Re: [PATCH v3 1/2] gpio: loongson: add dts/acpi gpio support

From: WANG Xuerui
Date: Wed Nov 16 2022 - 03:35:57 EST


On 2022/11/16 14:53, Yinbo Zhu wrote:
The latest Loongson series platform use dts or acpi framework to
register gpio device resources, such as the Loongson-2 series
SoC of LOONGARCH architecture. In order to support dts, acpi and
compatibility with previous platform device resources in driver,
this patch was added.

"LoongArch", not "LOONGARCH". The latter sounds too similar to a mass replace from the all-caps MIPS.

But again the commit message is overly verbose IMO, and contains minor grammatical mistakes that don't hamper understanding but are a nuisance nevertheless. I think the following could be enough:

"Subject: gpio: loongson: Add DTS and ACPI support"

"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: lvjianmin <lvjianmin@xxxxxxxxxxx>

He's canonically "Jianmin Lv <...>" in the Git history.

Signed-off-by: zhanghongchen <zhanghongchen@xxxxxxxxxxx>

Please use proper spelling, either "Zhang Hongchen" or "Hongchen Zhang". I think every people with a loongson.cn address is using the latter form i.e. the Western order of "Firstname Lastname" except the "Liu Peibao" below, but ask the person themselves for honoring their own preference.

Signed-off-by: Liu Peibao <liupeibao@xxxxxxxxxxx>
Signed-off-by: Juxin Gao <gaojuxin@xxxxxxxxxxx>
Signed-off-by: Yinbo Zhu <zhuyinbo@xxxxxxxxxxx>
---
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 | 424 ++++++++++++++++----
include/linux/platform_data/gpio-loongson.h | 22 +
4 files changed, 385 insertions(+), 75 deletions(-)
create mode 100644 include/linux/platform_data/gpio-loongson.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 5114db9c8f32..bbd7a0d946eb 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 SERIES GPIO DRIVER

Drop "series" here and everywhere else.

+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..fb8f0075a8ae 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 CPU_LOONGSON2EF || CPU_LOONGSON64 || LOONGARCH
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..1e553db03cf8 100644
--- a/drivers/gpio/gpio-loongson.c
+++ b/drivers/gpio/gpio-loongson.c
@@ -1,13 +1,15 @@
// SPDX-License-Identifier: GPL-2.0-or-later
/*
- * Loongson-2F/3A/3B GPIO Support
+ * Loongson Series GPIO Support
*
- * Copyright (c) 2008 Richard Liu, STMicroelectronics <richard.liu@xxxxxx>
+ * 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>
+ * Copyright (c) 2022-2023 Yinbo Zhu <zhuyinbo@xxxxxxxxxxx>

Is it 2023 already?

And do the people listed in the S-o-b tags need a mention here? Or is it more appropriate to remove some of them or demote to tags like Co-developed-by?

*/
+#include <linux/acpi.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
@@ -16,120 +18,398 @@
#include <linux/gpio/driver.h>
#include <linux/platform_device.h>
#include <linux/bitops.h>
+#include <linux/platform_data/gpio-loongson.h>
#include <asm/types.h>
-#include <loongson.h>
-
-#define STLS2F_N_GPIO 4
-#define STLS3A_N_GPIO 16
-
-#ifdef CONFIG_CPU_LOONGSON64
-#define LOONGSON_N_GPIO STLS3A_N_GPIO
+#if defined(CONFIG_LOONGARCH)
+#include <asm/loongson.h>
+#elif defined(CONFIG_CPU_LOONGSON2EF)
+#include <asm/mach-loongson2ef/loongson.h>
#else
-#define LOONGSON_N_GPIO STLS2F_N_GPIO
+#include <asm/mach-loongson64/loongson.h>
#endif
-/*
- * 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
+#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)
+
+#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)
+
+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;
+ bool support_irq;
+};
+
+static int loongson_gpio_request(
+ struct gpio_chip *chip, unsigned int pin)
+{
+ if (pin >= chip->ngpio)
+ return -EINVAL;
+ else

Drop the "else" because the true branch is an early return i.e. diverging.

+ return 0;
+}
+
+static inline void __set_direction(struct loongson_gpio_chip *lgpio,
+ unsigned int pin, int input)
+{
+ 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;
+ }
-static DEFINE_SPINLOCK(gpio_lock);
+ if (!strcmp(lgpio->chip.label, "loongson,ls7a-gpio") ||
+ !strncmp(lgpio->chip.label, "LOON0002", 8)) {
+ if (input)
+ bval = 1;
+ else
+ bval = 0;

bval = input ? 1 : 0;

+ writeb(bval, LOONGSON_GPIO_OEN_BYTE(lgpio, pin));
+ return;
+ }
+
+ if (!strcmp(lgpio->chip.label, "loongson,platform-gpio")) {
+ if (input)
+ LOONGSON_GPIOIE |= BIT(pin);
+ else
+ LOONGSON_GPIOIE &= ~BIT(pin);
+ return;
+ }
+}
-static int loongson_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
+static void __set_level(struct loongson_gpio_chip *lgpio, unsigned int pin,
+ int high)
{
- u32 val;
+ u64 qval;
+ u8 bval;
+
+ 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;
+ }
- 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)) {
+ if (high)
+ bval = 1;
+ else
+ bval = 0;

bval = high ? 1 : 0;

