iio: core: pass parent device as parameter during allocation

The change passes the parent device to the iio_device_alloc() call. This
also updates the devm_iio_device_alloc() call to consider the device object
as the parent device by default.

Having it passed like this, should ensure that any IIO device object
already has a device object as parent, allowing for neater control, like
passing the 'indio_dev' object for other stuff [like buffers/triggers/etc],
and potentially creating iiom_xxx(indio_dev) functions.

With this patch, only the 'drivers/platform/x86/toshiba_acpi.c' needs an
update to pass the parent object as a parameter.

In the next patch all devm_iio_device_alloc() calls will be handled.

Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/dummy/iio_simple_dummy.c

@@ -566,6 +566,13 @@ static struct iio_sw_device *iio_dummy_probe(const char *name)
 	struct iio_dev *indio_dev;
 	struct iio_dummy_state *st;
 	struct iio_sw_device *swd;
+	struct device *parent = NULL;
+
+	/*
+	 * With hardware: Set the parent device.
+	 * parent = &spi->dev;
+	 * parent = &client->dev;
+	 */
 
 	swd = kzalloc(sizeof(*swd), GFP_KERNEL);
 	if (!swd) {
@@ -580,7 +587,7 @@ static struct iio_sw_device *iio_dummy_probe(const char *name)
 	 * It also has a region (accessed by iio_priv()
 	 * for chip specific state information.
 	 */
-	indio_dev = iio_device_alloc(sizeof(*st));
+	indio_dev = iio_device_alloc(parent, sizeof(*st));
 	if (!indio_dev) {
 		ret = -ENOMEM;
 		goto error_ret;
@@ -590,11 +597,6 @@ static struct iio_sw_device *iio_dummy_probe(const char *name)
 	mutex_init(&st->lock);
 
 	iio_dummy_init_device(indio_dev);
-	/*
-	 * With hardware: Set the parent device.
-	 * indio_dev->dev.parent = &spi->dev;
-	 * indio_dev->dev.parent = &client->dev;
-	 */
 
 	 /*
 	 * Make the iio_dev struct available to remove function.

drivers/iio/industrialio-core.c

@@ -1493,7 +1493,7 @@ struct device_type iio_device_type = {
  * iio_device_alloc() - allocate an iio_dev from a driver
  * @sizeof_priv:	Space to allocate for private structure.
  **/
-struct iio_dev *iio_device_alloc(int sizeof_priv)
+struct iio_dev *iio_device_alloc(struct device *parent, int sizeof_priv)
 {
 	struct iio_dev *dev;
 	size_t alloc_size;
@@ -1510,6 +1510,7 @@ struct iio_dev *iio_device_alloc(int sizeof_priv)
 	if (!dev)
 		return NULL;
 
+	dev->dev.parent = parent;
 	dev->dev.groups = dev->groups;
 	dev->dev.type = &iio_device_type;
 	dev->dev.bus = &iio_bus_type;
@@ -1551,7 +1552,7 @@ static void devm_iio_device_release(struct device *dev, void *res)
 
 /**
  * devm_iio_device_alloc - Resource-managed iio_device_alloc()
- * @dev:		Device to allocate iio_dev for
+ * @parent:		Device to allocate iio_dev for, and parent for this IIO device
  * @sizeof_priv:	Space to allocate for private structure.
  *
  * Managed iio_device_alloc. iio_dev allocated with this function is
@@ -1560,7 +1561,7 @@ static void devm_iio_device_release(struct device *dev, void *res)
  * RETURNS:
  * Pointer to allocated iio_dev on success, NULL on failure.
  */
-struct iio_dev *devm_iio_device_alloc(struct device *dev, int sizeof_priv)
+struct iio_dev *devm_iio_device_alloc(struct device *parent, int sizeof_priv)
 {
 	struct iio_dev **ptr, *iio_dev;
 
@@ -1569,10 +1570,10 @@ struct iio_dev *devm_iio_device_alloc(struct device *dev, int sizeof_priv)
 	if (!ptr)
 		return NULL;
 
-	iio_dev = iio_device_alloc(sizeof_priv);
+	iio_dev = iio_device_alloc(parent, sizeof_priv);
 	if (iio_dev) {
 		*ptr = iio_dev;
-		devres_add(dev, ptr);
+		devres_add(parent, ptr);
 	} else {
 		devres_free(ptr);
 	}

drivers/platform/x86/toshiba_acpi.c

@@ -3114,7 +3114,7 @@ static int toshiba_acpi_add(struct acpi_device *acpi_dev)
 
 	toshiba_accelerometer_available(dev);
 	if (dev->accelerometer_supported) {
-		dev->indio_dev = iio_device_alloc(sizeof(*dev));
+		dev->indio_dev = iio_device_alloc(&acpi_dev->dev, sizeof(*dev));
 		if (!dev->indio_dev) {
 			pr_err("Unable to allocate iio device\n");
 			goto iio_error;
@@ -3124,7 +3124,6 @@ static int toshiba_acpi_add(struct acpi_device *acpi_dev)
 
 		dev->indio_dev->info = &toshiba_iio_accel_info;
 		dev->indio_dev->name = "Toshiba accelerometer";
-		dev->indio_dev->dev.parent = &acpi_dev->dev;
 		dev->indio_dev->modes = INDIO_DIRECT_MODE;
 		dev->indio_dev->channels = toshiba_iio_accel_channels;
 		dev->indio_dev->num_channels =

drivers/staging/iio/Documentation/device.txt

@@ -8,7 +8,7 @@ The crucial structure for device drivers in iio is iio_dev.
 
 First allocate one using:
 
-struct iio_dev *indio_dev = iio_device_alloc(sizeof(struct chip_state));
+struct iio_dev *indio_dev = iio_device_alloc(parent, sizeof(struct chip_state));
 where chip_state is a structure of local state data for this instance of
 the chip.
 
@@ -16,8 +16,6 @@ That data can be accessed using iio_priv(struct iio_dev *).
 
 Then fill in the following:
 
-- indio_dev->dev.parent
-	Struct device associated with the underlying hardware.
 - indio_dev->name
 	Name of the device being driven - made available as the name
 	attribute in sysfs.

include/linux/iio/iio.h

@@ -676,7 +676,7 @@ static inline void *iio_device_get_drvdata(const struct iio_dev *indio_dev)
 
 /* Can we make this smaller? */
 #define IIO_ALIGN L1_CACHE_BYTES
-struct iio_dev *iio_device_alloc(int sizeof_priv);
+struct iio_dev *iio_device_alloc(struct device *parent, int sizeof_priv);
 
 static inline void *iio_priv(const struct iio_dev *indio_dev)
 {
@@ -690,7 +690,7 @@ static inline struct iio_dev *iio_priv_to_dev(void *priv)
 }
 
 void iio_device_free(struct iio_dev *indio_dev);
-struct iio_dev *devm_iio_device_alloc(struct device *dev, int sizeof_priv);
+struct iio_dev *devm_iio_device_alloc(struct device *parent, int sizeof_priv);
 struct iio_trigger *devm_iio_trigger_alloc(struct device *dev,
 						const char *fmt, ...);
 /**