Documentation/i2c/i2c-topology.rst

38 mux-locked or parent-locked muxes. As is evident from below, it can be
39 useful to know if a mux is mux-locked or if it is parent-locked. The
45 i2c-arb-gpio-challenge    Parent-locked
46 i2c-mux-gpio              Normally parent-locked, mux-locked iff
49 i2c-mux-gpmux             Normally parent-locked, mux-locked iff
51 i2c-mux-ltc4306           Mux-locked
52 i2c-mux-mlxcpld           Parent-locked
53 i2c-mux-pca9541           Parent-locked
54 i2c-mux-pca954x           Parent-locked
55 i2c-mux-pinctrl           Normally parent-locked, mux-locked iff
58 i2c-mux-reg               Parent-locked
64 gyro/mpu3050              Mux-locked
65 imu/inv_mpu6050/          Mux-locked
71 dvb-frontends/lgdt3306a   Mux-locked
72 dvb-frontends/m88ds3103   Parent-locked
73 dvb-frontends/rtl2830     Parent-locked
74 dvb-frontends/rtl2832     Mux-locked
75 dvb-frontends/si2168      Mux-locked
76 usb/cx231xx/              Parent-locked
80 Mux-locked muxes
83 Mux-locked muxes does not lock the entire parent adapter during the
85 adapter are locked. Mux-locked muxes are mostly interesting if the
87 their tasks. Since the parent adapter is not fully locked during the
93 ML1. If you build a topology with a mux-locked mux being the parent
94      of a parent-locked mux, this might break the expectation from the
95      parent-locked mux that the root adapter is locked during the
99      mux-locked muxes that are not siblings, when there are address
108      but mux-locked muxes do not guarantee that in all topologies.
110 ML3. A mux-locked mux cannot be used by a driver for auto-closing
123 Mux-locked Example
131     |  root  |--+--|  locked  |     '--------'
157 Parent-locked muxes
160 Parent-locked muxes lock the parent adapter during the full select-
168 PL1. If you build a topology with a parent-locked mux being the child
173      This is especially the case if the parent mux is mux-locked, but
174      it may also happen if the parent mux is parent-locked.
184 Parent-locked Example
191     |  root  |--+--|  locked  |     '--------'
216 This means that accesses to both D2 and D3 are locked out for the full
223 Parent-locked mux as parent of parent-locked mux
230     |  root  |--+--|  locked  |     |  locked  |     '--------'
237 When any device is accessed, all other devices are locked out for
247 Mux-locked mux as parent of mux-locked mux
254     |  root  |--+--|  locked  |     |  locked  |     '--------'
261 When device D1 is accessed, accesses to D2 are locked out for the
263 are locked). But accesses to D3 and D4 are possibly interleaved at
268 Mux-locked mux as parent of parent-locked mux
275     |  root  |--+--|  locked  |     |  locked  |     '--------'
282 When device D1 is accessed, accesses to D2 and D3 are locked out
302 Parent-locked mux as parent of mux-locked mux
309     |  root  |--+--|  locked  |     |  locked  |     '--------'
316 When D1 is accessed, accesses to D2 are locked out for the full
318 are locked). Accesses to D3 and D4 are possibly interleaved at
319 any point, just as is expected for mux-locked muxes.
321 When D3 or D4 are accessed, everything else is locked out. For D3
323 adapter is locked directly.
326 Two mux-locked sibling muxes
334                 .--|  locked  |     .--------.
339     |  root  |--+--|  locked  |     '--------'
346 When D1 is accessed, accesses to D2, D3 and D4 are locked out. But
350 Two parent-locked sibling muxes
358                 .--|  locked  |     .--------.
363     |  root  |--+--|  locked  |     '--------'
370 When any device is accessed, accesses to all other devices are locked
374 Mux-locked and parent-locked sibling muxes
382                 .--|  locked  |     .--------.
387     |  root  |--+--|  locked  |     '--------'
394 When D1 or D2 are accessed, accesses to D3 and D4 are locked out while
396 all other devices are locked out.