Re: [PATCH v4 1/2] gpio: loongson: add dts and acpi support

From: Bartosz Golaszewski
Date: Thu Nov 17 2022 - 04:39:30 EST

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In reply to: Yinbo Zhu: "[PATCH v4 2/2] dt-bindings: gpio: add loongson gpio"
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On Thu, Nov 17, 2022 at 4:59 AM Yinbo Zhu <zhuyinbo@xxxxxxxxxxx> wrote:
>
> Latest Loongson platforms such as the Loongson-2 SoC series describe
> GPIO device resources with DTS or ACPI. Add such support to the
> existing platform device driver.
>
> Signed-off-by: Jianmin Lv <lvjianmin@xxxxxxxxxxx>
> Signed-off-by: Hongchen Zhang <zhanghongchen@xxxxxxxxxxx>
> Signed-off-by: Liu Peibao <liupeibao@xxxxxxxxxxx>
> Signed-off-by: Juxin Gao <gaojuxin@xxxxxxxxxxx>
> Signed-off-by: Yinbo Zhu <zhuyinbo@xxxxxxxxxxx>
> ---
> Change in v4:
> 1. Fixup name spelling about Signed-off-by.
> 2. Drop "series" here and everywhere else.
> 3. Fixup the copyright in driver.
> 4. Drop the "else" in loongson_gpio_request.
> 5. Use trinocular operation replace the related logic.
> 6. Remove lable judgement in context about "lgpio->chip.to_irq =
> loongson_gpio_to_irq"
> 7. Use dev_err replace pr_err in probe.
> 8. Make legacy platform_data should be left out of this patch.
> 9. Remove the mips config in gpio Kconfig.
> Change in v3:
> 1. Move the gpio platform data struct from arch/ into include/linux/
> platform_data/.
> 2. Replace platform_gpio_data with loongson_gpio_platform_data in .c.
> 3. Add maintainer in MAINTAINERS file for include/linux/platform_data/
> gpio-loongson.h and gpio-loongson.c
> Change in v2:
> 1. Fixup of_loongson_gpio_get_props and remove the parse logic about
> "loongson,conf_offset", "loongson,out_offset", "loongson,in_offset",
> "loongson,gpio_base", "loongson,support_irq" then kernel driver will
> initial them that depend compatible except "loongson,gpio_base".
>
> MAINTAINERS | 8 +
> drivers/gpio/Kconfig | 6 +-
> drivers/gpio/gpio-loongson.c | 403 ++++++++++++++++++++++++++++-------
> 3 files changed, 338 insertions(+), 79 deletions(-)
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 5114db9c8f32..838b920efcef 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -12051,6 +12051,14 @@ S: Maintained
> F: Documentation/devicetree/bindings/hwinfo/loongson,ls2k-chipid.yaml
> F: drivers/soc/loongson/loongson2_guts.c
>
> +LOONGSON GPIO DRIVER
> +M: Huacai Chen <chenhuacai@xxxxxxxxxx>
> +M: Yinbo Zhu <zhuyinbo@xxxxxxxxxxx>
> +L: linux-gpio@xxxxxxxxxxxxxxx
> +S: Maintained
> +F: drivers/gpio/gpio-loongson.c
> +F: include/linux/platform_data/gpio-loongson.h
> +
> LSILOGIC MPT FUSION DRIVERS (FC/SAS/SPI)
> M: Sathya Prakash <sathya.prakash@xxxxxxxxxxxx>
> M: Sreekanth Reddy <sreekanth.reddy@xxxxxxxxxxxx>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index a01af1180616..b4423c058b1d 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -376,10 +376,10 @@ config GPIO_LOGICVC
> programmable logic block.
>
> config GPIO_LOONGSON
> - bool "Loongson-2/3 GPIO support"
> - depends on CPU_LOONGSON2EF || CPU_LOONGSON64
> + bool "Loongson series GPIO support"
> + depends on LOONGARCH || COMPILE_TEST
> help
> - Driver for GPIO functionality on Loongson-2F/3A/3B processors.
> + Driver for GPIO functionality on Loongson seires processors.
>
> config GPIO_LPC18XX
> tristate "NXP LPC18XX/43XX GPIO support"
> diff --git a/drivers/gpio/gpio-loongson.c b/drivers/gpio/gpio-loongson.c
> index a42145873cc9..b9b191a541c0 100644
> --- a/drivers/gpio/gpio-loongson.c
> +++ b/drivers/gpio/gpio-loongson.c
> @@ -1,13 +1,11 @@
> -// SPDX-License-Identifier: GPL-2.0-or-later
> +// SPDX-License-Identifier: GPL-2.0+
> /*
> - * Loongson-2F/3A/3B GPIO Support
> + * Loongson GPIO Support
> *
> - * Copyright (c) 2008 Richard Liu, STMicroelectronics <richard.liu@xxxxxx>
> - * Copyright (c) 2008-2010 Arnaud Patard <apatard@xxxxxxxxxxxx>
> - * Copyright (c) 2013 Hongbing Hu <huhb@xxxxxxxxxx>
> - * Copyright (c) 2014 Huacai Chen <chenhc@xxxxxxxxxx>

Why are you removing other people's copyright notices?

