Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Colin Foster <colin.foster@in-advantage.com>
To:     linux-arm-kernel@lists.infradead.org, linux-gpio@vger.kernel.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org
Cc:     Terry Bowman <terry.bowman@amd.com>,
        Vladimir Oltean <vladimir.oltean@nxp.com>,
        Wolfram Sang <wsa@kernel.org>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        UNGLinuxDriver@microchip.com,
        Steen Hegelund <Steen.Hegelund@microchip.com>,
        Lars Povlsen <lars.povlsen@microchip.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        "David S. Miller" <davem@davemloft.net>,
        Russell King <linux@armlinux.org.uk>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Andrew Lunn <andrew@lunn.ch>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Lee Jones <lee.jones@linaro.org>,
        katie.morris@in-advantage.com,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Dan Williams <dan.j.williams@intel.com>
Subject: [PATCH v16 mfd 1/8] mfd: ocelot: add helper to get regmap from a resource
Date:   Sun, 14 Aug 2022 17:55:46 -0700
Message-Id: <20220815005553.1450359-2-colin.foster@in-advantage.com>
In-Reply-To: <20220815005553.1450359-1-colin.foster@in-advantage.com>
References: <20220815005553.1450359-1-colin.foster@in-advantage.com>
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?DHsFHiBQtHsLDsu0ftWeG3pzq9O1vPGTNC6jbHMBdXCEOrR+9bxldUhVGnI6?=
 =?us-ascii?Q?dH3Cuoj0yOK41jk2mVwvYk3yrzvvxCY29I5es9g/AHt5f5cBvU+mpCZUhL1n?=
 =?us-ascii?Q?q3Ql/k6GCPLPpo39GYzg/3aMYFtDkCI83jMIlHWLWpZyRJMwVrV06JFm+TOL?=
 =?us-ascii?Q?s8ws5j4Jxr8aIPm8+QsjeRHgQ8qrjEP9Aaw+51o/ryD7R5LkQupU7/QAGql2?=
 =?us-ascii?Q?0486biWkp7B/vcrIH+csUGAUBCErmt0p94M7GJ9KgvMXsHoriKuybM6JRsQg?=
 =?us-ascii?Q?dDuH8fnwCtalBdb8eUgWqTSjE31ciOUBvdXwzEdF8XSuB46uMHJhZL8TX71j?=
 =?us-ascii?Q?TO5Nfqa/k/EXWjxwL1L2drVp2lQ/X0MpbEZct2YSKVf+y9jOIPn59VKyjY4P?=
 =?us-ascii?Q?cDqbVDzTCQOqTqc2eGiWrnFGHNDVUUWrR8Ntl9AiSpyEBDwb4X4xWyEkwjkz?=
 =?us-ascii?Q?m2m4KLkQRpjyUq8pFnmf/d5BWYlzxssMgTVjwyzy9uJXJqNTlwqumQdZKu8c?=
 =?us-ascii?Q?1CFSNJ/PMiF1kmBMIKcq06UHzOZ9PmpS3loxmqpClhH2MRhiDiuIIvvngPl9?=
 =?us-ascii?Q?NSdGM2x5KiRz7Dt4vzj7B2REGoHKvZQN+pv0jSHFiy+t5HCGXCWHF6l/xyxe?=
 =?us-ascii?Q?mxi1aacoZ9FUnEI6i2t3jN+cgOc9EK4YCI8h17thPFeRcC+jq0qhzG3yQjKI?=
 =?us-ascii?Q?Mh0NztkyzEWJ363tsXapy9c88b2/cIzQAF1gtb8YHw74pgNyiVPAqaL6t8NS?=
 =?us-ascii?Q?Y1Awo9AHELeXVsre7uR3dXvidCUq+y8bxUrZGKYwS+A7EZAQnnFv7hiCCHZp?=
 =?us-ascii?Q?ftAUoQvXJAJL3FoGotTlkPaxRxXzkX5xzTg5hG3AcuyZk8UT7jbMwhY2SHGH?=
 =?us-ascii?Q?R4UpeOXM73ZZbhdtYh6LdubrkFrCKOiyQtMXmZ1dO9s1jCXDg9M7gTH0t39J?=
 =?us-ascii?Q?mJURhoC9r46JQrfCF39AXat+gPAn3+ivZCYxTzmtkTLU4Oott578nmJnPH/I?=
 =?us-ascii?Q?tnM0Q/fApQ/Calrsn1PTtBIPQa7TezBboZUjLv/U11R7tyf4F3dS7u38roEv?=
 =?us-ascii?Q?omhAncFpaLT16oQgF6fvgT7v0mdOdGF1pOr7zSsSsq8t+Vh5dWcbsNlRcQzw?=
 =?us-ascii?Q?g5nbu1UVS2y6OVvXu3WZuaYESaTk8O1rJG3ITmWxAeKxRJlfshsZvhR9RAn8?=
 =?us-ascii?Q?wxX1TMYCShaKP886B4JLBoFgc2EUZD1gvMQ/suOaKUlTf7F9KKlVQQ4qn4Yt?=
 =?us-ascii?Q?HjDmzVDbkttVMseIYkE309n8PoJUzSr8a/L5M5H4nqtevD5g/iDtIT9Y6ThN?=
 =?us-ascii?Q?gliBc8fqL9ci8SG3MrnvqjCP7RRNtkawgT1JcY3F8zI3dbOf/vA3t/6K9ABo?=
 =?us-ascii?Q?FBkVjsbuxT5tFppGTvPAxrZ7pRweR9vh3RgzAC6/jLMZpK9FRcuF7yCFU/Vj?=
 =?us-ascii?Q?Tx70pgjaEVraCeqJEkrnamhoM7YckdtqDJAaOThnxYLwcGrdBGudb7Qtgy6b?=
 =?us-ascii?Q?JNZr7dHFIWS16PJa1Y2SaF57qBgttrm79iaN4Mxx1AxOJf4xHUObBjicNiKK?=
 =?us-ascii?Q?GAbwi9B557abY3WLQ5se37TYtaM5YpgVmU9Yqu8NVvBWBQJNeZF+7NnC+i88?=
 =?us-ascii?Q?MnCAfmY2eEyPdW8p1WU1Efw=3D?=
X-OriginatorOrg: in-advantage.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 71a607ad-ca60-439e-dbde-08da7e58ef56
X-MS-Exchange-CrossTenant-AuthSource: MWHPR1001MB2351.namprd10.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Aug 2022 00:56:06.5733
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 48e842ca-fbd8-4633-a79d-0c955a7d3aae
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: l7rHDy6P1Twbxh05XnBNFrtWFRaW3WYPSwkfOH4f/H86a+wvqJcOmE8aArhPHlpAT15KC3VYPS+pvUZjoFUlsyXLpSLIARg3zrCc1DhAvdc=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN7PR10MB6286
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_PASS,SPF_PASS,
        T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Several ocelot-related modules are designed for MMIO / regmaps. As such,
they often use a combination of devm_platform_get_and_ioremap_resource()
and devm_regmap_init_mmio().

