From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751537AbeCNJmz (ORCPT ); Wed, 14 Mar 2018 05:42:55 -0400 Received: from mx07-00178001.pphosted.com ([62.209.51.94]:25243 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751348AbeCNJmx (ORCPT ); Wed, 14 Mar 2018 05:42:53 -0400 From: Gabriel FERNANDEZ To: Philipp Zabel , Rob Herring , Mark Rutland , Maxime Coquelin , Alexandre TORGUE CC: "linux-kernel@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "gabriel.fernandez.st@gmail.com" , Loic PALLARDY , Benjamin GAIGNARD , Michael Turquette , "sboyd@kernel.org" Subject: Re: [PATCH 0/2] Introduce STM32MP1 Reset driver Thread-Topic: [PATCH 0/2] Introduce STM32MP1 Reset driver Thread-Index: AQHTuukmXhLqwRGQGUGMtGZ7ugmTrqPPYnEAgAAIfgA= Date: Wed, 14 Mar 2018 09:42:26 +0000 Message-ID: <12ba9cee-f703-8fc7-75da-de213f5c8aa2@st.com> References: <1520958859-27911-1-git-send-email-gabriel.fernandez@st.com> <1521018722.4490.1.camel@pengutronix.de> In-Reply-To: <1521018722.4490.1.camel@pengutronix.de> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: user-agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.75.127.51] Content-Type: text/plain; charset="utf-8" Content-ID: <401DE63C1C05764D961C4CB5B5609FDB@st.com> MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-03-14_05:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id w2E9hOS9019939 Hi Philipp, Okay, i too support the idea to add custom  reset driver. Many Thanks Philipp. Best regards Gabriel On 03/14/2018 10:12 AM, Philipp Zabel wrote: > Hi Gabriel, > > On Tue, 2018-03-13 at 17:34 +0100, gabriel.fernandez@st.com wrote: >> From: Gabriel Fernandez >> >> This patch-set enables the reset of STM32MP1. >> It uses the reset simple driver by introducing the clear register offset >> parameter. >> STM32MP1 reset IP has a register to assert by writing '1' and another >> register to de-assert by writing '1'. >> The offset between this two registers is '0x4'. > I worry a bit about feature creep in the simple-reset driver. > Your patch on its own is simple enough, and I'm not opposed to add a > SET/CLR feature on principle, but there are a few issues: > > The RESET_SIMPLE Kconfig description currently says: >   "This enables a simple reset controller driver for reset lines that >    that can be asserted and deasserted by toggling bits in a contiguous, >    exclusive register space." > That would have to be extended to mention SET/CLR register pairs as an > alternative. > > What about status (reset_simple_status)? Can current reset line status > be read back from the SET register, as is currently tried? If not, is > there a way to read current reset line status back at all? > > The data->lock spinlock is only needed to protect the read-modify-write > cycle on a toggle register, for separate SET/CLR register access the > locking is not necessary. > > At this point, it may or may not be easier to add a custom reset driver. > Either way you go, this is missing binding documentation for the > st,stm32mp1-rcc compatible in Documentation/devicetree/bindings/reset. > >> The patch 'dt-bindings: reset: add STM32MP1 resets' could be squashed >> with the patch: >> 'dt-bindings: Document STM32MP1 Reset Clock Controller (RCC) bindings' >> commit 3830681d354f >> >> Gabriel Fernandez (2): >> dt-bindings: reset: add STM32MP1 resets >> reset: simple: Enable stm32mp1 reset driver >> >> drivers/reset/reset-simple.c | 27 +++++-- >> drivers/reset/reset-simple.h | 1 + >> include/dt-bindings/reset/stm32mp1-resets.h | 108 ++++++++++++++++++++++++++++ >> 3 files changed, 130 insertions(+), 6 deletions(-) >> create mode 100644 include/dt-bindings/reset/stm32mp1-resets.h > regards > Philipp