> + * Copyright (C) 2022 Loongson Technology Corporation Limited
> */
>
> +#include <linux/acpi.h>
> #include <linux/kernel.h>
> #include <linux/init.h>
> #include <linux/module.h>
> @@ -17,119 +15,372 @@
> #include <linux/platform_device.h>
> #include <linux/bitops.h>
> #include <asm/types.h>
> -#include <loongson.h>
> +#include <asm/loongson.h>
>
> -#define STLS2F_N_GPIO 4
> -#define STLS3A_N_GPIO 16
> +#define LOONGSON_GPIO_IN(x) (x->base + x->in_offset)
> +#define LOONGSON_GPIO_OUT(x) (x->base + x->out_offset)
> +#define LOONGSON_GPIO_OEN(x) (x->base + x->conf_offset)
>
> -#ifdef CONFIG_CPU_LOONGSON64
> -#define LOONGSON_N_GPIO STLS3A_N_GPIO
> -#else
> -#define LOONGSON_N_GPIO STLS2F_N_GPIO
> -#endif
> +#define LOONGSON_GPIO_IN_BYTE(x, gpio) (x->base +\
> + x->in_offset + gpio)
> +#define LOONGSON_GPIO_OUT_BYTE(x, gpio) (x->base +\
> + x->out_offset + gpio)
> +#define LOONGSON_GPIO_OEN_BYTE(x, gpio) (x->base +\
> + x->conf_offset + gpio)
>
> -/*
> - * Offset into the register where we read lines, we write them from offset 0.
> - * This offset is the only thing that stand between us and using
> - * GPIO_GENERIC.
> - */
> -#define LOONGSON_GPIO_IN_OFFSET 16
> +struct loongson_gpio_chip {
> + struct gpio_chip chip;
> + spinlock_t lock;
> + void __iomem *base;
> + int conf_offset;
> + int out_offset;
> + int in_offset;
> + u16 *gsi_idx_map;
> + u16 mapsize;
> +};
>
> -static DEFINE_SPINLOCK(gpio_lock);
> +static int loongson_gpio_request(
> + struct gpio_chip *chip, unsigned int pin)
> +{
> + if (pin >= chip->ngpio)
> + return -EINVAL;
> +
> + return 0;
> +}
>
> -static int loongson_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
> +static inline void __set_direction(struct loongson_gpio_chip *lgpio,
> + unsigned int pin, int input)
> {
> - u32 val;
> + u64 qval;
> + u8 bval;
> +
> + if (!strcmp(lgpio->chip.label, "loongson,ls2k-gpio")) {
> + qval = readq(LOONGSON_GPIO_OEN(lgpio));
> + if (input)
> + qval |= 1ULL << pin;
> + else
> + qval &= ~(1ULL << pin);
> + writeq(qval, LOONGSON_GPIO_OEN(lgpio));
> + return;
> + }
>
> - spin_lock(&gpio_lock);
> - val = LOONGSON_GPIODATA;
> - spin_unlock(&gpio_lock);
> + if (!strcmp(lgpio->chip.label, "loongson,ls7a-gpio") ||
> + !strncmp(lgpio->chip.label, "LOON0002", 8)) {

This is ugly - can you instead use chip data associated with the
relevant compatible to store whatever custom info you need? See the
data field in struct of_device_id and acpi_device_id. Same elsewhere,
I really dislike this label parsing everywhere.

