[PATCH RFC v2 6/7] pinctrl-scmi: Add GPIO support

Dan Carpenter
2025-07-20T19:51:03Z

This adds GPIO support to the SCMI pin controller driver. It's an RFC
patch because I'm not really sure how these are used and so I don't
know how they should be configured via devicetree. I've labeled the
places where I think devicetree configuration would go with a FIXME.

This driver was based on work from Takahiro AKASHI.

Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
---
drivers/pinctrl/core.c | 8 +-
drivers/pinctrl/pinctrl-scmi.c | 206 ++++++++++++++++++++++++++++++++-
2 files changed, 207 insertions(+), 7 deletions(-)

diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
index bbcc6881b119..91882c68bcd5 100644
--- a/drivers/pinctrl/core.c
+++ b/drivers/pinctrl/core.c
@@ -947,7 +947,6 @@ EXPORT_SYMBOL_GPL(pinctrl_gpio_set_config);
int pinctrl_gpio_get_config(struct gpio_chip *gc, unsigned int offset, unsigned long *config)
{
struct pinctrl_gpio_range *range;
- const struct pinconf_ops *ops;
struct pinctrl_dev *pctldev;
int ret, pin;

@@ -955,19 +954,16 @@ int pinctrl_gpio_get_config(struct gpio_chip *gc, unsigned int offset, unsigned
if (ret)
return ret;

- ops = pctldev->desc->confops;
- if (!ops || !ops->pin_config_get)
- return -EINVAL;
-
mutex_lock(&pctldev->mutex);
pin = gpio_to_pin(range, gc, offset);
- ret = ops->pin_config_get(pctldev, pin, config);
+ 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);
diff --git a/drivers/pinctrl/pinctrl-scmi.c b/drivers/pinctrl/pinctrl-scmi.c
index fba0a3a2fc10..9a947ced0df7 100644
--- a/drivers/pinctrl/pinctrl-scmi.c
+++ b/drivers/pinctrl/pinctrl-scmi.c
@@ -6,6 +6,7 @@
* Copyright 2024 NXP
*/

+#include <linux/bitmap.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/errno.h>
@@ -16,6 +17,9 @@
#include <linux/slab.h>
#include <linux/types.h>

+#include <linux/gpio/driver.h>
+
+#include <linux/pinctrl/consumer.h>
#include <linux/pinctrl/machine.h>
#include <linux/pinctrl/pinconf.h>
#include <linux/pinctrl/pinconf-generic.h>
@@ -42,6 +46,7 @@ struct scmi_pinctrl {
unsigned int nr_functions;
struct pinctrl_pin_desc *pins;
unsigned int nr_pins;
+ struct gpio_chip *gc;
};

static int pinctrl_scmi_get_groups_count(struct pinctrl_dev *pctldev)
@@ -505,6 +510,197 @@ static int pinctrl_scmi_get_pins(struct scmi_pinctrl *pmx,
return 0;
}

