[PATCH RFC v2 2/6] gpio: aggregator: refactor the forwarder part.
From: Thomas Richard
Date: Mon Mar 17 2025 - 11:39:32 EST
Prepare the code to create a gpio-fwd library. This library will allow to
create and register a gpiochip forwarder.
Signed-off-by: Thomas Richard <thomas.richard@xxxxxxxxxxx>
---
drivers/gpio/gpio-aggregator.c | 140 +++++++++++++++++++++++++++--------------
1 file changed, 94 insertions(+), 46 deletions(-)
diff --git a/drivers/gpio/gpio-aggregator.c b/drivers/gpio/gpio-aggregator.c
index d668ddb2e81d3..a86e76daf67ab 100644
--- a/drivers/gpio/gpio-aggregator.c
+++ b/drivers/gpio/gpio-aggregator.c
@@ -260,6 +260,7 @@ struct gpiochip_fwd_timing {
};
struct gpiochip_fwd {
+ struct device *dev;
struct gpio_chip chip;
struct gpio_desc **descs;
union {
@@ -466,10 +467,11 @@ static int gpiochip_fwd_delay_of_xlate(struct gpio_chip *chip,
return line;
}
-static int gpiochip_fwd_setup_delay_line(struct device *dev, struct gpio_chip *chip,
- struct gpiochip_fwd *fwd)
+static int gpiochip_fwd_setup_delay_line(struct gpiochip_fwd *fwd)
{
- fwd->delay_timings = devm_kcalloc(dev, chip->ngpio,
+ struct gpio_chip *chip = &fwd->chip;
+
+ fwd->delay_timings = devm_kcalloc(fwd->dev, chip->ngpio,
sizeof(*fwd->delay_timings),
GFP_KERNEL);
if (!fwd->delay_timings)
@@ -481,63 +483,30 @@ static int gpiochip_fwd_setup_delay_line(struct device *dev, struct gpio_chip *c
return 0;
}
#else
-static int gpiochip_fwd_setup_delay_line(struct device *dev, struct gpio_chip *chip,
- struct gpiochip_fwd *fwd)
+static int gpiochip_fwd_setup_delay_line(struct gpiochip_fwd *fwd)
{
return 0;
}
#endif /* !CONFIG_OF_GPIO */
-/**
- * gpiochip_fwd_create() - Create a new GPIO forwarder
- * @dev: Parent device pointer
- * @ngpios: Number of GPIOs in the forwarder.
- * @descs: Array containing the GPIO descriptors to forward to.
- * This array must contain @ngpios entries, and must not be deallocated
- * before the forwarder has been destroyed again.
- * @features: Bitwise ORed features as defined with FWD_FEATURE_*.
- *
- * This function creates a new gpiochip, which forwards all GPIO operations to
- * the passed GPIO descriptors.
- *
- * Return: An opaque object pointer, or an ERR_PTR()-encoded negative error
- * code on failure.
- */
-static struct gpiochip_fwd *gpiochip_fwd_create(struct device *dev,
- unsigned int ngpios,
- struct gpio_desc *descs[],
- unsigned long features)
+static struct gpiochip_fwd *devm_gpiochip_fwd_alloc(struct device *dev,
+ unsigned int ngpios)
{
const char *label = dev_name(dev);
struct gpiochip_fwd *fwd;
struct gpio_chip *chip;
- unsigned int i;
- int error;
fwd = devm_kzalloc(dev, struct_size(fwd, tmp, fwd_tmp_size(ngpios)),
GFP_KERNEL);
if (!fwd)
return ERR_PTR(-ENOMEM);
- chip = &fwd->chip;
+ fwd->descs = devm_kcalloc(dev, ngpios, sizeof(*fwd->descs),
+ GFP_KERNEL);
- /*
- * If any of the GPIO lines are sleeping, then the entire forwarder
- * will be sleeping.
- * If any of the chips support .set_config(), then the forwarder will
- * support setting configs.
