Add bridged amplifiers to cs42l43

Merge series from Charles Keepax <ckeepax@opensource.cirrus.com>:

In some cs42l43 systems a couple of cs35l56 amplifiers are attached
to the cs42l43's SPI and I2S. On Windows the cs42l43 is controlled
by a SDCA class driver and these two amplifiers are controlled by
firmware running on the cs42l43. However, under Linux the decision
was made to interact with the cs42l43 directly, affording the user
greater control over the audio system. However, this has resulted
in an issue where these two bridged cs35l56 amplifiers are not
populated in ACPI and must be added manually. There is at least an
SDCA extension unit DT entry we can key off.

The process of adding this is handled using a software node, firstly the
ability to add native chip selects to software nodes must be added.
Secondly, an additional flag for naming the SPI devices is added this
allows the machine driver to key to the correct amplifier. Then finally,
the cs42l43 SPI driver adds the two amplifiers directly onto its SPI
bus.

An additional series will follow soon to add the audio machine driver
parts (in the sof-sdw driver), however that is fairly orthogonal to
this part of the process, getting the actual amplifiers registered.

1 files changed, 21 insertions, 14 deletions

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index ce94e37bcbee..94903fc1c145 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1175,6 +1175,9 @@ struct gpio_device *gpio_device_find(const void *data,
 
 	list_for_each_entry_srcu(gdev, &gpio_devices, list,
 				 srcu_read_lock_held(&gpio_devices_srcu)) {
+		if (!device_is_registered(&gdev->dev))
+			continue;
+
 		guard(srcu)(&gdev->srcu);
 
 		gc = srcu_dereference(gdev->chip, &gdev->srcu);
@@ -2397,6 +2400,11 @@ char *gpiochip_dup_line_label(struct gpio_chip *gc, unsigned int offset)
 }
 EXPORT_SYMBOL_GPL(gpiochip_dup_line_label);
 
+static inline const char *function_name_or_default(const char *con_id)
+{
+	return con_id ?: "(default)";
+}
+
 /**
  * gpiochip_request_own_desc - Allow GPIO chip to request its own descriptor
  * @gc: GPIO chip
@@ -2425,10 +2433,11 @@ struct gpio_desc *gpiochip_request_own_desc(struct gpio_chip *gc,
 					    enum gpiod_flags dflags)
 {
 	struct gpio_desc *desc = gpiochip_get_desc(gc, hwnum);
+	const char *name = function_name_or_default(label);
 	int ret;
 
 	if (IS_ERR(desc)) {
-		chip_err(gc, "failed to get GPIO descriptor\n");
+		chip_err(gc, "failed to get GPIO %s descriptor\n", name);
 		return desc;
 	}
 
@@ -2438,8 +2447,8 @@ struct gpio_desc *gpiochip_request_own_desc(struct gpio_chip *gc,
 
 	ret = gpiod_configure_flags(desc, label, lflags, dflags);
 	if (ret) {
-		chip_err(gc, "setup of own GPIO %s failed\n", label);
 		gpiod_free_commit(desc);
+		chip_err(gc, "setup of own GPIO %s failed\n", name);
 		return ERR_PTR(ret);
 	}
 
@@ -4153,19 +4162,17 @@ static struct gpio_desc *gpiod_find_by_fwnode(struct fwnode_handle *fwnode,
 					      enum gpiod_flags *flags,
 					      unsigned long *lookupflags)
 {
+	const char *name = function_name_or_default(con_id);
 	struct gpio_desc *desc = ERR_PTR(-ENOENT);
 
 	if (is_of_node(fwnode)) {
-		dev_dbg(consumer, "using DT '%pfw' for '%s' GPIO lookup\n",
-			fwnode, con_id);
+		dev_dbg(consumer, "using DT '%pfw' for '%s' GPIO lookup\n", fwnode, name);
 		desc = of_find_gpio(to_of_node(fwnode), con_id, idx, lookupflags);
 	} else if (is_acpi_node(fwnode)) {
-		dev_dbg(consumer, "using ACPI '%pfw' for '%s' GPIO lookup\n",
-			fwnode, con_id);
+		dev_dbg(consumer, "using ACPI '%pfw' for '%s' GPIO lookup\n", fwnode, name);
 		desc = acpi_find_gpio(fwnode, con_id, idx, flags, lookupflags);
 	} else if (is_software_node(fwnode)) {
-		dev_dbg(consumer, "using swnode '%pfw' for '%s' GPIO lookup\n",
-			fwnode, con_id);
+		dev_dbg(consumer, "using swnode '%pfw' for '%s' GPIO lookup\n", fwnode, name);
 		desc = swnode_find_gpio(fwnode, con_id, idx, lookupflags);
 	}
 
@@ -4181,6 +4188,7 @@ struct gpio_desc *gpiod_find_and_request(struct device *consumer,
 					 bool platform_lookup_allowed)
 {
 	unsigned long lookupflags = GPIO_LOOKUP_FLAGS_DEFAULT;
+	const char *name = function_name_or_default(con_id);
 	/*
 	 * scoped_guard() is implemented as a for loop, meaning static
 	 * analyzers will complain about these two not being initialized.
@@ -4203,8 +4211,7 @@ struct gpio_desc *gpiod_find_and_request(struct device *consumer,
 		}
 
 		if (IS_ERR(desc)) {
-			dev_dbg(consumer, "No GPIO consumer %s found\n",
-				con_id);
+			dev_dbg(consumer, "No GPIO consumer %s found\n", name);
 			return desc;
 		}
 
@@ -4226,15 +4233,14 @@ struct gpio_desc *gpiod_find_and_request(struct device *consumer,
 		 *
 		 * FIXME: Make this more sane and safe.
 		 */
-		dev_info(consumer,
-			 "nonexclusive access to GPIO for %s\n", con_id);
+		dev_info(consumer, "nonexclusive access to GPIO for %s\n", name);
 		return desc;
 	}
 
 	ret = gpiod_configure_flags(desc, con_id, lookupflags, flags);
 	if (ret < 0) {
-		dev_dbg(consumer, "setup of GPIO %s failed\n", con_id);
 		gpiod_put(desc);
+		dev_dbg(consumer, "setup of GPIO %s failed\n", name);
 		return ERR_PTR(ret);
 	}
 
@@ -4350,6 +4356,7 @@ EXPORT_SYMBOL_GPL(gpiod_get_optional);
 int gpiod_configure_flags(struct gpio_desc *desc, const char *con_id,
 		unsigned long lflags, enum gpiod_flags dflags)
 {
+	const char *name = function_name_or_default(con_id);
 	int ret;
 
 	if (lflags & GPIO_ACTIVE_LOW)
@@ -4393,7 +4400,7 @@ int gpiod_configure_flags(struct gpio_desc *desc, const char *con_id,
 
 	/* No particular flag request, return here... */
 	if (!(dflags & GPIOD_FLAGS_BIT_DIR_SET)) {
-		gpiod_dbg(desc, "no flags found for %s\n", con_id);
+		gpiod_dbg(desc, "no flags found for GPIO %s\n", name);
 		return 0;
 	}