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From: Boris Brezillon <boris.brezillon@bootlin.com>
To: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
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 13:31:36 +0200
Message-ID: <20180821133136.1fada1b6@bbrezillon> (raw)
In-Reply-To: <81407b4d-a02f-4085-f333-a96102bd96ce@linaro.org>

On Tue, 21 Aug 2018 10:38:13 +0100
Srinivas Kandagatla <srinivas.kandagatla@linaro.org> wrote:

> Hi Boris/Bartosz,
> 
> On 21/08/18 06:44, Boris Brezillon wrote:
> >>> 4/ Add a ->of_xlate() hook that would be called if present by the
> >>>     framework instead of using the default parsing we have right now.  
> >> That is a bit cleaner, but I don't think it would be worse the
> >> complexity.  
> > But it's way more flexible than putting everything in the nvmem
> > framework. BTW, did you notice that nvmem-cells parsing does not work
> > with flashes bigger than 4GB, because the framework assumes
> > #address-cells and #size-cells are always 1. That's probably something
> > we'll have to fix for the MTD case.
> >   
> 
> I have hacked up some thing on these lines to add a custom match 
> function for nvmem provider and it looks like it can work for mtd case.
> 
> This addresses concern #1 "to ignore of_node from dev pointer passed to 
> nvmem_config" also provides way to do some sanity checks on nvmem cell node.
> In this patch I have just added a simple mtd_nvmem_match() example which 
> will be always true, however we can add checks here to see if the np is 
> actually a nvmem-cells node or something on those lines to enforce the 
> bindings. Please fix and remove this from nvmem-core patch incase you 
> plan to use/test this.
> 
> We still have one open issue of supporting #address-cells and 
> #size-cells in nvmem, which I can look at if you are happy with this 
> approach!
> 
> ----------------------------------->cut<---------------------------------  
> Author: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
> Date:   Tue Aug 21 10:07:24 2018 +0100
> 
>      nvmem: core: add custom match function support
> 
>      Some nvmem providers might not have a simple DT layout, nvmem cells
>      could be part of the unpartioned space or with-in partition or
>      even in sub partition of the provider.
> 
>      Current matching function is expecting that the provider should be
>      immediate parent of the cell, which might not be true for the above
>      cases. So allow a custom match function for such devices which can
>      validate and match the cell as per the provider specific bindings.
> 
>      Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
> 
> diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
> index a57302eaceb5..33541b18ac30 100644
> --- a/drivers/mtd/mtdcore.c
> +++ b/drivers/mtd/mtdcore.c
> @@ -502,6 +502,19 @@ static int mtd_nvmem_reg_read(void *priv, unsigned 
> int offset,
>          return retlen == bytes ? 0 : -EIO;
>   }
> 
> +static int mtd_nvmem_match(void *priv, struct device *dev,
> +                          struct device_node *np)
> +{
> +       struct mtd_info *mtd = priv;
> +
> +       /*
> +        * Add more checks to make sure device node is inline with
> +        * binding if required
> +        */
> +
> +       return &mtd->dev == dev->parent;
> +}
> +
>   static int mtd_nvmem_add(struct mtd_info *mtd)
>   {
>          struct nvmem_config config = { };
> @@ -516,6 +529,7 @@ static int mtd_nvmem_add(struct mtd_info *mtd)
>          config.read_only = true;
>          config.root_only = true;
>          config.priv = mtd;
> +       config.match = mtd_nvmem_match;
> 
>          mtd->nvmem = devm_nvmem_register(&mtd->dev, &config);
>          if (IS_ERR(mtd->nvmem)) {
> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
> index 3a8bf832243d..32bc4e70522c 100644
> --- a/drivers/nvmem/core.c
> +++ b/drivers/nvmem/core.c
> @@ -41,6 +41,7 @@ struct nvmem_device {
>          struct device           *base_dev;
>          nvmem_reg_read_t        reg_read;
>          nvmem_reg_write_t       reg_write;
> +       nvmem_match_t           match;
>          void *priv;
>   };
> 
> @@ -265,6 +266,11 @@ static struct bus_type nvmem_bus_type = {
> 
>   static int of_nvmem_match(struct device *dev, void *nvmem_np)
>   {
> +       struct nvmem_device *nvmem = to_nvmem_device(dev);
> +
> +       if (nvmem->match)
> +               return nvmem->match(nvmem->priv, dev, nvmem_np);
> +
>          return dev->of_node == nvmem_np;
>   }
> 
> @@ -482,7 +488,9 @@ struct nvmem_device *nvmem_register(const struct 
> nvmem_config *config)
>          nvmem->priv = config->priv;
>          nvmem->reg_read = config->reg_read;
>          nvmem->reg_write = config->reg_write;
> -       nvmem->dev.of_node = config->dev->of_node;
> +
> +       if (!config->match)
> +               nvmem->dev.of_node = config->dev->of_node;
> 
>          if (config->id == -1 && config->name) {
>                  dev_set_name(&nvmem->dev, "%s", config->name);
> diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h
> index 24def6ad09bb..b29059bb406e 100644
> --- a/include/linux/nvmem-provider.h
> +++ b/include/linux/nvmem-provider.h
> @@ -14,6 +14,7 @@
> 
>   #include <linux/err.h>
>   #include <linux/errno.h>
> +#include <linux/of.h>
> 
>   struct nvmem_device;
>   struct nvmem_cell_info;
> @@ -21,6 +22,9 @@ typedef int (*nvmem_reg_read_t)(void *priv, unsigned 
> int offset,
>                                  void *val, size_t bytes);
>   typedef int (*nvmem_reg_write_t)(void *priv, unsigned int offset,
>                                   void *val, size_t bytes);
> +typedef int (*nvmem_match_t)(void *priv, struct device *dev,
> +                            struct device_node *np);
> +
> 
>   /**
>    * struct nvmem_config - NVMEM device configuration
> @@ -58,6 +62,7 @@ struct nvmem_config {
>          bool                    root_only;
>          nvmem_reg_read_t        reg_read;
>          nvmem_reg_write_t       reg_write;
> +       nvmem_match_t           match;
>          int     size;
>          int     word_size;
>          int     stride;
> 

That might work if nvmem cells are defined directly under the mtdnode.
If we go for this approach, I'd recommend replacing this ->match() hook
by ->is_nvmem_cell() and pass it the cell node instead of the nvmem
node, because what we're really after here is knowing which subnode is
an nvmem cell and which subnode is not.

  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
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 [this message]
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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