linux-kernel - [RESEND PATCH v2] mfd: syscon: Use a unique name with regmap

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Date:   Mon, 27 Jul 2020 16:10:08 -0500
From:   Suman Anna <s-anna@...com>
To:     Lee Jones <lee.jones@...aro.org>, Arnd Bergmann <arnd@...db.de>
CC:     Grzegorz Jaszczyk <grzegorz.jaszczyk@...aro.org>,
        David Lechner <david@...hnology.com>,
        Tony Lindgren <tony@...mide.com>,
        Roger Quadros <rogerq@...com>, <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-omap@...r.kernel.org>, Suman Anna <s-anna@...com>
Subject: [RESEND PATCH v2] mfd: syscon: Use a unique name with regmap_config

The DT node full name is currently being used in regmap_config
which in turn is used to create the regmap debugfs directories.
This name however is not guaranteed to be unique and the regmap
debugfs registration can fail in the cases where the syscon nodes
have the same unit-address but are present in different DT node
hierarchies. Replace this logic using the syscon reg resource
address instead (inspired from logic used while creating platform
devices) to ensure a unique name is given for each syscon.

Signed-off-by: Suman Anna <s-anna@...com>
---
Hi Arnd,
Lee is looking for your review on this patch. Can you please
review and provide your comments.

This is a resend of the patch that was posted previously, rebased
now onto latest kernel.

v2: https://patchwork.kernel.org/patch/11353355/
 - Fix build warning reported by kbuild test bot
v1: https://patchwork.kernel.org/patch/11346363/

 drivers/mfd/syscon.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
index 3a97816d0cba..75859e492984 100644
--- a/drivers/mfd/syscon.c
+++ b/drivers/mfd/syscon.c
@@ -101,12 +101,14 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_clk)
 		}
 	}
 
-	syscon_config.name = of_node_full_name(np);
+	syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@...x", np,
+				       (u64)res.start);
 	syscon_config.reg_stride = reg_io_width;
 	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);
+	kfree(syscon_config.name);
 	if (IS_ERR(regmap)) {
 		pr_err("regmap init failed\n");
 		ret = PTR_ERR(regmap);
-- 
2.26.0