diff options
| -rw-r--r-- | mpm/python/usrp_mpm/sys_utils/i2c_dev.py | 58 |
1 files changed, 51 insertions, 7 deletions
diff --git a/mpm/python/usrp_mpm/sys_utils/i2c_dev.py b/mpm/python/usrp_mpm/sys_utils/i2c_dev.py index 7da5177f8..b84086e55 100644 --- a/mpm/python/usrp_mpm/sys_utils/i2c_dev.py +++ b/mpm/python/usrp_mpm/sys_utils/i2c_dev.py @@ -8,6 +8,21 @@ Utilities for i2c lookups """ import pyudev +from usrp_mpm.sys_utils.udev import get_device_from_dt_symbol + +def _get_i2c_adapter_from_parent(parent, context): + """ + Helper to get the i2c adapter from a given parent device. + This logic is common for different device lookup methods. + """ + if not parent: + return None + devices = list(context.list_devices(parent=parent, subsystem="i2c-dev")) + properties = [dict(d.properties) for d in devices] + # The i2c-adapter will have the lowest minor number + # FIXME: This likely isn't API--It just happens to work as of this writing + chosen = min([(int(p['MINOR']), p['DEVNAME']) for p in properties]) + return chosen[1] def of_get_i2c_adapter(of_name): """ @@ -26,11 +41,40 @@ def of_get_i2c_adapter(of_name): if len(parents) == 0: return None parent = parents[0] - if not parent: + return _get_i2c_adapter_from_parent(parent, context) + + +def dt_symbol_get_i2c_bus(symbol): + """ + Return i2c bus associated with the given device tree symbol + + The return value is a string, e.g. '/dev/i2c-0'. If nothing is found, it'll + return None. + """ + context = pyudev.Context() + parent = get_device_from_dt_symbol(symbol, subsystem='i2c', context=context) + return _get_i2c_adapter_from_parent(parent, context) + + +def sysname_get_i2c_adapter(sys_name): + """ + Return bus adapter device for given device tree sys_name. + + The return value is a string, e.g. '/dev/i2c-0'. If nothing is found, it'll + return None. + """ + parent = sysname_get_i2c_parent(sys_name) + return _get_i2c_adapter_from_parent(parent, pyudev.Context()) + +def sysname_get_i2c_parent(sys_name): + """ + Returns the parent of an i2c adapter found by sys_name + """ + # If has i2c-dev, follow to grab i2c-%d node + context = pyudev.Context() + parents = list(context.list_devices(subsystem="i2c-adapter", sys_name=sys_name)) + if len(parents) > 1: + raise RuntimeError("Non-unique sys_name when getting i2c bus id") + if len(parents) == 0: return None - devices = list(context.list_devices(parent=parent, subsystem="i2c-dev")) - properties = [dict(d.properties) for d in devices] - # The i2c-adapter will have the lowest minor number - # FIXME: This likely isn't API--It just happens to work as of this writing - chosen = min([(int(p['MINOR']), p['DEVNAME']) for p in properties]) - return chosen[1] + return parents[0] |