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Date: Thu, 21 Feb 2019 10:32:58 +0100
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Shravan Kumar Ramani <sramani@...lanox.com>
Cc: Linus Walleij <linus.walleij@...aro.org>,
Bartosz Golaszewski <bgolaszewski@...libre.com>,
"open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 1/1] gpio: add driver for Mellanox BlueField GPIO controller
śr., 20 lut 2019 o 23:07 Shravan Kumar Ramani <sramani@...lanox.com> napisał(a):
>
> This patch adds support for the GPIO controller used by Mellanox
> BlueField SOCs.
>
Starts to look good. Just some minor points.
First: when submitting new versions - please list the changes from the
last one (or even better: all changes between all versions). This is a
small driver, but with bigger patches it's important to know what
changed.
> Reviewed-by: David Woods <dwoods@...lanox.com>
> Signed-off-by: Shravan Kumar Ramani <sramani@...lanox.com>
> ---
> drivers/gpio/Kconfig | 6 ++
> drivers/gpio/Makefile | 1 +
> drivers/gpio/gpio-mlxbf.c | 222 ++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 229 insertions(+)
> create mode 100644 drivers/gpio/gpio-mlxbf.c
>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index b5a2845..c950fe8 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -1292,6 +1292,12 @@ config GPIO_MERRIFIELD
> help
> Say Y here to support Intel Merrifield GPIO.
>
> +config GPIO_MLXBF
> + tristate "Mellanox BlueField SoC GPIO"
> + depends on (MELLANOX_PLATFORM && ARM64 && ACPI) || COMPILE_TEST
> + help
> + Say Y here if you want GPIO support on Mellanox BlueField SoC.
> +
> config GPIO_ML_IOH
> tristate "OKI SEMICONDUCTOR ML7213 IOH GPIO support"
> depends on X86 || COMPILE_TEST
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index 37628f8..8d54279 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -83,6 +83,7 @@ obj-$(CONFIG_GPIO_MENZ127) += gpio-menz127.o
> obj-$(CONFIG_GPIO_MERRIFIELD) += gpio-merrifield.o
> obj-$(CONFIG_GPIO_MC33880) += gpio-mc33880.o
> obj-$(CONFIG_GPIO_MC9S08DZ60) += gpio-mc9s08dz60.o
> +obj-$(CONFIG_GPIO_MLXBF) += gpio-mlxbf.o
> obj-$(CONFIG_GPIO_ML_IOH) += gpio-ml-ioh.o
> obj-$(CONFIG_GPIO_MM_LANTIQ) += gpio-mm-lantiq.o
> obj-$(CONFIG_GPIO_MOCKUP) += gpio-mockup.o
> diff --git a/drivers/gpio/gpio-mlxbf.c b/drivers/gpio/gpio-mlxbf.c
> new file mode 100644
> index 0000000..c0f21f4
> --- /dev/null
> +++ b/drivers/gpio/gpio-mlxbf.c
> @@ -0,0 +1,222 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/acpi.h>
> +#include <linux/bitops.h>
> +#include <linux/device.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/io.h>
> +#include <linux/ioport.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm.h>
> +#include <linux/resource.h>
> +#include <linux/spinlock.h>
> +#include <linux/types.h>
> +#include <linux/version.h>
> +
> +/* Number of pins on BlueField */
> +#define MLXBF_GPIO_NR 54
> +
> +/* Pad Electrical Controls. */
> +#define MLXBF_GPIO_PAD_CONTROL__FIRST_WORD 0x0700
> +#define MLXBF_GPIO_PAD_CONTROL_1__FIRST_WORD 0x0708
> +#define MLXBF_GPIO_PAD_CONTROL_2__FIRST_WORD 0x0710
> +#define MLXBF_GPIO_PAD_CONTROL_3__FIRST_WORD 0x0718
> +
Why the double underscores? Maybe let's make it
MLXBF_GPIO_PADCTRL_FIRST_WORD and so on.
