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, 50 insertions, 8 deletions

diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index f384fa278764..d09c7d728365 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -728,6 +728,25 @@ static u32 line_event_id(int level)
 		       GPIO_V2_LINE_EVENT_FALLING_EDGE;
 }
 
+static inline char *make_irq_label(const char *orig)
+{
+	char *new;
+
+	if (!orig)
+		return NULL;
+
+	new = kstrdup_and_replace(orig, '/', ':', GFP_KERNEL);
+	if (!new)
+		return ERR_PTR(-ENOMEM);
+
+	return new;
+}
+
+static inline void free_irq_label(const char *label)
+{
+	kfree(label);
+}
+
 #ifdef CONFIG_HTE
 
 static enum hte_return process_hw_ts_thread(void *p)
@@ -1015,6 +1034,7 @@ static int debounce_setup(struct line *line, unsigned int debounce_period_us)
 {
 	unsigned long irqflags;
 	int ret, level, irq;
+	char *label;
 
 	/* try hardware */
 	ret = gpiod_set_debounce(line->desc, debounce_period_us);
@@ -1037,11 +1057,17 @@ static int debounce_setup(struct line *line, unsigned int debounce_period_us)
 			if (irq < 0)
 				return -ENXIO;
 
+			label = make_irq_label(line->req->label);
+			if (IS_ERR(label))
+				return -ENOMEM;
+
 			irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
 			ret = request_irq(irq, debounce_irq_handler, irqflags,
-					  line->req->label, line);
-			if (ret)
+					  label, line);
+			if (ret) {
+				free_irq_label(label);
 				return ret;
+			}
 			line->irq = irq;
 		} else {
 			ret = hte_edge_setup(line, GPIO_V2_LINE_FLAG_EDGE_BOTH);
@@ -1086,7 +1112,7 @@ static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc,
 static void edge_detector_stop(struct line *line)
 {
 	if (line->irq) {
-		free_irq(line->irq, line);
+		free_irq_label(free_irq(line->irq, line));
 		line->irq = 0;
 	}
 
@@ -1110,6 +1136,7 @@ static int edge_detector_setup(struct line *line,
 	unsigned long irqflags = 0;
 	u64 eflags;
 	int irq, ret;
+	char *label;
 
 	eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
 	if (eflags && !kfifo_initialized(&line->req->events)) {
@@ -1146,11 +1173,17 @@ static int edge_detector_setup(struct line *line,
 			IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
 	irqflags |= IRQF_ONESHOT;
 
+	label = make_irq_label(line->req->label);
+	if (IS_ERR(label))
+		return PTR_ERR(label);
+
 	/* Request a thread to read the events */
 	ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread,
-				   irqflags, line->req->label, line);
-	if (ret)
+				   irqflags, label, line);
+	if (ret) {
+		free_irq_label(label);
 		return ret;
+	}
 
 	line->irq = irq;
 	return 0;
@@ -1973,7 +2006,7 @@ static void lineevent_free(struct lineevent_state *le)
 		blocking_notifier_chain_unregister(&le->gdev->device_notifier,
 						   &le->device_unregistered_nb);
 	if (le->irq)
-		free_irq(le->irq, le);
+		free_irq_label(free_irq(le->irq, le));
 	if (le->desc)
 		gpiod_free(le->desc);
 	kfree(le->label);
@@ -2114,6 +2147,7 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip)
 	int fd;
 	int ret;
 	int irq, irqflags = 0;
+	char *label;
 
 	if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
 		return -EFAULT;
@@ -2198,15 +2232,23 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip)
 	if (ret)
 		goto out_free_le;
 
+	label = make_irq_label(le->label);
+	if (IS_ERR(label)) {
+		ret = PTR_ERR(label);
+		goto out_free_le;
+	}
+
 	/* Request a thread to read the events */
 	ret = request_threaded_irq(irq,
 				   lineevent_irq_handler,
 				   lineevent_irq_thread,
 				   irqflags,
-				   le->label,
+				   label,
 				   le);
-	if (ret)
+	if (ret) {
+		free_irq_label(label);
 		goto out_free_le;
+	}
 
 	le->irq = irq;