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,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 2ECDBC433DB for ; Tue, 2 Mar 2021 16:49:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F3FFA64F21 for ; Tue, 2 Mar 2021 16:49:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1579277AbhCBQqr (ORCPT ); Tue, 2 Mar 2021 11:46:47 -0500 Received: from mail.kernel.org ([198.145.29.99]:45606 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1448344AbhCBOUE (ORCPT ); Tue, 2 Mar 2021 09:20:04 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id C9D2C64FCA; Tue, 2 Mar 2021 11:59:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1614686372; bh=VPRE832pU0+LBG5pWKgG1aQ+yt+O0wX0qot67RDjVa4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RalFa7TDSIMnawl/3mKoRCf682EYRYV1ekAnqATjOvQHCy3UKL/D0pcroKzcoKmSy IEM1J+eJGvc3XooWDrgG27+xXooCuM3s/0zk4vvs+QuBI/6lKcbS1B5YRfmz+bgtbP jQXjV289Cmhpq/90Pji75x0zv3uOjv1f5z/zxKJhfeZctqqaspsn7txezTA44yH79k 6PpEM9I1DlCuRIkZqF9HQv48kO0KS+zyBUzIFNmPpr/AqiO4h9ZlxsXjhAcTE1IKf+ 5QA6NcbrIvc5acdAB7COQy5aCbs1NQ3Lq5FvWTxl45sAB8w5yrfff+h1GV7rBclb9f Pczyv5bErj2xg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Aswath Govindraju , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH AUTOSEL 4.9 08/10] misc: eeprom_93xx46: Add quirk to support Microchip 93LC46B eeprom Date: Tue, 2 Mar 2021 06:59:19 -0500 Message-Id: <20210302115921.63636-8-sashal@kernel.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210302115921.63636-1-sashal@kernel.org> References: <20210302115921.63636-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 94cc035aa841..a6409a362eb3 100644 --- a/drivers/misc/eeprom/eeprom_93xx46.c +++ b/drivers/misc/eeprom/eeprom_93xx46.c @@ -38,6 +38,10 @@ 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; @@ -58,6 +62,11 @@ 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) { @@ -99,6 +108,11 @@ 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; @@ -366,6 +380,7 @@ 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 885f587a3555..affe4d1d7d4a 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