Re: [PATCH v4 00/23] soc: renesas: Add R-Car RST driver for obtaining mode pin state
Hi Stephen, On Fri, Nov 4, 2016 at 8:49 PM, Stephen Boydwrote: > On 11/02, Geert Uytterhoeven wrote: >> On Tue, Nov 1, 2016 at 12:25 AM, Stephen Boyd wrote: >> > >> > Would the pull requests for clk also have dts changes at the base >> > of the tree? Perhaps clk side can just ack the clk patches and >> >> Yes they would: this is moving functionality from platform code to DT. >> Without the DT updates, it will break bisection (except for R-Car Gen2, >> where we have fallback code to handle old DTBs). >> >> > then have it all routed through arm-soc? The only worry I have is >> > if we need to make some sort of change in clk side that conflicts >> > with these changes. I don't usually like taking dts changes >> > through clk tree, so I'd like to avoid that if possible. >> >> Everything could go through arm-soc only with your Acked-by. >> However, there are new clock drivers pending on this series. >> Either they have to go through arm-soc, too, or this series would >> be pulled into the clk tree with these new clock drivers. >> >> > Part E could happen anytime after everything else happens, so >> > that doesn't seem like a concern. >> >> Part E can indeed by postponed. >> But if parts A-D are applied together, there's no reason to postpone part E. >> >> > Part C could also be made to >> > only call into the new reset drivers if the reset dts nodes are >> > present? If that's done then we could merge clk patches anytime >> > and remove the dead code and the node search at some later time >> > when everything has settled? >> >> That would require adding more backwards compatibility code for >> old DTBs, even for platform where we're not interested in maintaining >> that. In addition, Part C depends on the header file for the reset driver >> to compile the clock driver, even if you would add some DT detection, >> and on the reset driver to link. So I'm afraid this is not feasible. > > TL;DR: Sounds fine, I'll be on the lookout for the PR. Thank you very much! > Longer version: Let me step back a bit and actually think about > this longer than 2 minutes. From what I see > rcar_rst_read_mode_pins() already returns -ENODEV if the nodes > aren't present. Great. > > So clk tree could be given a pull for the clk patches, part C, on > top of part A, the reset driver. If the rcar_rst_read_mode_pins() > returns failure because the node is missing, we fall back to the > old style of doing things. Some drivers already do that anyway, For R-Car Gen2, we want to keep backwards compatibility for a while. But not for the others, and I didn't want to add more code that was going to be removed again soon. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
Re: [PATCH v4 00/23] soc: renesas: Add R-Car RST driver for obtaining mode pin state
On 11/02, Geert Uytterhoeven wrote: > On Tue, Nov 1, 2016 at 12:25 AM, Stephen Boydwrote: > > > > Would the pull requests for clk also have dts changes at the base > > of the tree? Perhaps clk side can just ack the clk patches and > > Yes they would: this is moving functionality from platform code to DT. > Without the DT updates, it will break bisection (except for R-Car Gen2, > where we have fallback code to handle old DTBs). > > > then have it all routed through arm-soc? The only worry I have is > > if we need to make some sort of change in clk side that conflicts > > with these changes. I don't usually like taking dts changes > > through clk tree, so I'd like to avoid that if possible. > > Everything could go through arm-soc only with your Acked-by. > However, there are new clock drivers pending on this series. > Either they have to go through arm-soc, too, or this series would > be pulled into the clk tree with these new clock drivers. > > > Part E could happen anytime after everything else happens, so > > that doesn't seem like a concern. > > Part E can indeed by postponed. > But if parts A-D are applied together, there's no reason to postpone part E. > > > Part C could also be made to > > only call into the new reset drivers if the reset dts nodes are > > present? If that's done then we could merge clk patches anytime > > and remove the dead code and the node search at some later time > > when everything has settled? > > That would require adding more backwards compatibility code for > old DTBs, even for platform where we're not interested in maintaining > that. In addition, Part C depends on the header file for the reset driver > to compile the clock driver, even if you would