From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bartosz Golaszewski Subject: Re: [PATCH v2 02/29] Documentation: nvmem: document lookup entries Date: Sat, 1 Sep 2018 15:11:05 +0200 Message-ID: References: <20180810080526.27207-1-brgl@bgdev.pl> <20180810080526.27207-3-brgl@bgdev.pl> <20180831203028.GC62862@ban.mtv.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: Jonathan Corbet , Sekhar Nori , Kevin Hilman , Russell King , Arnd Bergmann , Greg Kroah-Hartman , David Woodhouse , Boris Brezillon , Marek Vasut , Richard Weinberger , Grygorii Strashko , "David S . Miller" , Srinivas Kandagatla , Naren , Mauro Carvalho Chehab , Andrew Morton , Lukas Wunner , Dan Carpenter , Florian Fainelli , To: Brian Norris Return-path: Received: from mail-it0-f65.google.com ([209.85.214.65]:36427 "EHLO mail-it0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727399AbeIARXJ (ORCPT ); Sat, 1 Sep 2018 13:23:09 -0400 Received: by mail-it0-f65.google.com with SMTP id u13-v6so10530359iti.1 for ; Sat, 01 Sep 2018 06:11:06 -0700 (PDT) In-Reply-To: <20180831203028.GC62862@ban.mtv.corp.google.com> Sender: netdev-owner@vger.kernel.org List-ID: 2018-08-31 22:30 GMT+02:00 Brian Norris : > On Fri, Aug 10, 2018 at 10:04:59AM +0200, Bartosz Golaszewski wrote: >> From: Bartosz Golaszewski >> >> Describe the usage of nvmem cell lookup tables. >> >> Signed-off-by: Bartosz Golaszewski >> --- >> Documentation/nvmem/nvmem.txt | 28 ++++++++++++++++++++++++++++ >> 1 file changed, 28 insertions(+) >> >> diff --git a/Documentation/nvmem/nvmem.txt b/Documentation/nvmem/nvmem.txt >> index 8d8d8f58f96f..9d5e3ca2b4f3 100644 >> --- a/Documentation/nvmem/nvmem.txt >> +++ b/Documentation/nvmem/nvmem.txt >> @@ -58,6 +58,34 @@ static int qfprom_probe(struct platform_device *pdev) >> It is mandatory that the NVMEM provider has a regmap associated with its >> struct device. Failure to do would return error code from nvmem_register(). >> >> +Additionally it is possible to create nvmem cell lookup entries and register >> +them with the nvmem framework from machine code as shown in the example below: > > Maybe it's partially a lacking in the existing documentation, but what > does the "name" and the "nvmem_name" mean here? AFAICT, "nvmem_name" is > akin to a provider identifier; and "name" is a key to match with the > consumer. It feels like this should be in either the header / kerneldoc > or this file. Or maybe both. > > Does this mean there can only be a single "mac-address" cell in the > system? I have systems where there are multiple MACs provided in flash > storage, and we need to map them to ethernet0 and ethernet1. Is that > supported here? > This is a shortcoming of the nvmem subsystem we discussed under another patch in this series with Boris and Srinivas. I will try to post a series addressing this next week. Basically there's a global list of nvmem cells referenced only by name and unless you're using DT you can only have a single cell with given name. I will address it by introducing the standard dev_id/con_id resource association. Bart > Brian > >> +static struct nvmem_cell_lookup foobar_lookup = { >> + .info = { >> + .name = "mac-address", >> + .offset = 0xd000, >> + .bytes = ERH_ALEN, >> + }, >> + .nvmem_name = "foobar", >> +}; >> + >> +static void foobar_register(void) >> +{ >> + ... >> + nvmem_add_lookup_table(&foobar_lookup, 1); >> + ... >> +} >> + >> +A lookup entry table can be later removed if needed: >> + >> +static void foobar_fini(void) >> +{ >> + ... >> + nvmem_del_lookup_table(&foobar_lookup, 1); >> + ... >> +} >> + >> NVMEM Consumers >> +++++++++++++++ >> >> -- >> 2.18.0 >>