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Date: Wed, 14 Nov 2018 10:53:14 +0200
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: Florian Eckert <fe@....tdt.de>
Cc: Linus Walleij <linus.walleij@...aro.org>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
Joe Perches <joe@...ches.com>,
Christian Lamparter <chunkeey@...il.com>, piotr.krol@...eb.com,
Darren Hart <dvhart@...radead.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
"open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>
Subject: Re: [PATCH v3 1/2] gpio: Add driver for PC Engines APU2/APU3 GPIOs
On Wed, Nov 14, 2018 at 9:27 AM Florian Eckert <fe@....tdt.de> wrote:
>
> Add a new device driver "gpio-apu" which will handle the GPIOs onAPU2
> and APU3 devices from PC Engines.
>
> APU2 (https://pcengines.ch/schema/apu2c.pdf page 7):
> - G32 is "button_reset" connected to the smd-button on the frontpanel
> - G50 is "mpcie2_reset" connected to mPCIe2 reset line
> - G51 is "mpcie3_reset" connected to mPCIe3 reset line
>
> APU3 (https://pcengines.ch/schema/apu3c.pdf page 7):
> - G32 is "button_reset" connected to the smd-button on the frontpanel
> - G50 is "mpcie2_reset" connected to mPCIe2 reset line
> - G51 is "mpcie3_reset" connected to mPCIe3 reset line
> - G33 is "simswap" connected to SIM switch IC to swap the SIM between
> mPCIe2 and mPCIe3 slot
>
> Signed-off-by: Florian Eckert <fe@....tdt.de>
> ---
> drivers/gpio/Kconfig | 8 ++
> drivers/gpio/Makefile | 1 +
> drivers/gpio/gpio-apu.c | 312 ++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 321 insertions(+)
> create mode 100644 drivers/gpio/gpio-apu.c
>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index 833a1b51c948..f9e603d5670c 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -117,6 +117,14 @@ config GPIO_AMDPT
> driver for GPIO functionality on Promontory IOHub
> Require ACPI ASL code to enumerate as a platform device.
>
> +config GPIO_APU
> + tristate "PC Engines APU2/APU3 GPIO support"
> + depends on X86
> + select GPIO_GENERIC
> + help
> + Say Y here to support GPIO functionality on APU2/APU3 boards
> + from PC Engines.
> +
> config GPIO_ASPEED
> tristate "Aspeed GPIO support"
> depends on (ARCH_ASPEED || COMPILE_TEST) && OF_GPIO
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index 671c4477c951..9c27523fb189 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -29,6 +29,7 @@ obj-$(CONFIG_GPIO_ALTERA) += gpio-altera.o
> obj-$(CONFIG_GPIO_ALTERA_A10SR) += gpio-altera-a10sr.o
> obj-$(CONFIG_GPIO_AMD8111) += gpio-amd8111.o
> obj-$(CONFIG_GPIO_AMDPT) += gpio-amdpt.o
> +obj-$(CONFIG_GPIO_APU) += gpio-apu.o
> obj-$(CONFIG_GPIO_ARIZONA) += gpio-arizona.o
> obj-$(CONFIG_GPIO_ATH79) += gpio-ath79.o
> obj-$(CONFIG_GPIO_ASPEED) += gpio-aspeed.o
> diff --git a/drivers/gpio/gpio-apu.c b/drivers/gpio/gpio-apu.c
> new file mode 100644
> index 000000000000..df166c0d8258