add some DT detection, > and on the reset driver to link. So I'm afraid this is not feasible. > TL;DR: Sounds fine, I'll be on the lookout for the PR. Longer version: Let me step back a bit and actually think about this longer than 2 minutes. From what I see rcar_rst_read_mode_pins() already returns -ENODEV if the nodes aren't present. Great. So clk tree could be given a pull for the clk patches, part C, on top of part A, the reset driver. If the rcar_rst_read_mode_pins() returns failure because the node is missing, we fall back to the old style of doing things. Some drivers already do that anyway, so this looks to be replacing things like if (rcar_rst_read_mode_pins()) return; with if (rcar_rst_read_mode_pins() != -ENODEV) return; Then in arm-soc tree, the dts patches are merged. That causes us to do some duplicate work reading the pins twice in mach-shmobile and in the new reset driver. That's duplicate/wasteful, but it works. Finally, everything is merged together into a tagged release. The mach-shmobile changes can happen anytime after that (part D). Again we're left with dead code in the clk driver (part E) until the dependency merges, but that's ok. Once part D merges we can get rid of the dead code in part E and any backwards compatibility we don't want to maintain. In summary, it's all feasible to do this and most people wouldn't have had to know about the dependency chain but it's not fast by any means. Instead we merge everything in one shot and get it over with now. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v4 00/23] soc: renesas: Add R-Car RST driver for obtaining mode pin state
Hi Stephen, Thanks for your answers! On Tue, Nov 1, 2016 at 12:25 AM, Stephen Boydwrote: > On 10/31, Geert Uytterhoeven wrote: >> Hi Mike, Stephen, Arnd, Olof, Kevin, >> >> Is the merge strategy [see # below] OK for you? >> Thanks a lot! >> >> On Mon, Oct 31, 2016 at 9:19 AM, Simon Horman wrote: >> > On Wed, Oct 26, 2016 at 02:00:24PM +0200, Geert Uytterhoeven wrote: >> >> On Fri, Oct 21, 2016 at 3:17 PM, Geert Uytterhoeven >> >> wrote: >> >> > Currently the R-Car Clock Pulse Generator (CPG) drivers obtains the >> >> > state of the mode pins either by a call from the platform code, or >> >> > directly by using a hardcoded register access. This is a bit messy, and >> >> > creates a dependency between driver and platform code. >> >> > >> >> > This patch series converts the various Renesas R-Car clock drivers >> >> > and support code from reading the mode pin states using a hardcoded >> >> > register access to using a new minimalistic R-Car RST driver. >> >> > >> >> > All R-Car clock drivers will rely on the presence in DT of a device node >> >> > for the RST module. Backwards compatibility with old DTBs is retained >> >> > only for R-Car Gen2, which has fallback code using its own private copy >> >> > of rcar_gen2_read_mode_pins(). >> >> > >> >> > After this, there is still one remaining user of >> >> > rcar_gen2_read_mode_pins() left in platform code. A patch series to >> >> > remove that user has already been posted, though ("[PATCH/RFT 0/4] ARM: >> >> > shmobile: R-Car Gen2: Allow booting secondary CPU cores in debug mode"). >> >> > Since v3, the other user has been removed in commit 9f5ce39ddb8f68b3 >> >> > ("ARM: shmobile: rcar-gen2: Obtain extal frequency from DT"). >> >> > >> >> > This series consists of 5 parts: >> >> > A. Patches 1 and 2 add DT bindings and driver code for the R-Car RST >> >> > driver, >> >> > B. Patches 3-11 add device nodes for the RST modules to the R-Car DTS >> >> > files, >> >> > C. Patches 12-17 convert the clock drivers to call into the new R-Car >> >> > RST driver, >> >> > D. Patches 18-20 remove passing mode pin state to the clock drivers >> >> > from the platform code, >> >> > E. Patches 21-23 remove dead code from the clock drivers. >> >> > >> >> > As is usually the case with moving functionality from platform code to >> >> > DT, there are lots of hard dependencies: >> >> > - The DT updates in Part B can be merged as soon as the DT bindings in >> >> > Part A have been approved, >> >> > - The clock driver updates in Part C depend functionally on the driver >> >> > code in Part A, and on the DT updates in Part B, >> >> > - The board code cleanups in Part D depend on the clock driver updates >> >> > in Part C, >> >> > - The block driver cleanups in part E depend on the board code >> >> > cleanups in part D. >> >> > >> >> > Hence to maintain the required lockstep between SoC driver, clock >> >> > drivers, shmobile platform code, and shmobile DT, I