[PATCH v6 0/7] gpio: introduce a GPIO driver for SCMI

[PATCH v6 0/7] gpio: introduce a GPIO driver for SCMI

[Dan Carpenter]

This basically abandons my earlier attempts and goes back to Takahiro
Akashi's driver.  Here is the link to Takahiro's patchset:

https://lore.kernel.org/all/20231005025843.508689-1-takahiro.akashi@linaro.org/

v6: Fix a build error when CONFIG_PINCONF is disabled
    Fix the dt-binding subject and my email address
    Use pinconf_to_config_packed() instead of PIN_CONF_PACKED()

v5: Addresses Andy's cleanups to the driver.
    Adrresses Krzysztof's comments about the dt spec file.
    And almost all the subsystem prefixes were wrong.

v4: Addressed Andy's comments about kernel-doc
    Addressed Rob's comments on the spec file

v3: Forward ported Takahiro's patches and added some fixes ups to make
    it work on current kernels.

AKASHI Takahiro (3):
  pinctrl: introduce pinctrl_gpio_get_config()
  gpio: dt-bindings: Add GPIO on top of generic pin control
  gpio: gpio-by-pinctrl: add pinctrl based generic GPIO driver

Dan Carpenter (4):
  pinctrl: scmi: Add SCMI_PIN_INPUT_VALUE
  pinctrl: scmi: Delete PIN_CONFIG_OUTPUT_IMPEDANCE_OHMS support
  pinctrl: scmi: ignore PIN_CONFIG_PERSIST_STATE
  firmware: arm_scmi: Allow PINCTRL_REQUEST to return EOPNOTSUPP

 .../bindings/gpio/pin-control-gpio.yaml       |  59 ++++++++++
 drivers/firmware/arm_scmi/pinctrl.c           |   2 +
 drivers/gpio/Kconfig                          |  13 +++
 drivers/gpio/Makefile                         |   1 +
 drivers/gpio/gpio-by-pinctrl.c                | 101 ++++++++++++++++++
 drivers/pinctrl/core.c                        |  31 ++++++
 drivers/pinctrl/pinconf.h                     |   6 ++
 drivers/pinctrl/pinctrl-scmi.c                |  46 +++++---
 include/linux/pinctrl/consumer.h              |   9 ++
 9 files changed, 255 insertions(+), 13 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/gpio/pin-control-gpio.yaml
 create mode 100644 drivers/gpio/gpio-by-pinctrl.c

-- 
2.53.0

[PATCH v6 1/7] pinctrl: introduce pinctrl_gpio_get_config()

[Dan Carpenter]

From: AKASHI Takahiro <takahiro.akashi@linaro.org>

This is a counterpart of pinctrl_gpio_set_config(), which will be used
to implement the ->get() interface in a GPIO driver for SCMI.

This also requires that we create a stub so pin_config_get_for_pin()
can build when CONFIG_PINCONF is disabled.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
---
v6: Fix build breakage with !CONFIG_PINCONF
v5: No change
v4: Fix kernel-doc (Andy).  Add r-b tags
v3: Forward port

 drivers/pinctrl/core.c           | 31 +++++++++++++++++++++++++++++++
 drivers/pinctrl/pinconf.h        |  6 ++++++
 include/linux/pinctrl/consumer.h |  9 +++++++++
 3 files changed, 46 insertions(+)

diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
index 2edc9bdad183..c471f3fbd035 100644
--- a/drivers/pinctrl/core.c
+++ b/drivers/pinctrl/core.c
@@ -30,6 +30,7 @@
 #include <linux/pinctrl/consumer.h>
 #include <linux/pinctrl/devinfo.h>
 #include <linux/pinctrl/machine.h>
+#include <linux/pinctrl/pinconf.h>
 #include <linux/pinctrl/pinctrl.h>
 
 #include "core.h"
@@ -938,6 +939,36 @@ int pinctrl_gpio_set_config(struct gpio_chip *gc, unsigned int offset,
 }
 EXPORT_SYMBOL_GPL(pinctrl_gpio_set_config);
 
