Re: [PATCH] Input: silead: use msleep() for long delays

[Hans de Goede]

Hi,

On 01/12/2017 05:21 PM, Nicholas Mc Guire wrote:

the delays here are in the 10 to 20ms range so msleep() will do - no
need to burden the highres timer subsystem.

Signed-off-by: Nicholas Mc Guire <hof...@osadl.org>
---

Problem found by coccinelle script

While msleep(10) has a worst case uncertainty of 10ms (on HZ=100 systems)
this seems ok here as the delays are not called frequently (init and
reset functions)

By the same logic, this is not much of a burden on the high-res timer
subsys though.

and the uncertainty of 10ms fits the permitted range of
the original usleep_ranges().

Either way this patch is fine with me.

Regards,

Hans

Patch was compile tested with: x86_64_defconfig +
CONFIG_TOUCHSCREEN_SILEAD=m

Patch is against 4.10-rc3 (localversion-next is next-20170112)

 drivers/input/touchscreen/silead.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/input/touchscreen/silead.c 
b/drivers/input/touchscreen/silead.c
index 404830a..3aa885c 100644
--- a/drivers/input/touchscreen/silead.c
+++ b/drivers/input/touchscreen/silead.c
@@ -58,8 +58,7 @@
 #define SILEAD_POINT_X_MSB_OFF 0x03
 #define SILEAD_TOUCH_ID_MASK   0xF0

-#define SILEAD_CMD_SLEEP_MIN   10000
-#define SILEAD_CMD_SLEEP_MAX   20000
+#define SILEAD_CMD_SLEEP_MIN   10      /* 10+ ms */
 #define SILEAD_POWER_SLEEP     20
 #define SILEAD_STARTUP_SLEEP   30

@@ -190,25 +189,25 @@ static int silead_ts_init(struct i2c_client *client)
                                          SILEAD_CMD_RESET);
        if (error)
                goto i2c_write_err;
-       usleep_range(SILEAD_CMD_SLEEP_MIN, SILEAD_CMD_SLEEP_MAX);
+       msleep(SILEAD_CMD_SLEEP_MIN);

        error = i2c_smbus_write_byte_data(client, SILEAD_REG_TOUCH_NR,
                                        data->max_fingers);
        if (error)
                goto i2c_write_err;
-       usleep_range(SILEAD_CMD_SLEEP_MIN, SILEAD_CMD_SLEEP_MAX);
+       msleep(SILEAD_CMD_SLEEP_MIN);

        error = i2c_smbus_write_byte_data(client, SILEAD_REG_CLOCK,
                                          SILEAD_CLOCK);
        if (error)
                goto i2c_write_err;
-       usleep_range(SILEAD_CMD_SLEEP_MIN, SILEAD_CMD_SLEEP_MAX);
+       msleep(SILEAD_CMD_SLEEP_MIN);

        error = i2c_smbus_write_byte_data(client, SILEAD_REG_RESET,
                                          SILEAD_CMD_START);
        if (error)
                goto i2c_write_err;
-       usleep_range(SILEAD_CMD_SLEEP_MIN, SILEAD_CMD_SLEEP_MAX);
+       msleep(SILEAD_CMD_SLEEP_MIN);

        return 0;

@@ -225,19 +224,19 @@ static int silead_ts_reset(struct i2c_client *client)
                                          SILEAD_CMD_RESET);
        if (error)
                goto i2c_write_err;
-       usleep_range(SILEAD_CMD_SLEEP_MIN, SILEAD_CMD_SLEEP_MAX);
+       msleep(SILEAD_CMD_SLEEP_MIN);

        error = i2c_smbus_write_byte_data(client, SILEAD_REG_CLOCK,
                                          SILEAD_CLOCK);
        if (error)
                goto i2c_write_err;
-       usleep_range(SILEAD_CMD_SLEEP_MIN, SILEAD_CMD_SLEEP_MAX);
+       msleep(SILEAD_CMD_SLEEP_MIN);

        error = i2c_smbus_write_byte_data(client, SILEAD_REG_POWER,
                                          SILEAD_CMD_START);
        if (error)
                goto i2c_write_err;
-       usleep_range(SILEAD_CMD_SLEEP_MIN, SILEAD_CMD_SLEEP_MAX);
+       msleep(SILEAD_CMD_SLEEP_MIN);

        return 0;