From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1751510AbdB0Uoh (ORCPT <rfc822;w@1wt.eu>);
        Mon, 27 Feb 2017 15:44:37 -0500
Received: from mail-wm0-f67.google.com ([74.125.82.67]:34722 "EHLO
        mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1751181AbdB0Uoe (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Mon, 27 Feb 2017 15:44:34 -0500
Subject: Re: [RFC 0/3] drivers: Add an API to read device specific config data
To: Alban <albeu@free.fr>, linux-kernel@vger.kernel.org
References: <1488227292-18906-1-git-send-email-albeu@free.fr>
Cc: linux-mtd@lists.infradead.org,
        Cyrille Pitchen <cyrille.pitchen@atmel.com>,
        Richard Weinberger <richard@nod.at>,
        Boris Brezillon <boris.brezillon@free-electrons.com>,
        Brian Norris <computersforpeace@gmail.com>,
        David Woodhouse <dwmw2@infradead.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
From: Marek Vasut <marek.vasut@gmail.com>
Message-ID: <56dbc1bb-236f-09ff-dae9-f4afea1298e7@gmail.com>
Date: Mon, 27 Feb 2017 21:42:38 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101
 Icedove/45.4.0
MIME-Version: 1.0
In-Reply-To: <1488227292-18906-1-git-send-email-albeu@free.fr>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 02/27/2017 09:28 PM, Alban wrote:
> Hi all,
> 
> while looking at adding OF support for the ath9k driver I had the problem of
> reading the EEPROM data. On the SoC platforms this data is stored in an SPI
> flash along with a few other things. In OpenWRT/LEDE this data is read from
> the board init code using the fact that the flash is (normaly) readable from
> a memory map. A bit too hackish for my taste.
> 
> This is just one example, there is various other similar cases, mostly with
> MAC addresses. I thought it would be nicer if we had a clean API for this,
> similar to the firmware API but per device instance instead of beeing per
> driver. The device driver wouldn't have to care where the data is stored,
> they just request it and the backend take care of reading the EEPROM, MTD
> or whatever is used on the board.

Can't we use the NVMEM for this stuff ?

> This series implement such an API along with an implementation for MTD
> devices and a use in the ath9k driver. As this is an RFC I didn't yet
> write the OF binding documentation, that will come later if the feedback
> is positive.
> 
> Alban Bedel (3):
>   drivers: Add an API to read device specific config data
>   mtd: Add support for reading device data out of MTD devices
>   ath9k: ahb: Add OF support
> 
>  drivers/base/Kconfig                   |   6 +
>  drivers/base/Makefile                  |   1 +
>  drivers/base/devdata.c                 | 204 +++++++++++++++++++++++++++++++++
>  drivers/mtd/Kconfig                    |   9 ++
>  drivers/mtd/Makefile                   |   1 +
>  drivers/mtd/devdata.c                  |  70 +++++++++++
>  drivers/net/wireless/ath/ath9k/Kconfig |   1 +
>  drivers/net/wireless/ath/ath9k/ahb.c   |  55 +++++++--
>  drivers/net/wireless/ath/ath9k/init.c  |  41 ++++++-
>  include/linux/devdata.h                |  79 +++++++++++++
>  10 files changed, 459 insertions(+), 8 deletions(-)
>  create mode 100644 drivers/base/devdata.c
>  create mode 100644 drivers/mtd/devdata.c
>  create mode 100644 include/linux/devdata.h
> 


-- 
Best regards,
Marek Vasut