Commit ac663db3 authored by Alexander Koch's avatar Alexander Koch Committed by Jonathan Cameron
Browse files

iio: light: opt3001: enable operation w/o IRQ 



Enable operation of the TI OPT3001 light sensor without having an
interrupt line available to connect the INT pin to.

In this operation mode, we issue a conversion request and simply wait
for the conversion time available as timeout value, determined from
integration time configuration and the worst-case time given in the data
sheet (sect. 6.5, table on p. 5):

  short integration time (100ms): 110ms + 3ms = 113ms
   long integration time (800ms): 880ms + 3ms = 883ms

This change is transparent as behaviour defaults to using the interrupt
method if an interrupt no. is configured via device tree. Interrupt-less
operation mode is performed when no valid interrupt no. is given.

Signed-off-by: default avatarAlexander Koch <mail@alexanderkoch.net>
Signed-off-by: default avatarMichael Hornung <mhornung.linux@gmail.com>
Tested-by: default avatarAndreas Dannenberg <dannenberg@ti.com>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent 84e8d090

drivers/iio/light/opt3001.c

+95 −42
Original line number Diff line number Diff line
@@ -70,9 +70,12 @@ 


/*

 * Time to wait for conversion result to be ready. The device datasheet

 * worst-case max value is 880ms. Add some slack to be on the safe side.

 * sect. 6.5 states results are ready after total integration time plus 3ms.

 * This results in worst-case max values of 113ms or 883ms, respectively.

 * Add some slack to be on the safe side.

 */

#define OPT3001_RESULT_READY_TIMEOUT	msecs_to_jiffies(1000)

#define OPT3001_RESULT_READY_SHORT	150

#define OPT3001_RESULT_READY_LONG	1000



struct opt3001 {

	struct i2c_client	*client;
@@ -92,6 +95,8 @@ struct opt3001 { 


	u8			high_thresh_exp;

	u8			low_thresh_exp;



	bool			use_irq;

};



struct opt3001_scale {
@@ -230,13 +235,16 @@ static int opt3001_get_lux(struct opt3001 *opt, int *val, int *val2) 
	u16 reg;

	u8 exponent;

	u16 value;

	long timeout;



	if (opt->use_irq) {

		/*

	 * Enable the end-of-conversion interrupt mechanism. Note that doing

	 * so will overwrite the low-level limit value however we will restore

	 * this value later on.

		 * Enable the end-of-conversion interrupt mechanism. Note that

		 * doing so will overwrite the low-level limit value however we

		 * will restore this value later on.

		 */

	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_LOW_LIMIT,

		ret = i2c_smbus_write_word_swapped(opt->client,

					OPT3001_LOW_LIMIT,

					OPT3001_LOW_LIMIT_EOC_ENABLE);

		if (ret < 0) {

			dev_err(opt->dev, "failed to write register %02x\n",
@@ -244,11 +252,12 @@ static int opt3001_get_lux(struct opt3001 *opt, int *val, int *val2) 
			return ret;

		}



	/* Reset data-ready indicator flag (will be set in the IRQ routine) */

	opt->result_ready = false;



		/* Allow IRQ to access the device despite lock being set */

		opt->ok_to_ignore_lock = true;

	}



	/* Reset data-ready indicator flag */

	opt->result_ready = false;



	/* Configure for single-conversion mode and start a new conversion */

	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
@@ -269,11 +278,44 @@ static int opt3001_get_lux(struct opt3001 *opt, int *val, int *val2) 
		goto err;

	}



	if (opt->use_irq) {

		/* Wait for the IRQ to indicate the conversion is complete */

	ret = wait_event_timeout(opt->result_ready_queue, opt->result_ready,

			OPT3001_RESULT_READY_TIMEOUT);

		ret = wait_event_timeout(opt->result_ready_queue,

				opt->result_ready,

				msecs_to_jiffies(OPT3001_RESULT_READY_LONG));

	} else {

		/* Sleep for result ready time */

		timeout = (opt->int_time == OPT3001_INT_TIME_SHORT) ?

			OPT3001_RESULT_READY_SHORT : OPT3001_RESULT_READY_LONG;

		msleep(timeout);



		/* Check result ready flag */

		ret = i2c_smbus_read_word_swapped(opt->client,

						  OPT3001_CONFIGURATION);

		if (ret < 0) {

			dev_err(opt->dev, "failed to read register %02x\n",

				OPT3001_CONFIGURATION);

			goto err;

		}



		if (!(ret & OPT3001_CONFIGURATION_CRF)) {

			ret = -ETIMEDOUT;

			goto err;

		}



		/* Obtain value */

		ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_RESULT);

		if (ret < 0) {

			dev_err(opt->dev, "failed to read register %02x\n",

				OPT3001_RESULT);

			goto err;

		}

		opt->result = ret;

		opt->result_ready = true;

	}



err:

	if (opt->use_irq)

		/* Disallow IRQ to access the device while lock is active */

		opt->ok_to_ignore_lock = false;
@@ -282,20 +324,24 @@ err: 
	else if (ret < 0)

		return ret;



	if (opt->use_irq) {

		/*

	 * Disable the end-of-conversion interrupt mechanism by restoring the

	 * low-level limit value (clearing OPT3001_LOW_LIMIT_EOC_ENABLE). Note

	 * that selectively clearing those enable bits would affect the actual

	 * limit value due to bit-overlap and therefore can't be done.

		 * Disable the end-of-conversion interrupt mechanism by

		 * restoring the low-level limit value (clearing

		 * OPT3001_LOW_LIMIT_EOC_ENABLE). Note that selectively clearing

		 * those enable bits would affect the actual limit value due to

		 * bit-overlap and therefore can't be done.

		 */

		value = (opt->low_thresh_exp << 12) | opt->low_thresh_mantissa;

	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_LOW_LIMIT,

		ret = i2c_smbus_write_word_swapped(opt->client,

						   OPT3001_LOW_LIMIT,

						   value);

		if (ret < 0) {

			dev_err(opt->dev, "failed to write register %02x\n",

					OPT3001_LOW_LIMIT);

			return ret;

		}

	}



	exponent = OPT3001_REG_EXPONENT(opt->result);

	mantissa = OPT3001_REG_MANTISSA(opt->result);
@@ -736,6 +782,8 @@ static int opt3001_probe(struct i2c_client *client, 
		return ret;

	}



	/* Make use of INT pin only if valid IRQ no. is given */

	if (irq > 0) {

		ret = request_threaded_irq(irq, NULL, opt3001_irq,

				IRQF_TRIGGER_FALLING | IRQF_ONESHOT,

				"opt3001", iio);
@@ -743,6 +791,10 @@ static int opt3001_probe(struct i2c_client *client, 
			dev_err(dev, "failed to request IRQ #%d\n", irq);

			return ret;

		}

		opt->use_irq = true;

	} else {

		dev_dbg(opt->dev, "enabling interrupt-less operation\n");

	}



	return 0;

}
@@ -754,6 +806,7 @@ static int opt3001_remove(struct i2c_client *client) 
	int ret;

	u16 reg;



	if (opt->use_irq)

		free_irq(client->irq, iio);



	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);

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