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@xxxxxxxxxxxxxxxxxxxxx>
---
This slight semantic change of vref_mv should not introduce a regression.
All boards using the 7846 model didn't set vref_mv which results in the
expected behavior.
Alexander
drivers/input/touchscreen/ads7846.c | 8 +++-----
include/linux/spi/ads7846.h | 3 ++-
2 files changed, 5 insertions(+), 6 deletions(-)
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index 1de1c19..a19e340 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;
@@ -307,7 +308,6 @@ 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)
@@ -315,11 +315,8 @@ 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;
@@ -509,6 +506,7 @@ 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:
diff --git a/include/linux/spi/ads7846.h b/include/linux/spi/ads7846.h
index 92bd083..c64de9d 100644
--- a/include/linux/spi/ads7846.h
+++ b/include/linux/spi/ads7846.h
@@ -14,7 +14,8 @@ enum ads7846_filter {
struct ads7846_platform_data {
u16 model; /* 7843, 7845, 7846, 7873. */
u16 vref_delay_usecs; /* 0 for external vref; etc */
- u16 vref_mv; /* external vref value, milliVolts */
+ u16 vref_mv; /* external vref value, milliVolts
+ * ads7846: if 0, use internal vref */
bool keep_vref_on; /* set to keep vref on for differential
* measurements as well */
bool swap_xy; /* swap x and y axes */
--
1.7.3.4
--
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