From 3eac5c7e44f35eb07f0ecb28ce60f15b2dda1932 Mon Sep 17 00:00:00 2001 From: Anatolij Gustschin Date: Thu, 1 Jul 2010 09:01:56 -0700 Subject: Input: ads7846 - extend the driver for ads7845 controller support ADS7845 is a controller for 5-wire touch screens and somewhat different from 7846. It requires three serial communications to accomplish one complete conversion. Unlike 7846 it doesn't allow Z1-/Z2- position measurement. The patch extends the ads7846 driver to also support ads7845. The packet struct is extended to contain needed command and conversion buffers. ads7846_rx() and ads7846_rx_val() now differentiate between 7845 and 7846 case. ads7846_probe() is modified to setup ads7845 specific command and conversion messages and to switch ads7845 into power-down mode, since this is needed to be prepared to respond to pendown interrupts. Signed-off-by: Anatolij Gustschin Signed-off-by: Dmitry Torokhov --- drivers/input/touchscreen/ads7846.c | 172 ++++++++++++++++++++++++++++-------- 1 file changed, 135 insertions(+), 37 deletions(-) (limited to 'drivers/input/touchscreen/ads7846.c') diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c index a3771607ead5..16031933a8f6 100644 --- a/drivers/input/touchscreen/ads7846.c +++ b/drivers/input/touchscreen/ads7846.c @@ -68,6 +68,8 @@ struct ts_event { u16 y; u16 z1, z2; int ignore; + u8 x_buf[3]; + u8 y_buf[3]; }; /* @@ -79,6 +81,8 @@ struct ads7846_packet { u8 read_x, read_y, read_z1, read_z2, pwrdown; u16 dummy; /* for the pwrdown read */ struct ts_event tc; + /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */ + u8 read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3]; }; struct ads7846 { @@ -207,6 +211,14 @@ struct ser_req { struct spi_transfer xfer[6]; }; +struct ads7845_ser_req { + u8 command[3]; + u8 pwrdown[3]; + u8 sample[3]; + struct spi_message msg; + struct spi_transfer xfer[2]; +}; + static void ads7846_enable(struct ads7846 *ts); static void ads7846_disable(struct ads7846 *ts); @@ -287,6 +299,41 @@ static int ads7846_read12_ser(struct device *dev, unsigned command) return status; } +static int ads7845_read12_ser(struct device *dev, unsigned command) +{ + struct spi_device *spi = to_spi_device(dev); + struct ads7846 *ts = dev_get_drvdata(dev); + struct ads7845_ser_req *req = kzalloc(sizeof *req, GFP_KERNEL); + int status; + + if (!req) + return -ENOMEM; + + spi_message_init(&req->msg); + + req->command[0] = (u8) command; + req->xfer[0].tx_buf = req->command; + req->xfer[0].rx_buf = req->sample; + req->xfer[0].len = 3; + spi_message_add_tail(&req->xfer[0], &req->msg); + + ts->irq_disabled = 1; + disable_irq(spi->irq); + status = spi_sync(spi, &req->msg); + ts->irq_disabled = 0; + enable_irq(spi->irq); + + if (status == 0) { + /* BE12 value, then padding */ + status = be16_to_cpu(*((u16 *)&req->sample[1])); + status = status >> 3; + status &= 0x0fff; + } + + kfree(req); + return status; +} + #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE) #define SHOW(name, var, adjust) static ssize_t \ @@ -540,10 +587,17 @@ static void ads7846_rx(void *ads) /* ads7846_rx_val() did in-place conversion (including byteswap) from * on-the-wire format as part of debouncing to get stable readings. */ - x = packet->tc.x; - y = packet->tc.y; - z1 = packet->tc.z1; - z2 = packet->tc.z2; + if (ts->model == 7845) { + x = *(u16 *)packet->tc.x_buf; + y = *(u16 *)packet->tc.y_buf; + z1 = 0; + z2 = 0; + } else { + x = packet->tc.x; + y = packet->tc.y; + z1 = packet->tc.z1; + z2 = packet->tc.z2; + } /* range filtering */ if (x == MAX_12BIT) @@ -551,6 +605,12 @@ static void ads7846_rx(void *ads) if (ts->model == 7843) { Rt = ts->pressure_max / 2; + } else if (ts->model == 7845) { + if (get_pendown_state(ts)) + Rt = ts->pressure_max / 2; + else + Rt = 0; + dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt); } else if (likely(x && z1)) { /* compute touch