> --- /dev/null
> +++ b/drivers/gpio/gpio-apu.c
> @@ -0,0 +1,312 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* PC Engines APU2/APU3 GPIO device driver
> + *
> + * Copyright (C) 2018 Florian Eckert <fe@....tdt.de>
> + */
> +
> +#include <linux/dmi.h>
> +#include <linux/err.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/input.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +
> +#define DEVNAME "gpio-apu"
> +
> +#define APU_FCH_ACPI_MMIO_BASE 0xFED80000
> +#define APU_FCH_GPIO_BASE (APU_FCH_ACPI_MMIO_BASE + 0x1500)
> +#define APU_GPIO_BIT_RD 16
> +#define APU_GPIO_BIT_WR 22
> +#define APU_GPIO_BIT_DIR 23
> +
> +struct apu_gpio_pdata {
> + struct platform_device *pdev;
> + struct gpio_chip *chip;
> + unsigned long *offset; /* base register offset */
> + void __iomem **addr; /* remapped iomem addresses */
> + spinlock_t lock; /* lock register access */
> +};
> +
> +static struct apu_gpio_pdata *apu_gpio;
> +
> +/* APU2 */
> +static unsigned long apu2_gpio_offset[] = {
> + APU_FCH_GPIO_BASE + 89 * sizeof(u32),
> + APU_FCH_GPIO_BASE + 67 * sizeof(u32),
> + APU_FCH_GPIO_BASE + 66 * sizeof(u32),
> +};
> +static const char * const apu2_gpio_names[] = {
> + "button_reset",
> + "mpcie2_reset",
> + "mpcie3_reset",
> +};
> +
> +/* APU3 */
> +static unsigned long apu3_gpio_offset[] = {
> + APU_FCH_GPIO_BASE + 89 * sizeof(u32),
> + APU_FCH_GPIO_BASE + 67 * sizeof(u32),
> + APU_FCH_GPIO_BASE + 66 * sizeof(u32),
> + APU_FCH_GPIO_BASE + 90 * sizeof(u32),
> +};
> +static const char * const apu3_gpio_names[] = {
> + "button_reset",
> + "mpcie2_reset",
> + "mpcie3_reset",
> + "simswap",
> +};
> +
> +static int gpio_apu_get_dir(struct gpio_chip *chip, unsigned int offset)
> +{
> + u32 val;
> +
> + spin_lock(&apu_gpio->lock);
> +
> + val = ~ioread32(apu_gpio->addr[offset]);
> + val = (val >> APU_GPIO_BIT_DIR) & 1;
> +
> + spin_unlock(&apu_gpio->lock);
> +
> + return val;
> +}
> +
> +static int gpio_apu_dir_in(struct gpio_chip *chip, unsigned int offset)
> +{
> + u32 val;
> +
> + spin_lock(&apu_gpio->lock);
> +
> + val = ioread32(apu_gpio->addr[offset]);
> + val &= ~BIT(APU_GPIO_BIT_DIR);
> + iowrite32(val, apu_gpio->addr[offset]);
> +
> + spin_unlock(&apu_gpio->lock);
> +
> + return 0;
> +}
> +
> +static int gpio_apu_dir_out(struct gpio_chip *chip, unsigned int offset,
> + int value)
> +{
> + u32 val;
> +
> + spin_lock(&apu_gpio->lock);
> +
> + val = ioread32(apu_gpio->addr[offset]);
> + val |= BIT(APU_GPIO_BIT_DIR);
> + iowrite32(val, apu_gpio->addr[offset]);
> +
> + spin_unlock(&apu_gpio->lock);
> +
> + return 0;
> +}
> +
> +static int gpio_apu_get_data(struct gpio_chip *chip, unsigned int offset)
> +{
> + u32 val;
> +
> + spin_lock(&apu_gpio->lock);
> +
> + val = ioread32(apu_gpio->addr[offset]);
> + val = (val >> APU_GPIO_BIT_RD) & 1;
This can be done outside of spin lock as a part of return statement.