+/**
+ * pinctrl_gpio_get_config() - Get the config for a given GPIO pin
+ * @gc: GPIO chip structure from the GPIO subsystem
+ * @offset: hardware offset of the GPIO relative to the controller
+ * @config: the configuration to query.  On success it holds the result
+ * Return: 0 on success, negative errno otherwise
+ */
+int pinctrl_gpio_get_config(struct gpio_chip *gc, unsigned int offset, unsigned long *config)
+{
+	struct pinctrl_gpio_range *range;
+	struct pinctrl_dev *pctldev;
+	int ret, pin;
+
+	ret = pinctrl_get_device_gpio_range(gc, offset, &pctldev, &range);
+	if (ret)
+		return ret;
+
+	mutex_lock(&pctldev->mutex);
+	pin = gpio_to_pin(range, gc, offset);
+	ret = pin_config_get_for_pin(pctldev, pin, config);
+	mutex_unlock(&pctldev->mutex);
+
+	if (ret)
+		return ret;
+
+	*config = pinconf_to_config_argument(*config);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pinctrl_gpio_get_config);
+
 static struct pinctrl_state *find_state(struct pinctrl *p,
 					const char *name)
 {
diff --git a/drivers/pinctrl/pinconf.h b/drivers/pinctrl/pinconf.h
index 2880adef476e..659a781e2091 100644
--- a/drivers/pinctrl/pinconf.h
+++ b/drivers/pinctrl/pinconf.h
@@ -74,6 +74,12 @@ static inline int pinconf_set_config(struct pinctrl_dev *pctldev, unsigned int p
 	return -ENOTSUPP;
 }
 
+static inline int pin_config_get_for_pin(struct pinctrl_dev *pctldev, unsigned int pin,
+			   unsigned long *config)
+{
+	return -ENOTSUPP;
+}
+
 #endif
 
 #if defined(CONFIG_PINCONF) && defined(CONFIG_DEBUG_FS)
diff --git a/include/linux/pinctrl/consumer.h b/include/linux/pinctrl/consumer.h
index 63ce16191eb9..11b8f0b8da0c 100644
--- a/include/linux/pinctrl/consumer.h
+++ b/include/linux/pinctrl/consumer.h
@@ -35,6 +35,8 @@ int pinctrl_gpio_direction_output(struct gpio_chip *gc,
 				  unsigned int offset);
 int pinctrl_gpio_set_config(struct gpio_chip *gc, unsigned int offset,
 				unsigned long config);
+int pinctrl_gpio_get_config(struct gpio_chip *gc, unsigned int offset,
+			    unsigned long *config);
 
 struct pinctrl * __must_check pinctrl_get(struct device *dev);
 void pinctrl_put(struct pinctrl *p);
@@ -101,6 +103,13 @@ pinctrl_gpio_direction_output(struct gpio_chip *gc, unsigned int offset)
 	return 0;
 }
 
+static inline int
+pinctrl_gpio_get_config(struct gpio_chip *gc, unsigned int offset,
+			unsigned long *config)
+{
+	return 0;
+}
+
 static inline int
 pinctrl_gpio_set_config(struct gpio_chip *gc, unsigned int offset,
 			    unsigned long config)
-- 
2.53.0

[PATCH v6 2/7] pinctrl: scmi: Add SCMI_PIN_INPUT_VALUE

[Dan Carpenter]

The PIN_CONFIG_LEVEL parameter represents the value of the pin, whether
reading or writing to the pin.  In SCMI, the parameter is represented by
two different values SCMI_PIN_OUTPUT_VALUE for writing to a pin and
SCMI_PIN_INPUT_VALUE for reading.  The current code translates
PIN_CONFIG_LEVEL as SCMI_PIN_OUTPUT_VALUE (writing).

Add a function to translate it to either INPUT or OUTPUT depending on
whether it is called from a _get or _set() operation.

Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Acked-by: Sudeep Holla <sudeep.holla@kernel.org>
---
v5: no change
v4: add r-b tags
v3: new patch

 drivers/pinctrl/pinctrl-scmi.c | 33 ++++++++++++++++++++++++++-------
 1 file changed, 26 insertions(+), 7 deletions(-)

diff --git a/drivers/pinctrl/pinctrl-scmi.c b/drivers/pinctrl/pinctrl-scmi.c
index f4f296e07be5..5d347e6b2e4c 100644
--- a/drivers/pinctrl/pinctrl-scmi.c
+++ b/drivers/pinctrl/pinctrl-scmi.c
@@ -251,9 +251,6 @@ static int pinctrl_scmi_map_pinconf_type(enum pin_config_param param,
 	case PIN_CONFIG_MODE_LOW_POWER:
 		*type = SCMI_PIN_LOW_POWER_MODE;
 		break;
-	case PIN_CONFIG_LEVEL:
-		*type = SCMI_PIN_OUTPUT_VALUE;
-		break;
 	case PIN_CONFIG_OUTPUT_ENABLE:
 		*type = SCMI_PIN_OUTPUT_MODE;
 		break;
@@ -276,6 +273,28 @@ static int pinctrl_scmi_map_pinconf_type(enum pin_config_param param,
 	return 0;
 }
 
