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=-9.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 7D62FC3815B for ; Sat, 18 Apr 2020 01:57:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5AC78221EA for ; Sat, 18 Apr 2020 01:57:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="LJHx5Rqs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725939AbgDRBxq (ORCPT ); Fri, 17 Apr 2020 21:53:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56786 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1725535AbgDRBxp (ORCPT ); Fri, 17 Apr 2020 21:53:45 -0400 Received: from mail-pl1-x644.google.com (mail-pl1-x644.google.com [IPv6:2607:f8b0:4864:20::644]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2921CC061A0C for ; Fri, 17 Apr 2020 18:53:44 -0700 (PDT) Received: by mail-pl1-x644.google.com with SMTP id v2so1622024plp.9 for ; Fri, 17 Apr 2020 18:53:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=A9fgktb4vawbiefZhLEsxPgcZT5WQtSwsxwDz942ap4=; b=LJHx5Rqsfiz/dPYJ4Y0FCxgLNzMYEI3d1YLZs3k9tKMtqukM42mXir4uT9fUKZmax/ 1RqdpkP/TF4mrepto+xDelipkSzV8LzG/cckN/EkwLYdHDHxlDXh+0efZenGYUBxoBIM 1suwRa/ljULzb3MZICmPWLb4+PcVjynNAh5PeYD6Z53drjjD0i6Vg7/Y0Hr08JnX0RkD C93GyL4ii8w/mj3XS9cPlUlr3rzce4yC881EFIKCGwbF40coK/buZWL6RAmQtNOyu/Ym JGJvCN3omc14sPVbDcKcqtJ7uKkSELoO5iMxWO+mQf14G2D/jDxuS8WBBUdQ7GlqQmuH sdKg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=A9fgktb4vawbiefZhLEsxPgcZT5WQtSwsxwDz942ap4=; b=fZT5bXTeTU3PlMC6+mXbO2Koqq8sJS0I5HxXbMI5pvC5oBDBdzQz0uO+229ECxjlmT 7iaYiD+83EDx+9MTGfoDFBjPUcxpJfnTKBbJojcacXwqrr0VGBsp8mg7GhSesavMNNtC d2uSmqJHyTyg+nOff+t6tsQsSWd1z1KRIfLI5C52/Y3T8/RX3ifopwdEq7Fbjbbqj+KD f8cIwotAxgpcYRNkw2mgZ4i1UBSVByHYvPNrT8xpFdcPgqtvF5PZosoVtvj+kLPNw8KM inaab/zknHNn91uW2gUQgqi9NQvDU4a9+Ejwrg7oYvIIQINBdOEEe+AeR7pDy6bAblPI 6/IQ== X-Gm-Message-State: AGi0PuYFD8J51XkFkI15eyg2TYWZjcaCzEk/cxUkoWnZOdGSNL/uYYHt 6uTycA9bbhdyOgzXT6KVBAY= X-Google-Smtp-Source: APiQypKZZ8C04PV2P0Iw3R7pz9vka5Qz/7oTbWn8T8QEEH7UNHfo2g9r/83Z3t2RzFXmn6tB6vSwSA== X-Received: by 2002:a17:90a:dd45:: with SMTP id u5mr7475081pjv.19.1587174823649; Fri, 17 Apr 2020 18:53:43 -0700 (PDT) Received: from localhost.localdomain ([45.135.186.72]) by smtp.gmail.com with ESMTPSA id a22sm15539470pfg.169.2020.04.17.18.53.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 17 Apr 2020 18:53:42 -0700 (PDT) From: Baolin Wang To: lee.jones@linaro.org, arnd@arndb.de Cc: broonie@kernel.org, baolin.wang7@gmail.com, orsonzhai@gmail.com, zhang.lyra@gmail.com, linux-kernel@vger.kernel.org Subject: [PATCH v2] mfd: syscon: Add Spreadtrum physical regmap bus support Date: Sat, 18 Apr 2020 09:53:11 +0800 Message-Id: <328db39335b515b190b518445a777ee97751d393.1587173992.git.baolin.wang7@gmail.com> X-Mailer: git-send-email 2.17.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Some platforms such as Spreadtrum platform, define a special method to update bits of the registers instead of read-modify-write, which means we should use a physical regmap bus to define the reg_update_bits() operation instead of the MMIO regmap bus. Thus we can register a new physical regmap bus into syscon core to support this. Signed-off-by: Baolin Wang --- Changes from v1: - Add WARN_ONCE() for seting bits and clearing bits at the same time. - Remove the Spreadtrum SoC syscon driver, instead moving the regmap_bus instance into syscon.c driver. Changes from RFC v2: - Drop regmap change, which was applied by Mark. - Add more information about how to use set/clear. - Add checking to ensure the platform is compatible with using a new physical regmap bus. Changes from RFC v1: - Add new helper to registers a