diff options
Diffstat (limited to 'nuttx/drivers/input/ads7843e.c')
| -rw-r--r-- | nuttx/drivers/input/ads7843e.c | 224 |
1 files changed, 151 insertions, 73 deletions
diff --git a/nuttx/drivers/input/ads7843e.c b/nuttx/drivers/input/ads7843e.c index 07e5e515d..06969e6d2 100644 --- a/nuttx/drivers/input/ads7843e.c +++ b/nuttx/drivers/input/ads7843e.c @@ -79,6 +79,12 @@ * Pre-processor Definitions ****************************************************************************/ +/* This is a value for the threshold that guantees a big difference on the + * first pendown (but can't overflow). + */ + +#define INVALID_THRESHOLD 0x1000 + /**************************************************************************** * Private Types ****************************************************************************/ @@ -88,13 +94,14 @@ ****************************************************************************/ /* Low-level SPI helpers */ -static inline void ads7843e_configspi(FAR struct spi_dev_s *spi); #ifdef CONFIG_SPI_OWNBUS -static inline void ads7843e_select(FAR struct spi_dev_s *spi); -static inline void ads7843e_deselect(FAR struct spi_dev_s *spi); +static inline void ads7843e_configspi(FAR struct spi_dev_s *spi); +# define ads7843e_lock(spi) +# define ads7843e_unlock(spi) #else -static void ads7843e_select(FAR struct spi_dev_s *spi); -static void ads7843e_deselect(FAR struct spi_dev_s *spi); +# define ads7843e_configspi(spi); +static void ads7843e_lock(FAR struct spi_dev_s *spi); +static void ads7843e_unlock(FAR struct spi_dev_s *spi); #endif static inline void ads7843e_waitbusy(FAR struct ads7843e_dev_s *priv); @@ -157,13 +164,12 @@ static struct ads7843e_dev_s *g_ads7843elist; ****************************************************************************/ /**************************************************************************** - * Function: ads7843e_select + * Function: ads7843e_lock * * Description: - * Select the SPI, locking and re-configuring if necessary. This function - * must be called before initiating any sequence of SPI operations. If we - * are sharing the SPI bus with other devices (CONFIG_SPI_OWNBUS undefined) - * then we need to lock and configure the SPI bus for each transfer. + * Lock the SPI bus and re-configure as necessary. This function must be + * to assure: (1) exclusive access to the SPI bus, and (2) to assure that + * the shared bus is properly configured for the touchscreen controller. * * Parameters: * spi - Reference to the SPI driver structure @@ -175,42 +181,35 @@ static struct ads7843e_dev_s *g_ads7843elist; * ****************************************************************************/ -#ifdef CONFIG_SPI_OWNBUS -static inline void ads7843e_select(FAR struct spi_dev_s *spi) -{ - /* We own the SPI bus, so just select the chip */ - - SPI_SELECT(spi, SPIDEV_TOUCHSCREEN, true); -} -#else -static void ads7843e_select(FAR struct spi_dev_s *spi) +#ifndef CONFIG_SPI_OWNBUS +static void ads7843e_lock(FAR struct spi_dev_s *spi) { - /* Select ADS7843 chip (locking the SPI bus in case there are multiple - * devices competing for the SPI bus + /* Lock the SPI bus because there are multiple devices competing for the + * SPI bus */ (void)SPI_LOCK(spi, true); - SPI_SELECT(spi, SPIDEV_TOUCHSCREEN, true); - /* Now make sure that the SPI bus is configured for the ADS7843 (it - * might have gotten configured for a different device while unlocked) + /* We have the lock. Now make sure that the SPI bus is configured for the + * ADS7843 (it might have