I need an ACPI Ack on this. > This patch adds support to load a custom ACPI table that describes > devices connected via the DLN2 USB to I2C/SPI/GPIO bridge. > > The ACPI table can be loaded either externally (from QEMU or with > CONFIG_ACPI_CUSTOM_DSDT) or it can be loaded as firmware file with the > name dln2.aml. The driver looks for an ACPI device entry with _HID set > to "DLN20000" and makes it the ACPI companion for DLN2 USB > sub-drivers. > > Signed-off-by: Octavian Purdila <octavian.purd...@intel.com> > --- > Documentation/acpi/dln2-acpi.txt | 62 ++++++++++++++++++ > drivers/mfd/dln2.c | 134 > +++++++++++++++++++++++++++++++++++++++ > 2 files changed, 196 insertions(+) > create mode 100644 Documentation/acpi/dln2-acpi.txt > > diff --git a/Documentation/acpi/dln2-acpi.txt > b/Documentation/acpi/dln2-acpi.txt > new file mode 100644 > index 0000000..d76605f > --- /dev/null > +++ b/Documentation/acpi/dln2-acpi.txt > @@ -0,0 +1,62 @@ > +Diolan DLN2 custom APCI table > + > +The Diolan DLN2 is an USB to I2C/SPI/GPIO bridge and as such it can be used > to > +connect to various I2C or SPI devices. Because these busses lack an > enumeration > +protocol, the driver obtains various information about the device (such as > I2C > +address and GPIO pins) from either ACPI or device tree. > + > +To allow enumerating devices and their properties via ACPI, the Diolan > +driver looks for an ACPI tree with the root _HID set to "DLN20000". If > +it finds such an ACPI object it will set the ACPI companion to the > +DLN2 MFD driver and from their it will be propagated to all its > +sub-devices (I2C, GPIO, SPI). > + > +The user can either load the custom DSDT table with three methods: > + > +1. Via QEMU (see -acpitable) > + > +2. Via the CONFIG_ACPI_CUSTOM_DSDT kernel config option (see > +Documentation/acpi/dsdt-override.txt) > + > +3. By placing the custom DSDT in the firmware paths in a file name > +dln2.aml. > + > +Here is an example ACPI table that enumerates a BMC150 accelerometer > +and defines its I2C address and GPIO pin used as an interrupt source: > + > +DefinitionBlock ("ssdt.aml", "SSDT", 1, "INTEL ", "CpuDptf", 0x00000003) > +{ > + Device (DLN0) > + { > + Name (_ADR, Zero) > + Name (_HID, "DLN2000") > + > + Device (STAC) > + { > + Name (_ADR, Zero) > + Name (_HID, "BMC150A") > + Name (_CID, "INTACCL") > + Name (_UID, One) > + > + Method (_CRS, 0, Serialized) > + { > + Name (RBUF, ResourceTemplate () > + { > + I2cSerialBus (0x0010, > ControllerInitiated, 0x00061A80, > + AddressingMode7Bit, > "\\DLN0", > + 0x00, ResourceConsumer, ,) > + > + GpioInt (Level, ActiveHigh, Exclusive, > PullDown, 0x0000, > + "\\DLN0", 0x00, > ResourceConsumer, , ) > + { // Pin list > + 0 > + } > + }) > + Return (RBUF) > + } > + } > + } > +} > + > +The resources defined in the devices under the DLN0 are those > +supported by the I2C, GPIO and SPI sub-systems. > diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c > index f9c4a0b..93f6d1d 100644 > --- a/drivers/mfd/dln2.c > +++ b/drivers/mfd/dln2.c > @@ -23,6 +23,8 @@ > #include <linux/mfd/core.h> > #include <linux/mfd/dln2.h> > #include <linux/rculist.h> > +#include <linux/acpi.h> > +#include <linux/firmware.h> > > struct dln2_header { > __le16 size; > @@ -714,6 +716,134 @@ static void dln2_stop(struct dln2_dev *dln2) > > dln2_stop_rx_urbs(dln2); > } > + > +#if IS_ENABLED(CONFIG_ACPI) > + > +static struct dln2_acpi_info { > + const struct firmware *fw; > + acpi_owner_id table_id; > + struct acpi_device *dev; > + int users; > +} dln2_acpi_info; > + > +static