spi: Create helper API to lookup ACPI info for spi device

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>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20220121172431.6876-3-sbinding@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 1eb84101c4ad8338c0eada51398c50dff20397e6..13f4701f0694d8c726372e099d698d7a5dfe2653 100644 (file)
--- 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 0346a3ff27fd8b425772adc3d1f2f0ee6499dae0..d159cef12f1a9d4cacceccf084e25935ea92308b 100644 (file)
--- 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
  */