From mboxrd@z Thu Jan 1 00:00:00 1970 From: Philipp Zabel Subject: Re: [RFC v2: PATCH 1/2] dt-bindings: Document the hi3660 reset bindings Date: Fri, 25 Nov 2016 11:25:23 +0100 Message-ID: <1480069523.4058.17.camel@pengutronix.de> References: <1479888476-13138-1-git-send-email-zhangfei.gao@linaro.org> <1479888476-13138-2-git-send-email-zhangfei.gao@linaro.org> <1479979605.2472.4.camel@pengutronix.de> <1479981017.2472.14.camel@pengutronix.de> <8328a235-faeb-2218-4c49-a3f282599e95@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <8328a235-faeb-2218-4c49-a3f282599e95-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: zhangfei Cc: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@vger.kernel.org Am Donnerstag, den 24.11.2016, 18:20 +0800 schrieb zhangfei: > > On 2016年11月24日 17:50, Philipp Zabel wrote: > > Am Donnerstag, den 24.11.2016, 17:40 +0800 schrieb zhangfei: > >> On 2016年11月24日 17:26, Philipp Zabel wrote: > >>> Am Mittwoch, den 23.11.2016, 16:07 +0800 schrieb Zhangfei Gao: > >>>> Add DT bindings documentation for hi3660 SoC reset controller. > >>>> > >>>> Signed-off-by: Zhangfei Gao > >>>> --- > >>>> .../bindings/reset/hisilicon,hi3660-reset.txt | 51 ++++++++++++++++++++++ > >>>> 1 file changed, 51 insertions(+) > >>>> create mode 100644 Documentation/devicetree/bindings/reset/hisilicon,hi3660-reset.txt > >>>> > >>>> diff --git a/Documentation/devicetree/bindings/reset/hisilicon,hi3660-reset.txt b/Documentation/devicetree/bindings/reset/hisilicon,hi3660-reset.txt > >>>> new file mode 100644 > >>>> index 0000000..250daf2 > >>>> --- /dev/null > >>>> +++ b/Documentation/devicetree/bindings/reset/hisilicon,hi3660-reset.txt > >>>> @@ -0,0 +1,51 @@ > >>>> +Hisilicon System Reset Controller > >>>> +====================================== > >>>> + > >>>> +Please also refer to reset.txt in this directory for common reset > >>>> +controller binding usage. > >>>> + > >>>> +The reset controller registers are part of the system-ctl block on > >>>> +hi3660 SoC. > >>>> + > >>>> +Required properties: > >>>> +- compatible: should be > >>>> + "hisilicon,hi3660-reset" > >>>> +- #reset-cells: 1, see below > >>>> +- hisi,rst-syscon: phandle of the reset's syscon. > >>>> +- hisi,reset-bits: Contains the reset control register information > >>>> + Should contain 2 cells for each reset exposed to > >>>> + consumers, defined as: > >>>> + Cell #1 : offset from the syscon register base > >>>> + Cell #2 : bits position of the control register > >>>> + > >>>> +Example: > >>>> + iomcu: iomcu@ffd7e000 { > >>>> + compatible = "hisilicon,hi3660-iomcu", "syscon"; > >>>> + reg = <0x0 0xffd7e000 0x0 0x1000>; > >>>> + }; > >>>> + > >>>> + iomcu_rst: iomcu_rst_controller { > >>> This should be > >>> iomcu_rst: reset-controller { > >>> > >>>> + compatible = "hisilicon,hi3660-reset"; > >>>> + #reset-cells = <1>; > >>>> + hisi,rst-syscon = <&iomcu>; > >>>> + hisi,reset-bits = <0x20 0x8 /* 0: i2c0 */ > >>>> + 0x20 0x10 /* 1: i2c1 */ > >>>> + 0x20 0x20 /* 2: i2c2 */ > >>>> + 0x20 0x8000000>; /* 3: i2c6 */ > >>>> + }; > >>> The reset lines are controlled through iomcu bits, is there a reason not > >>> to put the iomcu_rst node inside the iomcu node? That way the > >>> hisi,rst-syscon property could be removed and the syscon could be > >>> retrieved via the reset-controller parent node. > >> iomcu is common registers, controls clock and reset, etc. > >> So we use syscon, without mapping the registers everywhere. > >> It is common case in hisilicon, same in hi6220. > >> > >> Also the #clock-cells and #reset-cells can not be put in the same node, > >> if they are both using probe, since reset_probe will not be called. > >> > >> So we use hisi,rst-syscon as a general solution. > > What I meant is this: > > > > iomcu: iomcu@ffd7e000 { > > compatible = "hisilicon,hi3660-iomcu", "syscon", "simple-mfd"; > > reg = <0x0 0xffd7e000 0x0 0x1000>; > #clock-cells = <1>; > > In my test, if there add #clock-cells = <1>, reset_probe will not be > called any more. > Since clk_probe is called first. > No matter iomcu_rst is child node or not. I don't understand this, does the clock driver bind to the iomcu node using CLK_OF_DECLARE_DRIVER(..., "hisilicon,hi3660-iomcu", ...)? My comment was based only on this reset binding documentation and the example DT snippet. Could you point me to the clock driver probe code and show me a more complete part of the hi3660 device tree? regards Philipp -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html