gotten configured for a different device while + * unlocked) */ + SPI_SELECT(spi, SPIDEV_TOUCHSCREEN, true); SPI_SETMODE(spi, CONFIG_ADS7843E_SPIMODE); SPI_SETBITS(spi, 8); SPI_SETFREQUENCY(spi, CONFIG_ADS7843E_FREQUENCY); + SPI_SELECT(spi, SPIDEV_TOUCHSCREEN, false); } #endif /**************************************************************************** - * Function: ads7843e_deselect + * Function: ads7843e_unlock * * Description: - * De-select the SPI, unlocking as necessary. This function must be - * after completing a sequence of SPI operations. If we are sharing the SPI - * bus with other devices (CONFIG_SPI_OWNBUS undefined) then we need to - * un-lock the SPI bus for each transfer, possibly losing the current - * configuration. + * If we are sharing the SPI bus with other devices (CONFIG_SPI_OWNBUS + * undefined) then we need to un-lock the SPI bus for each transfer, + * possibly losing the current configuration. * * Parameters: * spi - Reference to the SPI driver structure @@ -222,19 +221,11 @@ static void ads7843e_select(FAR struct spi_dev_s *spi) * ****************************************************************************/ -#ifdef CONFIG_SPI_OWNBUS -static inline void ads7843e_deselect(FAR struct spi_dev_s *spi) -{ - /* We own the SPI bus, so just de-select the chip */ - - SPI_SELECT(spi, SPIDEV_TOUCHSCREEN, false); -} -#else -static void ads7843e_deselect(FAR struct spi_dev_s *spi) +#ifndef CONFIG_SPI_OWNBUS +static void ads7843e_unlock(FAR struct spi_dev_s *spi) { - /* De-select ADS7843 chip and relinquish the SPI bus. */ + /* Relinquish the SPI bus. */ - SPI_SELECT(spi, SPIDEV_TOUCHSCREEN, false); (void)SPI_LOCK(spi, false); } #endif @@ -258,23 +249,20 @@ static void ads7843e_deselect(FAR struct spi_dev_s *spi) * ****************************************************************************/ +#ifdef CONFIG_SPI_OWNBUS static inline void ads7843e_configspi(FAR struct spi_dev_s *spi) { - idbg("Mode: %d Bits: 8 Frequency: %d\n", - CONFIG_ADS7843E_SPIMODE, CONFIG_ADS7843E_FREQUENCY); - /* Configure SPI for the ADS7843. But only if we own the SPI bus. Otherwise, don't * bother because it might change. */ -#ifdef CONFIG_SPI_OWNBUS SPI_SELECT(spi, SPIDEV_TOUCHSCREEN, true); SPI_SETMODE(spi, CONFIG_ADS7843E_SPIMODE); SPI_SETBITS(spi, 8); SPI_SETFREQUENCY(spi, CONFIG_ADS7843E_FREQUENCY); SPI_SELECT(spi, SPIDEV_TOUCHSCREEN, false); -#endif } +#endif /**************************************************************************** * Name: ads7843e_waitbusy @@ -296,7 +284,7 @@ static uint16_t ads7843e_sendcmd(FAR struct ads7843e_dev_s *priv, uint8_t cmd) /* Select the ADS7843E */ - ads7843e_select(priv->spi); + SPI_SELECT(priv->spi, SPIDEV_TOUCHSCREEN, true); /* Send the command */ @@ -306,7 +294,7 @@ static uint16_t ads7843e_sendcmd(FAR struct ads7843e_dev_s *priv, uint8_t cmd) /* Read the data */ SPI_RECVBLOCK(priv->spi, buffer, 2); - ads7843e_deselect(priv->spi); + SPI_SELECT(priv->spi, SPIDEV_TOUCHSCREEN, false); result = ((uint16_t)buffer[0] << 8) | (uint16_t)buffer[1]; result = result >> 4; @@ -554,7 +542,12 @@ static void ads7843e_worker(FAR void *arg) { FAR struct ads7843e_dev_s *priv = (FAR struct ads7843e_dev_s *)arg; FAR struct ads7843e_config_s *config; + uint16_t x; + uint16_t y; + uint16_t xdiff; + uint16_t ydiff; bool pendown; + int ret; ASSERT(priv != NULL); @@ -565,10 +558,30 @@ static void ads7843e_worker(FAR void *arg) config = priv->config; DEBUGASSERT(config != NULL); - /* Disable the watchdog timer */ + /* Disable the watchdog timer. This