> +
> + spin_unlock(&apu_gpio->lock);
> +
> + return val;
> +}
> +
> +static void gpio_apu_set_data(struct gpio_chip *chip, unsigned int offset,
> + int value)
> +{
> + u32 val;
> +
> + spin_lock(&apu_gpio->lock);
> +
> + val = ioread32(apu_gpio->addr[offset]);
> + if (value)
> + val |= BIT(APU_GPIO_BIT_WR);
> + else
> + val &= ~BIT(APU_GPIO_BIT_WR);
> + iowrite32(val, apu_gpio->addr[offset]);
> +
> + spin_unlock(&apu_gpio->lock);
> +}
> +
> +static const struct dmi_system_id apu_gpio_dmi_table[] __initconst = {
> + /* PC Engines APU2 with "Legacy" bios < 4.0.8 */
> + {
> + .ident = "apu2",
> + .matches = {
> + DMI_MATCH(DMI_SYS_VENDOR, "PC Engines"),
> + DMI_MATCH(DMI_BOARD_NAME, "APU2")
> + }
> + },
> + /* PC Engines APU2 with "Legacy" bios >= 4.0.8 */
> + {
> + .ident = "apu2",
> + .matches = {
> + DMI_MATCH(DMI_SYS_VENDOR, "PC Engines"),
> + DMI_MATCH(DMI_BOARD_NAME, "apu2")
> + }
> + },
> + /* PC Engines APU2 with "Mainline" bios */
> + {
> + .ident = "apu2",
> + .matches = {
> + DMI_MATCH(DMI_SYS_VENDOR, "PC Engines"),
> + DMI_MATCH(DMI_BOARD_NAME, "PC Engines apu2")
> + }
> + },
> + /* PC Engines APU3 with "Legacy" bios < 4.0.8 */
> + {
> + .ident = "apu3",
> + .matches = {
> + DMI_MATCH(DMI_SYS_VENDOR, "PC Engines"),
> + DMI_MATCH(DMI_BOARD_NAME, "APU3")
> + }
> + },
> + /* PC Engines APU3 with "Legacy" bios >= 4.0.8 */
> + {
> + .ident = "apu3",
> + .matches = {
> + DMI_MATCH(DMI_SYS_VENDOR, "PC Engines"),
> + DMI_MATCH(DMI_BOARD_NAME, "apu3")
> + }
> + },
> + /* PC Engines APU3 with "Mainline" bios */
> + {
> + .ident = "apu3",
> + .matches = {
> + DMI_MATCH(DMI_SYS_VENDOR, "PC Engines"),
> + DMI_MATCH(DMI_BOARD_NAME, "PC Engines apu3")
> + }
> + },
> + {}
> +};
> +MODULE_DEVICE_TABLE(dmi, apu_gpio_dmi_table);
> +
> +static struct gpio_chip gpio_apu_chip = {
> + .label = "gpio-apu",
> + .owner = THIS_MODULE,
> + .base = 20,
> + .get_direction = gpio_apu_get_dir,
> + .direction_input = gpio_apu_dir_in,
> + .direction_output = gpio_apu_dir_out,
> + .get = gpio_apu_get_data,
> + .set = gpio_apu_set_data,
> +};
> +
> +static int __init apu_gpio_probe(struct platform_device *pdev)
> +{
> + int i;
unsigned int i; ?
> +
> + apu_gpio = devm_kzalloc(&pdev->dev, sizeof(*apu_gpio), GFP_KERNEL);
> +
Redundant blank line.
> + if (!apu_gpio)
> + return -ENOMEM;
> +
> + apu_gpio->pdev = pdev;
> + apu_gpio->chip = &gpio_apu_chip;
> + spin_lock_init(&apu_gpio->lock);
> +
> + if (dmi_match(DMI_BOARD_NAME, "APU3") ||
> + dmi_match(DMI_BOARD_NAME, "apu3") ||
> + dmi_match(DMI_BOARD_NAME, "PC Engines apu3")) {
This branch...
