linux-kernel - [PATCH] memory: jz4780_nemc: Only request IO memory the driver will use

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Date:   Mon, 27 Jul 2020 18:20:34 +0200
From:   Paul Cercueil <paul@...pouillou.net>
To:     Krzysztof Kozlowski <krzk@...nel.org>
Cc:     od@...c.me, linux-kernel@...r.kernel.org,
        Paul Cercueil <paul@...pouillou.net>,
        "H . Nikolaus Schaller" <hns@...delico.com>
Subject: [PATCH] memory: jz4780_nemc: Only request IO memory the driver will use

The driver only uses the registers up to offset 0x54. Since the EFUSE
registers are in the middle of the NEMC registers, we only request
the registers we will use for now - that way the EFUSE driver can
probe too.

Tested-by: H. Nikolaus Schaller <hns@...delico.com>
Signed-off-by: Paul Cercueil <paul@...pouillou.net>
---
 drivers/memory/jz4780-nemc.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/memory/jz4780-nemc.c b/drivers/memory/jz4780-nemc.c
index b232ed279fc3..647267ea8c63 100644
--- a/drivers/memory/jz4780-nemc.c
+++ b/drivers/memory/jz4780-nemc.c
@@ -8,6 +8,7 @@
 
 #include <linux/clk.h>
 #include <linux/init.h>
+#include <linux/io.h>
 #include <linux/math64.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
@@ -288,7 +289,19 @@ static int jz4780_nemc_probe(struct platform_device *pdev)
 	nemc->dev = dev;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	nemc->base = devm_ioremap_resource(dev, res);
+
+	/*
+	 * The driver only uses the registers up to offset 0x54. Since the EFUSE
+	 * registers are in the middle of the NEMC registers, we only request
+	 * the registers we will use for now - that way the EFUSE driver can
+	 * probe too.
+	 */
+	if (!devm_request_mem_region(dev, res->start, 0x54, dev_name(dev))) {
+		dev_err(dev, "unable to request I/O memory region\n");
+		return -EBUSY;
+	}
+
+	nemc->base = devm_ioremap(dev, res->start, resource_size(res));
 	if (IS_ERR(nemc->base)) {
 		dev_err(dev, "failed to get I/O memory\n");
 		return PTR_ERR(nemc->base);
-- 
2.27.0