[PATCH 4/6] Input: mms114 - replace udelay with usleep_range

[Dmitry Torokhov]

The driver currently uses udelay(MMS114_I2C_DELAY) (50us) to ensure a
mandatory delay between I2C transfers in __mms114_read_reg() and
mms114_write_reg().

Both functions invoke underlying I2C core operations (i2c_transfer,
i2c_master_send) which acquire mutexes and sleep. Furthermore, the
interrupt handler mms114_interrupt() is registered as a threaded IRQ
handler. Since the entire execution path is fully sleepable,
busy-waiting with udelay() for 50us unnecessarily wastes CPU cycles.

Replace udelay() with usleep_range() to allow the CPU to enter low-power
states or execute other tasks during the delay.

Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
---
 drivers/input/touchscreen/mms114.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/input/touchscreen/mms114.c b/drivers/input/touchscreen/mms114.c
index c2e006ac1196..c59aec8f2feb 100644
--- a/drivers/input/touchscreen/mms114.c
+++ b/drivers/input/touchscreen/mms114.c
@@ -116,7 +116,7 @@ static int __mms114_read_reg(struct mms114_data *data, u8 reg,
 			"%s: i2c transfer failed (%d)\n", __func__, error);
 		return error < 0 ? error : -EIO;
 	}
-	udelay(MMS114_I2C_DELAY);
+	usleep_range(MMS114_I2C_DELAY, MMS114_I2C_DELAY + 50);
 
 	return 0;
 }
@@ -148,7 +148,7 @@ static int mms114_write_reg(struct mms114_data *data, u8 reg, u8 val)
 			"%s: i2c send failed (%d)\n", __func__, error);
 		return error < 0 ? error : -EIO;
 	}
-	udelay(MMS114_I2C_DELAY);
+	usleep_range(MMS114_I2C_DELAY, MMS114_I2C_DELAY + 50);
 
 	if (reg == MMS114_MODE_CONTROL)
 		data->cache_mode_control = val;
-- 
2.54.0.1136.gdb2ca164c4-goog