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From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
To: Boris Brezillon <boris.brezillon@bootlin.com>
Cc: Alban <albeu@free.fr>, Bartosz Golaszewski <brgl@bgdev.pl>,
	Jonathan Corbet <corbet@lwn.net>, Sekhar Nori <nsekhar@ti.com>,
	Kevin Hilman <khilman@kernel.org>,
	Russell King <linux@armlinux.org.uk>,
	Arnd Bergmann <arnd@arndb.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	David Woodhouse <dwmw2@infradead.org>,
	Brian Norris <computersforpeace@gmail.com>,
	Marek Vasut <marek.vasut@gmail.com>,
	Richard Weinberger <richard@nod.at>,
	Grygorii Strashko <grygorii.strashko@ti.com>,
	"David S . Miller" <davem@davemloft.net>,
	Naren <naren.kernel@gmail.com>,
	Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Lukas Wunner <lukas@wunner.de>,
	Dan Carpenter <dan.carpenter@oracle.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>,
	Sven Van Asbroeck <svendev@arcx.com>,
	Paolo Abeni <pabeni@redhat.com>, Rob Herring <robh@kernel.org>,
	David Lechner <david@lechnology.com>,
	Andrew Lunn <andrew@lunn.ch>,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org,
	linux-mtd@lists.infradead.org, linux-omap@vger.kernel.org,
	netdev@vger.kernel.org,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>
Subject: Re: [PATCH v2 06/29] mtd: Add support for reading MTD devices via the nvmem API
Date: Tue, 21 Aug 2018 11:11:58 +0100
Message-ID: <bd4dd892-3b6c-a77e-b2f3-386600c8c9bd@linaro.org> (raw)
In-Reply-To: <20180821115639.4894c1c9@bbrezillon>



On 21/08/18 10:56, Boris Brezillon wrote:
> On Tue, 21 Aug 2018 10:50:07 +0100
> Srinivas Kandagatla<srinivas.kandagatla@linaro.org>  wrote:
> 
>> On 20/08/18 19:20, Boris Brezillon wrote:
>>> On Mon, 20 Aug 2018 11:43:34 +0100
>>> Srinivas Kandagatla<srinivas.kandagatla@linaro.org>  wrote:
>>>    
>>>> Overall am still not able to clear visualize on how MTD bindings with
>>>> nvmem cells would look in both partition and un-partition usecases?
>>>> An example DT would be nice here!!
>>> Something along those lines:
>>>    
>> This looks good to me.
>>> 	mtdnode {
>>> 		nvmem-cells {
>>> 			#address-cells = <1>;
>>> 			#size-cells = <1>;
>>>
>>> 			cell@0 {
>>> 				reg = <0x0 0x14>;
>>> 			};
>>> 		};
>>>
>>> 		partitions {
>>> 			compatible = "fixed-partitions";
>>> 			#address-cells = <1>;
>>> 			#size-cells = <1>;
>>>
>>> 			partition@0 {
>>> 				reg = <0x0 0x20000>;
>>>
>>> 				nvmem-cells {
>>> 					#address-cells = <1>;
>>> 					#size-cells = <1>;
>>>
>>> 					cell@0 {
>>> 						reg = <0x0 0x10>;
>>> 					};
>>> 				};
>>> 			};
>>> 		};
>>> 	}; >
>> Just curious...Is there a reason why we can't do it like this?:
>> Is this because of issue of #address-cells and #size-cells Or mtd
>> bindings always prefer subnodes?
>>
>> 	mtdnode {
>> 		reg = <0x0123000 0x40000>;
>> 		#address-cells = <1>;
>> 		#size-cells = <1>;
>> 		cell@0 {
>> 			compatible = "nvmem-cell";
>> 			reg = <0x0 0x14>;
>> 		};
>>
>> 		partitions {
>> 			compatible = "fixed-partitions";
>> 			#address-cells = <1>;
>> 			#size-cells = <1>;
>>
>> 			partition@0 {
>> 				reg = <0x0 0x20000>;
>> 				cell@0 {
>> 					compatible = "nvmem-cell";
>> 					reg = <0x0 0x10>;
>> 				};
>> 			};
>> 		};
>> 	};
> It's because partitions were initially directly defined under the mtd
> node, so, if you have an old DT you might have something like:
> 
> 	mtdnode {
> 		reg = <0x0123000 0x40000>;
> 		#address-cells = <1>;
> 		#size-cells = <1>;
> 
> 		partition@0 {
> 			reg = <0x0 0x20000>;
> 			...
> 		};
> 		...
> 	};
> 
> If we use such a DT with this patch applied, the NVMEM framework will
> consider MTD partitions as nvmem cells, which is not what we want.
Yep, I agree.
TBH, I wanted to add compatible string to nvmem-cell at some point in 
time and it seems more natural update too. One of the reason we 
discussed this in the past was parsers. Looks like mtd can make use of this.

We should be able to add this as an optional flag in nvmem_config to 
enforce this check in case providers wanted to.

