[PATCH v3 13/18] media: ipu-bridge: Add a runtime-pm device-link between VCM and sensor

Hans de Goede
2023-07-05T21:33:05Z

In most cases when a VCM is used there is a single integrated module
with the sensor + VCM + lens. This means that the sensor and VCM often
share regulators and possibly also something like a powerdown pin.

In the ACPI tables this is modelled as a single ACPI device with
multiple I2cSerialBus resources.

On atomisp devices the regulators and clks are modelled as ACPI
power-resources, which are controlled by the (ACPI) power state
of the sensor. So the sensor must be in D0 power state for the VCM
to work.

To make this work add a device-link with DL_FLAG_PM_RUNTIME flag
so that the sensor will automatically be runtime-resumed whenever
the VCM is runtime-resumed.

This requires the probing of the VCM and thus the creation of the VCM
I2C-client to be delayed till after the sensor driver has bound.

Move the instantiation of the VCM I2C-client to the v4l2_async_notifier
bound op, so that it is done after the sensor driver has bound; and
add code to add the device-link.

This fixes the problem with the shared ACPI power-resources on atomisp2
and this avoids the need for VCM related workarounds on IPU3 / IPU6.

E.g. until now the dw9719 driver needed to get and control a Vsio
(V sensor IO) regulator since that needs to be enabled to enable I2C
pass-through on the PMIC on the sensor module. So the driver was
controlling this regulator even though the actual dw9719 chip has no
Vsio pin / power-plane.

This also removes the need for ipu_bridge_init() to return
-EPROBE_DEFER since the VCM is now instantiated later.

Reviewed-by: Andy Shevchenko <andy@kernel.org>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Tested-by: Daniel Scally <dan.scally@ideasonboard.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
Changes in v3:
-Rename local variables named work to data to avoid having
work->work (now data->work)
-Use snprintf "%pfwP" to set type to fwnode name
---
drivers/media/pci/intel/ipu-bridge.c | 159 +++++++++++++++--------
drivers/media/pci/intel/ipu3/ipu3-cio2.c | 5 +
include/media/ipu-bridge.h | 5 +-
3 files changed, 109 insertions(+), 60 deletions(-)

diff --git a/drivers/media/pci/intel/ipu-bridge.c b/drivers/media/pci/intel/ipu-bridge.c
index 6f7650a3a199..0e506ab541e8 100644
--- a/drivers/media/pci/intel/ipu-bridge.c
+++ b/drivers/media/pci/intel/ipu-bridge.c
@@ -4,7 +4,10 @@
#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/i2c.h>
+#include <linux/pm_runtime.h>
#include <linux/property.h>
+#include <linux/string.h>
+#include <linux/workqueue.h>

#include <media/ipu-bridge.h>
#include <media/v4l2-fwnode.h>
@@ -289,29 +292,111 @@ static void ipu_bridge_create_connection_swnodes(struct ipu_bridge *bridge,
ipu_bridge_init_swnode_group(sensor);
}

-static void ipu_bridge_instantiate_vcm_i2c_client(struct ipu_sensor *sensor)
-{
- struct i2c_board_info board_info = { };
+/*
+ * The actual instantiation must be done from a workqueue to avoid
+ * a deadlock on taking list_lock from v4l2-async twice.
+ */
+struct ipu_bridge_instantiate_vcm_work_data {
+ struct work_struct work;
+ struct device *sensor;
char name[16];
+ struct i2c_board_info board_info;
+};

- if (!sensor->vcm_type)
- return;
+static void ipu_bridge_instantiate_vcm_work(struct work_struct *work)
+{
+ struct ipu_bridge_instantiate_vcm_work_data *data =
+ container_of(work, struct ipu_bridge_instantiate_vcm_work_data,
+ work);
+ struct acpi_device *adev = ACPI_COMPANION(data->sensor);
+ struct i2c_client *vcm_client;
+ bool put_fwnode = true;
+ int ret;