+static int pinctrl_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
+{
+ unsigned long config;
+ bool in, out;
+ int ret;
+
+ config = PIN_CONFIG_INPUT_ENABLE;
+ ret = pinctrl_gpio_get_config(gc, offset, &config);
+ if (ret)
+ return ret;
+ in = config;
+
+ config = PIN_CONFIG_OUTPUT_ENABLE;
+ ret = pinctrl_gpio_get_config(gc, offset, &config);
+ if (ret)
+ return ret;
+ out = config;
+
+ /* Consistency check - in theory both can be enabled! */
+ if (in && !out)
+ return GPIO_LINE_DIRECTION_IN;
+ if (!in && out)
+ return GPIO_LINE_DIRECTION_OUT;
+
+ return -EINVAL;
+}
+
+static int pinctrl_gpio_direction_output_wrapper(struct gpio_chip *gc,
+ unsigned int offset, int val)
+{
+ return pinctrl_gpio_direction_output(gc, offset);
+}
+
+static int pinctrl_gpio_get(struct gpio_chip *gc, unsigned int offset)
+{
+ unsigned long config;
+ int ret;
+
+ config = PIN_CONFIG_INPUT_VALUE;
+ ret = pinctrl_gpio_get_config(gc, offset, &config);
+ if (ret)
+ return ret;
+
+ return config;
+}
+
+static void pinctrl_gpio_set(struct gpio_chip *gc, unsigned int offset, int val)
+{
+ unsigned long config;
+
+ config = PIN_CONF_PACKED(PIN_CONFIG_OUTPUT, val);
+ pinctrl_gpio_set_config(gc, offset, config);
+}
+
+static int pinctrl_gc_to_func(struct gpio_chip *gc)
+{
+ struct scmi_pinctrl *pmx = gpiochip_get_data(gc);
+
+ return (gc - pmx->gc);
+}
+
+static int gpio_add_pin_ranges(struct gpio_chip *gc)
+{
+ struct scmi_pinctrl *pmx = gpiochip_get_data(gc);
+ const char * const *p_groups;
+ unsigned int n_groups;
+ int func = pinctrl_gc_to_func(gc);
+ const unsigned int *pins;
+ unsigned int n_pins;
+ int offset = 0;
+ int group;
+ int ret;
+
+ ret = pmx->pctl_desc.pmxops->get_function_groups(pmx->pctldev, func, &p_groups, &n_groups);
+ if (ret)
+ return ret;
+
+ // FIXME: fix the correct group from the device tree
+ for (group = 0; group < n_groups; group++) {
+ ret = pinctrl_get_group_pins(pmx->pctldev, p_groups[group], &pins, &n_pins);
+ if (ret)
+ return ret;
+
+ ret = gpiochip_add_pingroup_range(gc, pmx->pctldev, offset, p_groups[group]);
+ if (ret)
+ return ret;
+
+ offset += n_pins;
+ }
+
+ return 0;
+}
+
+static int get_nr_pins_in_function(struct scmi_pinctrl *pmx, int func)
+{
+ const char * const *pin_groups;
+ unsigned int n_groups;
+ const unsigned int *pins;
+ unsigned int n_pins;
+ int total = 0;
+ int i, ret;
+
+ // FIXME: get the correct number of gc.ngpio
+ // Find the right group from the device tree
+ ret = pmx->pctl_desc.pmxops->get_function_groups(pmx->pctldev, func, &pin_groups, &n_groups);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < n_groups; i++) {
+ ret = pinctrl_get_group_pins(pmx->pctldev, pin_groups[i], &pins, &n_pins);
+ if (ret)
+ return ret;
+ total += n_pins;
+ }
+
+ return total;
+}
+
+static int register_scmi_pinctrl_gpio_handler(struct device *dev, struct scmi_pinctrl *pmx)
+{
+ struct fwnode_handle *gpio = NULL;
+ int ret, i;
+
+ gpio = fwnode_get_named_child_node(dev->fwnode, "gpio");
+ if (!gpio)
+ return 0;
+
+ pmx->gc = devm_kcalloc(dev, pmx->nr_functions, sizeof(*pmx->gc), GFP_KERNEL);
+ if (!pmx->gc)
+ return -ENOMEM;
+
+ for (i = 0; i < pmx->nr_functions; i++) {
+ const char *fn_name;
+
+ ret = pinctrl_ops->is_gpio(pmx->ph, i, FUNCTION_TYPE);
+ if (ret < 0)
+ return ret;
+ if (ret == false)
+ continue;
+
+ ret = pinctrl_ops->name_get(pmx->ph, i, FUNCTION_TYPE, &fn_name);
+ if (ret)
+ return ret;
+
+ pmx->gc[i].label = devm_kasprintf(dev, GFP_KERNEL, "%s", fn_name);
+ if (!pmx->gc[i].label)
+ return -ENOMEM;
+
+ pmx->gc[i].owner = THIS_MODULE;
+ pmx->gc[i].get = pinctrl_gpio_get;
+ pmx->gc[i].set = pinctrl_gpio_set;
+ pmx->gc[i].get_direction = pinctrl_gpio_get_direction;
+ pmx->gc[i].direction_input = pinctrl_gpio_direction_input;
+ pmx->gc[i].direction_output = pinctrl_gpio_direction_output_wrapper;
+ pmx->gc[i].add_pin_ranges = gpio_add_pin_ranges;
+
+ // FIXME: verify that this is correct
+ pmx->gc[i].can_sleep = true;
+
+ ret = get_nr_pins_in_function(pmx, i);
+ if (ret < 0)
+ return ret;
+ pmx->gc[i].ngpio = ret;
+
+ pmx->gc[i].parent = dev;
+ pmx->gc[i].base = -1;
+ }
+
+ return 0;
+}
+
+static int scmi_gpiochip_add_data(struct device *dev, struct scmi_pinctrl *pmx)
+{
+ int ret;
+ int i;
+
+ for (i = 0; i < pmx->nr_functions; i++) {
+ ret = pinctrl_ops->is_gpio(pmx->ph, i, FUNCTION_TYPE);
+ if (ret < 0)
+ return ret;
+ if (ret == false)
+ continue;
+
+ ret = devm_gpiochip_add_data(dev, &pmx->gc[i], pmx);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
static const char * const scmi_pinctrl_blocklist[] = {
"fsl,imx95",
"fsl,imx94",
@@ -559,7 +755,15 @@ static int scmi_pinctrl_probe(struct scmi_device *sdev)
if (!pmx->functions)
return -ENOMEM;

- return pinctrl_enable(pmx->pctldev);
+ ret = register_scmi_pinctrl_gpio_handler(dev, pmx);
+ if (ret)
+ return ret;
+
+ ret = pinctrl_enable(pmx->pctldev);
+ if (ret)
+ return ret;
+
+ return scmi_gpiochip_add_data(dev, pmx);
}

static const struct scmi_device_id scmi_id_table[] = {
--
2.47.2