diff options
Diffstat (limited to 'Documentation/i2c/i2c-topology.rst')
| -rw-r--r-- | Documentation/i2c/i2c-topology.rst | 24 |
1 files changed, 12 insertions, 12 deletions
diff --git a/Documentation/i2c/i2c-topology.rst b/Documentation/i2c/i2c-topology.rst index b413ef6a6773..2a18b53e3508 100644 --- a/Documentation/i2c/i2c-topology.rst +++ b/Documentation/i2c/i2c-topology.rst @@ -137,14 +137,14 @@ Mux-locked Example When there is an access to D1, this happens: - 1. Someone issues an I2C-transfer to D1. + 1. Someone issues an I2C transfer to D1. 2. M1 locks muxes on its parent (the root adapter in this case). 3. M1 calls ->select to ready the mux. - 4. M1 (presumably) does some I2C-transfers as part of its select. - These transfers are normal I2C-transfers that locks the parent + 4. M1 (presumably) does some I2C transfers as part of its select. + These transfers are normal I2C transfers that locks the parent adapter. - 5. M1 feeds the I2C-transfer from step 1 to its parent adapter as a - normal I2C-transfer that locks the parent adapter. + 5. M1 feeds the I2C transfer from step 1 to its parent adapter as a + normal I2C transfer that locks the parent adapter. 6. M1 calls ->deselect, if it has one. 7. Same rules as in step 4, but for ->deselect. 8. M1 unlocks muxes on its parent. @@ -169,7 +169,7 @@ PL1. If you build a topology with a parent-locked mux being the child of another mux, this might break a possible assumption from the child mux that the root adapter is unused between its select op and the actual transfer (e.g. if the child mux is auto-closing - and the parent mux issues I2C-transfers as part of its select). + and the parent mux issues I2C transfers as part of its select). This is especially the case if the parent mux is mux-locked, but it may also happen if the parent mux is parent-locked. @@ -197,15 +197,15 @@ Parent-locked Example When there is an access to D1, this happens: - 1. Someone issues an I2C-transfer to D1. + 1. Someone issues an I2C transfer to D1. 2. M1 locks muxes on its parent (the root adapter in this case). 3. M1 locks its parent adapter. 4. M1 calls ->select to ready the mux. - 5. If M1 does any I2C-transfers (on this root adapter) as part of - its select, those transfers must be unlocked I2C-transfers so + 5. If M1 does any I2C transfers (on this root adapter) as part of + its select, those transfers must be unlocked I2C transfers so that they do not deadlock the root adapter. - 6. M1 feeds the I2C-transfer from step 1 to the root adapter as an - unlocked I2C-transfer, so that it does not deadlock the parent + 6. M1 feeds the I2C transfer from step 1 to the root adapter as an + unlocked I2C transfer, so that it does not deadlock the parent adapter. 7. M1 calls ->deselect, if it has one. 8. Same rules as in step 5, but for ->deselect. @@ -293,7 +293,7 @@ device lockups and/or other problems. The topology is especially troublesome if M2 is an auto-closing mux. In that case, any interleaved accesses to D4 might close M2 -prematurely, as might any I2C-transfers part of M1->select. +prematurely, as might any I2C transfers part of M1->select. But if M2 is not making the above stated assumption, and if M2 is not auto-closing, the topology is fine. |