- snprintf(name, sizeof(name), "%s-VCM", acpi_dev_name(sensor->adev));
- board_info.dev_name = name;
- strscpy(board_info.type, sensor->vcm_type, ARRAY_SIZE(board_info.type));
- board_info.swnode = &sensor->swnodes[SWNODE_VCM];
-
- sensor->vcm_i2c_client =
- i2c_acpi_new_device_by_fwnode(acpi_fwnode_handle(sensor->adev),
- 1, &board_info);
- if (IS_ERR(sensor->vcm_i2c_client)) {
- dev_warn(&sensor->adev->dev, "Error instantiation VCM i2c-client: %ld\n",
- PTR_ERR(sensor->vcm_i2c_client));
- sensor->vcm_i2c_client = NULL;
+ /*
+ * The client may get probed before the device_link gets added below
+ * make sure the sensor is powered-up during probe.
+ */
+ ret = pm_runtime_get_sync(data->sensor);
+ if (ret < 0) {
+ dev_err(data->sensor, "Error %d runtime-resuming sensor, cannot instantiate VCM\n",
+ ret);
+ goto out_pm_put;
}
+
+ /*
+ * Note the client is created only once and then kept around
+ * even after a rmmod, just like the software-nodes.
+ */
+ vcm_client = i2c_acpi_new_device_by_fwnode(acpi_fwnode_handle(adev),
+ 1, &data->board_info);
+ if (IS_ERR(vcm_client)) {
+ dev_err(data->sensor, "Error instantiating VCM client: %ld\n",
+ PTR_ERR(vcm_client));
+ goto out_pm_put;
+ }
+
+ device_link_add(&vcm_client->dev, data->sensor, DL_FLAG_PM_RUNTIME);
+
+ dev_info(data->sensor, "Instantiated %s VCM\n", data->board_info.type);
+ put_fwnode = false; /* Ownership has passed to the i2c-client */
+
+out_pm_put:
+ pm_runtime_put(data->sensor);
+ put_device(data->sensor);
+ if (put_fwnode)
+ fwnode_handle_put(data->board_info.fwnode);
+ kfree(data);
}

+int ipu_bridge_instantiate_vcm(struct device *sensor)
+{
+ struct ipu_bridge_instantiate_vcm_work_data *data;
+ struct fwnode_handle *vcm_fwnode;
+ struct i2c_client *vcm_client;
+ struct acpi_device *adev;
+ char *sep;
+
+ adev = ACPI_COMPANION(sensor);
+ if (!adev)
+ return 0;
+
+ vcm_fwnode = fwnode_find_reference(dev_fwnode(sensor), "lens-focus", 0);
+ if (IS_ERR(vcm_fwnode))
+ return 0;
+
+ /* When reloading modules the client will already exist */
+ vcm_client = i2c_find_device_by_fwnode(vcm_fwnode);
+ if (vcm_client) {
+ fwnode_handle_put(vcm_fwnode);
+ put_device(&vcm_client->dev);
+ return 0;
+ }
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (!data) {
+ fwnode_handle_put(vcm_fwnode);
+ return -ENOMEM;
+ }
+
+ INIT_WORK(&data->work, ipu_bridge_instantiate_vcm_work);
+ data->sensor = get_device(sensor);
+ snprintf(data->name, sizeof(data->name), "%s-VCM",
+ acpi_dev_name(adev));
+ data->board_info.dev_name = data->name;
+ data->board_info.fwnode = vcm_fwnode;
+ snprintf(data->board_info.type, sizeof(data->board_info.type),
+ "%pfwP", vcm_fwnode);
+ /* Strip "- " postfix */
+ sep = strchrnul(data->board_info.type, '-');
+ *sep = 0;
+
+ queue_work(system_long_wq, &data->work);
+
+ return 0;
+}
+EXPORT_SYMBOL_NS_GPL(ipu_bridge_instantiate_vcm, INTEL_IPU_BRIDGE);
+
static void ipu_bridge_unregister_sensors(struct ipu_bridge *bridge)
{
struct ipu_sensor *sensor;
@@ -321,7 +406,6 @@ static void ipu_bridge_unregister_sensors(struct ipu_bridge *bridge)
sensor = &bridge->sensors[i];
software_node_unregister_node_group(sensor->group);
acpi_dev_put(sensor->adev);
- i2c_unregister_device(sensor->vcm_i2c_client);
}
}

@@ -371,8 +455,6 @@ static int ipu_bridge_connect_sensor(const struct ipu_sensor_config *cfg,
primary = acpi_fwnode_handle(adev);
primary->secondary = fwnode;

- ipu_bridge_instantiate_vcm_i2c_client(sensor);
-
dev_info(bridge->dev, "Found supported sensor %s\n",
acpi_dev_name(adev));

