From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752676AbdATOJl (ORCPT ); Fri, 20 Jan 2017 09:09:41 -0500 Received: from xavier.telenet-ops.be ([195.130.132.52]:32918 "EHLO xavier.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752372AbdATOIj (ORCPT ); Fri, 20 Jan 2017 09:08:39 -0500 From: Geert Uytterhoeven To: Philipp Zabel , Simon Horman , Magnus Damm , Michael Turquette , Stephen Boyd , Rob Herring , Mark Rutland Cc: linux-clk@vger.kernel.org, devicetree@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Geert Uytterhoeven Subject: [PATCH 0/8] Renesas CPG/MSSR Reset Control Support Date: Fri, 20 Jan 2017 15:08:18 +0100 Message-Id: <1484921306-9967-1-git-send-email-geert+renesas@glider.be> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi all, This patch series adds reset control support to the Renesas Clock Pulse Generator / Module Standby and Software Reset module, on the R-Car H3 and M3-W, RZ/G1M, and RZ/G1E SoCs. - Patch 1 amends the Renesas CPG/MSSR DT bindings for reset control, - Patches 2-4 add reset control to the Renesas CPG/MSSR driver, - Patches 5-8 add reset control properties to the R-Car H3 and M3-W, RZ/G1M, and RZ/G1E DTSes. Note that this patch series implements reset functionality only. Actual reset policy is to be defined and implemented separately. This is an optional feature, to be enabled explicitly using CONFIG_RESET_CONTROLLER=y. When enabled, an on-SoC device can be reset easily using device_reset(), or by using the reset_control_*() API when more fine-grained control is desired. Possible use cases are (not exhaustive): - Reset a device before use, to make sure it's in a predefined state, and doesn't depend on earlier configuration by e.g. the boot loader, - Reset a device after detecting an anomaly, - Reset a device to verify suspend/resume is handled correctly by the driver in case the device would be part of a power domain on a different/future SoC. Dependencies and upstreaming: - As patches 1-4 touch a driver under drivers/clk/renesas/, I think it's best if they go in through a pull request to the clock maintainers, like other Renesas clock driver changes, - Patches 5-8 have no dependencies nor impact as long as CONFIG_RESET_CONTROLLER=n. However, if CONFIG_RESET_CONTROLLER=y and resets properties are prsesent in DTS, the EHCI and OHCI drivers already deassert reset as part of their initialization sequences, and put the devices back into reset state in case initialization failed, or on unbind. Hence it's best to apply the DTS patches after the driver support has landed upstream. Else USB on R-Car H3 will fail to initialize when booting a kernel with CONFIG_RESET_CONTROLLER=y. I'm not aware of other relevant drivers already using reset control. For your convenience, the driver and DTS changes (incl. dependencies) are available in the topic/renesas-cpg-mssr-reset-driver-v1 resp. topic/renesas-cpg-mssr-reset-dts-v1 branches of my 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 the R-Car Gen3 Salvator-X (H3 and M3-W) and the R-Car M2-W (using out-of-tree driver modifications) Koelsch development boards, by inspecting device register contents before and after reset, and by comparing them with their documented reset values. Thanks for your comments! Geert Uytterhoeven (8): clk: renesas: cpg-mssr: Document reset control support clk: renesas: cpg-mssr: Document suitability for RZ/G1 clk: renesas: cpg-mssr: Rename cpg_mssr_priv.mstp_lock clk: renesas: cpg-mssr: Add support for reset control arm64: dts: r8a7795: Add reset control properties arm64: dts: r8a7796: Add reset control properties ARM: dts: r8a7743: Add reset control properties ARM: dts: r8a7745: Add reset control properties .../devicetree/bindings/clock/renesas,cpg-mssr.txt | 6 + arch/arm/boot/dts/r8a7743.dtsi | 24 ++++ arch/arm/boot/dts/r8a7745.dtsi | 24 ++++ arch/arm64/boot/dts/renesas/r8a7795.dtsi | 103 ++++++++++++++++ arch/arm64/boot/dts/renesas/r8a7796.dtsi | 34 ++++++ drivers/clk/renesas/renesas-cpg-mssr.c | 134 ++++++++++++++++++++- 6 files changed, 319 insertions(+), 6 deletions(-) -- 1.9.1 Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@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