From nobody Wed Sep 3 05:52:23 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3FA53C67871 for ; Mon, 24 Oct 2022 19:42:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233408AbiJXTmM (ORCPT ); Mon, 24 Oct 2022 15:42:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36834 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232772AbiJXTlS (ORCPT ); Mon, 24 Oct 2022 15:41:18 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EA83C25ED2E; Mon, 24 Oct 2022 11:11:00 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id C21D8B811E3; Mon, 24 Oct 2022 11:56:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1B85EC433D6; Mon, 24 Oct 2022 11:56:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666612574; bh=oPcGZNPOVZFp9ic2M+WBGGfeOaLqyr96TvPpJbQRVoo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jzqRBVDpilwy1GlvHyKHqfuD5wVVWezGWNItVf3GbMAqiWy/3ii+3NmQgLujWXC0k 29XScArLczgdYaf5/g9aKkSrFmsPSJkxXeznZaBZpZb6dUu6Z/R0Q/O6k+IVXFK7zb PjYj133+9e5fvPri9e2Qz5fe29lSNZJ1I6Dpo95E= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Michael Hennerich , =?UTF-8?q?Nuno=20S=C3=A1?= , Stable@vger.kernel.org, Jonathan Cameron Subject: [PATCH 4.19 038/229] iio: dac: ad5593r: Fix i2c read protocol requirements Date: Mon, 24 Oct 2022 13:29:17 +0200 Message-Id: <20221024113000.334009591@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024112959.085534368@linuxfoundation.org> References: <20221024112959.085534368@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Michael Hennerich commit 558a25f903b4af6361b7fbeea08a6446a0745653 upstream. For reliable operation across the full range of supported interface rates, the AD5593R needs a STOP condition between address write, and data read (like show in the datasheet Figure 40) so in turn i2c_smbus_read_word_swapped cannot be used. While at it, a simple helper was added to make the code simpler. Fixes: 56ca9db862bf ("iio: dac: Add support for the AD5592R/AD5593R ADCs/DA= Cs") Signed-off-by: Michael Hennerich Signed-off-by: Nuno S=C3=A1 Cc: Link: https://lore.kernel.org/r/20220913073413.140475-2-nuno.sa@analog.com Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- drivers/iio/dac/ad5593r.c | 46 +++++++++++++++++++++++++++--------------= ----- 1 file changed, 27 insertions(+), 19 deletions(-) --- a/drivers/iio/dac/ad5593r.c +++ b/drivers/iio/dac/ad5593r.c @@ -15,6 +15,8 @@ #include #include =20 +#include + #define AD5593R_MODE_CONF (0 << 4) #define AD5593R_MODE_DAC_WRITE (1 << 4) #define AD5593R_MODE_ADC_READBACK (4 << 4) @@ -22,6 +24,24 @@ #define AD5593R_MODE_GPIO_READBACK (6 << 4) #define AD5593R_MODE_REG_READBACK (7 << 4) =20 +static int ad5593r_read_word(struct i2c_client *i2c, u8 reg, u16 *value) +{ + int ret; + u8 buf[2]; + + ret =3D i2c_smbus_write_byte(i2c, reg); + if (ret < 0) + return ret; + + ret =3D i2c_master_recv(i2c, buf, sizeof(buf)); + if (ret < 0) + return ret; + + *value =3D get_unaligned_be16(buf); + + return 0; +} + static int ad5593r_write_dac(struct ad5592r_state *st, unsigned chan, u16 = value) { struct i2c_client *i2c =3D to_i2c_client(st->dev); @@ -40,13 +60,7 @@ static int ad5593r_read_adc(struct ad559 if (val < 0) return (int) val; =20 - val =3D i2c_smbus_read_word_swapped(i2c, AD5593R_MODE_ADC_READBACK); - if (val < 0) - return (int) val; - - *value =3D (u16) val; - - return 0; + return ad5593r_read_word(i2c, AD5593R_MODE_ADC_READBACK, value); } =20 static int ad5593r_reg_write(struct ad5592r_state *st, u8 reg, u16 value) @@ -60,25 +74,19 @@ static int ad5593r_reg_write(struct ad55 static int ad5593r_reg_read(struct ad5592r_state *st, u8 reg, u16 *value) { struct i2c_client *i2c =3D to_i2c_client(st->dev); - s32 val; - - val =3D i2c_smbus_read_word_swapped(i2c, AD5593R_MODE_REG_READBACK | reg); - if (val < 0) - return (int) val; =20 - *value =3D (u16) val; - - return 0; + return ad5593r_read_word(i2c, AD5593R_MODE_REG_READBACK | reg, value); } =20 static int ad5593r_gpio_read(struct ad5592r_state *st, u8 *value) { struct i2c_client *i2c =3D to_i2c_client(st->dev); - s32 val; + u16 val; + int ret; =20 - val =3D i2c_smbus_read_word_swapped(i2c, AD5593R_MODE_GPIO_READBACK); - if (val < 0) - return (int) val; + ret =3D ad5593r_read_word(i2c, AD5593R_MODE_GPIO_READBACK, &val); + if (ret) + return ret; =20 *value =3D (u8) val; =20