcmexp_gpio_get_direction;
> + ucb->gc.get = brcmexp_gpio_get;
> + ucb->gc.set = brcmexp_gpio_set;
> + ucb->gc.can_sleep = true;
> +
> + err = gpiochip_add(&ucb->gc);
> + if (err)
> + return err;
Please use devm_gpiochip_add_data() here as suggested by Linus [1] then all the container_of() could be replaced by gpiochip_get_data().
[1] - https://patchwork.kernel.org/patch/9339859/
> +
> + platform_set_drvdata(pdev, ucb);
> +
> + return 0;
> +}
> +
> +static int brcmexp_gpio_remove(struct platform_device *pdev)
> +{
> + struct brcmexp_gpio *ucb = platform_get_drvdata(pdev);
> +
> + gpiochip_remove(&ucb->gc);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id __maybe_unused brcmexp_gpio_ids[] = {
__maybe_unused is unnecessary
> + { .compatible = "brcm,bcm2835-expgpio" },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, brcmexp_gpio_ids);
> +
> +static struct platform_driver brcmexp_gpio_driver = {
> + .driver = {
> + .name = MODULE_NAME,
> + .owner = THIS_MODULE,
Please drop this
> + .of_match_table = of_match_ptr(brcmexp_gpio_ids),
> + },
> + .probe = brcmexp_gpio_probe,
> + .remove = brcmexp_gpio_remove,
> +};
> +module_platform_driver(brcmexp_gpio_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Dave Stevenson <dave.stevenson at raspberrypi.org>");
> +MODULE_DESCRIPTION("brcm-exp GPIO driver");
> +MODULE_ALIAS("platform:brcmexp-gpio");
> --
> 2.11.0
>
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