[PATCH 4/4] gpio: scmi: Add gpio_scmi driver
Dan Carpenter
dan.carpenter at linaro.org
Mon Feb 23 15:33:41 CET 2026
This provides gpio support over SCMI. The device tree entry would look
like this:
scmi_gpio1: gpio1 {
compatible = "scmi,gpio";
scmi,pinctrl = <&scmi_pinctrl 0 2>;
pinctrl-names = "default";
pinctrl-0 = <&pinmux1>;
gpio-controller;
};
The scmi,pinctrl phandle points to the function and the index within that
function. The pinctrl-0 phandle points to the initial pin configuration
if necessary.
Signed-off-by: Dan Carpenter <dan.carpenter at linaro.org>
---
drivers/gpio/Kconfig | 6 ++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio_scmi.c | 221 +++++++++++++++++++++++++++++++++++++++
3 files changed, 228 insertions(+)
create mode 100644 drivers/gpio/gpio_scmi.c
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 60c5c54688e6..7d22c1f792d1 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -723,6 +723,12 @@ config SLG7XL45106_I2C_GPO
8-bit gpo expander, all gpo lines are controlled by writing
value into data register.
+config GPIO_SCMI
+ bool "SCMI GPIO pinctrl driver"
+ depends on DM_GPIO && PINCTRL_SCMI
+ help
+ Support pinctrl GPIO over the SCMI interface.
+
config ADP5585_GPIO
bool "ADP5585 GPIO driver"
depends on DM_GPIO && DM_I2C
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 910478c0c7a9..0003ed74be67 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -77,6 +77,7 @@ obj-$(CONFIG_SL28CPLD_GPIO) += sl28cpld-gpio.o
obj-$(CONFIG_ADP5588_GPIO) += adp5588_gpio.o
obj-$(CONFIG_ZYNQMP_GPIO_MODEPIN) += zynqmp_gpio_modepin.o
obj-$(CONFIG_SLG7XL45106_I2C_GPO) += gpio_slg7xl45106.o
+obj-$(CONFIG_GPIO_SCMI) += gpio_scmi.o
obj-$(CONFIG_$(PHASE_)ADP5585_GPIO) += adp5585_gpio.o
obj-$(CONFIG_RZG2L_GPIO) += rzg2l-gpio.o
obj-$(CONFIG_MPFS_GPIO) += mpfs_gpio.o
diff --git a/drivers/gpio/gpio_scmi.c b/drivers/gpio/gpio_scmi.c
new file mode 100644
index 000000000000..a859ad610587
--- /dev/null
+++ b/drivers/gpio/gpio_scmi.c
@@ -0,0 +1,221 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2026 Linaro Ltd.
+ */
+
+#include <asm/gpio.h>
+#include <dm.h>
+#include <dm/device_compat.h>
+#include <scmi_protocols.h>
+
+struct scmi_gpio_priv {
+ struct udevice *pin_dev;
+ char *bank_name;
+ u32 num_pins;
+ u16 *pins;
+};
+
+static int scmi_gpio_request(struct udevice *dev, unsigned int offset, const char *label)
+{
+ struct scmi_gpio_priv *priv = dev_get_priv(dev);
+ int pin;
+ int ret;
+
+ if (offset >= priv->num_pins)
+ return -EINVAL;
+ pin = priv->pins[offset];
+
+ ret = scmi_pinctrl_request(priv->pin_dev, SCMI_PIN, pin);
+ if (ret == -EOPNOTSUPP)
+ ret = 0;
+ if (ret)
+ dev_err(dev, "%s(): request failed: %d\n", __func__, ret);
+ return ret;
+}
+
+static int scmi_gpio_rfree(struct udevice *dev, unsigned int offset)
+{
+ struct scmi_gpio_priv *priv = dev_get_priv(dev);
+ int pin;
+ int ret;
+
+ if (offset >= priv->num_pins)
+ return -EINVAL;
+ pin = priv->pins[offset];
+
+ ret = scmi_pinctrl_release(priv->pin_dev, SCMI_PIN, pin);
+ if (ret == -EOPNOTSUPP)
+ ret = 0;
+ if (ret)
+ dev_err(dev, "%s(): release failed: %d\n", __func__, ret);
+ return ret;
+}
+
+static int scmi_gpio_set_flags(struct udevice *dev, unsigned int offset, ulong flags)
+{
+ struct scmi_gpio_priv *priv = dev_get_priv(dev);
+ const int MAX_FLAGS = 10;
+ u32 configs[MAX_FLAGS * 2];
+ int cnt = 0;
+ u32 pin;
+
+ if (offset >= priv->num_pins)
+ return -EINVAL;
+ pin = priv->pins[offset];
+
+ if (flags & GPIOD_IS_OUT) {
+ configs[cnt++] = SCMI_PIN_OUTPUT_MODE;
+ configs[cnt++] = 1;
+ configs[cnt++] = SCMI_PIN_OUTPUT_VALUE;
+ if (flags & GPIOD_IS_OUT_ACTIVE)
+ configs[cnt++] = 1;
+ else
+ configs[cnt++] = 0;
+ }
+ if (flags & GPIOD_IS_IN) {
+ configs[cnt++] = SCMI_PIN_INPUT_MODE;
