linux-kernel - [PATCH 0/1] regmap: drop cache if the bus transfer error

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Date:	Thu, 18 Aug 2016 14:43:52 +0800
From:	Elaine Zhang <zhangqing@...k-chips.com>
To:	heiko@...ech.de
Cc:	huangtao@...k-chips.com, zyw@...k-chips.com, xxx@...k-chips.com,
	jay.xu@...k-chips.com, linux-kernel@...r.kernel.org,
	Elaine Zhang <zhangqing@...k-chips.com>
Subject: [PATCH 0/1] regmap: drop cache if the bus transfer error

regmap_write
->_regmap_raw_write
-->regcache_write first and than use map->bus->write to wirte i2c or spi
But if the i2c or spi transfer failed, But the cache is updated, So if I use
regmap_read will get the cache data which is not the real register value.

Signed-off-by: Elaine Zhang <zhangqing@...k-chips.com>
---
 drivers/base/regmap/regmap.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 1f011f9d6dcb..369a4c3c933e 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -1497,6 +1497,8 @@ int _regmap_raw_write(struct regmap *map, unsigned int reg,
 		ret = map->bus->write(map->bus_context, buf, len);
 
 		kfree(buf);
+	} else if (ret != 0 && !map->cache_bypass && map->format.parse_val) {
+		regcache_drop_region(map, reg, reg + 1);
 	}
 
 	trace_regmap_hw_write_done(map, reg, val_len / map->format.val_bytes);
-- 
1.9.1