Hi! On 2016-03-03 23:27, Peter Rosin wrote: > From: Peter Rosin <peda@xxxxxxxxxx> > > Hi! > > I have a pair of boards with this i2c topology: > > GPIO ---| ------ BAT1 > | v / > I2C -----+------B---+---- MUX > | \ > EEPROM ------ BAT2 > > (B denotes the boundary between the boards) > > The problem with this is that the GPIO controller sits on the same i2c bus > that it MUXes. For pca954x devices this is worked around by using unlocked > transfers when updating the MUX. I have no such luck as the GPIO is a general > purpose IO expander and the MUX is just a random bidirectional MUX, unaware > of the fact that it is muxing an i2c bus. Extending unlocked transfers > into the GPIO subsystem is too ugly to even think about. But the general hw > approach is sane in my opinion, with the number of connections between the > two boards minimized. To put is plainly, I need support for it. etc etc I've made a few changes, but instead of posting another copy of a rather long series, I decided to push it to github and only post a note about it here. The plan is to then rebase (if needed) on top of v4.6-rc1 and at that point post all the patches (this is, after all, at least 4.7 material). At the same time I do not want to hide the latest version from anyone wanting to have a look or test. The series will be posted again for review. This is just a heads up. v5 compared to v4: - Rebase on top of v4.5-rc7. - A new patch making me maintainer of i2c muxes (also sent separately). - A new file Documentation/i2c/i2c-topology that describes various muxing issues. - Rename "i2c-controlled" muxes "self-locked" instead, as it is perfectly reasonable to have i2c-controlled muxes that use the pre-existing locking scheme. The pre-existing locking scheme for i2c muxes is from here on called "parent-locked". - Rename i2c-mux.c:i2c_mux_master_xfer to __i2c_mux_master_xfer since it calls __i2c_transfer, which leaves room for a new i2c_mux_master_xfer that calls i2c_transfer. Similar rename shuffle for i2c_mux_smbus_xfer. - Use sizeof(*priv) instead of sizeof(struct i2c_mux_priv). One instance. - Some follow-up patches that were posted in response to v2-v4 cleaning up and simplifying various i2c muxes outside drivers/i2c/, among those is an unrelated cleanup patch to drivers/media/dvb-frontends/rtl2832.c that I carry here since it conflicts (trivially) with this series. That unrelated patch is (currently) the last patch in the series. The series looks like this now: The following changes since commit f6cede5b49e822ebc41a099fe41ab4989f64e2cb: Linux 4.5-rc7 (2016-03-06 14:48:03 -0800) are available in the git repository at: https://github.com/peda-r/i2c-mux.git mux-core-and-locking-5 for you to fetch changes up to c1ef4a249b0bd45ba97e14f15f6ee89e7fbc0222: [media] rtl2832: regmap is aware of lockdep, drop local locking hack (2016-03-15 10:02:15 +0100) ---------------------------------------------------------------- Antti Palosaari (1): [media] si2168: declare that the i2c gate is self-locked Peter Rosin (24): MAINTAINERS: add myself as i2c mux maintainer i2c-mux: add common data for every i2c-mux instance i2c: i2c-mux-gpio: convert to use an explicit i2c mux core i2c: i2c-mux-pinctrl: convert to use an explicit i2c mux core i2c: i2c-arb-gpio-challenge: convert to use an explicit i2c mux core i2c: i2c-mux-pca9541: convert to use an explicit i2c mux core i2c: i2c-mux-pca954x: convert to use an explicit i2c mux core i2c: i2c-mux-reg: convert to use an explicit i2c mux core iio: imu: inv_mpu6050: convert to use an explicit i2c mux core [media] m88ds3103: convert to use an explicit i2c mux core [media] rtl2830: convert to use an explicit i2c mux core [media] rtl2832: convert to use an explicit i2c mux core [media] si2168: convert to use an explicit i2c mux core [media] cx231xx: convert to use an explicit i2c mux core of/unittest: convert to use an explicit i2c mux core i2c-mux: drop old unused i2c-mux api i2c: allow adapter drivers to override the adapter locking i2c: muxes always lock the parent adapter i2c-mux: relax locking of the top i2c adapter during self-locked muxing i2c-mux: document i2c muxes and elaborate on parent-/self-locked muxes iio: imu: inv_mpu6050: declare that the i2c gate is self-locked [media] rtl2832: declare that the i2c gate is self-locked [media] rtl2832_sdr: get rid of empty regmap wrappers [media] rtl2832: regmap is aware of lockdep, drop local locking hack Documentation/i2c/i2c-topology | 312 ++++++++++++++++++++++++ MAINTAINERS | 11 + drivers/i2c/i2c-core.c | 65 +++-- drivers/i2c/i2c-mux.c | 347 ++++++++++++++++++++++----- drivers/i2c/muxes/i2c-arb-gpio-challenge.c | 47 ++-- drivers/i2c/muxes/i2c-mux-gpio.c | 72 +++--- drivers/i2c/muxes/i2c-mux-pca9541.c | 55 ++--- drivers/i2c/muxes/i2c-mux-pca954x.c | 64 ++--- drivers/i2c/muxes/i2c-mux-pinctrl.c | 124 +++++----- drivers/i2c/muxes/i2c-mux-reg.c | 63 ++--- drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c | 2 +- drivers/iio/imu/inv_mpu6050/inv_mpu_core.c | 75 ++---- drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h | 3 +- drivers/media/dvb-frontends/m88ds3103.c | 18 +- drivers/media/dvb-frontends/m88ds3103_priv.h | 2 +- drivers/media/dvb-frontends/rtl2830.c | 17 +- drivers/media/dvb-frontends/rtl2830_priv.h | 2 +- drivers/media/dvb-frontends/rtl2832.c | 236 +++--------------- drivers/media/dvb-frontends/rtl2832.h | 4 +- drivers/media/dvb-frontends/rtl2832_priv.h | 3 +- drivers/media/dvb-frontends/rtl2832_sdr.c | 303 ++++++++++------------- drivers/media/dvb-frontends/rtl2832_sdr.h | 5 +- drivers/media/dvb-frontends/si2168.c | 82 ++----- drivers/media/dvb-frontends/si2168_priv.h | 2 +- drivers/media/usb/cx231xx/cx231xx-core.c | 6 +- drivers/media/usb/cx231xx/cx231xx-i2c.c | 47 ++-- drivers/media/usb/cx231xx/cx231xx.h | 4 +- drivers/media/usb/dvb-usb-v2/rtl28xxu.c | 5 +- drivers/of/unittest.c | 40 ++- include/linux/i2c-mux.h | 65 ++++- include/linux/i2c.h | 28 ++- 31 files changed, 1206 insertions(+), 903 deletions(-) create mode 100644 Documentation/i2c/i2c-topology -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
