* Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> [140612 08:32]: > Hi Tony, > > On Thursday 12 June 2014 08:15:35 Tony Lindgren wrote: > > * Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> [140612 07:52]: > > > On Wednesday 11 June 2014 07:47:54 Tony Lindgren wrote: > > > > These should just use either pinctrl-single.c instead for muxing. > > > > Or if they are not mux registers, we do have the syscon mapping > > > > available in omap4.dtsi that pbias-regulator.c is already using. > > > > > > > > Laurent, got any better ideas? > > > > > > The ISS driver needs to write a single register, which contains several > > > independent fields. They thus need to be controlled by a single driver. > > > Some of them might be considered to be related to pinmuxing (although I > > > disagree on that), others are certainly not about muxing (there are clock > > > gate bits for instance). > > > > > > Using the syscon mapping seems like the best option. I'll give it a try. > > > > OK if it's not strictly pinctrl related then let's not use > > pinctrl-single,bits for it. You may be able to implement one or more > > framework drivers for it for pinctrl/regulator/clock/transceiver > > whatever that register is doing. > > > > In any case it's best to have that handling in a separate helper driver > > somewhere as it's a separate piece of hardware from the camera module. > > If it does not fit into any existing frameworks then it's best to have > > it in a separate driver with the camera driver. > > The register contains the following fields that control the two CSI2 PHYs > (PHY1 and PHY2). > > 31 CAMERARX_CSI22_LANEENABLE2 PHY2 Lane 2 (CSI22_DX2, CSI22_DY2) Enable > 30 CAMERARX_CSI22_LANEENABLE1 PHY2 Lane 1 (CSI22_DX1, CSI22_DY1) Enable > 29 CAMERARX_CSI22_LANEENABLE0 PHY2 Lane 0 (CSI22_DX0, CSI22_DY0) Enable > 28 CAMERARX_CSI21_LANEENABLE4 PHY1 Lane 4 (CSI21_DX4, CSI21_DY4) Enable > 27 CAMERARX_CSI21_LANEENABLE3 PHY1 Lane 3 (CSI21_DX3, CSI21_DY3) Enable > 26 CAMERARX_CSI21_LANEENABLE2 PHY1 Lane 2 (CSI21_DX2, CSI21_DY2) Enable > 25 CAMERARX_CSI21_LANEENABLE1 PHY1 Lane 1 (CSI21_DX1, CSI21_DY1) Enable > 24 CAMERARX_CSI21_LANEENABLE0 PHY1 Lane 0 (CSI21_DX0, CSI21_DY0) Enable > 21 CAMERARX_CSI22_CTRLCLKEN PHY2 Clock Enable > 20:19 CAMERARX_CSI22_CAMMODE PHY2 Mode (CCP2, CSI1, CSI2) > 18 CAMERARX_CSI21_CTRLCLKEN PHY1 Clock Enable > 17:16 CAMERARX_CSI21_CAMMODE PHY1 Mode (CCP2, CSI1, CSI2) > > Bits 18 and 21 could be exposed through CCF. Bits 24 to 31 enable/disable the > CSI2 lanes, so it could be argued that they could be exposed through the > pinctrl framework. However, they need to be configured independently, possibly > at runtime. I'm thus not sure pinctrl would be a good idea. Bits 17:16 and > 20:19 don't fit in existing frameworks. OK thanks for the info. Sounds like drivers/phy might be the right location for it then and then the phy driver can use the syscon regmap. > Given that this register is specific to the ISS, I think handling it as a > separate device through a separate driver would only complicate the > implementation without any real benefit. Even though it's one register, it shoud still be treated separately from the camera driver. The problems with keeping the register access to the control module in the camera driver are at least following: 1. They live in separate hardware modules that can be clocked separately 2. Doing a read-back to flush a posted write in one hardware module most likely won't flush the write to other and that can lead into hard to find mysterious bugs 3. If we ever have a common system control module driver, we need to rewrite all the system control module register tinkering in the drivers So it's best to try to use an existing framework for it. That avoids tons of pain later on ;) Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