propose to queue up >> >> > all patches in a single branch against v4.9-rc1, and send pull requests >> >> > to both Mike/Stephen (clock) and Simon (rest). >> >> > >> >> > *** >> >> >> >> > - Mike/Stephen/Simon/Magnus: Are you OK with the suggested merge >> >> > approach above? >> >> >> >> Is this OK for you? >> >> # >> >> (link to the full series at >> https://groups.google.com/forum/#!topic/linux.kernel/fLSFsjOgPT8) > > Would the pull requests for clk also have dts changes at the base > of the tree? Perhaps clk side can just ack the clk patches and Yes they would: this is moving functionality from platform code to DT. Without the DT updates, it will break bisection (except for R-Car Gen2, where we have fallback code to handle old DTBs). > then have it all routed through arm-soc? The only worry I have is > if we need to make some sort of change in clk side that conflicts > with these changes. I don't usually like taking dts changes > through clk tree, so I'd like to avoid that if possible. Everything could go through arm-soc only with your Acked-by. However, there are new clock drivers pending on this series. Either they have to go through arm-soc, too, or this series would be pulled into the clk tree with these new clock drivers. > Part E could happen anytime after everything else happens, so > that doesn't seem like a concern. Part E can indeed by postponed. But if parts A-D are applied together, there's no reason to postpone part E. > Part C could also be made to > only call into the new reset drivers if the reset dts nodes are > present? If that's done then we could merge clk patches anytime > and remove the dead code and the node search at some later time > when everything has settled? That would require adding more backwards compatibility code for old DTBs, even for platform where we're not interested in maintaining that. In addition, Part C depends on the header file for the
Re: [PATCH v4 00/23] soc: renesas: Add R-Car RST driver for obtaining mode pin state
On 10/31, Geert Uytterhoeven wrote: > Hi Mike, Stephen, Arnd, Olof, Kevin, > > Is the merge strategy [see # below] OK for you? > Thanks a lot! > > On Mon, Oct 31, 2016 at 9:19 AM, Simon Hormanwrote: > > On Wed, Oct 26, 2016 at 02:00:24PM +0200, Geert Uytterhoeven wrote: > >> On Fri, Oct 21, 2016 at 3:17 PM, Geert Uytterhoeven > >> wrote: > >> > Currently the R-Car Clock Pulse Generator (CPG) drivers obtains the > >> > state of the mode pins either by a call from the platform code, or > >> > directly by using a hardcoded register access. This is a bit messy, and > >> > creates a dependency between driver and platform code. > >> > > >> > This patch series converts the various Renesas R-Car clock drivers > >> > and support code from reading the mode pin states using a hardcoded > >> > register access to using a new minimalistic R-Car RST driver. > >> > > >> > All R-Car clock drivers will rely on the presence in DT of a device node > >> > for the RST module. Backwards compatibility with old DTBs is retained > >> > only for R-Car Gen2, which has fallback code using its own private copy > >> > of rcar_gen2_read_mode_pins(). > >> > > >> > After this, there is still one remaining user of > >> > rcar_gen2_read_mode_pins() left in platform code. A patch series to > >> > remove that user has already been posted, though ("[PATCH/RFT 0/4] ARM: > >> > shmobile: R-Car Gen2: Allow booting secondary CPU cores in debug mode"). > >> > Since v3, the other user has been removed in commit 9f5ce39ddb8f68b3 > >> > ("ARM: shmobile: rcar-gen2: Obtain extal frequency from DT"). > >> > > >> > This series consists of 5 parts: > >> > A. Patches 1 and 2 add DT bindings and driver code for the R-Car RST > >> > driver, > >> > B. Patches 3-11 add device nodes for the RST modules to the R-Car DTS > >> > files, > >> > C. Patches 12-17 convert the clock drivers to call into the new R-Car > >> > RST driver, > >> > D. Patches 18-20 remove passing mode pin state to the clock drivers > >> > from the platform code, > >> > E. Patches 21-23 remove dead code from the clock drivers. > >> > > >> > As is usually the case with moving functionality from platform code to > >> > DT, there are lots of hard dependencies: > >> > - The DT updates in Part B can be merged as soon as the DT bindings in > >> > Part A have been approved, > >> > - The clock driver updates in Part C depend functionally on the driver > >> > code in Part A, and on the DT updates in Part B, > >> > - The board code cleanups in Part D depend on the clock driver updates > >> > in Part C, > >> > - The