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    Subject[PATCH 4/4] iio: adc: mcp3422: reduce sleep for fast sampling rates
    Date
    - reduced sleep time for 240 & 60 sps rates
    - minor roundup fix for sleep times

    Signed-off-by: Mitja Spes <mitja@lxnav.com>
    ---
    drivers/iio/adc/mcp3422.c | 16 +++++++++++-----
    1 file changed, 11 insertions(+), 5 deletions(-)

    diff --git a/drivers/iio/adc/mcp3422.c b/drivers/iio/adc/mcp3422.c
    index eef35fb2fc22..dbcc8fe91aaa 100644
    --- a/drivers/iio/adc/mcp3422.c
    +++ b/drivers/iio/adc/mcp3422.c
    @@ -70,10 +70,11 @@ static const int mcp3422_scales[MCP3422_SRATE_COUNT][MCP3422_PGA_COUNT] = {

    /* Constant msleep times for data acquisitions */
    static const int mcp3422_read_times[MCP3422_SRATE_COUNT] = {
    - [MCP3422_SRATE_240] = 1000 / 240,
    - [MCP3422_SRATE_60] = 1000 / 60,
    - [MCP3422_SRATE_15] = 1000 / 15,
    - [MCP3422_SRATE_3] = 1000 / 3 };
    + [MCP3422_SRATE_240] = DIV_ROUND_UP(1000, 240),
    + [MCP3422_SRATE_60] = DIV_ROUND_UP(1000, 60),
    + [MCP3422_SRATE_15] = DIV_ROUND_UP(1000, 15),
    + [MCP3422_SRATE_3] = (100000 + 375 - 100) / 375 /* real rate is 3.75 sps */
    +};

    /* sample rates to integer conversion table */
    static const int mcp3422_sample_rates[MCP3422_SRATE_COUNT] = {
    @@ -137,6 +138,7 @@ static int mcp3422_read_channel(struct mcp3422 *adc,
    struct iio_chan_spec const *channel, int *value)
    {
    int ret;
    + int sleep_duration;
    u8 config;
    u8 req_channel = channel->channel;

    @@ -148,7 +150,11 @@ static int mcp3422_read_channel(struct mcp3422 *adc,
    mutex_unlock(&adc->lock);
    return ret;
    }
    - msleep(mcp3422_read_times[MCP3422_SAMPLE_RATE(adc->active_config)]);
    + sleep_duration = mcp3422_read_times[MCP3422_SAMPLE_RATE(adc->active_config)];
    + if (sleep_duration < 20)
    + usleep_range(sleep_duration * 1000, sleep_duration * 1300);
    + else
    + msleep(sleep_duration);
    }

    ret = mcp3422_read(adc, value, &config);
    --
    2.34.1
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