> + bval = input ? 1 : 0;
> + writeb(bval, LOONGSON_GPIO_OEN_BYTE(lgpio, pin));
> + return;
> + }
>
> - return !!(val & BIT(gpio + LOONGSON_GPIO_IN_OFFSET));
> + if (!strcmp(lgpio->chip.label, "loongson,platform-gpio")) {
> + if (input)
> + LOONGSON_GPIOIE |= BIT(pin);
> + else
> + LOONGSON_GPIOIE &= ~BIT(pin);
> + return;
> + }
> }
>
> -static void loongson_gpio_set_value(struct gpio_chip *chip,
> - unsigned gpio, int value)
> +static void __set_level(struct loongson_gpio_chip *lgpio, unsigned int pin,
> + int high)
> {
> - u32 val;
> + u64 qval;
> + u8 bval;
>
> - spin_lock(&gpio_lock);
> - val = LOONGSON_GPIODATA;
> - if (value)
> - val |= BIT(gpio);
> - else
> - val &= ~BIT(gpio);
> - LOONGSON_GPIODATA = val;
> - spin_unlock(&gpio_lock);
> + if (!strcmp(lgpio->chip.label, "loongson,ls2k-gpio")) {
> + qval = readq(LOONGSON_GPIO_OUT(lgpio));
> + if (high)
> + qval |= 1ULL << pin;
> + else
> + qval &= ~(1ULL << pin);
> + writeq(qval, LOONGSON_GPIO_OUT(lgpio));
> + return;
> + }
> +
> + if (!strcmp(lgpio->chip.label, "loongson,ls7a-gpio") ||
> + !strncmp(lgpio->chip.label, "LOON0002", 8)) {
> + bval = high ? 1 : 0;
> + writeb(bval, LOONGSON_GPIO_OUT_BYTE(lgpio, pin));
> + return;
> + }
> +
> + if (!strcmp(lgpio->chip.label, "loongson,platform-gpio")) {
> + if (LOONGSON_GPIODATA)
> + LOONGSON_GPIODATA |= BIT(pin);
> + else
> + LOONGSON_GPIODATA &= ~BIT(pin);
> + return;
> + }
> }
>
> -static int loongson_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
> +static int loongson_gpio_direction_input(
> + struct gpio_chip *chip, unsigned int pin)
> {
> - u32 temp;
> + unsigned long flags;
> + struct loongson_gpio_chip *lgpio =
> + container_of(chip, struct loongson_gpio_chip, chip);
>
> - spin_lock(&gpio_lock);
> - temp = LOONGSON_GPIOIE;
> - temp |= BIT(gpio);
> - LOONGSON_GPIOIE = temp;
> - spin_unlock(&gpio_lock);
> + spin_lock_irqsave(&lgpio->lock, flags);
> + __set_direction(lgpio, pin, 1);
> + spin_unlock_irqrestore(&lgpio->lock, flags);
>
> return 0;
> }
>
> -static int loongson_gpio_direction_output(struct gpio_chip *chip,
> - unsigned gpio, int level)
> +static int loongson_gpio_direction_output(
> + struct gpio_chip *chip, unsigned int pin,
> + int value)
> {
> - u32 temp;
> + struct loongson_gpio_chip *lgpio =
> + container_of(chip, struct loongson_gpio_chip, chip);
> + unsigned long flags;
>
> - loongson_gpio_set_value(chip, gpio, level);
> - spin_lock(&gpio_lock);
> - temp = LOONGSON_GPIOIE;
> - temp &= ~BIT(gpio);
> - LOONGSON_GPIOIE = temp;
> - spin_unlock(&gpio_lock);
> + spin_lock_irqsave(&lgpio->lock, flags);
> + __set_level(lgpio, pin, value);
> + __set_direction(lgpio, pin, 0);
> + spin_unlock_irqrestore(&lgpio->lock, flags);
>
> return 0;
> }
>
> +static int loongson_gpio_get(struct gpio_chip *chip, unsigned int pin)
> +{
> + u64 qval;
> + u8 bval;
> + int val;
> + struct loongson_gpio_chip *lgpio =
> + container_of(chip, struct loongson_gpio_chip, chip);
> +
> + if (!strcmp(lgpio->chip.label, "loongson,ls2k-gpio")) {
> + qval = readq(LOONGSON_GPIO_IN(lgpio));
> + return ((qval & (1ULL << pin)) != 0);
> + }
> +
> + if (!strcmp(lgpio->chip.label, "loongson,ls7a-gpio") ||
> + !strncmp(lgpio->chip.label, "LOON0002", 8)) {
> + bval = readb(LOONGSON_GPIO_IN_BYTE(lgpio, pin));
> + return (bval & 1);
> + }
> +
> + if (!strcmp(lgpio->chip.label, "loongson,platform-gpio")) {
> + val = LOONGSON_GPIODATA;
> + return !!(val & BIT(pin + lgpio->in_offset));
