diff options
Diffstat (limited to 'mpm')
| -rw-r--r-- | mpm/python/usrp_mpm/sys_utils/sysfs_gpio.py | 36 |
1 files changed, 30 insertions, 6 deletions
diff --git a/mpm/python/usrp_mpm/sys_utils/sysfs_gpio.py b/mpm/python/usrp_mpm/sys_utils/sysfs_gpio.py index 668342592..b542123bc 100644 --- a/mpm/python/usrp_mpm/sys_utils/sysfs_gpio.py +++ b/mpm/python/usrp_mpm/sys_utils/sysfs_gpio.py @@ -229,12 +229,32 @@ class SysFSGPIO(object): self.log.trace("Reading value {} from `{}'...".format(read_value, value_path)) return read_value -class GPIOBank(object): +class GPIOBank: """ - Extension of a SysFSGPIO + Usability / convenience wrapper for GPIO banks accessed by SysFSGPIO + + This class is useful when: + - Accessing a GPIO bank that is hanging off of a SysFSGPIO node + - All pins in this bank are consecutive pins on the SysFSGPIO node + - The pins can be at an offset (i.e., do not have to start at pin 0 of the + SysFSGPIO node) + - The pins might have to be written/read as a whole + + For example, assume that a device has 8 GPIO pins, starting at pin 10. The + user wants to read all pins at once as a single byte: + + >>> gpio_bank = GPIOBank( + label_dict, # See SysFSGPIO for this parameter + 10, # Pin offset + 0xFF, # 8 pins. Must be consecutive ones! + 0x00) # All pins are readable + >>> if gpio_bank.get_all() == 3: + print("Pins 0 and 1 are high!") """ def __init__(self, uio_identifiers, offset, usemask, ddr): self._gpiosize = bin(usemask).count("1") + # Make sure the pins are all one: + assert (1 << self._gpiosize) == usemask+1 self._offset = offset self._ddr = ddr self._usemask = usemask @@ -256,29 +276,33 @@ class GPIOBank(object): Clear all pins """ for i in range(self._gpiosize): - self._gpios.reset(self._offset+i) + if self._ddr & i: + self._gpios.reset(self._offset+i) def reset(self, index): """ Clear a pin by index + + Read back a pin by index. See also SysFSGPIO.reset(). The DDR value for + this pin must be high. """ assert index in range(self._gpiosize) self._gpios.reset(self._offset + index) def get_all(self): """ - Read back all pins + Read back all pins. Pins with a DDR value of 1 ("output") are left zero. """ result = 0 for i in range(self._gpiosize): - if not (1<<i)&self._ddr: + if not (1<<i) & self._ddr: value = self._gpios.get(self._offset + i) result = (result << 1) | value return result def get(self, index): """ - Read back a pin by index + Read back a pin by index. See also SysFSGPIO.get() """ assert index in range(self._gpiosize) return self._gpios.get(self._offset + index) |