+ configs[cnt++] = 1;
+ }
+ if (flags & GPIOD_OPEN_DRAIN) {
+ configs[cnt++] = SCMI_PIN_DRIVE_OPEN_DRAIN;
+ configs[cnt++] = 1;
+ }
+ if (flags & GPIOD_OPEN_SOURCE) {
+ configs[cnt++] = SCMI_PIN_DRIVE_OPEN_SOURCE;
+ configs[cnt++] = 1;
+ }
+ if (flags & GPIOD_PULL_UP) {
+ configs[cnt++] = SCMI_PIN_BIAS_PULL_UP;
+ configs[cnt++] = 1;
+ }
+ if (flags & GPIOD_PULL_DOWN) {
+ configs[cnt++] = SCMI_PIN_BIAS_PULL_DOWN;
+ configs[cnt++] = 1;
+ }
+ /* TODO: handle GPIOD_ACTIVE_LOW and GPIOD_IS_AF flags */
+
+ return scmi_pinctrl_settings_configure(priv->pin_dev, SCMI_PIN, pin,
+ cnt / 2, &configs[0]);
+}
+
+static int scmi_gpio_get_value(struct udevice *dev, unsigned int offset)
+{
+ struct scmi_gpio_priv *priv = dev_get_priv(dev);
+ u32 value;
+ int pin;
+ int ret;
+
+ if (offset >= priv->num_pins)
+ return -EINVAL;
+ pin = priv->pins[offset];
+
+ ret = scmi_pinctrl_settings_get_one(priv->pin_dev, SCMI_PIN, pin,
+ SCMI_PIN_INPUT_VALUE, &value);
+ if (ret) {
+ dev_err(dev, "settings_get_one() failed: %d\n", ret);
+ return ret;
+ }
+
+ return value;
+}
+
+static int scmi_gpio_get_function(struct udevice *dev, unsigned int offset)
+{
+ struct scmi_gpio_priv *priv = dev_get_priv(dev);
+ u32 value;
+ int pin;
+ int ret;
+
+ if (offset >= priv->num_pins)
+ return -EINVAL;
+ pin = priv->pins[offset];
+
+ ret = scmi_pinctrl_settings_get_one(priv->pin_dev, SCMI_PIN, pin,
+ SCMI_PIN_INPUT_MODE,
+ &value);
+ if (ret) {
+ dev_err(dev, "settings_get() failed %d\n", ret);
+ return ret;
+ }
+
+ if (value)
+ return GPIOF_INPUT;
+ return GPIOF_OUTPUT;
+}
+
+static const struct dm_gpio_ops scmi_gpio_ops = {
+ .request = scmi_gpio_request,
+ .rfree = scmi_gpio_rfree,
+ .set_flags = scmi_gpio_set_flags,
+ .get_value = scmi_gpio_get_value,
+ .get_function = scmi_gpio_get_function,
+};
+
+static int get_pins(struct udevice *dev, u32 function, u32 index, char **f_name,
+ u16 **pins, u32 *npins)
+{
+ struct scmi_gpio_priv *priv = dev_get_priv(dev);
+ struct pinctrl_scmi_priv *pin_info = dev_get_priv(priv->pin_dev);
+ u32 group;
+
+ if (function >= pin_info->num_functions)
+ return -EINVAL;
+ if (index >= pin_info->function_info[function].num_groups)
+ return -EINVAL;
+ group = pin_info->function_info[function].groups[index];
+ if (group >= pin_info->num_groups)
+ return -EINVAL;
+
+ *f_name = pin_info->function_info[function].name;
+ *pins = pin_info->group_info[group].pins;
+ *npins = pin_info->group_info[group].num_pins;
+
+ return 0;
+}
+
+static int scmi_gpio_probe(struct udevice *dev)
+{
+ struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
+ struct scmi_gpio_priv *priv = dev_get_priv(dev);
+ struct ofnode_phandle_args args;
+ int ret;
+
+ ret = dev_read_phandle_with_args(dev, "scmi,pinctrl", NULL, 2, 0, &args);
+ if (ret) {
+ dev_err(dev, "failed to read scmi,pinctrl phandle: %d\n", ret);
+ return ret;
+ }
+
+ ret = uclass_get_device_by_ofnode(UCLASS_PINCTRL, args.node, &priv->pin_dev);
+ if (ret) {
+ dev_err(dev, "failed to find pinctrl device: %d\n", ret);
+ return ret;
+ }
+
+ ret = get_pins(dev, args.args[0], args.args[1], &priv->bank_name,
+ &priv->pins, &priv->num_pins);
+ if (ret) {
+ dev_err(dev, "failed to get pins for %u %u\n", args.args[0], args.args[1]);
+ return ret;
+ }
+
+ uc_priv->bank_name = priv->bank_name;
+ uc_priv->gpio_count = priv->num_pins;
+
+ return 0;
+}
+
+static const struct udevice_id scmi_gpio_match[] = {
+ { .compatible = "scmi,gpio" },
+ { }
+};
+
+U_BOOT_DRIVER(scmi_pinctrl_gpio) = {
+ .name = "scmi_pinctrl_gpio",
+ .id = UCLASS_GPIO,
+ .of_match = scmi_gpio_match,
+ .probe = scmi_gpio_probe,
+ .priv_auto = sizeof(struct scmi_gpio_priv),
+ .ops = &scmi_gpio_ops,
+};
+
--
2.51.0
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