[PATCH v2 0/2] gpio: fxl6408: add optional reset and suspend/resume

[PATCH v2 0/2] gpio: fxl6408: add optional reset and suspend/resume

[Jisheng Zhang]

Two improvements to the fxl6408 gpio driver:
Add opitonal reset gpio control.
Add suspend/resume support.

since v1:
  -fix W=1 build error on nios2 platform

Jisheng Zhang (2):
  gpio: fxl6408: Add optional reset gpio control
  gpio: fxl6408: Add suspend/resume support

 drivers/gpio/gpio-fxl6408.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

-- 
2.51.0

[PATCH v2 1/2] gpio: fxl6408: Add optional reset gpio control

[Jisheng Zhang]

Add optional active low reset-gpios pin control. If present, de-assert
the specified reset gpio pin to bring the chip out of reset.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
 drivers/gpio/gpio-fxl6408.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpio/gpio-fxl6408.c b/drivers/gpio/gpio-fxl6408.c
index 86ebc66b1104..7074831639ce 100644
--- a/drivers/gpio/gpio-fxl6408.c
+++ b/drivers/gpio/gpio-fxl6408.c
@@ -13,6 +13,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
 
 #define FXL6408_REG_DEVICE_ID		0x01
 #define FXL6408_MF_FAIRCHILD		0b101
@@ -104,6 +105,7 @@ static int fxl6408_identify(struct device *dev, struct regmap *regmap)
 static int fxl6408_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
+	struct gpio_desc *reset_gpio;
 	int ret;
 	struct gpio_regmap_config gpio_config = {
 		.parent = dev,
@@ -114,6 +116,10 @@ static int fxl6408_probe(struct i2c_client *client)
 		.ngpio_per_reg = FXL6408_NGPIO,
 	};
 
+	reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(reset_gpio))
+		return dev_err_probe(dev, PTR_ERR(reset_gpio), "Failed to get reset gpio\n");
+
 	gpio_config.regmap = devm_regmap_init_i2c(client, &regmap);
 	if (IS_ERR(gpio_config.regmap))
 		return dev_err_probe(dev, PTR_ERR(gpio_config.regmap),
-- 
2.51.0

[PATCH v2 2/2] gpio: fxl6408: Add suspend/resume support

[Jisheng Zhang]

Currently, during suspend, do nothing; during resume, just sync the
regmap cache to hw regs.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
 drivers/gpio/gpio-fxl6408.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/gpio/gpio-fxl6408.c b/drivers/gpio/gpio-fxl6408.c
index 7074831639ce..89cf14b5e3a2 100644
--- a/drivers/gpio/gpio-fxl6408.c
+++ b/drivers/gpio/gpio-fxl6408.c
@@ -44,6 +44,10 @@
 
 #define FXL6408_NGPIO			8
 
+struct fxl6408_chip {
+	struct regmap *regmap;
+};
+
 static const struct regmap_range rd_range[] = {
 	{ FXL6408_REG_DEVICE_ID, FXL6408_REG_DEVICE_ID },
 	{ FXL6408_REG_IO_DIR, FXL6408_REG_OUTPUT },
@@ -106,6 +110,7 @@ static int fxl6408_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
 	struct gpio_desc *reset_gpio;
+	struct fxl6408_chip *chip;
 	int ret;
 	struct gpio_regmap_config gpio_config = {
 		.parent = dev,
@@ -116,6 +121,10 @@ static int fxl6408_probe(struct i2c_client *client)
 		.ngpio_per_reg = FXL6408_NGPIO,
 	};
 
+	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
 	reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
 	if (IS_ERR(reset_gpio))
 		return dev_err_probe(dev, PTR_ERR(reset_gpio), "Failed to get reset gpio\n");
@@ -129,6 +138,9 @@ static int fxl6408_probe(struct i2c_client *client)
 	if (ret)
 		return ret;
 
+	chip->regmap = gpio_config.regmap;
+	i2c_set_clientdata(client, chip);
+
 	/* Disable High-Z of outputs, so that our OUTPUT updates actually take effect. */
 	ret = regmap_write(gpio_config.regmap, FXL6408_REG_OUTPUT_HIGH_Z, 0);
 	if (ret)
@@ -137,6 +149,16 @@ static int fxl6408_probe(struct i2c_client *client)
 	return PTR_ERR_OR_ZERO(devm_gpio_regmap_register(dev, &gpio_config));
 }
 
+static int fxl6408_resume(struct device *dev)
+{
+	struct fxl6408_chip *chip = dev_get_drvdata(dev);
+
+	regcache_mark_dirty(chip->regmap);
+	return regcache_sync(chip->regmap);
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(fxl6408_pm_ops, NULL, fxl6408_resume);
+
 static const __maybe_unused struct of_device_id fxl6408_dt_ids[] = {
 	{ .compatible = "fcs,fxl6408" },
 	{ }
@@ -152,6 +174,7 @@ MODULE_DEVICE_TABLE(i2c, fxl6408_id);
 static struct i2c_driver fxl6408_driver = {
 	.driver = {
 		.name	= "fxl6408",
+		.pm	= pm_sleep_ptr(&fxl6408_pm_ops),
 		.of_match_table = fxl6408_dt_ids,
 	},
 	.probe		= fxl6408_probe,
-- 
2.51.0

Re: [PATCH v2 1/2] gpio: fxl6408: Add optional reset gpio control

[Bartosz Golaszewski]

On Mon, Nov 17, 2025 at 1:32 AM Jisheng Zhang <jszhang@kernel.org> wrote:
>
> Add optional active low reset-gpios pin control. If present, de-assert
> the specified reset gpio pin to bring the chip out of reset.
>
> Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> ---

This is covered by the bindings at gpio/trivial-gpio.yaml but the
document does not describe a reset-gpios pin. This series doesn't add
any users of it either. What platform do you want to use it on?