> + apu_gpio->addr = devm_kzalloc(&pdev->dev,
> + sizeof(apu3_gpio_offset),
> + GFP_KERNEL);
> +
> + if (!apu_gpio->addr)
> + return -ENOMEM;
> +
> + apu_gpio->offset = apu3_gpio_offset;
> + apu_gpio->chip->names = apu3_gpio_names;
> + apu_gpio->chip->ngpio = ARRAY_SIZE(apu3_gpio_offset);
> + for (i = 0; i < ARRAY_SIZE(apu3_gpio_offset); i++) {
> + apu_gpio->addr[i] = devm_ioremap(&pdev->dev,
> + apu_gpio->offset[i], sizeof(u32));
> + if (!apu_gpio->addr[i])
> + return -ENOMEM;
> + }
> + } else if (dmi_match(DMI_BOARD_NAME, "APU2") ||
> + dmi_match(DMI_BOARD_NAME, "apu2") ||
> + dmi_match(DMI_BOARD_NAME, "PC Engines apu2")) {
...and this one can be done as a callback functions in a regular DMI
table. See, for example, drivers in drivers/platform/x86.
> + apu_gpio->addr = devm_kzalloc(&pdev->dev,
> + sizeof(apu2_gpio_offset),
> + GFP_KERNEL);
> +
> + if (!apu_gpio->addr)
> + return -ENOMEM;
> +
> + apu_gpio->offset = apu2_gpio_offset;
> + apu_gpio->chip->names = apu2_gpio_names;
> + apu_gpio->chip->ngpio = ARRAY_SIZE(apu2_gpio_offset);
> + for (i = 0; i < ARRAY_SIZE(apu2_gpio_offset); i++) {
> + apu_gpio->addr[i] = devm_ioremap(&pdev->dev,
> + apu_gpio->offset[i], sizeof(u32));
> + if (!apu_gpio->addr[i])
> + return -ENOMEM;
> + }
> + }
> +
> + return devm_gpiochip_add_data(&pdev->dev, apu_gpio->chip, NULL);
> +}
> +
> +static struct platform_driver apu_gpio_driver = {
> + .driver = {
> + .name = KBUILD_MODNAME,
> + },
> +};
> +
> +static int __init apu_gpio_init(void)
> +{
> + struct platform_device *pdev;
> + int err;
> +
> + if (!dmi_match(DMI_SYS_VENDOR, "PC Engines")) {
> + pr_err("No PC Engines board detected\n");
> + return -ENODEV;
> + }
> + if (!(dmi_match(DMI_PRODUCT_NAME, "APU2") ||
> + dmi_match(DMI_PRODUCT_NAME, "apu2") ||
> + dmi_match(DMI_PRODUCT_NAME, "PC Engines apu2") ||
> + dmi_match(DMI_PRODUCT_NAME, "APU3") ||
> + dmi_match(DMI_PRODUCT_NAME, "apu3") ||
> + dmi_match(DMI_PRODUCT_NAME, "PC Engines apu3"))) {
> + pr_err("Unknown PC Engines board: %s\n",
> + dmi_get_system_info(DMI_PRODUCT_NAME));
> + return -ENODEV;
> + }
Similar here, you can get a first match in the table and if none, bail out.
> +
> + pdev = platform_device_register_simple(KBUILD_MODNAME, -1, NULL, 0);
> + if (IS_ERR(pdev)) {
> + pr_err("Device allocation failed\n");
> + return PTR_ERR(pdev);
> + }
> +
> + err = platform_driver_probe(&apu_gpio_driver, apu_gpio_probe);
> + if (err) {
> + pr_err("Probe platform driver failed\n");
> + platform_device_unregister(pdev);
> + }
> +
> + pr_info("%s: APU2/3 GPIO driver module loaded\n", DEVNAME);
Noise
> +
> + return err;
> +}
> +
> +static void __exit apu_gpio_exit(void)
> +{
> + gpiochip_remove(apu_gpio->chip);
> + platform_device_unregister(apu_gpio->pdev);
> + platform_driver_unregister(&apu_gpio_driver);
> + pr_info("%s: APU2/3 GPIO driver module unloaded\n", DEVNAME);
Noise
> +}
> +
> +module_init(apu_gpio_init);
> +module_exit(apu_gpio_exit);
> +
> +MODULE_AUTHOR("Florian Eckert");
> +MODULE_DESCRIPTION("PC Engines APU2/3 family GPIO driver");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:gpio_apu");
> --
> 2.11.0
>
--
With Best Regards,
Andy Shevchenko
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