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authorAlexander Stein <alexander.stein@systec-electronic.com>2011-05-11 16:24:08 -0700
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2011-05-12 08:28:56 -0700
commitebcaaad9d5e8fd284b8dcf25a24999420f0f56d8 (patch)
tree041e210499460d21c7acb75ced6b819f88bb4749 /drivers/input/touchscreen/ads7846.c
parente70bdd41bd0ead91b4a43e9d656ac1569d7c8779 (diff)
Input: ads7846 - add possibility to use external vref on ads7846
Just set vref_mv in your platform config to use external vref. Otherwise the internal one is used. Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Diffstat (limited to 'drivers/input/touchscreen/ads7846.c')
-rw-r--r--drivers/input/touchscreen/ads7846.c19
1 files changed, 11 insertions, 8 deletions
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index c24946f5125..e4ee43e159d 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -109,6 +109,7 @@ struct ads7846 {
u16 pressure_max;
bool swap_xy;
+ bool use_internal;
struct ads7846_packet *packet;
@@ -300,7 +301,6 @@ static int ads7846_read12_ser(struct device *dev, unsigned command)
struct ads7846 *ts = dev_get_drvdata(dev);
struct ser_req *req;
int status;
- int use_internal;
req = kzalloc(sizeof *req, GFP_KERNEL);
if (!req)
@@ -308,11 +308,8 @@ static int ads7846_read12_ser(struct device *dev, unsigned command)
spi_message_init(&req->msg);
- /* FIXME boards with ads7846 might use external vref instead ... */
- use_internal = (ts->model == 7846);
-
/* maybe turn on internal vREF, and let it settle */
- if (use_internal) {
+ if (ts->use_internal) {
req->ref_on = REF_ON;
req->xfer[0].tx_buf = &req->ref_on;
req->xfer[0].len = 1;
@@ -324,8 +321,14 @@ static int ads7846_read12_ser(struct device *dev, unsigned command)
/* for 1uF, settle for 800 usec; no cap, 100 usec. */
req->xfer[1].delay_usecs = ts->vref_delay_usecs;
spi_message_add_tail(&req->xfer[1], &req->msg);
+
+ /* Enable reference voltage */
+ command |= ADS_PD10_REF_ON;
}
+ /* Enable ADC in every case */
+ command |= ADS_PD10_ADC_ON;
+
/* take sample */
req->command = (u8) command;
req->xfer[2].tx_buf = &req->command;
@@ -409,7 +412,7 @@ name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
{ \
struct ads7846 *ts = dev_get_drvdata(dev); \
ssize_t v = ads7846_read12_ser(dev, \
- READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \
+ READ_12BIT_SER(var)); \
if (v < 0) \
return v; \
return sprintf(buf, "%u\n", adjust(ts, v)); \
@@ -502,6 +505,7 @@ static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
if (!ts->vref_mv) {
dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
ts->vref_mv = 2500;
+ ts->use_internal = true;
}
break;
case 7845:
@@ -1333,8 +1337,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
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);
+ (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
if (err)