DEFINE_MUTEX(dln2_acpi_lock); > + > +static acpi_status dln2_find_acpi_handle(acpi_handle handle, u32 level, > + void *ctxt, void **retv) > +{ > + acpi_handle *dln2_handle = (acpi_handle *)retv; > + > + *dln2_handle = handle; > + > + return AE_CTRL_TERMINATE; > +} > + > +static void dln2_probe_acpi(struct dln2_dev *dln2) > +{ > + struct device *dev = &dln2->interface->dev; > + struct dln2_acpi_info *ai = &dln2_acpi_info; > + acpi_handle h = NULL; > + int ret; > + bool fw_loaded = false; > + > + mutex_lock(&dln2_acpi_lock); > + > + if (ai->dev) > + goto out_success; > + > + /* > + * Look for the DLN2000 HID in case the ACPI table was loaded > + * externally (e.g. from qemu). > + */ > + acpi_get_devices("DLN20000", dln2_find_acpi_handle, NULL, &h); > + if (!h) { > + /* Try to load the ACPI table via a firmware file */ > + ret = request_firmware(&ai->fw, "dln2.aml", NULL); > + if (ret) > + goto out_unlock; > + > + ret = acpi_load_table((void *)ai->fw->data); > + if (ret) { > + dev_err(dev, "invalid ACPI table\n"); > + goto out_release_fw; > + } > + > + acpi_get_devices("DLN20000", dln2_find_acpi_handle, NULL, &h); > + if (!h) { > + dev_err(dev, "not a DLN2 ACPI table\n"); > + goto out_leak_fw; > + } > + > + ret = acpi_get_id(h, &ai->table_id); > + if (ret) { > + dev_err(dev, "acpi_get_id failed: %d\n", ret); > + goto out_leak_fw; > + } > + > + ret = acpi_bus_scan(h); > + if (ret) { > + dev_err(dev, "acpi_bus_scan failed: %d\n", ret); > + goto out_leak_fw; > + } > + > + fw_loaded = true; > + } > + > + ret = acpi_bus_get_device(h, &ai->dev); > + if (ret) { > + dev_err(dev, "failed to get ACPI device: %d\n", ret); > + if (fw_loaded) { > + acpi_unload_table_id(ai->table_id); > + goto out_leak_fw; > + } > + goto out_unlock; > + } > + > +out_success: > + ACPI_COMPANION_SET(dev, ai->dev); > + ai->users++; > + mutex_unlock(&dln2_acpi_lock); > + return; > + > +out_release_fw: > + release_firmware(ai->fw); > +out_leak_fw: > + /* > + * Once a table is loaded we can't release the firmware anymore because > + * acpi_unload_table does not actually unload the table but keeps it in > + * memory to speed up subsequent loads. > + */ > + ai->fw = NULL; > +out_unlock: > + mutex_unlock(&dln2_acpi_lock); > +} > + > +static void dln2_disconnect_acpi(struct dln2_dev *dln2) > +{ > + struct dln2_acpi_info *ai = &dln2_acpi_info; > + > + mutex_lock(&dln2_acpi_lock); > + if (--ai->users == 0 && ai->fw) { > + acpi_scan_lock_acquire(); > + acpi_bus_trim(ai->dev); > + acpi_scan_lock_release(); > + acpi_unload_table_id(ai->table_id); > + ai->dev = NULL; > + /* we can't release firmware see comment in dln2_probe_acpi */ > + ai->fw = NULL; > + } > + mutex_unlock(&dln2_acpi_lock); > +} > +#else > +static void dln2_probe_acpi(struct dln2_dev *dln2) > +{ > +} > + > +static void dln2_disconnect_acpi(struct dln2_dev *dln2) > +{ > +} > +#endif > + > static void dln2_disconnect(struct usb_interface *interface) > { > struct dln2_dev *dln2 = usb_get_intfdata(interface); > @@ -722,6 +852,8 @@ static void dln2_disconnect(struct usb_interface > *interface) > > mfd_remove_devices(&interface->dev); > > + dln2_disconnect_acpi(dln2); > + > dln2_free(dln2); > } > > @@ -774,6 +906,8 @@ static int dln2_probe(struct usb_interface *interface, > goto out_stop_rx; > } > > + dln2_probe_acpi(dln2); > + > ret = mfd_add_hotplug_devices(dev, dln2_devs, ARRAY_SIZE(dln2_devs)); > if (ret != 0) { > dev_err(dev, "failed to add mfd devices to core\n"); > -- > 1.9.1 >
-- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html