[PATCH v5 2/9] spi: Create helper API to lookup ACPI info for spi device

Stefan Binding
2022-01-21T14:34:03Z

This can then be used to find a spi resource inside an
ACPI node, and allocate a spi device.

Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>
---
drivers/spi/spi.c | 46 ++++++++++++++++++++++++++++++++---------
include/linux/spi/spi.h | 6 ++++++
2 files changed, 42 insertions(+), 10 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 1eb84101c4ad..13f4701f0694 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2410,8 +2410,18 @@ static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
return 1;
}

-static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
- struct acpi_device *adev)
+/**
+ * acpi_spi_device_alloc - Allocate a spi device, and fill it in with ACPI information
+ * @ctlr: controller to which the spi device belongs
+ * @adev: ACPI Device for the spi device
+ *
+ * This should be used to allocate a new spi device from and ACPI Node.
+ * The caller is responsible for calling spi_add_device to register the spi device.
+ *
+ * Return: a pointer to the new device, or ERR_PTR on error.
+ */
+struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
+ struct acpi_device *adev)
{
acpi_handle parent_handle = NULL;
struct list_head resource_list;
@@ -2419,10 +2429,6 @@ static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
struct spi_device *spi;
int ret;

- if (acpi_bus_get_status(adev) || !adev->status.present ||
- acpi_device_enumerated(adev))
- return AE_OK;
-
lookup.ctlr = ctlr;
lookup.irq = -1;

@@ -2433,7 +2439,7 @@ static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,

if (ret < 0)
/* found SPI in _CRS but it points to another controller */
- return AE_OK;
+ return ERR_PTR(-ENODEV);

if (!lookup.max_speed_hz &&
ACPI_SUCCESS(acpi_get_parent(adev->handle, &parent_handle)) &&
@@ -2443,16 +2449,15 @@ static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
}

if (!lookup.max_speed_hz)
- return AE_OK;
+ return ERR_PTR(-ENODEV);

spi = spi_alloc_device(ctlr);
if (!spi) {
dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
dev_name(&adev->dev));
- return AE_NO_MEMORY;
+ return ERR_PTR(-ENOMEM);
}

-
ACPI_COMPANION_SET(&spi->dev, adev);
spi->max_speed_hz = lookup.max_speed_hz;
spi->mode |= lookup.mode;
@@ -2460,6 +2465,27 @@ static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
spi->bits_per_word = lookup.bits_per_word;
spi->chip_select = lookup.chip_select;

+ return spi;
+}
+EXPORT_SYMBOL_GPL(acpi_spi_device_alloc);
+
+static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
+ struct acpi_device *adev)
+{
+ struct spi_device *spi;
+
+ if (acpi_bus_get_status(adev) || !adev->status.present ||
+ acpi_device_enumerated(adev))
+ return AE_OK;
+
+ spi = acpi_spi_device_alloc(ctlr, adev);
+ if (IS_ERR(spi)) {
+ if (PTR_ERR(spi) == -ENOMEM)
+ return AE_NO_MEMORY;
+ else
+ return AE_OK;
+ }
+
acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
sizeof(spi->modalias));

diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 0346a3ff27fd..d159cef12f1a 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -16,6 +16,7 @@
#include <linux/gpio/consumer.h>

#include <uapi/linux/spi/spi.h>
+#include <linux/acpi.h>

struct dma_chan;
struct software_node;
@@ -759,6 +760,11 @@ extern int devm_spi_register_controller(struct device *dev,
struct spi_controller *ctlr);
extern void spi_unregister_controller(struct spi_controller *ctlr);

+#if IS_ENABLED(CONFIG_ACPI)
+extern struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
+ struct acpi_device *adev);
+#endif
+
/*
* SPI resource management while processing a SPI message
*/
--
2.25.1