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From:   INAGAKI Hiroshi <musashino.open@gmail.com>
To:     rogerq@kernel.org, tony@atomide.com, krzysztof.kozlowski@linaro.org
Cc:     linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org,
        INAGAKI Hiroshi <musashino.open@gmail.com>
Subject: [PATCH] memory: omap-gpmc: fix multi-device handling on the same CS
Date:   Wed, 11 Jan 2023 23:13:46 +0900
Message-Id: <20230111141346.1516-1-musashino.open@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

This patch fixes the handling of multiple devices on the same CS by
replacing CS name to "name" of node instead of "full_name".

In c2ade654dbf7d02f09ad491f5621fc321d4af96b
("memory: omap-gpmc: Use of_node_name_eq for node name comparisons"),
the name for setting to CS was replaced but it doesn't fit for the
comparison by of_node_name_eq.
In of_node_name_eq, the length for strncmp will be obtained from the
node that trying to register and it doesn't contain the length of
"@<cs>,<offset>". But the base name for comparison passed from
registered CS name contains the prefix, then, that two lengths won't
match and false will be returned, and registration on the same CS
will be failed.

example (Century Systems MA-E350/N, AM3352):

- Device Tree

  /* memory mapped gpio controllers on GPMC */
  gpio@2,2 {
      reg = <2 0x2 0x1>; /* CS2, offset 0x2, IO size 0x1 */
      ...
  };

  gpio@2,10 {
      reg = <2 0x10 0x1>; /* CS2, offset 0x10, IO size 0x1 */
      ...
  };

  gpio@2,12 {
      reg = <2 0x12 0x1>; /* CS2, offset 0x12, IO size 0x1 */
      ...
  };

  gpio@2,14 {
      reg = <2 0x14 0x1>; /* CS2, offset 0x14, IO size 0x1 */
      ...
  };

- dmesg

  [    1.596402] omap-gpmc 50000000.gpmc: cannot request GPMC CS 2
  [    1.596434] omap-gpmc 50000000.gpmc: failed to probe DT child 'gpio': -16
  [    1.596489] omap-gpmc 50000000.gpmc: cannot request GPMC CS 2
  [    1.596511] omap-gpmc 50000000.gpmc: failed to probe DT child 'gpio': -16
  [    1.596564] omap-gpmc 50000000.gpmc: cannot request GPMC CS 2
  [    1.596586] omap-gpmc 50000000.gpmc: failed to probe DT child 'gpio': -16

  ("gpio@2,2" is ok, "gpio@2,10", "gpio@2,12", "gpio@2.14" are fail)

Fixes: c2ade654dbf7d02f09ad491f5621fc321d4af96b
("memory: omap-gpmc: Use of_node_name_eq for node name comparisons")

Signed-off-by: INAGAKI Hiroshi <musashino.open@gmail.com>
---
 drivers/memory/omap-gpmc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/memory/omap-gpmc.c b/drivers/memory/omap-gpmc.c
index d78f73db37c8..3e3e84e34795 100644
--- a/drivers/memory/omap-gpmc.c
+++ b/drivers/memory/omap-gpmc.c
@@ -2202,7 +2202,7 @@ static int gpmc_probe_generic_child(struct platform_device *pdev,
 		dev_err(&pdev->dev, "cannot request GPMC CS %d\n", cs);
 		return ret;
 	}
-	gpmc_cs_set_name(cs, child->full_name);
+	gpmc_cs_set_name(cs, child->name);
 
 	gpmc_read_settings_dt(child, &gpmc_s);
 	gpmc_read_timings_dt(child, &gpmc_t);

base-commit: 13f35b3c72f4075e13a974f439b20b9e26f8f243
-- 
2.25.1