> +#define MLXBF_GPIO_PIN_DIR_I 0x1040
> +#define MLXBF_GPIO_PIN_DIR_O 0x1048
> +#define MLXBF_GPIO_PIN_STATE 0x1000
> +#define MLXBF_GPIO_SCRATCHPAD 0x20
> +
> +#ifdef CONFIG_PM
> +struct mlxbf_gpio_context_save_regs {
> + u64 scratchpad;
> + u64 pad_control[MLXBF_GPIO_NR];
> + u64 pin_dir_i;
> + u64 pin_dir_o;
> +};
> +#endif
> +
> +/* Device state structure. */
> +struct mlxbf_gpio_state {
> + struct gpio_chip gc;
> +
> + /* Must hold this lock to modify shared data. */
> + spinlock_t lock;
> +
> + /* Memory Address */
> + void __iomem *dc_base;
> +
> +#ifdef CONFIG_PM
> + struct mlxbf_gpio_context_save_regs csave_regs;
> +#endif
> +};
> +
> +static int mlxbf_gpio_set_input(struct gpio_chip *chip, unsigned int offset)
> +{
> + struct mlxbf_gpio_state *gs = gpiochip_get_data(chip);
> + u64 in;
> + u64 out;
> +
> + out = readq(gs->dc_base + MLXBF_GPIO_PIN_DIR_O);
> + in = readq(gs->dc_base + MLXBF_GPIO_PIN_DIR_I);
> +
Please protect the entire read/modify operations. Same below. What if
someone was writing to the registers while we're reading them here?
> + spin_lock(&gs->lock);
> + writeq(out & ~BIT(offset), gs->dc_base + MLXBF_GPIO_PIN_DIR_O);
> + writeq(in | BIT(offset), gs->dc_base + MLXBF_GPIO_PIN_DIR_I);
> + spin_unlock(&gs->lock);
> +
> + return 0;
> +}
> +
> +static int mlxbf_gpio_set_output(struct gpio_chip *chip, unsigned int offset,
> + int value)
> +{
> + struct mlxbf_gpio_state *gs = gpiochip_get_data(chip);
> + u64 in;
> + u64 out;
> +
> + out = readq(gs->dc_base + MLXBF_GPIO_PIN_DIR_O);
> + in = readq(gs->dc_base + MLXBF_GPIO_PIN_DIR_I);
> +
> + spin_lock(&gs->lock);
> + writeq(out | BIT(offset), gs->dc_base + MLXBF_GPIO_PIN_DIR_O);
> + writeq(in & ~BIT(offset), gs->dc_base + MLXBF_GPIO_PIN_DIR_I);
> + spin_unlock(&gs->lock);
> +
> + return 0;
> +}
> +
> +static int mlxbf_gpio_get(struct gpio_chip *chip, unsigned int offset)
> +{
> + u64 value;
> + struct mlxbf_gpio_state *gs = gpiochip_get_data(chip);
> +
> + spin_lock(&gs->lock);
> + value = readq(gs->dc_base + MLXBF_GPIO_PIN_STATE);
> + spin_unlock(&gs->lock);
> +
> + return (value >> offset) & 1;
> +}
> +
> +static void mlxbf_gpio_set(struct gpio_chip *chip, unsigned int offset,
> + int value)
> +{
> + u64 data;
> + struct mlxbf_gpio_state *gs = gpiochip_get_data(chip);
> +
> + spin_lock(&gs->lock);
> + data = readq(gs->dc_base + MLXBF_GPIO_PIN_STATE);
> +
> + if (value)
> + data |= BIT(offset);
> + else
> + data &= ~BIT(offset);
> + writeq(data, gs->dc_base + MLXBF_GPIO_PIN_STATE);
> + spin_unlock(&gs->lock);
> +}
> +
> +static int mlxbf_gpio_probe(struct platform_device *pdev)
> +{
> + struct mlxbf_gpio_state *gs;
> + struct device *dev = &pdev->dev;
> + struct gpio_chip *gc;
> + struct resource *dc_res;
This is a minor nit: why do you use the dc_ prefix? Maybe let's use
more standard names for these variables like "base", "res" etc.? If
there is a valid reason - feel free to ignore it.
