diff options
Diffstat (limited to 'drivers/input/touchscreen/ads7846.c')
| -rw-r--r-- | drivers/input/touchscreen/ads7846.c | 56 |
1 files changed, 29 insertions, 27 deletions
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c index 1494175ac6fe..66e411badf70 100644 --- a/drivers/input/touchscreen/ads7846.c +++ b/drivers/input/touchscreen/ads7846.c @@ -36,13 +36,10 @@ /* - * This code has been tested on an ads7846 / N770 device. + * This code has been heavily tested on a Nokia 770, and lightly + * tested on other ads7846 devices (OSK/Mistral, Lubbock). * Support for ads7843 and ads7845 has only been stubbed in. * - * Not yet done: How accurate are the temperature and voltage - * readings? (System-specific calibration should support - * accuracy of 0.3 degrees C; otherwise it's 2.0 degrees.) - * * IRQ handling needs a workaround because of a shortcoming in handling * edge triggered IRQs on some platforms like the OMAP1/2. These * platforms don't handle the ARM lazy IRQ disabling properly, thus we @@ -248,10 +245,13 @@ static int ads7846_read12_ser(struct device *dev, unsigned command) if (req->msg.status) status = req->msg.status; + + /* on-wire is a must-ignore bit, a BE12 value, then padding */ sample = be16_to_cpu(req->sample); - sample = sample >> 4; - kfree(req); + sample = sample >> 3; + sample &= 0x0fff; + kfree(req); return status ? status : sample; } @@ -336,13 +336,13 @@ static void ads7846_rx(void *ads) u16 x, y, z1, z2; unsigned long flags; - /* adjust: 12 bit samples (left aligned), built from - * two 8 bit values writen msb-first. + /* adjust: on-wire is a must-ignore bit, a BE12 value, then padding; + * built from two 8 bit values written msb-first. */ - x = be16_to_cpu(ts->tc.x) >> 4; - y = be16_to_cpu(ts->tc.y) >> 4; - z1 = be16_to_cpu(ts->tc.z1) >> 4; - z2 = be16_to_cpu(ts->tc.z2) >> 4; + x = (be16_to_cpu(ts->tc.x) >> 3) & 0x0fff; + y = (be16_to_cpu(ts->tc.y) >> 3) & 0x0fff; + z1 = (be16_to_cpu(ts->tc.z1) >> 3) & 0x0fff; + z2 = (be16_to_cpu(ts->tc.z2) >> 3) & 0x0fff; /* range filtering */ if (x == MAX_12BIT) @@ -420,7 +420,7 @@ static void ads7846_debounce(void *ads) m = &ts->msg[ts->msg_idx]; t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list); - val = (*(u16 *)t->rx_buf) >> 3; + val = (be16_to_cpu(*(__be16 *)t->rx_buf) >> 3) & 0x0fff; if (!ts->read_cnt || (abs(ts->last_read - val) > ts->debounce_tol)) { /* Repeat it, if this was the first read or the read * wasn't consistent enough. */ @@ -469,7 +469,7 @@ static void ads7846_timer(unsigned long handle) spin_lock_irq(&ts->lock); if (unlikely(ts->msg_idx && !ts->pendown)) { - /* measurment cycle ended */ + /* measurement cycle ended */ if (!device_suspended(&ts->spi->dev)) { ts->irq_disabled = 0; enable_irq(ts->spi->irq); @@ -495,11 +495,10 @@ static irqreturn_t ads7846_irq(int irq, void *handle, struct pt_regs *regs) spin_lock_irqsave(&ts->lock, flags); if (likely(ts->get_pendown_state())) { if (!ts->irq_disabled) { - /* REVISIT irq logic for many ARM chips has cloned a - * bug wherein disabling an irq in its handler won't - * work;(it's disabled lazily, and too late to work. - * until all their irq logic is fixed, we must shadow - * that state here. + /* The ARM do_simple_IRQ() dispatcher doesn't act + * like the other dispatchers: it will report IRQs + * even after they've been disabled. We work around + * that here. (The "generic irq" framework may help...) */ ts->irq_disabled = 1; disable_irq(ts->spi->irq); @@ -609,16 +608,20 @@ static int __devinit ads7846_probe(struct spi_device *spi) return -EINVAL; } + /* REVISIT when the irq can be triggered active-low, or if for some + * reason the touchscreen isn't hooked up, we don't need to access + * the pendown state. + */ if (pdata->get_pendown_state == NULL) { dev_dbg(&spi->dev, "no get_pendown_state function?\n"); return -EINVAL; } - /* We'd set the wordsize to 12 bits ... except that some controllers - * will then treat the 8 bit command words as 12 bits (and drop the - * four MSBs of the 12 bit result). Result: inputs must be shifted - * to discard the four garbage LSBs. + /* We'd set TX wordsize 8 bits and RX wordsize to 13 bits ... except + * that even if the hardware can do that, the SPI controller driver + * may not. So we stick to very-portable 8 bit words, both RX and TX. */ + spi->bits_per_word = 8; ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL); input_dev = input_allocate_device(); @@ -770,9 +773,8 @@ static int __devinit ads7846_probe(struct spi_device *spi) ts->last_msg = m; - if (request_irq(spi->irq, ads7846_irq, - SA_SAMPLE_RANDOM | SA_TRIGGER_FALLING, - spi->dev.bus_id, ts)) { + if (request_irq(spi->irq, ads7846_irq, IRQF_TRIGGER_FALLING, + spi->dev.driver->name, ts)) { dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq); err = -EBUSY; goto err_free_mem; |