+ writeb(bval, LOONGSON_GPIO_OUT_BYTE(lgpio, pin));
+ return;
+ }
- return !!(val & BIT(gpio + LOONGSON_GPIO_IN_OFFSET));
+ if (!strcmp(lgpio->chip.label, "loongson,platform-gpio")) {
+ if (LOONGSON_GPIODATA)
+ LOONGSON_GPIODATA |= BIT(pin);
+ else
+ LOONGSON_GPIODATA &= ~BIT(pin);
+ return;
+ }
}
-static void loongson_gpio_set_value(struct gpio_chip *chip,
- unsigned gpio, int value)
+static int loongson_gpio_direction_input(
+ struct gpio_chip *chip, unsigned int pin)
{
- u32 val;
+ unsigned long flags;
+ struct loongson_gpio_chip *lgpio =
+ container_of(chip, struct loongson_gpio_chip, chip);
- spin_lock(&gpio_lock);
- val = LOONGSON_GPIODATA;
- if (value)
- val |= BIT(gpio);
- else
- val &= ~BIT(gpio);
- LOONGSON_GPIODATA = val;
- 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_input(struct gpio_chip *chip, unsigned gpio)
+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;
- 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_direction_output(struct gpio_chip *chip,
- unsigned gpio, int level)
+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)
{
- u32 temp;
+ unsigned long flags;
+ struct loongson_gpio_chip *lgpio =
+ container_of(chip, struct loongson_gpio_chip, chip);
- 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);
+ 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;
+
+ if (!strcmp(lgpio->chip.label, "loongson,ls7a-gpio") ||
+ !strncmp(lgpio->chip.label, "LOON0002", 8) ||
+ !strcmp(lgpio->chip.label, "loongson,ls2k-gpio"))

Aren't these 3 device IDs the only models we support/have right now? If so I think the check could safely be dropped.

+ 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->support_irq = true;
+ lgpio->conf_offset = 0x0;
+ lgpio->out_offset = 0x10;
+ lgpio->in_offset = 0x20;
+ return;
+ }
+
+ if (!strcmp(name, "loongson,ls7a-gpio")) {
+ lgpio->support_irq = true;
+ lgpio->conf_offset = 0x800;
+ lgpio->out_offset = 0x900;
+ lgpio->in_offset = 0xa00;

Aren't configurations like these usually described in the DT? Are you trying to maintain compatibility with the pre-existing DT structure that is missing such data?

+ 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)
+{
+ struct loongson_gpio_platform_data *gpio_data =
+ (struct loongson_gpio_platform_data *)pdev->dev.platform_data;
+
+ lgpio->chip.ngpio = gpio_data->ngpio;
+ lgpio->chip.base = gpio_data->gpio_base;
+ lgpio->conf_offset = gpio_data->gpio_conf;
+ lgpio->out_offset = gpio_data->gpio_out;
+ lgpio->in_offset = gpio_data->gpio_in;
+ lgpio->chip.label = kstrdup(gpio_data->label, GFP_KERNEL);
+}
+
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);
+ 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);
+
+ 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;
+ }
+
+ platform_set_drvdata(pdev, lgpio);
+
+ loongson_gpio_init(dev, lgpio, np, base);
+
+ return 0;
+out:
+ pr_err("%s: %s: missing mandatory property\n", __func__, np->name);

I suggest checking out <linux/dev_printk.h> and use dev_* printk's everywhere you have a `dev` at hand (which is the case here).

+ return ret;
+}
+
+static int loongson_gpio_remove(struct platform_device *pdev)
+{
+ struct loongson_gpio_chip *lgpio = platform_get_drvdata(pdev);
+ struct resource *mem;
+
+ platform_set_drvdata(pdev, NULL);
- return gpiochip_add_data(gc, 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));
+
+ 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);
+}
diff --git a/include/linux/platform_data/gpio-loongson.h b/include/linux/platform_data/gpio-loongson.h
new file mode 100644
index 000000000000..f102d2650576
--- /dev/null
+++ b/include/linux/platform_data/gpio-loongson.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Author: Yinbo Zhu <zhuyinbo@xxxxxxxxxxx>
+ * Copyright (C) 2022-2023 Loongson Technology Corporation Limited
+ */
+
+#ifndef __LOONGSON_GPIO_PLATFORM_H
+#define __LOONGSON_GPIO_PLATFORM_H
+
+/* ============== Data structrues =============== */

This comment could be removed as the code here is very trivial hence self-commentary.

But again, please check out Arnd's review comment; still I think this might not be necessary at all because the legacy users already have to modify many other things elsewhere before they can rebase on the more recent upstream versions.

+
+struct loongson_gpio_platform_data {
+ u32 gpio_conf;
+ u32 gpio_out;
+ u32 gpio_in;
+ u32 support_irq;
+ char *label;
+ int gpio_base;
+ int ngpio;
+};
+
+#endif

--
WANG "xen0n" Xuerui

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