From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 195C5C433E3 for ; Sat, 25 Jul 2020 20:30:15 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D99AF206D8 for ; Sat, 25 Jul 2020 20:30:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="H7g1iib3"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="qghJpyNy" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D99AF206D8 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Type:Cc: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: In-Reply-To:MIME-Version:References:Message-ID:Subject:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=pSgtvnlv1eaAPLuFVX5zqVWRzqwZ3cWDMqkRpXDLPCE=; b=H7g1iib36Acip2zQAH3ZSQD7a tbDykPvrSWULim9T2wsHBT+FfJ7Wao1vMWi2Y4Ql1nnvuHMtDQiwN+ooNlbkP1YBVjv42GQt58gYN ukoH/lUjX2qU3Az9YaTBufQ8LijEXCWPQbXcus7hT1fv5I2jP0NCAZSnGGUCMB2iBo7PSndNmz0kH xachVoXHeHjA3Bm+laJNPOjs+AWcfPaFCQrCd0Bf1Q1+WsarIsJ6yUrlB5EOei8EQNtPePqA4BfUK AHZ3yH6a/7wWdKt2ob7p/O5D8w7sybihaD5ousExU6jbe80H/NswY6v3n212h7iE2rQ7bmdPrxH3X jPNPVv57g==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jzQlj-0000SG-Lw; Sat, 25 Jul 2020 20:27:43 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jzQlg-0000Rm-TX for linux-arm-kernel@lists.infradead.org; Sat, 25 Jul 2020 20:27:42 +0000 Received: from localhost (p5486c508.dip0.t-ipconnect.de [84.134.197.8]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 80740206D8; Sat, 25 Jul 2020 20:27:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595708859; bh=Rlk0OrPrYUGz4CtQc/3pWURmeCJwxiy6dgHl1X4U7A0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qghJpyNyf723L7jxgRpHb4Z7Z4mCBp18vPfyWGerTV/Wqtymasm3/by/8F/vtbQLK Hk6o8JEVhSpJ6Rf8C9cpKH/SSW0hvdQ9L5dAOdOo3Y49Oi3EfUyEGPPMPhwGG/0vAz Nm+znu0kiw0BZ3nN30Ed9IHoBktLVnMy3Uje+q24= Date: Sat, 25 Jul 2020 22:27:33 +0200 From: Wolfram Sang To: Alain Volmat Subject: Re: [PATCH v2 1/2] i2c: smbus: add core function handling SMBus host-notify Message-ID: <20200725202733.GA946@kunai> References: <1593776168-17867-1-git-send-email-alain.volmat@st.com> <1593776168-17867-2-git-send-email-alain.volmat@st.com> MIME-Version: 1.0 In-Reply-To: <1593776168-17867-2-git-send-email-alain.volmat@st.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200725_162741_209241_AD703783 X-CRM114-Status: GOOD ( 32.50 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: alexandre.torgue@st.com, linux-kernel@vger.kernel.org, pierre-yves.mordret@st.com, linux-i2c@vger.kernel.org, fabrice.gasnier@st.com, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org Content-Type: multipart/mixed; boundary="===============6881851560516646637==" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org --===============6881851560516646637== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="gBBFr7Ir9EOA20Yy" Content-Disposition: inline --gBBFr7Ir9EOA20Yy Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Alain, some more comments for this one. I hope to come to a conclusion with Rob regarding the binding for patch 2, so we are then ready to go. On Fri, Jul 03, 2020 at 01:36:07PM +0200, Alain Volmat wrote: > SMBus Host-Notify protocol, from the adapter point of view > consist of receiving a message from a client, including the > client address and some other data. >=20 > It can be simply handled by creating a new slave device > and registering a callback performing the parsing of the > message received from the client. >=20 > This commit introduces two new core functions > * i2c_new_slave_host_notify_device > * i2c_free_slave_host_notify_device > that take care of registration of the new slave device and > callback and will call i2c_handle_smbus_host_notify once a > Host-Notify event is received. >=20 > Signed-off-by: Alain Volmat > --- > v2: identical to v1 >=20 > drivers/i2c/i2c-core-smbus.c | 114 +++++++++++++++++++++++++++++++++++++= ++++++ I came to the conclusion that this code should be in i2c-smbus.c. Because it is SMBus only. I agree that the current code layout is confusing. I will try to move the whole host-notify support to i2c-smbus in the next cycle. Yes, that means that one needs to select I2C_SMBUS in the config, too (unless you want to 'select' it with your driver). But most people won't need it so they can compile it away. This is what I2C_SMBUS is for. > include/linux/i2c-smbus.h | 12 +++++ > 2 files changed, 126 insertions(+) >=20 > diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c > index f5c9787992e9..23ab9dc5ac85 100644 > --- a/drivers/i2c/i2c-core-smbus.c > +++ b/drivers/i2c/i2c-core-smbus.c > @@ -715,3 +715,117 @@ int of_i2c_setup_smbus_alert(struct i2c_adapter *ad= apter) > } > EXPORT_SYMBOL_GPL(of_i2c_setup_smbus_alert); > #endif > + > +#if IS_ENABLED(CONFIG_I2C_SLAVE) > +#define SMBUS_HOST_NOTIFY_LEN 3 > +struct