From patchwork Sat Jun 12 21:12:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sander Vanheule X-Patchwork-Id: 459235 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=-18.8 required=3.0 tests=BAYES_00,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=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 CA563C49EA2 for ; Sat, 12 Jun 2021 21:13:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A8B9861029 for ; Sat, 12 Jun 2021 21:13:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231597AbhFLVPk (ORCPT ); Sat, 12 Jun 2021 17:15:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59194 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231562AbhFLVPi (ORCPT ); Sat, 12 Jun 2021 17:15:38 -0400 Received: from polaris.svanheule.net (polaris.svanheule.net [IPv6:2a00:c98:2060:a004:1::200]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 01DE5C061766 for ; Sat, 12 Jun 2021 14:13:38 -0700 (PDT) Received: from terra.local.svanheule.net (unknown [IPv6:2a02:a03f:eafb:ee01:a4dd:c59:8cbd:ee0d]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: sander@svanheule.net) by polaris.svanheule.net (Postfix) with ESMTPSA id 4A2EE20C9CE; Sat, 12 Jun 2021 23:13:35 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=svanheule.net; s=mail1707; t=1623532415; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=317W/muonwzc8HyyIWPeaiAscRYe6DIw3INbtrhWtnM=; b=RuCEaKtiUTzxYp/z23JXa71RRL9w5iN+5OQaQKxpJAXMoOgumORYPsBRakUWfcZiWSaAlY s7kxGe0yVVIvzgB13qclbFAPPeMnMucXX5H9bPVrxUNLF2oe28nt3lS6Wsm5FM4REYhNye eMHDRzgOKW54n6/YmKyKNhtWnX4v7pY81GtZBzFeChxxpZyfLMA1gnI5TBrmPeUrRj5n1u fWmpLfPornw8GBY91LkkziaFgwLQRadl18URvbew+T5ojUMK4Y5Fe/Phw+KIhSPazgE81n pKVJ55PKXBM3W9oRoH86Mj4+luMW3Fp09S5HrW4itOwTQweVsWq48xWuG1THwQ== From: Sander Vanheule To: Pavel Machek , Rob Herring , Lee Jones , Mark Brown , Greg Kroah-Hartman , "Rafael J . Wysocki" , Michael Walle , Linus Walleij , Bartosz Golaszewski , linux-leds@vger.kernel.org, devicetree@vger.kernel.org, linux-gpio@vger.kernel.org Cc: Andrew Lunn , Andy Shevchenko , linux-kernel@vger.kernel.org, Sander Vanheule Subject: [PATCH v5 2/8] gpio: regmap: Add quirk for aliased data registers Date: Sat, 12 Jun 2021 23:12:32 +0200 Message-Id: <5d8e5e8a29ecf39da48beb94c42003a5c686ec4e.1623532208.git.sander@svanheule.net> X-Mailer: git-send-email 2.31.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Some chips have the read-only input and write-only output data registers aliased to the same offset. As a result it is not possible to perform read-modify-writes on the output values, when a line is still configured as input. Add a quirk for aliased data registers, and document how the regmap should be set up for correct operation. Signed-off-by: Sander Vanheule --- drivers/gpio/gpio-regmap.c | 7 ++++++- include/linux/gpio/regmap.h | 13 +++++++++++++ 2 files changed, 19 insertions(+), 1 deletion(-) diff --git a/drivers/gpio/gpio-regmap.c b/drivers/gpio/gpio-regmap.c index 134cedf151a7..3a3d0d9a945c 100644 --- a/drivers/gpio/gpio-regmap.c +++ b/drivers/gpio/gpio-regmap.c @@ -15,6 +15,7 @@ struct gpio_regmap { struct device *parent; struct regmap *regmap; struct gpio_chip gpio_chip; + unsigned int quirks; int reg_stride; int ngpio_per_reg; @@ -68,7 +69,10 @@ static int gpio_regmap_get(struct gpio_chip *chip, unsigned int offset) if (ret) return ret; - ret = regmap_read(gpio->regmap, reg, &val); + if (gpio->quirks & GPIO_REGMAP_QUIRK_ALIASED_DATA) + ret = regmap_read_bypassed(gpio->regmap, reg, &val); + else + ret = regmap_read(gpio->regmap, reg, &val); if (ret) return ret; @@ -227,6 +231,7 @@ struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config gpio->parent = config->parent; gpio->regmap = config->regmap; + gpio->quirks = config->quirks; gpio->ngpio_per_reg = config->ngpio_per_reg; gpio->reg_stride = config->reg_stride; gpio->reg_mask_xlate = config->reg_mask_xlate; diff --git a/include/linux/gpio/regmap.h b/include/linux/gpio/regmap.h index 334dd928042b..b0751a10fa4a 100644 --- a/include/linux/gpio/regmap.h +++ b/include/linux/gpio/regmap.h @@ -12,6 +12,17 @@ struct regmap; #define GPIO_REGMAP_ADDR_ZERO ((unsigned int)(-1)) #define GPIO_REGMAP_ADDR(addr) ((addr) ? : GPIO_REGMAP_ADDR_ZERO) +enum gpio_regmap_quirk { + /* + * For hardware where the (read-only) input and (write-only) output + * registers are aliased to the same offset. In this case the register + * must not be marked as volatile and a regcache must be used, to cache + * the write-only output values. Register reads for the input values + * will be performed by bypassing the cache. + */ + GPIO_REGMAP_QUIRK_ALIASED_DATA = BIT(0), +}; + /** * struct gpio_regmap_config - Description of a generic regmap gpio_chip. * @parent: The parent device @@ -31,6 +42,7 @@ struct regmap; * @reg_stride: (Optional) May be set if the registers (of the * same type, dat, set, etc) are not consecutive. * @ngpio_per_reg: Number of GPIOs per register + * @quirks: Flags indicating GPIO chip hardware issues * @irq_domain: (Optional) IRQ domain if the controller is * interrupt-capable * @reg_mask_xlate: (Optional) Translates base address and GPIO @@ -73,6 +85,7 @@ struct gpio_regmap_config { unsigned int reg_dir_out_base; int reg_stride; int ngpio_per_reg; + unsigned int quirks; struct irq_domain *irq_domain; int (*reg_mask_xlate)(struct gpio_regmap *gpio, unsigned int base,