block driver cleanups in part E depend on the board code > >> > cleanups in part D. > >> > > >> > Hence to maintain the required lockstep between SoC driver, clock > >> > drivers, shmobile platform code, and shmobile DT, I propose to queue up > >> > all patches in a single branch against v4.9-rc1, and send pull requests > >> > to both Mike/Stephen (clock) and Simon (rest). > >> > > >> > *** > >> > >> > - Mike/Stephen/Simon/Magnus: Are you OK with the suggested merge > >> > approach above? > >> > >> Is this OK for you? > > # > > (link to the full series at > https://groups.google.com/forum/#!topic/linux.kernel/fLSFsjOgPT8) Would the pull requests for clk also have dts changes at the base of the tree? Perhaps clk side can just ack the clk patches and then have it all routed through arm-soc? The only worry I have is if we need to make some sort of change in clk side that conflicts with these changes. I don't usually like taking dts changes through clk tree, so I'd like to avoid that if possible. Part E could happen anytime after everything else happens, so that doesn't seem like a concern. Part C could also be made to only call into the new reset drivers if the reset dts nodes are present? If that's done then we could merge clk patches anytime and remove the dead code and the node search at some later time when everything has settled? -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v4 00/23] soc: renesas: Add R-Car RST driver for obtaining mode pin state
On Wed, Oct 26, 2016 at 02:00:24PM +0200, Geert Uytterhoeven wrote: > Hi Mike, Stephen, > > On Fri, Oct 21, 2016 at 3:17 PM, Geert Uytterhoeven >wrote: > > Currently the R-Car Clock Pulse Generator (CPG) drivers obtains the > > state of the mode pins either by a call from the platform code, or > > directly by using a hardcoded register access. This is a bit messy, and > > creates a dependency between driver and platform code. > > > > This patch series converts the various Renesas R-Car clock drivers > > and support code from reading the mode pin states using a hardcoded > > register access to using a new minimalistic R-Car RST driver. > > > > All R-Car clock drivers will rely on the presence in DT of a device node > > for the RST module. Backwards compatibility with old DTBs is retained > > only for R-Car Gen2, which has fallback code using its own private copy > > of rcar_gen2_read_mode_pins(). > > > > After this, there is still one remaining user of > > rcar_gen2_read_mode_pins() left in platform code. A patch series to > > remove that user has already been posted, though ("[PATCH/RFT 0/4] ARM: > > shmobile: R-Car Gen2: Allow booting secondary CPU cores in debug mode"). > > Since v3, the other user has been removed in commit 9f5ce39ddb8f68b3 > > ("ARM: shmobile: rcar-gen2: Obtain extal frequency from DT"). > > > > This series consists of 5 parts: > > A. Patches 1 and 2 add DT bindings and driver code for the R-Car RST > > driver, > > B. Patches 3-11 add device nodes for the RST modules to the R-Car DTS > > files, > > C. Patches 12-17 convert the clock drivers to call into the new R-Car > > RST driver, > > D. Patches 18-20 remove passing mode pin state to the clock drivers > > from the platform code, > > E. Patches 21-23 remove dead code from the clock drivers. > > > > As is usually the case with moving functionality from platform code to > > DT, there are lots of hard dependencies: > > - The DT updates in Part B can be merged as soon as the DT bindings in > > Part A have been approved, > > - The clock driver updates in Part C depend functionally on the driver > > code in Part A, and on the DT updates in Part B, > > - The board code cleanups in Part D depend on the clock driver updates > > in Part C, > > - The block driver cleanups in part E depend on the board code > > cleanups in part D. > > > > Hence to maintain the required lockstep between SoC driver, clock > > drivers, shmobile platform code, and shmobile DT, I propose to queue up > > all patches in a single branch against v4.9-rc1, and send pull requests > > to both Mike/Stephen (clock) and Simon (rest). > > > > *** > > > - Mike/Stephen/Simon/Magnus: Are you OK with the suggested merge > > approach above? > > Is this OK for you? > > I'd like to move forward with this, as this is a prerequisite for adding > support for new SoCs (RZ/G) without adding more copies of > rcar_gen2_read_mode_pins(), and removing that function from platform code > for good. This seems reasonable to me but likely the ARM SoC maintainers will want to know about this plan before it is executed.
