diff options
author | Alexander Koch <mail@alexanderkoch.net> | 2016-01-16 17:14:38 +0100 |
---|---|---|
committer | Jonathan Cameron <jic23@kernel.org> | 2016-01-30 16:26:47 +0000 |
commit | ac663db3678a62f69a2a73126e51a9a302b27ff2 (patch) | |
tree | a2ac193d50fda7f870af9d1683fcaa4f71f2f099 /drivers/iio | |
parent | 84e8d090c57522c5f8ae59f5b922bedb929165c7 (diff) | |
download | linux-ac663db3678a62f69a2a73126e51a9a302b27ff2.tar.bz2 |
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: Alexander Koch <mail@alexanderkoch.net>
Signed-off-by: Michael Hornung <mhornung.linux@gmail.com>
Tested-by: Andreas Dannenberg <dannenberg@ti.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Diffstat (limited to 'drivers/iio')
-rw-r--r-- | drivers/iio/light/opt3001.c | 137 |
1 files changed, 95 insertions, 42 deletions
diff --git a/drivers/iio/light/opt3001.c b/drivers/iio/light/opt3001.c index b05c484a1646..b776c8ed4387 100644 --- a/drivers/iio/light/opt3001.c +++ b/drivers/iio/light/opt3001.c @@ -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 { @@ -230,26 +235,30 @@ static int opt3001_get_lux(struct opt3001 *opt, int *val, int *val2) u16 reg; u8 exponent; u16 value; + long timeout; - /* - * 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, - OPT3001_LOW_LIMIT_EOC_ENABLE); - if (ret < 0) { - dev_err(opt->dev, "failed to write register %02x\n", - OPT3001_LOW_LIMIT); - return ret; + 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. + */ + 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", + OPT3001_LOW_LIMIT); + return ret; + } + + /* Allow IRQ to access the device despite lock being set */ + opt->ok_to_ignore_lock = true; } - /* Reset data-ready indicator flag (will be set in the IRQ routine) */ + /* Reset data-ready indicator flag */ opt->result_ready = false; - /* Allow IRQ to access the device despite lock being set */ - opt->ok_to_ignore_lock = true; - /* Configure for single-conversion mode and start a new conversion */ ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION); if (ret < 0) { @@ -269,32 +278,69 @@ static int opt3001_get_lux(struct opt3001 *opt, int *val, int *val2) goto err; } - /* 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); + 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, + 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: - /* Disallow IRQ to access the device while lock is active */ - opt->ok_to_ignore_lock = false; + if (opt->use_irq) + /* Disallow IRQ to access the device while lock is active */ + opt->ok_to_ignore_lock = false; if (ret == 0) return -ETIMEDOUT; else if (ret < 0) return ret; - /* - * 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, - value); - if (ret < 0) { - dev_err(opt->dev, "failed to write register %02x\n", - OPT3001_LOW_LIMIT); - 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. + */ + value = (opt->low_thresh_exp << 12) | opt->low_thresh_mantissa; + 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); @@ -736,12 +782,18 @@ static int opt3001_probe(struct i2c_client *client, return ret; } - ret = request_threaded_irq(irq, NULL, opt3001_irq, - IRQF_TRIGGER_FALLING | IRQF_ONESHOT, - "opt3001", iio); - if (ret) { - dev_err(dev, "failed to request IRQ #%d\n", irq); - 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); + if (ret) { + 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; @@ -754,7 +806,8 @@ static int opt3001_remove(struct i2c_client *client) int ret; u16 reg; - free_irq(client->irq, iio); + if (opt->use_irq) + free_irq(client->irq, iio); ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION); if (ret < 0) { |