is safe because it is started only + * by this function and this function is serialized on the worker thread. + */ wd_cancel(priv->wdog); + /* Lock the SPI bus so that we have exclusive access */ + + ads7843e_lock(priv->spi); + + /* Get exclusive access to the driver data structure */ + + do + { + ret = sem_wait(&priv->devsem); + + /* This should only fail if the wait was canceled by an signal + * (and the worker thread will receive a lot of signals). + */ + + DEBUGASSERT(ret == OK || errno == EINTR); + } + while (ret < 0); + /* Check for pen up or down by reading the PENIRQ GPIO. */ pendown = config->pendown(config); @@ -577,13 +590,20 @@ static void ads7843e_worker(FAR void *arg) if (!pendown) { - /* Ignore the interrupt if the pen was already up (CONTACT_NONE == pen up and - * already reported. CONTACT_UP == pen up, but not reported) + /* The pen is up.. reset thresholding variables. */ + + priv->threshx = INVALID_THRESHOLD; + priv->threshy = INVALID_THRESHOLD; + + /* Ignore the interrupt if the pen was already up (CONTACT_NONE == pen up + * and already reported; CONTACT_UP == pen up, but not reported) */ - if (priv->sample.contact == CONTACT_NONE) + if (priv->sample.contact == CONTACT_NONE || + priv->sample.contact == CONTACT_UP) + { - goto errout; + goto ignored; } /* The pen is up. NOTE: We know from a previous test, that this is a @@ -601,14 +621,57 @@ static void ads7843e_worker(FAR void *arg) else if (priv->sample.contact == CONTACT_UP) { - goto errout; + /* If we have not yet processed the last pen up event, then we + * cannot handle this pen down event. We will have to discard it. That + * should be okay because we will set the timer to to sample again + * later. + */ + + wd_start(priv->wdog, ADS7843E_WDOG_DELAY, ads7843e_wdog, 1, (uint32_t)priv); + goto ignored; } else { /* Handle pen down events. First, sample positional values. */ - priv->sample.x = ads7843e_sendcmd(priv, ADS7843_CMD_XPOSITION); - priv->sample.y = ads7843e_sendcmd(priv, ADS7843_CMD_YPOSITION); +#ifdef CONFIG_ADS7843E_SWAPXY + x = ads7843e_sendcmd(priv, ADS7843_CMD_YPOSITION); + y = ads7843e_sendcmd(priv, ADS7843_CMD_XPOSITION); +#else + x = ads7843e_sendcmd(priv, ADS7843_CMD_XPOSITION); + y = ads7843e_sendcmd(priv, ADS7843_CMD_YPOSITION); +#endif + + /* Perform a thresholding operation so that the results will be more stable. + * If the difference from the last sample is small, then ignore the event. + * REVISIT: Should a large change in pressure also generate a event? + */ + + xdiff = x > priv->threshx ? (x - priv->threshx) : (priv->threshx - x); + ydiff = y > priv->threshy ? (y - priv->threshy) : (priv->threshy - y); + + /* Continue to sample the position while the pen is down */ + + wd_start(priv->wdog, ADS7843E_WDOG_DELAY, ads7843e_wdog, 1, (uint32_t)priv); + + /* Check the thresholds. Bail if there is no significant difference */ + + if (xdiff < CONFIG_ADS7843E_THRESHX && ydiff < CONFIG_ADS7843E_THRESHY) + { + /* Little or no change in either direction ... don't report anything. */ + + goto ignored; + } + + /* When we see a big difference, snap to the new x/y thresholds */ + + priv->threshx = x; + priv->threshy = y; + + /* Update the x/y position in the sample data */ + + priv->sample.x = priv->threshx; + priv->sample.y = priv->threshy; /* The X/Y positional data is now valid */ @@ -625,10 +688,6 @@ static void ads7843e_worker(FAR void *arg) priv->sample.contact = CONTACT_DOWN; } - - /* Continue to sample the position while the pen is down */ - - wd_start(priv->wdog, ADS7843E_WDOG_DELAY, ads7843e_wdog, 1, (uint32_t)priv); } /* Indicate the availability of new sample data for this ID */ @@ -642,9 +701,15 @@ static void ads7843e_worker(FAR void *arg) /* Exit, re-enabling ADS7843E interrupts */ -errout: +ignored: + (void)ads7843e_sendcmd(priv, ADS7843_CMD_ENABPINIRQ); config->enable(config, true); + + /* Release our lock on the state structure and unlock the SPI bus */ + + sem_post(&priv->devsem); + ads7843e_unlock(priv->spi); } /**************************************************************************** @@ -871,7 +936,7 @@ static ssize_t ads7843e_read(FAR struct file *filep, FAR char *buffer, size_t le report = (FAR struct touch_sample_s *)buffer; memset(report, 0, SIZEOF_TOUCH_SAMPLE_S(1)); report->npoints = 1; - report->point[0].id = priv->id; + report->point[0].id = sample.id; report->point[0].x = sample.x; report->point[0].y = sample.y; @@ -886,8 +951,7 @@ static ssize_t ads7843e_read(FAR struct file *filep, FAR char *buffer, size_t le if (sample.valid) { - report->point[0].flags = TOUCH_UP | TOUCH_ID_VALID | - TOUCH_POS_VALID | TOUCH_PRESSURE_VALID; + report->point[0].flags = TOUCH_UP | TOUCH_ID_VALID | TOUCH_POS_VALID; } else { @@ -1098,7 +1162,7 @@ errout: * ****************************************************************************/ -int ads7843e_register(FAR struct spi_dev_s *dev, +int ads7843e_register(FAR struct spi_dev_s *spi, FAR struct ads7843e_config_s *config, int minor) { FAR struct ads7843e_dev_s *priv; @@ -1108,11 +1172,11 @@ int ads7843e_register(FAR struct spi_dev_s *dev, #endif int ret; - ivdbg("dev: %p minor: %d\n", dev, minor); + ivdbg("spi: %p minor: %d\n", spi, minor); /* Debug-only sanity checks */ - DEBUGASSERT(dev != NULL && config != NULL && minor >= 0 && minor < 100); + DEBUGASSERT(spi != NULL && config != NULL && minor >= 0 && minor < 100); /* Create and initialize a ADS7843E device driver instance */ @@ -1130,11 +1194,14 @@ int ads7843e_register(FAR struct spi_dev_s *dev, /* Initialize the ADS7843E device driver instance */ memset(priv, 0, sizeof(struct ads7843e_dev_s)); - priv->spi = dev; /* Save the SPI device handle */ - priv->config = config; /* Save the board configuration */ - priv->wdog = wd_create(); /* Create a watchdog timer */ - sem_init(&priv->devsem, 0, 1); /* Initialize device structure semaphore */ - sem_init(&priv->waitsem, 0, 0); /* Initialize pen event wait semaphore */ + priv->spi = spi; /* Save the SPI device handle */ + priv->config = config; /* Save the board configuration */ + priv->wdog = wd_create(); /* Create a watchdog timer */ + priv->threshx = INVALID_THRESHOLD; /* Initialize thresholding logic */ + priv->threshy = INVALID_THRESHOLD; /* Initialize thresholding logic */ + + sem_init(&priv->devsem, 0, 1); /* Initialize device structure semaphore */ + sem_init(&priv->waitsem, 0, 0); /* Initialize pen event wait semaphore */ /* Make sure that interrupts are disabled */ @@ -1150,14 +1217,25 @@ int ads7843e_register(FAR struct spi_dev_s *dev, goto errout_with_priv; } + idbg("Mode: %d Bits: 8 Frequency: %d\n", + CONFIG_ADS7843E_SPIMODE, CONFIG_ADS7843E_FREQUENCY); + + /* Lock the SPI bus so that we have exclusive access */ + + ads7843e_lock(spi); + /* Configure the SPI interface */ - ads7843e_configspi(dev); + ads7843e_configspi(spi); /* Enable the PEN IRQ */ ads7843e_sendcmd(priv, ADS7843_CMD_ENABPINIRQ); + /* Unlock the bus */ + + ads7843e_unlock(spi); + /* Register the device as an input device */ (void)snprintf(devname, DEV_NAMELEN, DEV_FORMAT, minor); |