> + }
> +
> + return -ENXIO;
> +}
> +
> +static void loongson_gpio_set(struct gpio_chip *chip, unsigned int pin,
> + int value)
> +{
> + unsigned long flags;
> + struct loongson_gpio_chip *lgpio =
> + container_of(chip, struct loongson_gpio_chip, chip);
> +
> + spin_lock_irqsave(&lgpio->lock, flags);
> + __set_level(lgpio, pin, value);
> + spin_unlock_irqrestore(&lgpio->lock, flags);
> +}
> +
> +static int loongson_gpio_to_irq(
> + struct gpio_chip *chip, unsigned int offset)
> +{
> + struct platform_device *pdev =
> + container_of(chip->parent, struct platform_device, dev);
> + struct loongson_gpio_chip *lgpio =
> + container_of(chip, struct loongson_gpio_chip, chip);
> +
> + if (offset >= chip->ngpio)
> + return -EINVAL;
> +
> + if ((lgpio->gsi_idx_map != NULL) && (offset < lgpio->mapsize))
> + offset = lgpio->gsi_idx_map[offset];
> +
> + return platform_get_irq(pdev, offset);
> +}
> +
> +static int loongson_gpio_init(
> + struct device *dev, struct loongson_gpio_chip *lgpio,
> + struct device_node *np, void __iomem *base)
> +{
> + lgpio->chip.request = loongson_gpio_request;
> + lgpio->chip.direction_input = loongson_gpio_direction_input;
> + lgpio->chip.get = loongson_gpio_get;
> + lgpio->chip.direction_output = loongson_gpio_direction_output;
> + lgpio->chip.set = loongson_gpio_set;
> + lgpio->chip.can_sleep = 0;
> + lgpio->chip.of_node = np;
> + lgpio->chip.parent = dev;
> + spin_lock_init(&lgpio->lock);
> + lgpio->base = (void __iomem *)base;
> + lgpio->chip.to_irq = loongson_gpio_to_irq;
> +
> + gpiochip_add(&lgpio->chip);
> +
> + return 0;
> +}
> +
> +static void of_loongson_gpio_get_props(struct device_node *np,
> + struct loongson_gpio_chip *lgpio)
> +{
> + const char *name;
> +
> + of_property_read_u32(np, "ngpios", (u32 *)&lgpio->chip.ngpio);
> +
> + of_property_read_string(np, "compatible", &name);
> + lgpio->chip.label = kstrdup(name, GFP_KERNEL);
> +
> + if (!strcmp(name, "loongson,ls2k-gpio")) {
> + lgpio->conf_offset = 0x0;
> + lgpio->out_offset = 0x10;
> + lgpio->in_offset = 0x20;
> + return;
> + }
> +
> + if (!strcmp(name, "loongson,ls7a-gpio")) {
> + lgpio->conf_offset = 0x800;
> + lgpio->out_offset = 0x900;
> + lgpio->in_offset = 0xa00;
> + return;
> + }
> +}
> +
> +static void acpi_loongson_gpio_get_props(struct platform_device *pdev,
> + struct loongson_gpio_chip *lgpio)
> +{
> +
> + struct device *dev = &pdev->dev;
> + int rval;
> +
> + device_property_read_u32(dev, "ngpios", (u32 *)&lgpio->chip.ngpio);
> + device_property_read_u32(dev, "gpio_base", (u32 *)&lgpio->chip.base);
> + device_property_read_u32(dev, "conf_offset",
> + (u32 *)&lgpio->conf_offset);
> + device_property_read_u32(dev, "out_offset",
> + (u32 *)&lgpio->out_offset);
> + device_property_read_u32(dev, "in_offset", (u32 *)&lgpio->in_offset);
> +
> + rval = device_property_read_u16_array(dev, "gsi_idx_map", NULL, 0);
> + if (rval > 0) {
> + lgpio->gsi_idx_map =
> + kmalloc_array(rval, sizeof(*lgpio->gsi_idx_map),
> + GFP_KERNEL);
> + if (unlikely(!lgpio->gsi_idx_map)) {
> + dev_err(dev, "Alloc gsi_idx_map fail!\n");
> + } else {
> + lgpio->mapsize = rval;
> + device_property_read_u16_array(dev, "gsi_idx_map",
> + lgpio->gsi_idx_map, lgpio->mapsize);
> + }
> + }
> +
> + lgpio->chip.label = kstrdup(pdev->name, GFP_KERNEL);
> +}
> +
> +static void platform_loongson_gpio_get_props(struct platform_device *pdev,
> + struct loongson_gpio_chip *lgpio)
> +{
> +}