pressure resistance using equation #2 */ Rt = z2; @@ -671,10 +731,14 @@ static void ads7846_rx_val(void *ads) m = &ts->msg[ts->msg_idx]; t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list); - /* adjust: on-wire is a must-ignore bit, a BE12 value, then padding; - * built from two 8 bit values written msb-first. - */ - val = be16_to_cpup((__be16 *)t->rx_buf) >> 3; + if (ts->model == 7845) { + val = be16_to_cpup((__be16 *)&(((char*)t->rx_buf)[1])) >> 3; + } else { + /* adjust: on-wire is a must-ignore bit, a BE12 value, then + * padding; built from two 8 bit values written msb-first. + */ + val = be16_to_cpup((__be16 *)t->rx_buf) >> 3; + } action = ts->filter(ts->filter_data, ts->msg_idx, &val); switch (action) { @@ -1009,16 +1073,26 @@ static int __devinit ads7846_probe(struct spi_device *spi) spi_message_init(m); - /* y- still on; turn on only y+ (and ADC) */ - packet->read_y = READ_Y(vref); - x->tx_buf = &packet->read_y; - x->len = 1; - spi_message_add_tail(x, m); + if (ts->model == 7845) { + packet->read_y_cmd[0] = READ_Y(vref); + packet->read_y_cmd[1] = 0; + packet->read_y_cmd[2] = 0; + x->tx_buf = &packet->read_y_cmd[0]; + x->rx_buf = &packet->tc.y_buf[0]; + x->len = 3; + spi_message_add_tail(x, m); + } else { + /* y- still on; turn on only y+ (and ADC) */ + packet->read_y = READ_Y(vref); + x->tx_buf = &packet->read_y; + x->len = 1; + spi_message_add_tail(x, m); - x++; - x->rx_buf = &packet->tc.y; - x->len = 2; - spi_message_add_tail(x, m); + x++; + x->rx_buf = &packet->tc.y; + x->len = 2; + spi_message_add_tail(x, m); + } /* the first sample after switching drivers can be low quality; * optionally discard it, using a second one after the signals @@ -1044,17 +1118,28 @@ static int __devinit ads7846_probe(struct spi_device *spi) m++; spi_message_init(m); - /* turn y- off, x+ on, then leave in lowpower */ - x++; - packet->read_x = READ_X(vref); - x->tx_buf = &packet->read_x; - x->len = 1; - spi_message_add_tail(x, m); + if (ts->model == 7845) { + x++; + packet->read_x_cmd[0] = READ_X(vref); + packet->read_x_cmd[1] = 0; + packet->read_x_cmd[2] = 0; + x->tx_buf = &packet->read_x_cmd[0]; + x->rx_buf = &packet->tc.x_buf[0]; + x->len = 3; + spi_message_add_tail(x, m); + } else { + /* turn y- off, x+ on, then leave in lowpower */ + x++; + packet->read_x = READ_X(vref); + x->tx_buf = &packet->read_x; + x->len = 1; + spi_message_add_tail(x, m); - x++; - x->rx_buf = &packet->tc.x; - x->len = 2; - spi_message_add_tail(x, m); + x++; + x->rx_buf = &packet->tc.x; + x->len = 2; + spi_message_add_tail(x, m); + } /* ... maybe discard first sample ... */ if (pdata->settle_delay_usecs) { @@ -1145,15 +1230,25 @@ static int __devinit ads7846_probe(struct spi_device *spi) m++; spi_message_init(m); - x++; - packet->pwrdown = PWRDOWN; - x->tx_buf = &packet->pwrdown; - x->len = 1; - spi_message_add_tail(x, m); + if (ts->model == 7845) { + x++; + packet->pwrdown_cmd[0] = PWRDOWN; + packet->pwrdown_cmd[1] = 0; + packet->pwrdown_cmd[2] = 0; + x->tx_buf = &packet->pwrdown_cmd[0]; + x->len = 3; + } else { + x++; + packet->pwrdown = PWRDOWN; + x->tx_buf = &packet->pwrdown; + x->len = 1; + spi_message_add_tail(x, m); + + x++; + x->rx_buf = &packet->dummy; + x->len = 2; + } - x++; - x->rx_buf = &packet->dummy; - x->len = 2; CS_CHANGE(*x); spi_message_add_tail(x, m); @@ -1202,8 +1297,11 @@ static int __devinit ads7846_probe(struct spi_device *spi) /* take a first sample, leaving nPENIRQ active and vREF off; avoid * the touchscreen, in case it's not connected. */ - (void) ads7846_read12_ser(&spi->dev, - READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON); + if (ts->model == 7845) + ads7845_read12_ser(&spi->dev, PWRDOWN); + else + (void) ads7846_read12_ser(&spi->dev, + READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON); err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group); if (err) -- cgit v1.2.3