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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 A654BC43381 for ; Wed, 10 Mar 2021 13:28:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 818226509D for ; Wed, 10 Mar 2021 13:28:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233162AbhCJN2Z (ORCPT ); Wed, 10 Mar 2021 08:28:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:47144 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233016AbhCJNZN (ORCPT ); Wed, 10 Mar 2021 08:25:13 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id D20AD65018; Wed, 10 Mar 2021 13:25:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1615382712; bh=rm6DqlWdxExheEFrTIm7HKdHfRwI34gv2u13oCfVEQc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RkGnqtcjX3OwK03sDeR08+S2H8d3ShGs90n4Y69281qdtDWvWQY5nTv1D4mJ9her2 Z/6Sh14ktZMVjjFyTURn5tpd0pxOZG6Vt7e+dGRKeQlDtCury9cWz6O3zWpwdPb3r0 GNtoW0G/LQtLUiiNshaTEf7B5E6Jk3wycgmJXHgM= From: gregkh@linuxfoundation.org To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Aswath Govindraju , Sasha Levin Subject: [PATCH 5.4 19/24] misc: eeprom_93xx46: Add quirk to support Microchip 93LC46B eeprom Date: Wed, 10 Mar 2021 14:24:31 +0100 Message-Id: <20210310132321.131967802@linuxfoundation.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210310132320.550932445@linuxfoundation.org> References: <20210310132320.550932445@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg Kroah-Hartman From: Aswath Govindraju [ Upstream commit f6f1f8e6e3eea25f539105d48166e91f0ab46dd1 ] A dummy zero bit is sent preceding the data during a read transfer by the Microchip 93LC46B eeprom (section 2.7 of[1]). This results in right shift of data during a read. In order to ignore this bit a quirk can be added to send an extra zero bit after the read address. Add a quirk to ignore the zero bit sent before data by adding a zero bit after the read address. [1] - https://www.mouser.com/datasheet/2/268/20001749K-277859.pdf Signed-off-by: Aswath Govindraju Link: https://lore.kernel.org/r/20210105105817.17644-3-a-govindraju@ti.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/misc/eeprom/eeprom_93xx46.c | 15 +++++++++++++++ include/linux/eeprom_93xx46.h | 2 ++ 2 files changed, 17 insertions(+) diff --git a/drivers/misc/eeprom/eeprom_93xx46.c b/drivers/misc/eeprom/eeprom_93xx46.c index 414dcbd3c3c2..8b355fc0607b 100644 --- a/drivers/misc/eeprom/eeprom_93xx46.c +++ b/drivers/misc/eeprom/eeprom_93xx46.c @@ -35,6 +35,10 @@ static const struct eeprom_93xx46_devtype_data atmel_at93c46d_data = { EEPROM_93XX46_QUIRK_INSTRUCTION_LENGTH, }; +static const struct eeprom_93xx46_devtype_data microchip_93lc46b_data = { + .quirks = EEPROM_93XX46_QUIRK_EXTRA_READ_CYCLE, +}; + struct eeprom_93xx46_dev { struct spi_device *spi; struct eeprom_93xx46_platform_data *pdata; @@ -55,6 +59,11 @@ static inline bool has_quirk_instruction_length(struct eeprom_93xx46_dev *edev) return edev->pdata->quirks & EEPROM_93XX46_QUIRK_INSTRUCTION_LENGTH; } +static inline bool has_quirk_extra_read_cycle(struct eeprom_93xx46_dev *edev) +{ + return edev->pdata->quirks & EEPROM_93XX46_QUIRK_EXTRA_READ_CYCLE; +} + static int eeprom_93xx46_read(void *priv, unsigned int off, void *val, size_t count) { @@ -96,6 +105,11 @@ static int eeprom_93xx46_read(void *priv, unsigned int off, dev_dbg(&edev->spi->dev, "read cmd 0x%x, %d Hz\n", cmd_addr, edev->spi->max_speed_hz); + if (has_quirk_extra_read_cycle(edev)) { + cmd_addr <<= 1; + bits += 1; + } + spi_message_init(&m); t[0].tx_buf = (char *)&cmd_addr; @@ -363,6 +377,7 @@ static void select_deassert(void *context) static const struct of_device_id eeprom_93xx46_of_table[] = { { .compatible = "eeprom-93xx46", }, { .compatible = "atmel,at93c46d", .data = &atmel_at93c46d_data, }, + { .compatible = "microchip,93lc46b", .data = µchip_93lc46b_data, }, {} }; MODULE_DEVICE_TABLE(of, eeprom_93xx46_of_table); diff --git a/include/linux/eeprom_93xx46.h b/include/linux/eeprom_93xx46.h index eec7928ff8fe..99580c22f91a 100644 --- a/include/linux/eeprom_93xx46.h +++ b/include/linux/eeprom_93xx46.h @@ -16,6 +16,8 @@ struct eeprom_93xx46_platform_data { #define EEPROM_93XX46_QUIRK_SINGLE_WORD_READ (1 << 0) /* Instructions such as EWEN are (addrlen + 2) in length. */ #define EEPROM_93XX46_QUIRK_INSTRUCTION_LENGTH (1 << 1) +/* Add extra cycle after address during a read */ +#define EEPROM_93XX46_QUIRK_EXTRA_READ_CYCLE BIT(2) /* * optional hooks to control additional logic -- 2.30.1