physical regmap bus instead of using the MMIO bus. --- drivers/mfd/syscon.c | 81 ++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 79 insertions(+), 2 deletions(-) diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c index 3a97816d0cba..f85420d14ce3 100644 --- a/drivers/mfd/syscon.c +++ b/drivers/mfd/syscon.c @@ -40,6 +40,70 @@ static const struct regmap_config syscon_regmap_config = { .reg_stride = 4, }; +#if IS_ENABLED(CONFIG_ARCH_SPRD) +#define SPRD_REG_SET_OFFSET 0x1000 +#define SPRD_REG_CLR_OFFSET 0x2000 + +/* + * The Spreadtrum platform defines a special set/clear method to update + * registers' bits, which means it can write values to the register's SET + * address (offset is 0x1000) to set bits, and write values to the register's + * CLEAR address (offset is 0x2000) to clear bits. + * + * This set/clear method can help to remove the race of accessing the global + * registers between the multiple subsystems instead of using hardware + * spinlocks. + * + * Note: there is a potential risk when users want to set and clear bits + * at the same time, since the set/clear method will always do bits setting + * before bits clearing, which may cause some unexpected results if the + * operation sequence is strict. Thus we recommend that do not set and + * clear bits at the same time if you are not sure about the results. + */ +static int sprd_syscon_update_bits(void *context, unsigned int reg, + unsigned int mask, unsigned int val) +{ + void __iomem *base = context; + unsigned int set, clr; + + set = val & mask; + clr = ~set & mask; + + if (set) + writel(set, base + reg + SPRD_REG_SET_OFFSET); + + if (clr) + writel(clr, base + reg + SPRD_REG_CLR_OFFSET); + + WARN_ONCE(set && clr, "%s: non-atomic update", __func__); + return 0; +} + +static int sprd_syscon_read(void *context, unsigned int reg, unsigned int *val) +{ + void __iomem *base = context; + + *val = readl(base + reg); + return 0; +} + +static int sprd_syscon_write(void *context, unsigned int reg, unsigned int val) +{ + void __iomem *base = context; + + writel(val, base + reg); + return 0; +} + +static struct regmap_bus sprd_syscon_regmap_bus = { + .fast_io = true, + .reg_write = sprd_syscon_write, + .reg_read = sprd_syscon_read, + .reg_update_bits = sprd_syscon_update_bits, + .val_format_endian_default = REGMAP_ENDIAN_LITTLE, +}; +#endif + static struct syscon *of_syscon_register(struct device_node *np, bool check_clk) { struct clk *clk; @@ -50,6 +114,7 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_clk) int ret; struct regmap_config syscon_config = syscon_regmap_config; struct resource res; + bool use_phy_regmap_bus = false; syscon = kzalloc(sizeof(*syscon), GFP_KERNEL); if (!syscon) @@ -106,14 +171,26 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_clk) syscon_config.val_bits = reg_io_width * 8; syscon_config.max_register = resource_size(&res) - reg_io_width; - regmap = regmap_init_mmio(NULL, base, &syscon_config); + /* + * The Spreadtrum syscon need register a real physical regmap bus + * with new atomic bits updating operation instead of using + * read-modify-write. + */ + if (IS_ENABLED(CONFIG_ARCH_SPRD) && + of_device_is_compatible(np, "sprd,atomic-syscon")) { + use_phy_regmap_bus = true; + regmap = regmap_init(NULL, &sprd_syscon_regmap_bus, base, + &syscon_config); + } else { + regmap = regmap_init_mmio(NULL, base, &syscon_config); + } if (IS_ERR(regmap)) { pr_err("regmap init failed\n"); ret = PTR_ERR(regmap); goto err_regmap; } - if (check_clk) { + if (!use_phy_regmap_bus && check_clk) { clk = of_clk_get(np, 0); if (IS_ERR(clk)) { ret = PTR_ERR(clk); -- 2.17.1