> + int ret;
> +
> + gs = devm_kzalloc(&pdev->dev, sizeof(*gs), GFP_KERNEL);
> + if (!gs)
> + return -ENOMEM;
> +
> + dc_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + gs->dc_base = devm_ioremap_resource(&pdev->dev, dc_res);
> + if (IS_ERR(gs->dc_base))
> + return PTR_ERR(gs->dc_base);
> +
> + gc = &gs->gc;
> + gc->direction_input = mlxbf_gpio_set_input;
> + gc->direction_output = mlxbf_gpio_set_output;
> + gc->get = mlxbf_gpio_get;
> + gc->set = mlxbf_gpio_set;
> + gc->label = dev_name(dev);
> + gc->parent = &pdev->dev;
> + gc->owner = THIS_MODULE;
> + gc->base = -1;
> + gc->ngpio = MLXBF_GPIO_NR;
> +
> + ret = devm_gpiochip_add_data(dev, &gs->gc, gs);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed adding memory mapped gpiochip\n");
> + return ret;
> + }
> +
> + spin_lock_init(&gs->lock);
> + platform_set_drvdata(pdev, gs);
> + dev_info(&pdev->dev, "registered Mellanox BlueField GPIO");
> + return 0;
> +}
> +
> +#ifdef CONFIG_PM
> +static int mlxbf_gpio_suspend(struct platform_device *pdev, pm_message_t state)
> +{
> + struct mlxbf_gpio_state *gs = platform_get_drvdata(pdev);
> +
> + gs->csave_regs.scratchpad = readq(gs->dc_base + MLXBF_GPIO_SCRATCHPAD);
> + gs->csave_regs.pad_control[0] =
> + readq(gs->dc_base + MLXBF_GPIO_PAD_CONTROL__FIRST_WORD);
> + gs->csave_regs.pad_control[1] =
> + readq(gs->dc_base + MLXBF_GPIO_PAD_CONTROL_1__FIRST_WORD);
> + gs->csave_regs.pad_control[2] =
> + readq(gs->dc_base + MLXBF_GPIO_PAD_CONTROL_2__FIRST_WORD);
> + gs->csave_regs.pad_control[3] =
> + readq(gs->dc_base + MLXBF_GPIO_PAD_CONTROL_3__FIRST_WORD);
> + gs->csave_regs.pin_dir_i = readq(gs->dc_base + MLXBF_GPIO_PIN_DIR_I);
> + gs->csave_regs.pin_dir_o = readq(gs->dc_base + MLXBF_GPIO_PIN_DIR_O);
> +
> + return 0;
> +}
> +
> +static int mlxbf_gpio_resume(struct platform_device *pdev)
> +{
> + struct mlxbf_gpio_state *gs = platform_get_drvdata(pdev);
> +
> + writeq(gs->csave_regs.scratchpad, gs->dc_base + MLXBF_GPIO_SCRATCHPAD);
> + writeq(gs->csave_regs.pad_control[0],
> + gs->dc_base + MLXBF_GPIO_PAD_CONTROL__FIRST_WORD);
> + writeq(gs->csave_regs.pad_control[1],
> + gs->dc_base + MLXBF_GPIO_PAD_CONTROL_1__FIRST_WORD);
> + writeq(gs->csave_regs.pad_control[2],
> + gs->dc_base + MLXBF_GPIO_PAD_CONTROL_2__FIRST_WORD);
> + writeq(gs->csave_regs.pad_control[3],
> + gs->dc_base + MLXBF_GPIO_PAD_CONTROL_3__FIRST_WORD);
> + writeq(gs->csave_regs.pin_dir_i, gs->dc_base + MLXBF_GPIO_PIN_DIR_I);
> + writeq(gs->csave_regs.pin_dir_o, gs->dc_base + MLXBF_GPIO_PIN_DIR_O);
> +
> + return 0;
> +}
> +#endif
> +
> +static const struct acpi_device_id mlxbf_gpio_acpi_match[] = {
> + { "MLNXBF02", 0 },
> + {}
> +};
> +MODULE_DEVICE_TABLE(acpi, mlxbf_gpio_acpi_match);
> +
> +static struct platform_driver mlxbf_gpio_driver = {
> + .driver = {
> + .name = "mlxbf_gpio",
> + .acpi_match_table = ACPI_PTR(mlxbf_gpio_acpi_match),
> + },
> + .probe = mlxbf_gpio_probe,
> +#ifdef CONFIG_PM
> + .suspend = mlxbf_gpio_suspend,
> + .resume = mlxbf_gpio_resume,
> +#endif
> +};
> +
> +module_platform_driver(mlxbf_gpio_driver);
> +
> +MODULE_DESCRIPTION("Mellanox BlueField GPIO Driver");
> +MODULE_AUTHOR("Mellanox Technologies");
> +MODULE_LICENSE("GPL");
> --
> 2.1.2
>
Best regards,
Bartosz Golaszewski
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