i2c_slave_host_notify_status { > + u8 index; > + u8 addr; > +}; > + > +static int i2c_slave_host_notify_cb(struct i2c_client *client, > + enum i2c_slave_event event, u8 *val) > +{ > + struct i2c_slave_host_notify_status *status =3D client->dev.platform_da= ta; > + int ret; > + Can't we simplify 'index' handling similar to the testunit driver... > + switch (event) { > + case I2C_SLAVE_WRITE_REQUESTED: > + status->index =3D 0; =2E.. by removing this line... > + break; > + case I2C_SLAVE_WRITE_RECEIVED: > + /* We only retrieve the first byte received (addr) > + * since there is currently no support to retrieve the data > + * parameter from the client. > + */ > + if (status->index =3D=3D 0) > + status->addr =3D *val; > + if (status->index < U8_MAX) > + status->index++; > + break; > + case I2C_SLAVE_STOP: > + /* Handle host-notify if whole message received only */ > + if (status->index !=3D SMBUS_HOST_NOTIFY_LEN) { > + status->index =3D U8_MAX; > + break; > + } > + > + ret =3D i2c_handle_smbus_host_notify(client->adapter, > + status->addr); > + if (ret < 0) > + return ret; > + status->index =3D U8_MAX; =2E.. and handling the logic here like: + if (status->index =3D=3D SMBUS_HOST_NOTIFY_LEN) + i2c_handle_smbus_host_notify(client->adapter, status->addr); + status->index =3D 0; Note that I2C_SLAVE_STOP doesn't return a retval, so we don't need to check i2c_handle_smbus_host_notify(). > + break; > + case I2C_SLAVE_READ_REQUESTED: > + case I2C_SLAVE_READ_PROCESSED: > + *val =3D 0xff; > + break; > + } > + > + return 0; > +} > + > +/** > + * i2c_new_slave_host_notify_device - get a client for SMBus host-notify= support > + * @adapter: the target adapter > + * Context: can sleep > + * > + * Setup handling of the SMBus host-notify protocol on a given I2C bus s= egment. > + * > + * Handling is done by creating a device and its callback and handling d= ata > + * received via the SMBus host-notify address (0x8) > + * > + * This returns the client, which should be ultimately freed using > + * i2c_free_slave_host_notify_device(); or an ERRPTR to indicate an erro= r. > + */ > +struct i2c_client *i2c_new_slave_host_notify_device(struct i2c_adapter *= adapter) > +{ > + struct i2c_board_info host_notify_board_info =3D { > + I2C_BOARD_INFO("smbus_host_notify", 0x08), > + .flags =3D I2C_CLIENT_SLAVE, > + }; > + struct i2c_slave_host_notify_status *status; > + struct i2c_client *client; > + int ret; > + > + status =3D kzalloc(sizeof(struct i2c_slave_host_notify_status), > + GFP_KERNEL); > + if (!status) > + return ERR_PTR(-ENOMEM); > + status->index =3D U8_MAX; This line could go, too, if my simplification above works. > + > + host_notify_board_info.platform_data =3D status; > + > + client =3D i2c_new_client_device(adapter, &host_notify_board_info); > + if (IS_ERR(client)) { > + kfree(status); > + return client; > + } > + > + ret =3D i2c_slave_register(client, i2c_slave_host_notify_cb); > + if (ret) { > + i2c_unregister_device(client); > + kfree(status); > + return ERR_PTR(ret); > + } > + > + return client; > +} > +EXPORT_SYMBOL_GPL(i2c_new_slave_host_notify_device); > + > +/** > + * i2c_free_slave_host_notify_device - free the client for SMBus host-no= tify > + * support > + * @client: the client to free > + * Context: can sleep > + * > + * Free the i2c_client allocated via i2c_new_slave_host_notify_device > + */ > +void i2c_free_slave_host_notify_device(struct i2c_client *client) > +{ > + i2c_slave_unregister(client); > + kfree(client->dev.platform_data); > + i2c_unregister_device(client); > +} > +EXPORT_SYMBOL_GPL(i2c_free_slave_host_notify_device); Sidenote: With my recent series "i2c: slave: improve sanity checks when un-/registering" this code became NULL-safe (and IS_ERR safe, too). > +#endif > diff --git a/include/linux/i2c-smbus.h b/include/linux/i2c-smbus.h > index 1e4e0de4ef8b..52e62f398f1c 100644 > --- a/include/linux/i2c-smbus.h > +++ b/include/linux/i2c-smbus.h > @@ -38,6 +38,18 @@ static inline int of_i2c_setup_smbus_alert(struct i2c_= adapter *adap) > return 0; > } > #endif > +#if IS_ENABLED(CONFIG_I2C_SLAVE) > +struct i2c_client *i2c_new_slave_host_notify_device(struct i2c_adapter *= adapter); > +void i2c_free_slave_host_notify_device(struct i2c_client *client); > +#else > +static inline struct i2c_client *i2c_new_slave_host_notify_device(struct= i2c_adapter *adapter) > +{ > + return NULL; return ERR_PTR(-ENOSYS); As the docs say, this function either returns a valid client or an ERR_PTR. > +} > +static inline void i2c_free_slave_host_notify_device(struct i2c_client *= client) > +{ > +} > +#endif > =20 > #if IS_ENABLED(CONFIG_I2C_SMBUS) && IS_ENABLED(CONFIG_DMI) > void i2c_register_spd(struct i2c_adapter *adap); 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