+static int pinctrl_scmi_map_pinconf_type_get(enum pin_config_param param,
+					     enum scmi_pinctrl_conf_type *type)
+{
+	if (param == PIN_CONFIG_LEVEL) {
+		*type = SCMI_PIN_INPUT_VALUE;
+		return 0;
+	}
+
+	return pinctrl_scmi_map_pinconf_type(param, type);
+}
+
+static int pinctrl_scmi_map_pinconf_type_set(enum pin_config_param param,
+					     enum scmi_pinctrl_conf_type *type)
+{
+	if (param == PIN_CONFIG_LEVEL) {
+		*type = SCMI_PIN_OUTPUT_VALUE;
+		return 0;
+	}
+
+	return pinctrl_scmi_map_pinconf_type(param, type);
+}
+
 static int pinctrl_scmi_pinconf_get(struct pinctrl_dev *pctldev,
 				    unsigned int pin, unsigned long *config)
 {
@@ -290,7 +309,7 @@ static int pinctrl_scmi_pinconf_get(struct pinctrl_dev *pctldev,
 
 	config_type = pinconf_to_config_param(*config);
 
-	ret = pinctrl_scmi_map_pinconf_type(config_type, &type);
+	ret = pinctrl_scmi_map_pinconf_type_get(config_type, &type);
 	if (ret)
 		return ret;
 
@@ -363,7 +382,7 @@ static int pinctrl_scmi_pinconf_set(struct pinctrl_dev *pctldev,
 
 	for (i = 0; i < num_configs; i++) {
 		param = pinconf_to_config_param(configs[i]);
-		ret = pinctrl_scmi_map_pinconf_type(param, &p_config_type[i]);
+		ret = pinctrl_scmi_map_pinconf_type_set(param, &p_config_type[i]);
 		if (ret) {
 			dev_err(pmx->dev, "Error map pinconf_type %d\n", ret);
 			goto free_config;
@@ -405,7 +424,7 @@ static int pinctrl_scmi_pinconf_group_set(struct pinctrl_dev *pctldev,
 
 	for (i = 0; i < num_configs; i++) {
 		param = pinconf_to_config_param(configs[i]);
-		ret = pinctrl_scmi_map_pinconf_type(param, &p_config_type[i]);
+		ret = pinctrl_scmi_map_pinconf_type_set(param, &p_config_type[i]);
 		if (ret) {
 			dev_err(pmx->dev, "Error map pinconf_type %d\n", ret);
 			goto free_config;
@@ -440,7 +459,7 @@ static int pinctrl_scmi_pinconf_group_get(struct pinctrl_dev *pctldev,
 		return -EINVAL;
 
 	config_type = pinconf_to_config_param(*config);
-	ret = pinctrl_scmi_map_pinconf_type(config_type, &type);
+	ret = pinctrl_scmi_map_pinconf_type_get(config_type, &type);
 	if (ret) {
 		dev_err(pmx->dev, "Error map pinconf_type %d\n", ret);
 		return ret;
-- 
2.53.0

[PATCH v6 4/7] pinctrl: scmi: ignore PIN_CONFIG_PERSIST_STATE

[Dan Carpenter]

The PIN_CONFIG_PERSIST_STATE setting ensures that the pin state persists
across a sleep or controller reset.  The SCMI spec does not have an
equivalent command to this so just ignore it.

Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Linus Walleij <linusw@kernel.org>
---
v5: fix subsystem prefix
v4: Add r-b tags
v3: No change

 drivers/pinctrl/pinctrl-scmi.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/pinctrl/pinctrl-scmi.c b/drivers/pinctrl/pinctrl-scmi.c
index de8c113bc61d..f22be6b7b82a 100644
--- a/drivers/pinctrl/pinctrl-scmi.c
+++ b/drivers/pinctrl/pinctrl-scmi.c
@@ -361,7 +361,7 @@ static int pinctrl_scmi_pinconf_set(struct pinctrl_dev *pctldev,
 				    unsigned long *configs,
 				    unsigned int num_configs)
 {
-	int i, ret;
+	int i, cnt, ret;
 	struct scmi_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);
 	enum scmi_pinctrl_conf_type config_type[SCMI_NUM_CONFIGS];
 	u32 config_value[SCMI_NUM_CONFIGS];
@@ -377,17 +377,21 @@ static int pinctrl_scmi_pinconf_set(struct pinctrl_dev *pctldev,
 	if (ret)
 		return ret;
 
+	cnt = 0;
 	for (i = 0; i < num_configs; i++) {
 		param = pinconf_to_config_param(configs[i]);
-		ret = pinctrl_scmi_map_pinconf_type_set(param, &p_config_type[i]);
+		if (param == PIN_CONFIG_PERSIST_STATE)
+			continue;
+		ret = pinctrl_scmi_map_pinconf_type_set(param, &p_config_type[cnt]);
 		if (ret) {
 			dev_err(pmx->dev, "Error map pinconf_type %d\n", ret);
 			goto free_config;
 		}
-		p_config_value[i] = pinconf_to_config_argument(configs[i]);
+		p_config_value[cnt] = pinconf_to_config_argument(configs[i]);
+		cnt++;
 	}
 
-	ret = pinctrl_ops->settings_conf(pmx->ph, pin, PIN_TYPE, num_configs,
+	ret = pinctrl_ops->settings_conf(pmx->ph, pin, PIN_TYPE, cnt,
 					 p_config_type,  p_config_value);
 	if (ret)
 		dev_err(pmx->dev, "Error parsing config %d\n", ret);
-- 
2.53.0

[PATCH v6 3/7] pinctrl: scmi: Delete PIN_CONFIG_OUTPUT_IMPEDANCE_OHMS support

[Dan Carpenter]

The argument for PIN_CONFIG_OUTPUT_IMPEDANCE_OHMS is supposed to
be expressed in terms of ohms.  But the pinctrl-scmi driver was
implementing it the same as PIN_CONFIG_OUTPUT and writing either a
zero or one to the pin.

The SCMI protocol doesn't have an support configuration type so just
delete this code instead of replacing it.

Cc: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Linus Walleij <linusw@kernel.org>
---
v5: fix subystem prefix
v4: add r-b tags
v3: new patch

 drivers/pinctrl/pinctrl-scmi.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/pinctrl/pinctrl-scmi.c b/drivers/pinctrl/pinctrl-scmi.c
index 5d347e6b2e4c..de8c113bc61d 100644
--- a/drivers/pinctrl/pinctrl-scmi.c
+++ b/drivers/pinctrl/pinctrl-scmi.c
@@ -254,9 +254,6 @@ static int pinctrl_scmi_map_pinconf_type(enum pin_config_param param,
 	case PIN_CONFIG_OUTPUT_ENABLE:
 		*type = SCMI_PIN_OUTPUT_MODE;
 		break;
-	case PIN_CONFIG_OUTPUT_IMPEDANCE_OHMS:
-		*type = SCMI_PIN_OUTPUT_VALUE;
-		break;
 	case PIN_CONFIG_POWER_SOURCE:
 		*type = SCMI_PIN_POWER_SOURCE;
 		break;
-- 
2.53.0

[PATCH v6 5/7] firmware: arm_scmi: Allow PINCTRL_REQUEST to return EOPNOTSUPP

[Dan Carpenter]

The SCMI protocol specification says that the PINCTRL_REQUEST and
PINCTRL_RELEASE commands are optional.  So if the SCMI server returns
-EOPNOTSUPP, then treat that as success and continue.

Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Reviewed-by: Sudeep Holla <sudeep.holla@kernel.org>
---
v5: fix subsytem prefix
v4: add r-b tags
v3: new patch

 drivers/firmware/arm_scmi/pinctrl.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/firmware/arm_scmi/pinctrl.c b/drivers/firmware/arm_scmi/pinctrl.c
index a020e23d7c49..42cb1aef1fe1 100644
--- a/drivers/firmware/arm_scmi/pinctrl.c
+++ b/drivers/firmware/arm_scmi/pinctrl.c
@@ -578,6 +578,8 @@ static int scmi_pinctrl_request_free(const struct scmi_protocol_handle *ph,
 	tx->flags = cpu_to_le32(type);
 
 	ret = ph->xops->do_xfer(ph, t);
+	if (ret == -EOPNOTSUPP)
+		ret = 0;
 	ph->xops->xfer_put(ph, t);
 
 	return ret;
-- 
2.53.0

[PATCH v6 6/7] gpio: dt-bindings: Add GPIO on top of generic pin control

[Dan Carpenter]

From: AKASHI Takahiro <takahiro.akashi@linaro.org>

Traditionally, firmware will provide a GPIO interface or a pin control
interface.  However, the SCMI protocol provides a generic pin control
interface and the GPIO support is built on top of that using the normal
pin control interfaces.  Potentially, other firmware will adopt a
similar generic approach in the future.

Document how to configure the GPIO device.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
---
v6: Fix the subject.  Sorry!
    Fix typo in my email.
    Add Krzysztof's reviewed-by tag.
v5: Fix subsystem prefix
    Re-word the commit message
    I removed all references to the driver.  I also removed the
    reference to pin muxing because that's described in the pin control
    spec file.
    Fix 3 vs 4 typo in the example.
v4: Changed additionalProperties: true to false.
    Add gpio-line-names.
    Deleted one example.
    Add r-b tags
v3: Forward port and update

 .../bindings/gpio/pin-control-gpio.yaml       | 59 +++++++++++++++++++
 1 file changed, 59 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/pin-control-gpio.yaml

diff --git a/Documentation/devicetree/bindings/gpio/pin-control-gpio.yaml b/Documentation/devicetree/bindings/gpio/pin-control-gpio.yaml
new file mode 100644
index 000000000000..a05cd339253a
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/pin-control-gpio.yaml
@@ -0,0 +1,59 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/gpio/pin-control-gpio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Pin control based generic GPIO controller
+
+description:
+  The pin control-based GPIO will facilitate a pin controller's ability
+  to drive electric lines high/low and other generic properties of a
+  pin controller to perform general-purpose one-bit binary I/O.
+
+maintainers:
+  - Dan Carpenter <dan.carpenter@linaro.org>
+
+properties:
+  compatible:
+    const: scmi-pinctrl-gpio
+
+  gpio-controller: true
+
+  "#gpio-cells":
+    const: 2
+
+  gpio-line-names: true
+
+  gpio-ranges: true
+
+  ngpios: true
+
+patternProperties:
+  "^.+-hog(-[0-9]+)?$":
+    type: object
+
+    required:
+      - gpio-hog
+
+required:
+  - compatible
+  - gpio-controller
+  - "#gpio-cells"
+  - gpio-ranges
+  - ngpios
+
+additionalProperties: false
+
+examples:
+  - |
+    gpio {
+        compatible = "scmi-pinctrl-gpio";
+        gpio-controller;
+        #gpio-cells = <2>;
+        ngpios = <4>;
+        gpio-line-names = "gpio_5_17", "gpio_5_20", "gpio_5_22", "gpio_2_1";
+        gpio-ranges = <&scmi_pinctrl 0 30 4>;
+        pinctrl-names = "default";
+        pinctrl-0 = <&keys_pins>;
+    };
-- 
2.53.0

[PATCH v6 7/7] gpio: gpio-by-pinctrl: add pinctrl based generic GPIO driver

[Dan Carpenter]

From: AKASHI Takahiro <takahiro.akashi@linaro.org>

The ARM SCMI pinctrl protocol allows GPIO access.  Instead of creating
a new SCMI GPIO driver, this driver is a generic GPIO driver that uses
standard pinctrl interfaces.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Acked-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
---
v6: Use pinconf_to_config_packed() instead of PIN_CONF_PACKED()
v5: Clean up based on Andy's feedback:
    Update Kconfig entry
    Update Copyright date
    Fix includes
    Get rid of unused private data
    Simplify pin_control_gpio_get_direction()
v4: Add r-b tags
v3: Forward port and update
---
 drivers/gpio/Kconfig           |  13 +++++
 drivers/gpio/Makefile          |   1 +
 drivers/gpio/gpio-by-pinctrl.c | 101 +++++++++++++++++++++++++++++++++
 3 files changed, 115 insertions(+)
 create mode 100644 drivers/gpio/gpio-by-pinctrl.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index b45fb799e36c..c631ecb01e07 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -246,6 +246,19 @@ config GPIO_BRCMSTB
 	help
 	  Say yes here to enable GPIO support for Broadcom STB (BCM7XXX) SoCs.
 
