linux/drivers/mfd/intel-lpss.c

550 lines
13 KiB

asm-generic cleanups The asm-generic changes for 4.4 are mostly a series from Christoph Hellwig to clean up various abuses of headers in there. The patch to rename the io-64-nonatomic-*.h headers caused some conflicts with new users, so I added a workaround that we can remove in the next merge window. The only other patch is a warning fix from Marek Vasut -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIVAwUAVjzaf2CrR//JCVInAQImmhAA20fZ91sUlnA5skKNPT1phhF6Z7UF2Sx5 nPKcHQD3HA3lT1OKfPBYvCo+loYflvXFLaQThVylVcnE/8ecAEMtft4nnGW2nXvh sZqHIZ8fszTB53cynAZKTjdobD1wu33Rq7XRzg0ugn1mdxFkOzCHW/xDRvWRR5TL rdQjzzgvn2PNlqFfHlh6cZ5ykShM36AIKs3WGA0H0Y/aYsE9GmDOAUp41q1mLXnA 4lKQaIxoeOa+kmlsUB0wEHUecWWWJH4GAP+CtdKzTX9v12bGNhmiKUMCETG78BT3 uL8irSqaViNwSAS9tBxSpqvmVUsa5aCA5M3MYiO+fH9ifd7wbR65g/wq39D3Pc01 KnZ3BNVRW5XSA3c86pr8vbg/HOynUXK8TN0lzt6rEk8bjoPBNEDy5YWzy0t6reVe wX65F+ver8upjOKe9yl2Jsg+5Kcmy79GyYjLUY3TU2mZ+dIdScy/jIWatXe/OTKZ iB4Ctc4MDe9GDECmlPOWf98AXqsBUuKQiWKCN/OPxLtFOeWBvi4IzvFuO8QvnL9p jZcRDmIlIWAcDX/2wMnLjV+Hqi3EeReIrYznxTGnO7HHVInF555GP51vFaG5k+SN smJQAB0/sostmC1OCCqBKq5b6/li95/No7+0v0SUhJJ5o76AR5CcNsnolXesw1fu vTUkB/I66Hk= =dQKG -----END PGP SIGNATURE----- Merge tag 'asm-generic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic Pull asm-generic cleanups from Arnd Bergmann: "The asm-generic changes for 4.4 are mostly a series from Christoph Hellwig to clean up various abuses of headers in there. The patch to rename the io-64-nonatomic-*.h headers caused some conflicts with new users, so I added a workaround that we can remove in the next merge window. The only other patch is a warning fix from Marek Vasut" * tag 'asm-generic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: asm-generic: temporarily add back asm-generic/io-64-nonatomic*.h asm-generic: cmpxchg: avoid warnings from macro-ized cmpxchg() implementations gpio-mxc: stop including <asm-generic/bug> n_tracesink: stop including <asm-generic/bug> n_tracerouter: stop including <asm-generic/bug> mlx5: stop including <asm-generic/kmap_types.h> hifn_795x: stop including <asm-generic/kmap_types.h> drbd: stop including <asm-generic/kmap_types.h> move count_zeroes.h out of asm-generic move io-64-nonatomic*.h out of asm-generic
2015-11-06 14:22:15 -08:00
mfd: intel-lpss: Put I2C and SPI controllers into reset state on suspend Commit 274e43edcda6f ("mfd: intel-lpss: Do not put device in reset state on suspend") changed the behavior on suspend by not putting LPSS controllers into reset. This was done because S3/S0ix fail if UART device is put into reset and no_console_suspend flag is enabled. Because of the above change, I2C controller gets into a bad state if it observes that the I2C lines are pulled low when power to I2C device is cut off during suspend (generally, I2C lines are pulled to power rail of the I2C device in order to ensure that there is no leakage because of the pulls when device is turned off). This results in the controller timing out for all future I2C operations after resume. It is primarily because of the following sequence of operations: During suspend: 1. I2C controller is disabled, but it is not put into reset. 2. Power to I2C device is cut off. 3. #2 results in the I2C lines being pulled low. ==> At this point the I2C controller gets into a bad state On resume: 1. Power to I2C device is enabled. 2. #2 results in the I2C lines being pulled high. 3. I2C controller is enabled. However, even after enabling the I2C controller, all future I2C xfers fail since the controller is in a bad state and does not attempt to make any transactions and hence times out. In order to ensure that the controller does not get into a bad state, this change puts it into reset if the controller type is not UART. With this change, the order of operations is: During suspend: 1. I2C controller is disabled and put into reset. 2. Power to I2C device is cut off. 3. #2 results in the I2C lines being pulled low. On resume: 1. Power to I2C device is enabled. 2. #2 results in the I2C lines being pulled high. 3. I2C controller is enabled and taken out of reset. Signed-off-by: Furquan Shaikh <furquan@google.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2017-07-23 23:02:19 -07:00