Re: [PATCH v4 00/23] soc: renesas: Add R-Car RST driver for obtaining mode pin state
A. Hi Geert, Am Freitag, den 21.10.2016, 15:17 +0200 schrieb Geert Uytterhoeven: > Hi Philipp, Mike, Stephen, Simon, Magnus, > (see questions *** below!) > > Currently the R-Car Clock Pulse Generator (CPG) drivers obtains the > state of the mode pins either by a call from the platform code, or > directly by using a hardcoded register access. This is a bit messy, and > creates a dependency between driver and platform code. > > This patch series converts the various Renesas R-Car clock drivers > and support code from reading the mode pin states using a hardcoded > register access to using a new minimalistic R-Car RST driver. > > All R-Car clock drivers will rely on the presence in DT of a device node > for the RST module. Backwards compatibility with old DTBs is retained > only for R-Car Gen2, which has fallback code using its own private copy > of rcar_gen2_read_mode_pins(). I think you should add a binding doc even though the DT bindings are still trivial. > After this, there is still one remaining user of > rcar_gen2_read_mode_pins() left in platform code. A patch series to > remove that user has already been posted, though ("[PATCH/RFT 0/4] ARM: > shmobile: R-Car Gen2: Allow booting secondary CPU cores in debug mode"). > Since v3, the other user has been removed in commit 9f5ce39ddb8f68b3 > ("ARM: shmobile: rcar-gen2: Obtain extal frequency from DT"). > > This series consists of 5 parts: > A. Patches 1 and 2 add DT bindings and driver code for the R-Car RST > driver, > B. Patches 3-11 add device nodes for the RST modules to the R-Car DTS > files, > C. Patches 12-17 convert the clock drivers to call into the new R-Car > RST driver, > D. Patches 18-20 remove passing mode pin state to the clock drivers > from the platform code, > E. Patches 21-23 remove dead code from the clock drivers. > > As is usually the case with moving functionality from platform code to > DT, there are lots of hard dependencies: > - The DT updates in Part B can be merged as soon as the DT bindings in > Part A have been approved, > - The clock driver updates in Part C depend functionally on the driver > code in Part A, and on the DT updates in Part B, > - The board code cleanups in Part D depend on the clock driver updates > in Part C, > - The block driver cleanups in part E depend on the board code > cleanups in part D. > > Hence to maintain the required lockstep between SoC driver, clock > drivers, shmobile platform code, and shmobile DT, I propose to queue up > all patches in a single branch against v4.9-rc1, and send pull requests > to both Mike/Stephen (clock) and Simon (rest). > > *** > > - Philip: While this is a driver for a reset-controller, currently it > doesn't provide any reset-controller functionality. Hence I added it > to drivers/soc/renesas/. Is that OK for you? Absolutely, as long as the driver isn't even a reset controller provider, this is the right place. regards Philipp
[PATCH v4 00/23] soc: renesas: Add R-Car RST driver for obtaining mode pin state
Hi Philipp, Mike, Stephen, Simon, Magnus, (see questions *** below!) Currently the R-Car Clock Pulse Generator (CPG) drivers obtains the state of the mode pins either by a call from the platform code, or directly by using a hardcoded register access. This is a bit messy, and creates a dependency between driver and platform code. This patch series converts the various Renesas R-Car clock drivers and support code from reading the mode pin states using a hardcoded register access to using a new minimalistic R-Car RST driver. All R-Car clock drivers will rely on the presence in DT of a device node for the RST module. Backwards compatibility with old DTBs is retained only for R-Car Gen2, which has fallback code using its own private copy of rcar_gen2_read_mode_pins(). After this, there is still one remaining user of rcar_gen2_read_mode_pins() left