@@ -409,40 +491,6 @@ static int ipu_bridge_connect_sensors(struct ipu_bridge *bridge)
return ret;
}

-/*
- * The VCM cannot be probed until the PMIC is completely setup. We cannot rely
- * on -EPROBE_DEFER for this, since the consumer<->supplier relations between
- * the VCM and regulators/clks are not described in ACPI, instead they are
- * passed as board-data to the PMIC drivers. Since -PROBE_DEFER does not work
- * for the clks/regulators the VCM i2c-clients must not be instantiated until
- * the PMIC is fully setup.
- *
- * The sensor/VCM ACPI device has an ACPI _DEP on the PMIC, check this using the
- * acpi_dev_ready_for_enumeration() helper, like the i2c-core-acpi code does
- * for the sensors.
- */
-static int ipu_bridge_sensors_are_ready(void)
-{
- struct acpi_device *adev;
- bool ready = true;
- unsigned int i;
-
- for (i = 0; i < ARRAY_SIZE(ipu_supported_sensors); i++) {
- const struct ipu_sensor_config *cfg =
- &ipu_supported_sensors[i];
-
- for_each_acpi_dev_match(adev, cfg->hid, NULL, -1) {
- if (!adev->status.enabled)
- continue;
-
- if (!acpi_dev_ready_for_enumeration(adev))
- ready = false;
- }
- }
-
- return ready;
-}
-
int ipu_bridge_init(struct device *dev,
ipu_parse_sensor_fwnode_t parse_sensor_fwnode)
{
@@ -451,9 +499,6 @@ int ipu_bridge_init(struct device *dev,
unsigned int i;
int ret;

- if (!ipu_bridge_sensors_are_ready())
- return -EPROBE_DEFER;
-
bridge = kzalloc(sizeof(*bridge), GFP_KERNEL);
if (!bridge)
return -ENOMEM;
diff --git a/drivers/media/pci/intel/ipu3/ipu3-cio2.c b/drivers/media/pci/intel/ipu3/ipu3-cio2.c
index 51a6d7cc44d2..690fc1c919af 100644
--- a/drivers/media/pci/intel/ipu3/ipu3-cio2.c
+++ b/drivers/media/pci/intel/ipu3/ipu3-cio2.c
@@ -1388,10 +1388,15 @@ static int cio2_notifier_bound(struct v4l2_async_notifier *notifier,
struct cio2_device *cio2 = to_cio2_device(notifier);
struct sensor_async_subdev *s_asd = to_sensor_asd(asd);
struct cio2_queue *q;
+ int ret;

if (cio2->queue[s_asd->csi2.port].sensor)
return -EBUSY;

+ ret = ipu_bridge_instantiate_vcm(sd->dev);
+ if (ret)
+ return ret;
+
q = &cio2->queue[s_asd->csi2.port];

q->csi2 = s_asd->csi2;
diff --git a/include/media/ipu-bridge.h b/include/media/ipu-bridge.h
index 7d84b22b2111..ceda2a801948 100644
--- a/include/media/ipu-bridge.h
+++ b/include/media/ipu-bridge.h
@@ -7,8 +7,6 @@
#include <linux/types.h>
#include <media/v4l2-fwnode.h>

-struct i2c_client;
-
#define IPU_HID "INT343E"
#define IPU_MAX_LANES 4
#define IPU_MAX_PORTS 4
@@ -117,7 +115,6 @@ struct ipu_sensor {
/* append ssdb.link(u8) in "-%u" format as suffix of HID */
char name[ACPI_ID_LEN + 4];
struct acpi_device *adev;
- struct i2c_client *vcm_i2c_client;

/* SWNODE_COUNT + 1 for terminating NULL */
const struct software_node *group[SWNODE_COUNT + 1];
@@ -157,9 +154,11 @@ struct ipu_bridge {
int ipu_bridge_init(struct device *dev,
ipu_parse_sensor_fwnode_t parse_sensor_fwnode);
int ipu_bridge_parse_ssdb(struct acpi_device *adev, struct ipu_sensor *sensor);
+int ipu_bridge_instantiate_vcm(struct device *sensor);
#else
/* Use a define to avoid the @parse_sensor_fwnode argument getting evaluated */
#define ipu_bridge_init(dev, parse_sensor_fwnode) (0)
+static inline int ipu_bridge_instantiate_vcm(struct device *s) { return 0; }
#endif

#endif
--
2.41.0