+config GPIO_BY_PINCTRL
+	tristate "GPIO support based on a pure pin control backend"
+	depends on GPIOLIB
+	help
+	  Support for generic GPIO handling based on top of pin control.
+	  Traditionally, firmware creates a GPIO interface or a pin
+	  controller interface and we have a driver to support it.  But
+	  in SCMI, the pin control interface is generic and we can
+	  create a simple GPIO device based on the pin control interface
+	  without doing anything custom.
+
+	  This driver used to do GPIO over the ARM SCMI protocol.
+
 config GPIO_CADENCE
 	tristate "Cadence GPIO support"
 	depends on OF_GPIO
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index c05f7d795c43..20d4a57afdaa 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -51,6 +51,7 @@ obj-$(CONFIG_GPIO_BD9571MWV)		+= gpio-bd9571mwv.o
 obj-$(CONFIG_GPIO_BLZP1600)		+= gpio-blzp1600.o
 obj-$(CONFIG_GPIO_BRCMSTB)		+= gpio-brcmstb.o
 obj-$(CONFIG_GPIO_BT8XX)		+= gpio-bt8xx.o
+obj-$(CONFIG_GPIO_BY_PINCTRL)		+= gpio-by-pinctrl.o
 obj-$(CONFIG_GPIO_CADENCE)		+= gpio-cadence.o
 obj-$(CONFIG_GPIO_CGBC)			+= gpio-cgbc.o
 obj-$(CONFIG_GPIO_CLPS711X)		+= gpio-clps711x.o
diff --git a/drivers/gpio/gpio-by-pinctrl.c b/drivers/gpio/gpio-by-pinctrl.c
new file mode 100644
index 000000000000..ddfdc479d38a
--- /dev/null
+++ b/drivers/gpio/gpio-by-pinctrl.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (C) 2026 Linaro Inc.
+//   Author: AKASHI takahiro <takahiro.akashi@linaro.org>
+
+#include <linux/errno.h>
+#include <linux/gpio/driver.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+
+#include "gpiolib.h"
+
+static int pin_control_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
+{
+	unsigned long config;
+	int ret;
+
+	config = PIN_CONFIG_OUTPUT_ENABLE;
+	ret = pinctrl_gpio_get_config(gc, offset, &config);
+	if (ret)
+		return ret;
+	if (config)
+		return GPIO_LINE_DIRECTION_OUT;
+
+	return GPIO_LINE_DIRECTION_IN;
+}
+
+static int pin_control_gpio_direction_output(struct gpio_chip *chip,
+					     unsigned int offset, int val)
+{
+	return pinctrl_gpio_direction_output(chip, offset);
+}
+
+static int pin_control_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+	unsigned long config;
+	int ret;
+
+	config = PIN_CONFIG_LEVEL;
+	ret = pinctrl_gpio_get_config(chip, offset, &config);
+	if (ret)
+		return ret;
+
+	return !!config;
+}
+
+static int pin_control_gpio_set(struct gpio_chip *chip, unsigned int offset,
+				int val)
+{
+	unsigned long config;
+
+	config = pinconf_to_config_packed(PIN_CONFIG_LEVEL, val);
+	return pinctrl_gpio_set_config(chip, offset, config);
+}
+
+static int pin_control_gpio_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct gpio_chip *chip;
+
+	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	chip->label = dev_name(dev);
+	chip->parent = dev;
+	chip->base = -1;
+
+	chip->request = gpiochip_generic_request;
+	chip->free = gpiochip_generic_free;
+	chip->get_direction = pin_control_gpio_get_direction;
+	chip->direction_input = pinctrl_gpio_direction_input;
+	chip->direction_output = pin_control_gpio_direction_output;
+	chip->get = pin_control_gpio_get;
+	chip->set = pin_control_gpio_set;
+	chip->set_config = gpiochip_generic_config;
+
+	return devm_gpiochip_add_data(dev, chip, NULL);
+}
+
+static const struct of_device_id pin_control_gpio_match[] = {
+	{ .compatible = "scmi-pinctrl-gpio" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, pin_control_gpio_match);
+
+static struct platform_driver pin_control_gpio_driver = {
+	.probe = pin_control_gpio_probe,
+	.driver = {
+		.name = "pin-control-gpio",
+		.of_match_table = pin_control_gpio_match,
+	},
+};
+module_platform_driver(pin_control_gpio_driver);
+
+MODULE_AUTHOR("AKASHI Takahiro <takahiro.akashi@linaro.org>");
+MODULE_DESCRIPTION("Pinctrl based GPIO driver");
+MODULE_LICENSE("GPL");
-- 
2.53.0

