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From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
	<devicetree@vger.kernel.org>,
	"Kieran Bingham" <kieran@ksquared.org.uk>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	"Jacopo Mondi" <jacopo@jmondi.org>,
	"Vladimir Zapolskiy" <vz@mleia.com>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
	"Luca Ceresoli" <luca@lucaceresoli.net>,
	"Linux I2C" <linux-i2c@vger.kernel.org>,
	"Niklas Söderlund" <niklas.soderlund@ragnatech.se>,
	linux-i3c@lists.infradead.org,
	"Laurent Pinchart" <laurent.pinchart@ideasonboard.com>
Subject: Re: [RFC PATCH 7/7] i2c: core: hand over reserved devices when requesting ancillary addresses
Date: Fri, 21 Feb 2020 11:13:48 +0100
Message-ID: <CAMuHMdV-dfjukuSKiFg4vb4Ntn+XWU0XwHPxyoaWs1vtQVg4cw@mail.gmail.com> (raw)
In-Reply-To: <20200220172403.26062-8-wsa+renesas@sang-engineering.com>

Hi Wolfram,

On Thu, Feb 20, 2020 at 6:26 PM Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
> With i2c_new_ancillary_address, we can check if the intended driver is
> requesting a reserved address. Update the function to do these checks.
> If the check passes, the "reserved" device will become a regular "dummy"
> device.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Thanks for your patch!

> --- a/drivers/i2c/i2c-core-base.c
> +++ b/drivers/i2c/i2c-core-base.c
> @@ -975,6 +975,8 @@ struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
>                                                 u16 default_addr)
>  {
>         struct device_node *np = client->dev.of_node;
> +       struct device *reserved_dev, *adapter_dev = &client->adapter->dev;
> +       struct i2c_client *reserved_client;
>         u32 addr = default_addr;
>         int i;
>
> @@ -984,7 +986,21 @@ struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
>                         of_property_read_u32_index(np, "reg", i, &addr);
>         }
>
> -       dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
> +       dev_info(adapter_dev, "Address for %s : 0x%x\n", name, addr);
> +
> +       /* No need to scan muxes, siblings must sit on the same adapter */
> +       reserved_dev = device_find_child(adapter_dev, &addr, __i2c_check_addr_busy);
> +       reserved_client = i2c_verify_client(reserved_dev);
> +
> +       if (reserved_client) {
> +               if (reserved_client->dev.of_node != np ||
> +                   strcmp(reserved_client->name, I2C_RESERVED_DRV_NAME) != 0)
> +                       return ERR_PTR(-EBUSY);

Missing put_device(reserved_dev).

> +
> +               strlcpy(reserved_client->name, I2C_DUMMY_DRV_NAME, sizeof(client->name));
> +               return reserved_client;
> +       }

else put_device(reserved_dev)

(perhaps i2c_verify_client() checking dev was not such a great idea, as
 callers need to act on dev && !verified anyway?)

> +
>         return i2c_new_dummy_device(client->adapter, addr);
>  }
>  EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

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Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-20 17:23 [RFC PATCH 0/7] i2c: of: reserve unknown and " Wolfram Sang
2020-02-20 17:23 ` [RFC PATCH 1/7] i2c: add sanity check for parameter of i2c_verify_client() Wolfram Sang
2020-02-21  9:36   ` Geert Uytterhoeven
2020-02-20 17:23 ` [RFC PATCH 2/7] i2c: use DEFINE for the dummy driver name Wolfram Sang
2020-02-21  9:38   ` Geert Uytterhoeven
2020-02-20 17:23 ` [RFC PATCH 3/7] i2c: allow DT nodes without 'compatible' Wolfram Sang
2020-02-21  9:45   ` Geert Uytterhoeven
2020-02-21  9:48     ` Geert Uytterhoeven
2020-02-23 23:11     ` Luca Ceresoli
2020-03-12 11:19       ` Wolfram Sang
2020-03-12 11:44         ` Alexandre Belloni
2020-04-10 13:47         ` Luca Ceresoli
2020-02-26 16:30   ` Rob Herring
2020-02-20 17:24 ` [RFC PATCH 4/7] i2c: of: remove superfluous parameter from exported function Wolfram Sang
2020-02-21  9:50   ` Geert Uytterhoeven
2020-02-24  8:12   ` Luca Ceresoli
2020-02-20 17:24 ` [RFC PATCH 5/7] i2c: of: error message unification Wolfram Sang
2020-02-21  9:54   ` Geert Uytterhoeven
2020-02-20 17:24 ` [RFC PATCH 6/7] i2c: of: mark a whole array of regs as reserved Wolfram Sang
2020-02-21 10:09   ` Geert Uytterhoeven
2020-03-12 11:21     ` Wolfram Sang
2020-03-18 14:33     ` Wolfram Sang
2020-02-28 12:11   ` Luca Ceresoli
2020-02-20 17:24 ` [RFC PATCH 7/7] i2c: core: hand over reserved devices when requesting ancillary addresses Wolfram Sang
2020-02-21 10:13   ` Geert Uytterhoeven [this message]
2020-02-28 12:11     ` Luca Ceresoli
2020-03-12 11:30       ` Wolfram Sang
2020-03-12 11:21     ` Wolfram Sang
2020-03-13 12:42     ` Wolfram Sang
2020-02-21 10:15 ` [RFC PATCH 0/7] i2c: of: reserve unknown and " Geert Uytterhoeven

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