Drop it, if you don't use it.

> +
> static int loongson_gpio_probe(struct platform_device *pdev)
> {
> - struct gpio_chip *gc;
> + struct resource *iores;
> + void __iomem *base;
> + struct loongson_gpio_chip *lgpio;
> + struct device_node *np = pdev->dev.of_node;
> struct device *dev = &pdev->dev;
> + int ret = 0;
>
> - gc = devm_kzalloc(dev, sizeof(*gc), GFP_KERNEL);
> - if (!gc)
> + lgpio = kzalloc(sizeof(struct loongson_gpio_chip), GFP_KERNEL);

Why stop using devres? Same elsewhere.

> + if (!lgpio)
> return -ENOMEM;
>
> - gc->label = "loongson-gpio-chip";
> - gc->base = 0;
> - gc->ngpio = LOONGSON_N_GPIO;
> - gc->get = loongson_gpio_get_value;
> - gc->set = loongson_gpio_set_value;
> - gc->direction_input = loongson_gpio_direction_input;
> - gc->direction_output = loongson_gpio_direction_output;
> + if (np)
> + of_loongson_gpio_get_props(np, lgpio);
> + else if (ACPI_COMPANION(&pdev->dev))
> + acpi_loongson_gpio_get_props(pdev, lgpio);
> + else
> + platform_loongson_gpio_get_props(pdev, lgpio);

I would prefer if you used generic device properties - like you
already do for acpi. They work for OF too thanks to the fwnode
abstraction.

> +
> + iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!iores) {
> + ret = -ENODEV;
> + goto out;
> + }
> +
> + if (!request_mem_region(iores->start, resource_size(iores),
> + pdev->name)) {
> + ret = -EBUSY;
> + goto out;
> + }
> +
> + base = ioremap(iores->start, resource_size(iores));
> + if (!base) {
> + ret = -ENOMEM;
> + goto out;
> + }

Are you aware of the gpio-regmap interface? It seems to me that this
code could benefit from using it. There are already some good examples
in the tree.

> +
> + platform_set_drvdata(pdev, lgpio);
> +
> + loongson_gpio_init(dev, lgpio, np, base);
> +
> + return 0;
> +out:
> + dev_err(dev, "missing mandatory property\n");
> +

So if request_mem_region() or ioremap() fails, we're printing this
error message? Doesn't seem right.

> + return ret;
> +}
> +
> +static int loongson_gpio_remove(struct platform_device *pdev)
> +{
> + struct loongson_gpio_chip *lgpio = platform_get_drvdata(pdev);
> + struct resource *mem;
>
> - return gpiochip_add_data(gc, NULL);
> + platform_set_drvdata(pdev, NULL);
> +
> + gpiochip_remove(&lgpio->chip);
> + iounmap(lgpio->base);
> + kfree(lgpio->gsi_idx_map);
> + kfree(lgpio);
> + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + release_mem_region(mem->start, resource_size(mem));
> +

This entire function can be dropped if you used devres.

> + return 0;
> }
>
> +static const struct of_device_id loongson_gpio_dt_ids[] = {
> + { .compatible = "loongson,ls2k-gpio"},
> + { .compatible = "loongson,ls7a-gpio"},
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, loongson_gpio_dt_ids);
> +
> +static const struct acpi_device_id loongson_gpio_acpi_match[] = {
> + {"LOON0002"},
> + {}
> +};
> +MODULE_DEVICE_TABLE(acpi, loongson_gpio_acpi_match);
> +
> static struct platform_driver loongson_gpio_driver = {
> .driver = {
> .name = "loongson-gpio",
> + .owner = THIS_MODULE,
> + .of_match_table = loongson_gpio_dt_ids,
> + .acpi_match_table = ACPI_PTR(loongson_gpio_acpi_match),
> },
> .probe = loongson_gpio_probe,
> + .remove = loongson_gpio_remove,
> };
>
> static int __init loongson_gpio_setup(void)
> {
> - struct platform_device *pdev;
> - int ret;
> -
> - ret = platform_driver_register(&loongson_gpio_driver);
> - if (ret) {
> - pr_err("error registering loongson GPIO driver\n");
> - return ret;
> - }
> -
> - pdev = platform_device_register_simple("loongson-gpio", -1, NULL, 0);
> - return PTR_ERR_OR_ZERO(pdev);
> + return platform_driver_register(&loongson_gpio_driver);
> }
> postcore_initcall(loongson_gpio_setup);
> +
> +static void __exit loongson_gpio_exit(void)
> +{
> + platform_driver_unregister(&loongson_gpio_driver);
> +}

This module cannot be unloaded so you can drop this. The __exit macro
will make the compiler drop it anyway.

Bart

> +
> +MODULE_DESCRIPTION("Loongson gpio driver");
> +MODULE_LICENSE("GPL");
> --
> 2.31.1
>

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