Bartosz

Re: [PATCH v2 1/2] gpio: fxl6408: Add optional reset gpio control

[kernel test robot]

Hi Jisheng,

kernel test robot noticed the following build errors:

[auto build test ERROR on brgl/gpio/for-next]
[also build test ERROR on linus/master v6.18-rc6 next-20251118]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Jisheng-Zhang/gpio-fxl6408-Add-optional-reset-gpio-control/20251117-083516
base:   https://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux.git gpio/for-next
patch link:    https://lore.kernel.org/r/20251117001502.12618-2-jszhang%40kernel.org
patch subject: [PATCH v2 1/2] gpio: fxl6408: Add optional reset gpio control
config: riscv-randconfig-001-20251118 (https://download.01.org/0day-ci/archive/20251118/202511181705.QWVZhvN1-lkp@intel.com/config)
compiler: riscv64-linux-gcc (GCC) 10.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251118/202511181705.QWVZhvN1-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202511181705.QWVZhvN1-lkp@intel.com/

All errors (new ones prefixed by >>):

   drivers/gpio/gpio-fxl6408.c: In function 'fxl6408_probe':
>> drivers/gpio/gpio-fxl6408.c:119:15: error: implicit declaration of function 'devm_gpiod_get_optional'; did you mean 'devm_regulator_get_optional'? [-Werror=implicit-function-declaration]
     119 |  reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
         |               ^~~~~~~~~~~~~~~~~~~~~~~
         |               devm_regulator_get_optional
>> drivers/gpio/gpio-fxl6408.c:119:53: error: 'GPIOD_OUT_LOW' undeclared (first use in this function)
     119 |  reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
         |                                                     ^~~~~~~~~~~~~
   drivers/gpio/gpio-fxl6408.c:119:53: note: each undeclared identifier is reported only once for each function it appears in
   cc1: some warnings being treated as errors


vim +119 drivers/gpio/gpio-fxl6408.c

   104	
   105	static int fxl6408_probe(struct i2c_client *client)
   106	{
   107		struct device *dev = &client->dev;
   108		struct gpio_desc *reset_gpio;
   109		int ret;
   110		struct gpio_regmap_config gpio_config = {
   111			.parent = dev,
   112			.ngpio = FXL6408_NGPIO,
   113			.reg_dat_base = GPIO_REGMAP_ADDR(FXL6408_REG_INPUT_STATUS),
   114			.reg_set_base = GPIO_REGMAP_ADDR(FXL6408_REG_OUTPUT),
   115			.reg_dir_out_base = GPIO_REGMAP_ADDR(FXL6408_REG_IO_DIR),
   116			.ngpio_per_reg = FXL6408_NGPIO,
   117		};
   118	
 > 119		reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
   120		if (IS_ERR(reset_gpio))
   121			return dev_err_probe(dev, PTR_ERR(reset_gpio), "Failed to get reset gpio\n");
   122	
   123		gpio_config.regmap = devm_regmap_init_i2c(client, &regmap);
   124		if (IS_ERR(gpio_config.regmap))
   125			return dev_err_probe(dev, PTR_ERR(gpio_config.regmap),
   126					     "failed to allocate register map\n");
   127	
   128		ret = fxl6408_identify(dev, gpio_config.regmap);
   129		if (ret)
   130			return ret;
   131	
   132		/* Disable High-Z of outputs, so that our OUTPUT updates actually take effect. */
   133		ret = regmap_write(gpio_config.regmap, FXL6408_REG_OUTPUT_HIGH_Z, 0);
   134		if (ret)
   135			return dev_err_probe(dev, ret, "failed to write 'output high Z' register\n");
   136	
   137		return PTR_ERR_OR_ZERO(devm_gpio_regmap_register(dev, &gpio_config));
   138	}
   139	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v2 1/2] gpio: fxl6408: Add optional reset gpio control

[Jisheng Zhang]

On Mon, Nov 17, 2025 at 11:01:47AM +0100, Bartosz Golaszewski wrote:
> On Mon, Nov 17, 2025 at 1:32 AM Jisheng Zhang <jszhang@kernel.org> wrote:
> >
> > Add optional active low reset-gpios pin control. If present, de-assert
> > the specified reset gpio pin to bring the chip out of reset.
> >
> > Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> > ---
> 
> This is covered by the bindings at gpio/trivial-gpio.yaml but the
> document does not describe a reset-gpios pin. This series doesn't add
> any users of it either. What platform do you want to use it on?

the platform hasn't been upstreamed, but you raise a good question, let
me drop this patch now. Will send out a v2.
> 
> Bartosz