Do you think that would help mtd nvmem case?
Also I felt like nvmem-cells subnode seems to be a bit heavy!

thanks,
srini

  reply index

Thread overview: 92+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-10  8:04 [PATCH v2 00/29] at24: remove at24_platform_data Bartosz Golaszewski
2018-08-10  8:04 ` [PATCH v2 01/29] nvmem: add support for cell lookups Bartosz Golaszewski
2018-08-24 15:08   ` Boris Brezillon
2018-08-24 15:27     ` Andrew Lunn
2018-08-25  6:27       ` Boris Brezillon
2018-08-27  8:56         ` Bartosz Golaszewski
2018-08-27  9:00           ` Boris Brezillon
2018-08-27 13:37             ` Bartosz Golaszewski
2018-08-27 14:01               ` Boris Brezillon
2018-08-28 10:15               ` Srinivas Kandagatla
2018-08-28 11:56                 ` Bartosz Golaszewski
2018-08-28 13:45                   ` Srinivas Kandagatla
2018-08-28 14:41                     ` Bartosz Golaszewski
2018-08-28 14:48                       ` Srinivas Kandagatla
2018-08-28 14:53                       ` Boris Brezillon
2018-08-28 15:09                         ` Srinivas Kandagatla
2018-08-10  8:04 ` [PATCH v2 02/29] Documentation: nvmem: document lookup entries Bartosz Golaszewski
2018-08-31 20:30   ` Brian Norris
2018-09-01 13:11     ` Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 03/29] nvmem: add a notifier chain Bartosz Golaszewski
2018-08-10  8:33   ` Srinivas Kandagatla
2018-08-10  8:05 ` [PATCH v2 04/29] nvmem: provide nvmem_dev_name() Bartosz Golaszewski
2018-08-10  8:10   ` Srinivas Kandagatla
2018-08-10  8:05 ` [PATCH v2 05/29] nvmem: remove the name field from struct nvmem_device Bartosz Golaszewski
2018-08-10  8:33   ` Srinivas Kandagatla
2018-08-10  8:05 ` [PATCH v2 06/29] mtd: Add support for reading MTD devices via the nvmem API Bartosz Golaszewski
2018-08-17 16:27   ` Boris Brezillon
2018-08-19 11:31     ` Alban
2018-08-19 16:46       ` Boris Brezillon
2018-08-20 10:43         ` Srinivas Kandagatla
2018-08-20 18:20           ` Boris Brezillon
2018-08-20 18:50             ` Bartosz Golaszewski
2018-08-20 19:06               ` Boris Brezillon
2018-08-20 21:27             ` Alban
2018-08-21  5:07               ` Boris Brezillon
2018-08-21  9:50             ` Srinivas Kandagatla
2018-08-21  9:56               ` Boris Brezillon
2018-08-21 10:11                 ` Srinivas Kandagatla [this message]
2018-08-21 10:43                   ` Boris Brezillon
2018-08-21 11:39               ` Alban
2018-08-21 12:00                 ` Srinivas Kandagatla
2018-08-21 13:01                   ` Boris Brezillon
2018-08-23 10:29                     ` Alban
2018-08-24 14:39                       ` Boris Brezillon
2018-08-28 10:20                       ` Srinivas Kandagatla
2018-08-20 22:53         ` Alban
2018-08-21  5:44           ` Boris Brezillon
2018-08-21  9:38             ` Srinivas Kandagatla
2018-08-21 11:31               ` Boris Brezillon
2018-08-21 13:34                 ` Srinivas Kandagatla
2018-08-21 13:37                   ` Srinivas Kandagatla
2018-08-21 13:57                     ` Boris Brezillon
2018-08-21 12:27             ` Alban
2018-08-21 12:57               ` Boris Brezillon
2018-08-21 13:57                 ` Alban
2018-08-21 14:26                   ` Boris Brezillon
2018-08-21 14:33                     ` Srinivas Kandagatla
2018-08-10  8:05 ` [PATCH v2 07/29] ARM: davinci: dm365-evm: use nvmem lookup for mac address Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 08/29] ARM: davinci: dm644-evm: " Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 09/29] ARM: davinci: dm646x-evm: " Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 10/29] ARM: davinci: da830-evm: " Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 11/29] ARM: davinci: mityomapl138: add nvmem cells lookup entries Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 12/29] ARM: davinci: da850-evm: use nvmem lookup for mac address Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 13/29] ARM: davinci: da850-evm: remove unnecessary include Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 14/29] net: simplify eth_platform_get_mac_address() Bartosz Golaszewski
2018-08-10 14:39   ` Andy Shevchenko
2018-08-10 16:17     ` Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 15/29] net: split eth_platform_get_mac_address() into subroutines Bartosz Golaszewski
2018-08-31 19:54   ` Brian Norris
2018-08-10  8:05 ` [PATCH v2 16/29] net: add support for nvmem to eth_platform_get_mac_address() Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 17/29] net: davinci_emac: use eth_platform_get_mac_address() Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 18/29] ARM: davinci: da850-evm: remove dead MTD code Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 19/29] ARM: davinci: mityomapl138: don't read the MAC address from machine code Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 20/29] ARM: davinci: dm365-evm: use device properties for at24 eeprom Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 21/29] ARM: davinci: da830-evm: " Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 22/29] ARM: davinci: dm644x-evm: " Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 23/29] ARM: davinci: dm646x-evm: " Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 24/29] ARM: davinci: sffsdr: fix the at24 eeprom device name Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 25/29] ARM: davinci: sffsdr: use device properties for at24 eeprom Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 26/29] ARM: davinci: remove dead code related to MAC address reading Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 27/29] ARM: davinci: mityomapl138: use nvmem notifiers Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 28/29] ARM: davinci: mityomapl138: use device properties for at24 eeprom Bartosz Golaszewski
2018-08-10  8:05 ` [PATCH v2 29/29] eeprom: at24: kill at24_platform_data Bartosz Golaszewski
2018-08-10  8:41 ` [PATCH v2 00/29] at24: remove at24_platform_data Srinivas Kandagatla
2018-08-31 19:46 ` Brian Norris
2018-10-03 20:15   ` Bartosz Golaszewski
2018-10-03 20:30     ` Lukas Wunner
2018-10-03 21:04     ` Florian Fainelli
2018-10-04 11:06       ` Bartosz Golaszewski
2018-10-04 13:58         ` Arnd Bergmann
2018-10-04 14:35           ` Sowmini Varadhan
2018-10-04 14:38             ` Arnd Bergmann

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