Operating in an MFD might be different, in that it could be memory mapped,
or it could be SPI, I2C... In these cases a fallback to use IORESOURCE_REG
instead of IORESOURCE_MEM becomes necessary.

When this happens, there's redundant logic that needs to be implemented in
every driver. In order to avoid this redundancy, utilize a single function
that, if the MFD scenario is enabled, will perform this fallback logic.

Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
---
v16
    * Add Andy Reviewed-by tag

v15
    * Add missed errno.h and ioport.h includes
    * Add () to function references in both the commit log and comments

v14
    * Add header guard
    * Change regs type from u32* to void*
    * Add Reviewed-by tag

---
 MAINTAINERS                |  5 +++
 include/linux/mfd/ocelot.h | 62 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+)
 create mode 100644 include/linux/mfd/ocelot.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 8a5012ba6ff9..e0732e9f9090 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14741,6 +14741,11 @@ F:	net/dsa/tag_ocelot.c
 F:	net/dsa/tag_ocelot_8021q.c
 F:	tools/testing/selftests/drivers/net/ocelot/*
 
+OCELOT EXTERNAL SWITCH CONTROL
+M:	Colin Foster <colin.foster@in-advantage.com>
+S:	Supported
+F:	include/linux/mfd/ocelot.h
+
 OCXL (Open Coherent Accelerator Processor Interface OpenCAPI) DRIVER
 M:	Frederic Barrat <fbarrat@linux.ibm.com>
 M:	Andrew Donnellan <ajd@linux.ibm.com>
diff --git a/include/linux/mfd/ocelot.h b/include/linux/mfd/ocelot.h
new file mode 100644
index 000000000000..dd72073d2d4f
--- /dev/null
+++ b/include/linux/mfd/ocelot.h
@@ -0,0 +1,62 @@
+/* SPDX-License-Identifier: GPL-2.0 OR MIT */
+/* Copyright 2022 Innovative Advantage Inc. */
+
+#ifndef _LINUX_MFD_OCELOT_H
+#define _LINUX_MFD_OCELOT_H
+
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/ioport.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+
+struct resource;
+
+static inline struct regmap *
+ocelot_regmap_from_resource_optional(struct platform_device *pdev,
+				     unsigned int index,
+				     const struct regmap_config *config)
+{
+	struct device *dev = &pdev->dev;
+	struct resource *res;
+	void __iomem *regs;
+
+	/*
+	 * Don't use _get_and_ioremap_resource() here, since that will invoke
+	 * prints of "invalid resource" which will simply add confusion.
+	 */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, index);
+	if (res) {
+		regs = devm_ioremap_resource(dev, res);
+		if (IS_ERR(regs))
+			return ERR_CAST(regs);
+		return devm_regmap_init_mmio(dev, regs, config);
+	}
+
+	/*
+	 * Fall back to using REG and getting the resource from the parent
+	 * device, which is possible in an MFD configuration
+	 */
+	if (dev->parent) {
+		res = platform_get_resource(pdev, IORESOURCE_REG, index);
+		if (!res)
+			return NULL;
+
+		return dev_get_regmap(dev->parent, res->name);
+	}
+
+	return NULL;
+}
+
+static inline struct regmap *
+ocelot_regmap_from_resource(struct platform_device *pdev, unsigned int index,
+			    const struct regmap_config *config)
+{
+	struct regmap *map;
+
+	map = ocelot_regmap_from_resource_optional(pdev, index, config);
+	return map ?: ERR_PTR(-ENOENT);
+}
+
+#endif
-- 
2.25.1