- */
- for (i = 0; i < ngpios; i++) {
- struct gpio_chip *parent = gpiod_to_chip(descs[i]);
+ fwd->dev = dev;
- dev_dbg(dev, "%u => gpio %d irq %d\n", i,
- desc_to_gpio(descs[i]), gpiod_to_irq(descs[i]));
-
- if (gpiod_cansleep(descs[i]))
- chip->can_sleep = true;
- if (parent && parent->set_config)
- chip->set_config = gpio_fwd_set_config;
- }
+ chip = &fwd->chip;
chip->label = label;
chip->parent = dev;
@@ -552,20 +521,99 @@ static struct gpiochip_fwd *gpiochip_fwd_create(struct device *dev,
chip->to_irq = gpio_fwd_to_irq;
chip->base = -1;
chip->ngpio = ngpios;
- fwd->descs = descs;
+
+ return fwd;
+}
+
+static int gpiochip_fwd_add_gpio_desc(struct gpiochip_fwd *fwd, struct gpio_desc *desc,
+ unsigned int offset)
+{
+ struct gpio_chip *chip = &fwd->chip;
+ struct gpio_chip *parent = gpiod_to_chip(desc);
+
+ if (offset > chip->ngpio)
+ return -EINVAL;
+
+ if (fwd->descs[offset])
+ return -EEXIST;
+
+ /*
+ * If any of the GPIO lines are sleeping, then the entire forwarder
+ * will be sleeping.
+ * If any of the chips support .set_config(), then the forwarder will
+ * support setting configs.
+ */
+ if (gpiod_cansleep(desc))
+ chip->can_sleep = true;
+
+ if (parent && parent->set_config)
+ chip->set_config = gpio_fwd_set_config;
+
+ fwd->descs[offset] = desc;
+
+ dev_dbg(fwd->dev, "%u => gpio %d irq %d\n", offset,
+ desc_to_gpio(desc), gpiod_to_irq(desc));
+
+ return 0;
+}
+
+static int gpiochip_fwd_register(struct gpiochip_fwd *fwd)
+{
+ struct gpio_chip *chip = &fwd->chip;
+ struct device *dev = fwd->dev;
+ int error;
if (chip->can_sleep)
mutex_init(&fwd->mlock);
else
spin_lock_init(&fwd->slock);
+ error = devm_gpiochip_add_data(dev, chip, fwd);
+
+ return error;
+}
+
+/**
+ * gpiochip_fwd_create() - Create a new GPIO forwarder
+ * @dev: Parent device pointer
+ * @ngpios: Number of GPIOs in the forwarder.
+ * @descs: Array containing the GPIO descriptors to forward to.
+ * This array must contain @ngpios entries, and must not be deallocated
+ * before the forwarder has been destroyed again.
+ * @features: Bitwise ORed features as defined with FWD_FEATURE_*.
+ *
+ * This function creates a new gpiochip, which forwards all GPIO operations to
+ * the passed GPIO descriptors.
+ *
+ * Return: An opaque object pointer, or an ERR_PTR()-encoded negative error
+ * code on failure.
+ */
+static struct gpiochip_fwd *gpiochip_fwd_create(struct device *dev,
+ unsigned int ngpios,
+ struct gpio_desc *descs[],
+ unsigned long features)
+{
+ struct gpiochip_fwd *fwd;
+ unsigned int i;
+ int error;
+
+ fwd = devm_gpiochip_fwd_alloc(dev, ngpios);
+ if (!fwd)
+ return fwd;
+
+ for (i = 0; i < ngpios; i++) {
+ error = gpiochip_fwd_add_gpio_desc(fwd, descs[i], i);
+ if (error)
+ return ERR_PTR(error);
+ }
+
if (features & FWD_FEATURE_DELAY) {
- error = gpiochip_fwd_setup_delay_line(dev, chip, fwd);
+ error = gpiochip_fwd_setup_delay_line(fwd);
if (error)
return ERR_PTR(error);
}
- error = devm_gpiochip_add_data(dev, chip, fwd);
+ error = gpiochip_fwd_register(fwd);
if (error)
return ERR_PTR(error);
--
2.39.5