[PATCH 2/2] soundwire: bus: Allow SoundWire peripherals to register IRQ handlers

From: Charles Keepax
Date: Thu Jan 19 2023 - 11:51:55 EST


From: Lucas Tanure <tanureal@xxxxxxxxxxxxxxxxxxxxx>

Allow SoundWire peripherals to register a normal IRQ handler to receive
SoundWire alerts. This allows sharing the IRQ code between I2C/SPI which
typically use a normal IRQ handler, and SoundWire which historically
used a callback.

Signed-off-by: Lucas Tanure <tanureal@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxx>
---
drivers/soundwire/bus.c | 39 +++++++++++++++++++++++++++++++++++
include/linux/soundwire/sdw.h | 9 ++++++++
2 files changed, 48 insertions(+)

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index daee2cca94a4d..49087e0ca3c3c 100644
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -3,6 +3,7 @@

#include <linux/acpi.h>
#include <linux/delay.h>
+#include <linux/irq.h>
#include <linux/mod_devicetable.h>
#include <linux/pm_runtime.h>
#include <linux/soundwire/sdw_registers.h>
@@ -25,6 +26,23 @@ static int sdw_get_id(struct sdw_bus *bus)
return 0;
}

+static int sdw_irq_map(struct irq_domain *h, unsigned int virq,
+ irq_hw_number_t hw)
+{
+ struct sdw_bus *bus = h->host_data;
+
+ irq_set_chip_data(virq, bus);
+ irq_set_chip(virq, &bus->irq_chip);
+ irq_set_nested_thread(virq, 1);
+ irq_set_noprobe(virq);
+
+ return 0;
+}
+
+static const struct irq_domain_ops sdw_domain_ops = {
+ .map = sdw_irq_map,
+};
+
/**
* sdw_bus_master_add() - add a bus Master instance
* @bus: bus instance
@@ -142,6 +160,13 @@ int sdw_bus_master_add(struct sdw_bus *bus, struct device *parent,
bus->params.curr_bank = SDW_BANK0;
bus->params.next_bank = SDW_BANK1;

+ bus->irq_chip.name = dev_name(bus->dev);
+ bus->domain = irq_domain_add_linear(NULL, SDW_MAX_DEVICES, &sdw_domain_ops, bus);
+ if (!bus->domain) {
+ dev_err(bus->dev, "Failed to add IRQ domain\n");
+ return -EINVAL;
+ }
+
return 0;
}
EXPORT_SYMBOL(sdw_bus_master_add);
@@ -158,6 +183,8 @@ static int sdw_delete_slave(struct device *dev, void *data)
mutex_lock(&bus->bus_lock);

if (slave->dev_num) { /* clear dev_num if assigned */
+ irq_dispose_mapping(irq_find_mapping(bus->domain, slave->dev_num));
+
clear_bit(slave->dev_num, bus->assigned);
if (bus->dev_num_ida_min)
ida_free(&sdw_peripheral_ida, slave->dev_num);
@@ -178,6 +205,9 @@ static int sdw_delete_slave(struct device *dev, void *data)
void sdw_bus_master_delete(struct sdw_bus *bus)
{
device_for_each_child(bus->dev, NULL, sdw_delete_slave);
+
+ irq_domain_remove(bus->domain);
+
sdw_master_device_del(bus);

sdw_bus_debugfs_exit(bus);
@@ -717,6 +747,12 @@ static int sdw_assign_device_num(struct sdw_slave *slave)
slave->dev_num = dev_num;
slave->dev_num_sticky = dev_num;
new_device = true;
+
+ slave->irq = irq_create_mapping(bus->domain, dev_num);
+ if (!slave->irq) {
+ dev_err(bus->dev, "Failed to map IRQ\n");
+ return -EINVAL;
+ }
} else {
slave->dev_num = slave->dev_num_sticky;
}
@@ -1682,6 +1718,9 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
struct device *dev = &slave->dev;
struct sdw_driver *drv = drv_to_sdw_driver(dev->driver);

+ if (slave->prop.irq && slave->irq)
+ handle_nested_irq(slave->irq);
+
if (drv->ops && drv->ops->interrupt_callback) {
slave_intr.sdca_cascade = sdca_cascade;
slave_intr.control_port = clear;
diff --git a/include/linux/soundwire/sdw.h b/include/linux/soundwire/sdw.h
index 3cd2a761911ff..7627c459ab20f 100644
--- a/include/linux/soundwire/sdw.h
+++ b/include/linux/soundwire/sdw.h
@@ -5,6 +5,8 @@
#define __SOUNDWIRE_H

#include <linux/bug.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
#include <linux/mod_devicetable.h>
#include <linux/bitfield.h>

@@ -369,6 +371,7 @@ struct sdw_dpn_prop {
* @clock_reg_supported: the Peripheral implements the clock base and scale
* registers introduced with the SoundWire 1.2 specification. SDCA devices
* do not need to set this boolean property as the registers are required.
+ * @irq: call actual IRQ handler on slave, as well as callback
*/
struct sdw_slave_prop {
u32 mipi_revision;
@@ -393,6 +396,7 @@ struct sdw_slave_prop {
u8 scp_int1_mask;
u32 quirks;
bool clock_reg_supported;
+ bool irq;
};

#define SDW_SLAVE_QUIRKS_INVALID_INITIAL_PARITY BIT(0)
@@ -638,6 +642,7 @@ struct sdw_slave_ops {
* struct sdw_slave - SoundWire Slave
* @id: MIPI device ID
* @dev: Linux device
+ * @irq: IRQ number
* @status: Status reported by the Slave
* @bus: Bus handle
* @prop: Slave properties
@@ -667,6 +672,7 @@ struct sdw_slave_ops {
struct sdw_slave {
struct sdw_slave_id id;
struct device dev;
+ int irq;
enum sdw_slave_status status;
struct sdw_bus *bus;
struct sdw_slave_prop prop;
@@ -884,6 +890,7 @@ struct sdw_master_ops {
* is used to compute and program bus bandwidth, clock, frame shape,
* transport and port parameters
* @debugfs: Bus debugfs
+ * @domain: IRQ domain
* @defer_msg: Defer message
* @clk_stop_timeout: Clock stop timeout computed
* @bank_switch_timeout: Bank switch timeout computed
@@ -917,6 +924,8 @@ struct sdw_bus {
#ifdef CONFIG_DEBUG_FS
struct dentry *debugfs;
#endif
+ struct irq_chip irq_chip;
+ struct irq_domain *domain;
struct sdw_defer defer_msg;
unsigned int clk_stop_timeout;
u32 bank_switch_timeout;
--
2.30.2