From patchwork Fri Jul 22 09:37:48 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gabriel Fernandez X-Patchwork-Id: 651600 Return-Path: X-Original-To: incoming-dt@patchwork.ozlabs.org Delivered-To: patchwork-incoming-dt@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3rwlxG4dLqz9sRZ for ; Fri, 22 Jul 2016 19:40:02 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753849AbcGVJjk (ORCPT ); Fri, 22 Jul 2016 05:39:40 -0400 Received: from mx08-00178001.pphosted.com ([91.207.212.93]:54694 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752357AbcGVJii (ORCPT ); Fri, 22 Jul 2016 05:38:38 -0400 Received: from pps.filterd (m0046661.ppops.net [127.0.0.1]) by mx08-00178001.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u6M9YjPp023708; Fri, 22 Jul 2016 11:37:59 +0200 Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx08-00178001.pphosted.com with ESMTP id 2495a46n2w-1 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT); Fri, 22 Jul 2016 11:37:59 +0200 Received: from zeta.dmz-eu.st.com (zeta.dmz-eu.st.com [164.129.230.9]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 16DA931; Fri, 22 Jul 2016 09:37:59 +0000 (GMT) Received: from Webmail-eu.st.com (Safex1hubcas21.st.com [10.75.90.44]) by zeta.dmz-eu.st.com (STMicroelectronics) with ESMTP id E6EF413D2; Fri, 22 Jul 2016 09:37:58 +0000 (GMT) Received: from localhost (10.48.0.158) by Webmail-ga.st.com (10.75.90.48) with Microsoft SMTP Server (TLS) id 14.3.279.2; Fri, 22 Jul 2016 11:37:58 +0200 From: To: Philipp Zabel , Rob Herring , Mark Rutland , Maxime Coquelin , Russell King , , CC: , , , Gabriel Fernandez Subject: [PATCH v3 2/4] dt-bindings: Document the STM32 reset bindings Date: Fri, 22 Jul 2016 11:37:48 +0200 Message-ID: <1469180270-5446-3-git-send-email-gabriel.fernandez@st.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1469180270-5446-1-git-send-email-gabriel.fernandez@st.com> References: <1469180270-5446-1-git-send-email-gabriel.fernandez@st.com> MIME-Version: 1.0 X-Originating-IP: [10.48.0.158] X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2016-07-22_07:, , signatures=0 Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org From: Maxime Coquelin This adds documentation of device tree bindings for the STM32 reset controller. Signed-off-by: Maxime Coquelin Signed-off-by: Gabriel Fernandez Acked-by: Rob Herring --- .../devicetree/bindings/clock/st,stm32-rcc.txt | 42 ++++++++++++++++++---- .../devicetree/bindings/reset/st,stm32-rcc.txt | 6 ++++ 2 files changed, 41 insertions(+), 7 deletions(-) create mode 100644 Documentation/devicetree/bindings/reset/st,stm32-rcc.txt diff --git a/Documentation/devicetree/bindings/clock/st,stm32-rcc.txt b/Documentation/devicetree/bindings/clock/st,stm32-rcc.txt index fee3205..c209de6 100644 --- a/Documentation/devicetree/bindings/clock/st,stm32-rcc.txt +++ b/Documentation/devicetree/bindings/clock/st,stm32-rcc.txt @@ -1,16 +1,16 @@ STMicroelectronics STM32 Reset and Clock Controller =================================================== -The RCC IP is both a reset and a clock controller. This documentation only -describes the clock part. +The RCC IP is both a reset and a clock controller. -Please also refer to clock-bindings.txt in this directory for common clock -controller binding usage. +Please refer to clock-bindings.txt for common clock controller binding usage. +Please also refer to reset.txt for common reset controller binding usage. Required properties: - compatible: Should be "st,stm32f42xx-rcc" - reg: should be register base and length as documented in the datasheet +- #reset-cells: 1, see below - #clock-cells: 2, device nodes should specify the clock in their "clocks" property, containing a phandle to the clock device node, an index selecting between gated clocks and other clocks and an index specifying the clock to @@ -19,6 +19,7 @@ Required properties: Example: rcc: rcc@40023800 { + #reset-cells = <1>; #clock-cells = <2> compatible = "st,stm32f42xx-rcc", "st,stm32-rcc"; reg = <0x40023800 0x400>; @@ -35,16 +36,23 @@ from the first RCC clock enable register (RCC_AHB1ENR, address offset 0x30). It is calculated as: index = register_offset / 4 * 32 + bit_offset. Where bit_offset is the bit offset within the register (LSB is 0, MSB is 31). +To simplify the usage and to share bit definition with the reset and clock +drivers of the RCC IP, macros are available to generate the index in +human-readble format. + +For STM32F4 series, the macro are available here: + - include/dt-bindings/mfd/stm32f4-rcc.h + Example: /* Gated clock, AHB1 bit 0 (GPIOA) */ ... { - clocks = <&rcc 0 0> + clocks = <&rcc 0 STM32F4_AHB1_CLOCK(GPIOA)> }; /* Gated clock, AHB2 bit 4 (CRYP) */ ... { - clocks = <&rcc 0 36> + clocks = <&rcc 0 STM32F4_AHB2_CLOCK(CRYP)> }; Specifying other clocks @@ -61,5 +69,25 @@ Example: /* Misc clock, FCLK */ ... { - clocks = <&rcc 1 1> + clocks = <&rcc 1 STM32F4_APB1_CLOCK(TIM2)> + }; + + +Specifying softreset control of devices +======================================= + +Device nodes should specify the reset channel required in their "resets" +property, containing a phandle to the reset device node and an index specifying +which channel to use. +The index is the bit number within the RCC registers bank, starting from RCC +base address. +It is calculated as: index = register_offset / 4 * 32 + bit_offset. +Where bit_offset is the bit offset within the register. +For example, for CRC reset: + crc = AHB1RSTR_offset / 4 * 32 + CRCRST_bit_offset = 0x10 / 4 * 32 + 12 = 140 + +example: + + timer2 { + resets = <&rcc STM32F4_APB1_RESET(TIM2)>; }; diff --git a/Documentation/devicetree/bindings/reset/st,stm32-rcc.txt b/Documentation/devicetree/bindings/reset/st,stm32-rcc.txt new file mode 100644 index 0000000..01db343 --- /dev/null +++ b/Documentation/devicetree/bindings/reset/st,stm32-rcc.txt @@ -0,0 +1,6 @@ +STMicroelectronics STM32 Peripheral Reset Controller +==================================================== + +The RCC IP is both a reset and a clock controller. + +Please see Documentation/devicetree/bindings/clock/st,stm32-rcc.txt