4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Troy Kisky <troy.kisky@xxxxxxxxxxxxxxxxxxx>
commit 13bb1d78f2e372ec0d9b30489ac63768240140fc upstream.
This is a little more efficient and avoids the warning
WARNING: possible circular locking dependency detected
4.14.0-rc7-00010 #16 Not tainted
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kworker/2:1/70 is trying to acquire lock:
(prepare_lock){+.+.}, at: [<c049300c>] clk_prepare_lock+0x80/0xf4
but task is already holding lock:
(i2c_register_adapter){+.+.}, at: [<c0690b04>]
i2c_adapter_lock_bus+0x14/0x18
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (i2c_register_adapter){+.+.}:
rt_mutex_lock+0x44/0x5c
i2c_adapter_lock_bus+0x14/0x18
i2c_transfer+0xa8/0xbc
i2c_smbus_xfer+0x20c/0x5d8
i2c_smbus_read_byte_data+0x38/0x48
m41t80_sqw_is_prepared+0x18/0x28
Signed-off-by: Troy Kisky <troy.kisky@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
Cc: Christoph Fritz <chf.fritz@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/rtc/rtc-m41t80.c | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)
--- a/drivers/rtc/rtc-m41t80.c
+++ b/drivers/rtc/rtc-m41t80.c
@@ -155,6 +155,7 @@ struct m41t80_data {
#ifdef CONFIG_COMMON_CLK
struct clk_hw sqw;
unsigned long freq;
+ unsigned int sqwe;
#endif
};
@@ -527,7 +528,10 @@ static int m41t80_sqw_control(struct clk
else
ret &= ~M41T80_ALMON_SQWE;
- return i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, ret);
+ ret = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, ret);
+ if (!ret)
+ m41t80->sqwe = enable;
+ return ret;
}
static int m41t80_sqw_prepare(struct clk_hw *hw)
@@ -542,14 +546,7 @@ static void m41t80_sqw_unprepare(struct
static int m41t80_sqw_is_prepared(struct clk_hw *hw)
{
- struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw);
- struct i2c_client *client = m41t80->client;
- int ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
-
- if (ret < 0)
- return ret;
-
- return !!(ret & M41T80_ALMON_SQWE);
+ return sqw_to_m41t80_data(hw)->sqwe;
}
static const struct clk_ops m41t80_sqw_ops = {