in platform code. A patch series to remove that user has already been posted, though ("[PATCH/RFT 0/4] ARM: shmobile: R-Car Gen2: Allow booting secondary CPU cores in debug mode"). Since v3, the other user has been removed in commit 9f5ce39ddb8f68b3 ("ARM: shmobile: rcar-gen2: Obtain extal frequency from DT"). This series consists of 5 parts: A. Patches 1 and 2 add DT bindings and driver code for the R-Car RST driver, B. Patches 3-11 add device nodes for the RST modules to the R-Car DTS files, C. Patches 12-17 convert the clock drivers to call into the new R-Car RST driver, D. Patches 18-20 remove passing mode pin state to the clock drivers from the platform code, E. Patches 21-23 remove dead code from the clock drivers. As is usually the case with moving functionality from platform code to DT, there are lots of hard dependencies: - The DT updates in Part B can be merged as soon as the DT bindings in Part A have been approved, - The clock driver updates in Part C depend functionally on the driver code in Part A, and on the DT updates in Part B, - The board code cleanups in Part D depend on the clock driver updates in Part C, - The block driver cleanups in part E depend on the board code cleanups in part D. Hence to maintain the required lockstep between SoC driver, clock drivers, shmobile platform code, and shmobile DT, I propose to queue up all patches in a single branch against v4.9-rc1, and send pull requests to both Mike/Stephen (clock) and Simon (rest). *** - Philip: While this is a driver for a reset-controller, currently it doesn't provide any reset-controller functionality. Hence I added it to drivers/soc/renesas/. Is that OK for you? - Mike/Stephen/Simon/Magnus: Are you OK with the suggested merge approach above? This series has evolved over time, cfr.: - "[PATCH/RFC v3 00/22] soc: renesas: Add R-Car RST driver for obtaining mode pin state" (http://www.spinics.net/lists/linux-renesas-soc/msg04289.html), - "[PATCH/RFC 00/11] ARM: shmobile: Let CPG use syscon for MD pin values" (http://www.spinics.net/lists/linux-clk/msg01478.html), - "[PATCH 00/10] arm64: renesas: Obtain MD pin values using syscon/regmap". (http://www.spinics.net/lists/linux-sh/msg44757.html) Changes compared to v3: - Add Acked-by, Reviewed-by, - Add support for R-Car V2H, - Add support for RZ/G1M and RZ/G1E, - Remove the initcall and the rcar_rst_base check in rcar_rst_init(), as rcar_rst_init() is only used as a support function for rcar_rst_read_mode_pins(), - Refer to rcar_rst_gen2 for R-Car Gen3 instead of providing an identical copy, - Use our own private copy of rcar_gen2_read_mode_pins() instead of the one in the R-Car Gen2 platform code, as the latter is planned to be removed, - Rebase on top of "ARM: shmobile: rcar-gen2: Obtain extal frequency from DT", Changes compared to v2: - Use "renesas,-rst" instead of "renesas,rst-", - Drop "syscon" compatible value and "renesas,modemr" property, use a real driver instead, - Add support for R-Car M1A, H1, and M3-W. Changes compared to v1: - Add support for R-Car H3. This patch series is against v4.9-rc1. When applying it to renesas-devel-20161021-v4.9-rc1, there's a small conflict in drivers/soc/renesas/Makefile (both sides added lines). For your convenience, this series is also available in the topic/rcar-rst-v4 branch of my renesas-drivers git repository at git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git This has been tested on r8a7778/bockw, r8a7779/marzen, r8a7791/koelsch, r8a7795/salvator-x, and r8a7796/salvator-x. Thanks! Geert Uytterhoeven (23): reset: Add renesas,rst DT bindings soc: renesas: Add R-Car RST driver ARM: dts: r8a7778: Add device node for RESET/WDT module ARM: dts: r8a7779: Add device node for RESET/WDT module ARM: dts: r8a7790: Add device node for RST module ARM: dts: r8a7791: Add device node for RST module ARM: dts: r8a7792: Add device node for RST module ARM: dts: r8a7793: Add device node for RST