Hi Baruch,
additionally the my comments on Michael's patches in March 2017, some new below.
> Baruch Siach <baruch@xxxxxxxxxx> hat am 2. Januar 2018 um 14:19 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>
> ---
> drivers/gpio/Kconfig | 7 ++
> drivers/gpio/Makefile | 1 +
> drivers/gpio/gpio-bcm-exp.c | 254 ++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 262 insertions(+)
> create mode 100644 drivers/gpio/gpio-bcm-exp.c
>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index d6a8e851ad13..e2aab64ea772 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -128,6 +128,13 @@ config GPIO_AXP209
> help
> Say yes to enable GPIO support for the AXP209 PMIC
>
> +config GPIO_BCM_EXP
> + bool "Broadcom Exp GPIO"
same as in the binding, i don't think this is specific to Broadcom.
> + depends on OF_GPIO && RASPBERRYPI_FIRMWARE && (ARCH_BCM2835 || COMPILE_TEST)
This is too long. Please split up.
> + help
> + Turn on GPIO support for Broadcom chips 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..c5f481b1d53c 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-$(CONFIG_GPIO_BCM_EXP) += gpio-bcm-exp.o
> obj-$(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-bcm-exp.c b/drivers/gpio/gpio-bcm-exp.c
> new file mode 100644
> index 000000000000..d68adafaee4a
> --- /dev/null
> +++ b/drivers/gpio/gpio-bcm-exp.c
> @@ -0,0 +1,254 @@
> +/*
> + * 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@xxxxxxxxxxxxxxx>
> + * Based on gpio-bcm-virt.c by Dom Cobley <popcornmix@xxxxxxxxx>
> + *
> + * 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.
> + */
SPDX identifier?
> +
> +#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;
> +};
> +
> +struct gpio_get_config {
> + u32 gpio, direction, polarity, term_en, term_pull_up;
> +};
> +
> +struct gpio_get_set_state {
> + u32 gpio, state;
> +};
> +
> +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 */
Please don't misuse the gpiochip base to communicate with the firmware. AFAIK the gc.base should be -1 (dynamic), so better use a define for the base.
> +
> + 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;
> + }
Shouldn't we also check the in-bound status at get.gpio?
And in all the other gpio ops?
> ...
> +
> +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;
> +
> + 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;
> +
> + 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;
As said above this should be -1
Stefan
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