spi: spidev: Add ACPI probing support

[karo-tx-linux.git] / drivers / spi / spidev.c

diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index e3c19f30f591115a823467033702ff1b232c5ebc..2e05046f866bd01bf87edcdeff0d5b76d4d0aea7 100644 (file)
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -29,6 +29,7 @@
 #include <linux/compat.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/acpi.h>
 
 #include <linux/spi/spi.h>
 #include <linux/spi/spidev.h>
@@ -700,6 +701,43 @@ static const struct of_device_id spidev_dt_ids[] = {
 MODULE_DEVICE_TABLE(of, spidev_dt_ids);
 #endif
 
+#ifdef CONFIG_ACPI
+
+/* Dummy SPI devices not to be used in production systems */
+#define SPIDEV_ACPI_DUMMY      1
+
+static const struct acpi_device_id spidev_acpi_ids[] = {
+       /*
+        * The ACPI SPT000* devices are only meant for development and
+        * testing. Systems used in production should have a proper ACPI
+        * description of the connected peripheral and they should also use
+        * a proper driver instead of poking directly to the SPI bus.
+        */
+       { "SPT0001", SPIDEV_ACPI_DUMMY },
+       { "SPT0002", SPIDEV_ACPI_DUMMY },
+       { "SPT0003", SPIDEV_ACPI_DUMMY },
+       {},
+};
+MODULE_DEVICE_TABLE(acpi, spidev_acpi_ids);
+
+static void spidev_probe_acpi(struct spi_device *spi)
+{
+       const struct acpi_device_id *id;
+
+       if (!has_acpi_companion(&spi->dev))
+               return;
+
+       id = acpi_match_device(spidev_acpi_ids, &spi->dev);
+       if (WARN_ON(!id))
+               return;
+
+       if (id->driver_data == SPIDEV_ACPI_DUMMY)
+               dev_warn(&spi->dev, "do not use this driver in production systems!\n");
+}
+#else
+static inline void spidev_probe_acpi(struct spi_device *spi) {}
+#endif
+
 /*-------------------------------------------------------------------------*/
 
 static int spidev_probe(struct spi_device *spi)
@@ -719,6 +757,8 @@ static int spidev_probe(struct spi_device *spi)
                        !of_match_device(spidev_dt_ids, &spi->dev));
        }
 
+       spidev_probe_acpi(spi);
+
        /* Allocate driver data */
        spidev = kzalloc(sizeof(*spidev), GFP_KERNEL);
        if (!spidev)
@@ -789,6 +829,7 @@ static struct spi_driver spidev_spi_driver = {
        .driver = {
                .name =         "spidev",
                .of_match_table = of_match_ptr(spidev_dt_ids),
+               .acpi_match_table = ACPI_PTR(spidev_acpi_ids),
        },
        .probe =        spidev_probe,
        .remove =       spidev_remove,