Re: [PATCH v6 7/7] gpio: gpio-by-pinctrl: add pinctrl based generic GPIO driver

[Andy Shevchenko]

On Mon, Mar 23, 2026 at 10:01:47PM +0300, Dan Carpenter wrote:

> The ARM SCMI pinctrl protocol allows GPIO access.  Instead of creating
> a new SCMI GPIO driver, this driver is a generic GPIO driver that uses
> standard pinctrl interfaces.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v6 7/7] gpio: gpio-by-pinctrl: add pinctrl based generic GPIO driver

[Dan Carpenter]

On Tue, Mar 24, 2026 at 01:15:46PM +0200, Andy Shevchenko wrote:
> On Mon, Mar 23, 2026 at 10:01:47PM +0300, Dan Carpenter wrote:
> 
> > The ARM SCMI pinctrl protocol allows GPIO access.  Instead of creating
> > a new SCMI GPIO driver, this driver is a generic GPIO driver that uses
> > standard pinctrl interfaces.
> 
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
> 

Thanks Andy,

The driver is much cleaner after your review.

regards,
dan carpenter

Re: [PATCH v6 0/7] gpio: introduce a GPIO driver for SCMI

[Linus Walleij]

On Mon, Mar 23, 2026 at 8:01 PM Dan Carpenter <dan.carpenter@linaro.org> wrote:

> This basically abandons my earlier attempts and goes back to Takahiro
> Akashi's driver.  Here is the link to Takahiro's patchset:
>
> https://lore.kernel.org/all/20231005025843.508689-1-takahiro.akashi@linaro.org/
>
> v6: Fix a build error when CONFIG_PINCONF is disabled
>     Fix the dt-binding subject and my email address
>     Use pinconf_to_config_packed() instead of PIN_CONF_PACKED()

v6 applied to this immutable branch:
https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl.git/log/?h=ib-scmi-pinctrl-gpio

Then merged into my devel branch for next.

Bartosz, you might want to pull it in!

Dan: thanks for your efforts to fix up the remaining hurdles and
bringing this to completion! Sometimes the last few % of work are
the hardest.

Also thanks to Takahiro for this idea: it worked out just like you
imagined.

Yours,
Linus Walleij

Re: [PATCH v6 0/7] gpio: introduce a GPIO driver for SCMI

[Bartosz Golaszewski]

On Tue, Mar 24, 2026 at 2:11 PM Linus Walleij <linusw@kernel.org> wrote:
>
> On Mon, Mar 23, 2026 at 8:01 PM Dan Carpenter <dan.carpenter@linaro.org> wrote:
>
> > This basically abandons my earlier attempts and goes back to Takahiro
> > Akashi's driver.  Here is the link to Takahiro's patchset:
> >
> > https://lore.kernel.org/all/20231005025843.508689-1-takahiro.akashi@linaro.org/
> >
> > v6: Fix a build error when CONFIG_PINCONF is disabled
> >     Fix the dt-binding subject and my email address
> >     Use pinconf_to_config_packed() instead of PIN_CONF_PACKED()
>
> v6 applied to this immutable branch:
> https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl.git/log/?h=ib-scmi-pinctrl-gpio
>
> Then merged into my devel branch for next.
>
> Bartosz, you might want to pull it in!
>
> Dan: thanks for your efforts to fix up the remaining hurdles and
> bringing this to completion! Sometimes the last few % of work are
> the hardest.
>
> Also thanks to Takahiro for this idea: it worked out just like you
> imagined.
>

Pulled, thanks!

Bart