iio: adc: hx711: optimize performance in read cycle (68d8ab3c) · Commits · 戴 / test

Set gain in hx711_reset() to its default value after a reset cycle. This omits one precautionary read cycle, because the read is performed in hx711_set_gain_for_channel() anyway if gain has changed. Check for DOUT low and if its high wait some time if it goes down instead of doing a blind reset cycle when DOUT is not down. This is a performance optimization which allows to query the sensor with a higher frequency. Signed-off-by:

Andreas Klinger <ak@it-klinger.de> Signed-off-by:

Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/hx711.c

+5 −17

Original line number	Diff line number	Diff line
		@@ -23,6 +23,7 @@

		/* gain to pulse and scale conversion */
		#define HX711_GAIN_MAX 3
		#define HX711_RESET_GAIN 128

		struct hx711_gain_to_scale {
		int gain;
		@@ -185,8 +186,7 @@ static int hx711_wait_for_ready(struct hx711_data *hx711_data)

		static int hx711_reset(struct hx711_data *hx711_data)
		{
		int ret;
		int val = gpiod_get_value(hx711_data->gpiod_dout);
		int val = hx711_wait_for_ready(hx711_data);

		if (val) {
		/*
		@@ -202,22 +202,10 @@ static int hx711_reset(struct hx711_data *hx711_data)
		msleep(10);
		gpiod_set_value(hx711_data->gpiod_pd_sck, 0);

		ret = hx711_wait_for_ready(hx711_data);
		if (ret)
		return ret;
		/*
		* after a reset the gain is 128 so we do a dummy read
		* to set the gain for the next read
		*/
		ret = hx711_read(hx711_data);
		if (ret < 0)
		return ret;

		/*
		* after a dummy read we need to wait vor readiness
		* for not mixing gain pulses with the clock
		*/
		val = hx711_wait_for_ready(hx711_data);

		/* after a reset the gain is 128 */
		hx711_data->gain_set = HX711_RESET_GAIN;
		}

		return val;

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