From: Peter Rosin <peda@axentia.se>
To: Luca Ceresoli <lucaceresoli77@gmail.com>,
"linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Luca Ceresoli <luca@lucaceresoli.net>,
Wolfram Sang <wsa@the-dreams.de>
Subject: Re: [PATCH v3] i2c: mux: remove duplicated i2c_algorithm
Date: Mon, 8 Oct 2018 21:43:55 +0000 [thread overview]
Message-ID: <99cfa6a2-9a60-6bdd-2542-9dd78af75758@axentia.se> (raw)
In-Reply-To: <20181003151928.17713-1-lucaceresoli77@gmail.com>
On 2018-10-03 17:19, Luca Ceresoli wrote:
> From: Luca Ceresoli <luca@lucaceresoli.net>
>
> i2c-mux instantiates one i2c_algorithm for each downstream adapter.
> However these algorithms are all identical, depending only on the
> parent adapter.
>
> Avoid duplication by hoisting the i2c_algorithm from the adapters to
> the i2c_mux_core object, and reuse it in all the adapters.
Ouch, while I like the concept of having one i2c_algorithm per mux,
this patch is not working. Various i2c-mux drivers set the
muxc->mux_locked variable *after* the i2c_mux_alloc call, and this
patch breaks such use.
So, the patch needs some reworking. Sorry for not noticing this
earlier.
Cheers,
Peter
> Cc: Peter Rosin <peda@axentia.se>
> Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
>
> ---
>
> Changes v2 -> v3:
> - fix coding style of comment when moving it (Peter Rosin)
> - move the 'algo' member between parent and dev (Peter Rosin)
>
> Changes v1 -> v2:
> - include i2c.h (fixes build failure on i2c-mux-ltc4306)
> ---
> drivers/i2c/i2c-mux.c | 38 +++++++++++++++++++-------------------
> include/linux/i2c-mux.h | 2 ++
> 2 files changed, 21 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
> index f330690b4125..6ac23004fb2a 100644
> --- a/drivers/i2c/i2c-mux.c
> +++ b/drivers/i2c/i2c-mux.c
> @@ -30,7 +30,6 @@
> /* multiplexer per channel data */
> struct i2c_mux_priv {
> struct i2c_adapter adap;
> - struct i2c_algorithm algo;
> struct i2c_mux_core *muxc;
> u32 chan_id;
> };
> @@ -263,6 +262,24 @@ struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent,
> muxc->deselect = deselect;
> muxc->max_adapters = max_adapters;
>
> + /*
> + * Need to do algo dynamically because we don't know ahead of
> + * time what sort of physical adapter we'll be dealing with.
> + */
> + if (parent->algo->master_xfer) {
> + if (muxc->mux_locked)
> + muxc->algo.master_xfer = i2c_mux_master_xfer;
> + else
> + muxc->algo.master_xfer = __i2c_mux_master_xfer;
> + }
> + if (parent->algo->smbus_xfer) {
> + if (muxc->mux_locked)
> + muxc->algo.smbus_xfer = i2c_mux_smbus_xfer;
> + else
> + muxc->algo.smbus_xfer = __i2c_mux_smbus_xfer;
> + }
> + muxc->algo.functionality = i2c_mux_functionality;
> +
> return muxc;
> }
> EXPORT_SYMBOL_GPL(i2c_mux_alloc);
> @@ -301,28 +318,11 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
> priv->muxc = muxc;
> priv->chan_id = chan_id;
>
> - /* Need to do algo dynamically because we don't know ahead
> - * of time what sort of physical adapter we'll be dealing with.
> - */
> - if (parent->algo->master_xfer) {
> - if (muxc->mux_locked)
> - priv->algo.master_xfer = i2c_mux_master_xfer;
> - else
> - priv->algo.master_xfer = __i2c_mux_master_xfer;
> - }
> - if (parent->algo->smbus_xfer) {
> - if (muxc->mux_locked)
> - priv->algo.smbus_xfer = i2c_mux_smbus_xfer;
> - else
> - priv->algo.smbus_xfer = __i2c_mux_smbus_xfer;
> - }
> - priv->algo.functionality = i2c_mux_functionality;
> -
> /* Now fill out new adapter structure */
> snprintf(priv->adap.name, sizeof(priv->adap.name),
> "i2c-%d-mux (chan_id %d)", i2c_adapter_id(parent), chan_id);
> priv->adap.owner = THIS_MODULE;
> - priv->adap.algo = &priv->algo;
> + priv->adap.algo = &muxc->algo;
> priv->adap.algo_data = priv;
> priv->adap.dev.parent = &parent->dev;
> priv->adap.retries = parent->retries;
> diff --git a/include/linux/i2c-mux.h b/include/linux/i2c-mux.h
> index bd74d5706f3b..3d89600d5a9e 100644
> --- a/include/linux/i2c-mux.h
> +++ b/include/linux/i2c-mux.h
> @@ -28,9 +28,11 @@
> #ifdef __KERNEL__
>
> #include <linux/bitops.h>
> +#include <linux/i2c.h>
>
> struct i2c_mux_core {
> struct i2c_adapter *parent;
> + struct i2c_algorithm algo;
> struct device *dev;
> unsigned int mux_locked:1;
> unsigned int arbitrator:1;
>
next prev parent reply other threads:[~2018-10-08 21:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-03 15:19 [PATCH v3] i2c: mux: remove duplicated i2c_algorithm Luca Ceresoli
2018-10-08 21:43 ` Peter Rosin [this message]
2018-10-10 15:48 ` Luca Ceresoli
2018-11-18 11:13 ` Luca Ceresoli
2018-11-27 18:51 ` Peter Rosin
2018-12-09 21:46 ` Luca Ceresoli
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=99cfa6a2-9a60-6bdd-2542-9dd78af75758@axentia.se \
--to=peda@axentia.se \
--cc=linux-i2c@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=luca@lucaceresoli.net \
--cc=lucaceresoli77@gmail.com \
--cc=wsa@the-dreams.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).