linux-kernel - [PATCH 4/5] nvmem: qfprom: fix different address space warnings of sparse

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Message-Id: <1505134864-11975-5-git-send-email-yamada.masahiro@socionext.com>
Date:   Mon, 11 Sep 2017 22:01:03 +0900
From:   Masahiro Yamada <yamada.masahiro@...ionext.com>
To:     Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Cc:     Keiji Hayashibara <hayashibara.keiji@...ionext.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Jassi Brar <jaswinder.singh@...aro.org>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 4/5] nvmem: qfprom: fix different address space warnings of sparse

Fix the following sparse warnings:

drivers/nvmem/qfprom.c:23:30: warning: incorrect type in initializer (different address spaces)
drivers/nvmem/qfprom.c:23:30:    expected void [noderef] <asn:2>*base
drivers/nvmem/qfprom.c:23:30:    got void *context
drivers/nvmem/qfprom.c:36:30: warning: incorrect type in initializer (different address spaces)
drivers/nvmem/qfprom.c:36:30:    expected void [noderef] <asn:2>*base
drivers/nvmem/qfprom.c:36:30:    got void *context
drivers/nvmem/qfprom.c:76:22: warning: incorrect type in assignment (different address spaces)
drivers/nvmem/qfprom.c:76:22:    expected void *static [toplevel] [assigned] priv
drivers/nvmem/qfprom.c:76:22:    got void [noderef] <asn:2>*[assigned] base

The type of nvmem_config->priv is (void *), so sparse complains
about assignment of the base address with (void __iomem *) type.

Even if we cast it out, sparse still warns:
warning: cast removes address space of expression

Of course, we can shut up the sparse by marking __force, but a more
correct way is to put the base address into driver private data.

Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
---

 drivers/nvmem/qfprom.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/drivers/nvmem/qfprom.c b/drivers/nvmem/qfprom.c
index 2bdb6c3..b96730e 100644
--- a/drivers/nvmem/qfprom.c
+++ b/drivers/nvmem/qfprom.c
@@ -17,15 +17,19 @@
 #include <linux/nvmem-provider.h>
 #include <linux/platform_device.h>
 
+struct qfprom_priv {
+	void __iomem *base;
+};
+
 static int qfprom_reg_read(void *context,
 			unsigned int reg, void *_val, size_t bytes)
 {
-	void __iomem *base = context;
+	struct qfprom_priv *priv = context;
 	u8 *val = _val;
 	int i = 0, words = bytes;
 
 	while (words--)
-		*val++ = readb(base + reg + i++);
+		*val++ = readb(priv->base + reg + i++);
 
 	return 0;
 }
@@ -33,12 +37,12 @@ static int qfprom_reg_read(void *context,
 static int qfprom_reg_write(void *context,
 			 unsigned int reg, void *_val, size_t bytes)
 {
-	void __iomem *base = context;
+	struct qfprom_priv *priv = context;
 	u8 *val = _val;
 	int i = 0, words = bytes;
 
 	while (words--)
-		writeb(*val++, base + reg + i++);
+		writeb(*val++, priv->base + reg + i++);
 
 	return 0;
 }
@@ -64,16 +68,20 @@ static int qfprom_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct resource *res;
 	struct nvmem_device *nvmem;
-	void __iomem *base;
+	struct qfprom_priv *priv;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	base = devm_ioremap_resource(dev, res);
-	if (IS_ERR(base))
-		return PTR_ERR(base);
+	priv->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
 
 	econfig.size = resource_size(res);
 	econfig.dev = dev;
-	econfig.priv = base;
+	econfig.priv = priv;
 
 	nvmem = nvmem_register(&econfig);
 	if (IS_ERR(nvmem))
-- 
2.7.4