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Date: Fri, 9 Oct 2015 17:41:46 -0700
From: Dustin Byford <dustin@...ulusnetworks.com>
To: Wolfram Sang <wsa@...-dreams.de>,
Mika Westerberg <mika.westerberg@...ux.intel.com>
Cc: linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
rjw@...ysocki.net
Subject: [PATCH 1/2] i2c: scan entire ACPI namespace for I2C connections
An I2cSerialBus connection resource descriptor may indicate a
ResourceSource (a string uniquely identifying the I2C bus controller)
anywhere in the ACPI namespace. However, when enumerating connections to a
I2C bus controller, i2c-core.c:acpi_i2c_register_devices() as only
searching devices that are descendants of the bus controller.
This change corrects acpi_i2c_register_devices() to walk the entire ACPI
namespace searching for I2C connections.
Suggested-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
Signed-off-by: Dustin Byford <dustin@...ulusnetworks.com>
---
drivers/i2c/i2c-core.c | 82 ++++++++++++++++++++++++++++++++++++--------------
1 file changed, 59 insertions(+), 23 deletions(-)
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 5f89f1e..3a4c54e 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -99,27 +99,40 @@ struct gsb_buffer {
};
} __packed;
-static int acpi_i2c_add_resource(struct acpi_resource *ares, void *data)
+struct acpi_i2c_lookup {
+ struct i2c_board_info *info;
+ acpi_handle adapter_handle;
+ acpi_handle device_handle;
+};
+
+static int acpi_i2c_find_address(struct acpi_resource *ares, void *data)
{
- struct i2c_board_info *info = data;
+ struct acpi_i2c_lookup *lookup = data;
+ struct i2c_board_info *info = lookup->info;
+ struct acpi_resource_i2c_serialbus *sb;
+ acpi_handle adapter_handle;
+ acpi_status status;
- if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
- struct acpi_resource_i2c_serialbus *sb;
+ if (info->addr || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
+ return 1;
- sb = &ares->data.i2c_serial_bus;
- if (!info->addr && sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
- info->addr = sb->slave_address;
- if (sb->access_mode == ACPI_I2C_10BIT_MODE)
- info->flags |= I2C_CLIENT_TEN;
- }
- } else if (!info->irq) {
- struct resource r;
+ sb = &ares->data.i2c_serial_bus;
+ if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
+ return 1;
- if (acpi_dev_resource_interrupt(ares, 0, &r))
- info->irq = r.start;
+ /*
+ * Extract the ResourceSource and make sure that the handle matches
+ * with the I2C adapter handle.
+ */
+ status = acpi_get_handle(lookup->device_handle,
+ sb->resource_source.string_ptr,
+ &adapter_handle);
+ if (ACPI_SUCCESS(status) && adapter_handle == lookup->adapter_handle) {
+ info->addr = sb->slave_address;
+ if (sb->access_mode == ACPI_I2C_10BIT_MODE)
+ info->flags |= I2C_CLIENT_TEN;
}
- /* Tell the ACPI core to skip this resource */
return 1;
}
@@ -128,6 +141,8 @@ static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
{
struct i2c_adapter *adapter = data;
struct list_head resource_list;
+ struct acpi_i2c_lookup lookup;
+ struct resource_entry *entry;
struct i2c_board_info info;
struct acpi_device *adev;
int ret;
@@ -140,14 +155,37 @@ static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
memset(&info, 0, sizeof(info));
info.fwnode = acpi_fwnode_handle(adev);
+ memset(&lookup, 0, sizeof(lookup));
+ lookup.adapter_handle = ACPI_HANDLE(adapter->dev.parent);
+ lookup.device_handle = handle;
+ lookup.info = &info;
+
+ /*
+ * Look up for I2cSerialBus resource with ResourceSource that
+ * matches with this adapter.
+ */
INIT_LIST_HEAD(&resource_list);
ret = acpi_dev_get_resources(adev, &resource_list,
- acpi_i2c_add_resource, &info);
+ acpi_i2c_find_address, &lookup);
acpi_dev_free_resource_list(&resource_list);
if (ret < 0 || !info.addr)
return AE_OK;
+ /* Then fill IRQ number if any */
+ ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
+ if (ret < 0)
+ return AE_OK;
+
+ resource_list_for_each_entry(entry, &resource_list) {
+ if (resource_type(entry->res) == IORESOURCE_IRQ) {
+ info.irq = entry->res->start;
+ break;
+ }
+ }
+
+ acpi_dev_free_resource_list(&resource_list);
+
adev->power.flags.ignore_parent = true;
strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type));
if (!i2c_new_device(adapter, &info)) {
@@ -160,6 +198,8 @@ static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
return AE_OK;
}
+#define ACPI_I2C_MAX_SCAN_DEPTH 32
+
/**
* acpi_i2c_register_devices - enumerate I2C slave devices behind adapter
* @adap: pointer to adapter
@@ -170,17 +210,13 @@ static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
*/
static void acpi_i2c_register_devices(struct i2c_adapter *adap)
{
- acpi_handle handle;
acpi_status status;
- if (!adap->dev.parent)
- return;
-
- handle = ACPI_HANDLE(adap->dev.parent);
- if (!handle)
+ if (!adap->dev.parent || !has_acpi_companion(adap->dev.parent))
return;
- status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
+ status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
+ ACPI_I2C_MAX_SCAN_DEPTH,
acpi_i2c_add_device, NULL,
adap, NULL);
if (ACPI_FAILURE(status))
--
2.1.4
--
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