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authorTroy Kisky <troy.kisky@boundarydevices.com>2017-11-02 18:58:15 -0700
committerAlexandre Belloni <alexandre.belloni@free-electrons.com>2017-11-08 07:52:24 +0100
commit13bb1d78f2e372ec0d9b30489ac63768240140fc (patch)
treeb8fad55d3f307c4d7e3802d66935bf5841c849e8 /drivers/rtc
parent2cb90ed3de1e279dbaf23df141f54eb9fb1861e6 (diff)
rtc: m41t80: avoid i2c read in m41t80_sqw_is_prepared
This is a little more efficient and avoids the warning WARNING: possible circular locking dependency detected 4.14.0-rc7-00010 #16 Not tainted ------------------------------------------------------ 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@boundarydevices.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Diffstat (limited to 'drivers/rtc')
-rw-r--r--drivers/rtc/rtc-m41t80.c15
1 files changed, 6 insertions, 9 deletions
diff --git a/drivers/rtc/rtc-m41t80.c b/drivers/rtc/rtc-m41t80.c
index f44dcf628c87..96a606d5f6e6 100644
--- 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_hw *hw, bool enable)
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 clk_hw *hw)
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 = {

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