On some boards, the SPI controller is limited to half-duplex and the driver
is just spamming "ads7846 spi2.0: spi_sync --> -22". Restore half-duplex
support using multiple SPI transfers.
Fixes: 9c9509717b53 ("Input: ads7846 - convert to full duplex")
Signed-off-by: Aaro Koskinen <aaro.koskinen@xxxxxx>
---
drivers/input/touchscreen/ads7846.c | 168 +++++++++++++++++++++++++++-
1 file changed, 166 insertions(+), 2 deletions(-)
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index 54280ecca0a7..276591c682ad 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -134,6 +134,9 @@ struct ads7846 {
bool disabled; /* P: lock */
bool suspended; /* P: lock */
+ int (*setup_spi_msg)(struct ads7846 *ts,
+ const struct ads7846_platform_data *pdata);
+ void (*read_state)(struct ads7846 *ts);
int (*filter)(void *data, int data_idx, int *val);
void *filter_data;
int (*get_pendown_state)(void);
@@ -797,6 +800,22 @@ static int ads7846_filter(struct ads7846 *ts)
return 0;
}
+static int ads7846_filter_one(struct ads7846 *ts, unsigned int cmd_idx)
+{
+ struct ads7846_packet *packet = ts->packet;
+ struct ads7846_buf_layout *l = &packet->l[cmd_idx];
+ int action, val;
+
+ val = ads7846_get_value(&packet->rx[l->offset + l->count - 1]);
+ action = ts->filter(ts->filter_data, cmd_idx, &val);
+ if (action == ADS7846_FILTER_REPEAT)
+ return -EAGAIN;
+ else if (action != ADS7846_FILTER_OK)
+ return -EIO;
+ ads7846_set_cmd_val(ts, cmd_idx, val);
+ return 0;
+}
+
static void ads7846_wait_for_hsync(struct ads7846 *ts)
{
if (ts->wait_for_sync) {
@@ -819,6 +838,45 @@ static void ads7846_wait_for_hsync(struct ads7846 *ts)
cpu_relax();
}
+static void ads7846_halfd_read_state(struct ads7846 *ts)
+{
+ struct ads7846_packet *packet = ts->packet;
+ int msg_idx = 0;
+
+ packet->ignore = false;
+
+ while (msg_idx < ts->msg_count) {
+ int error;
+
+ ads7846_wait_for_hsync(ts);
+
+ error = spi_sync(ts->spi, &ts->msg[msg_idx]);
+ if (error) {
+ dev_err_ratelimited(&ts->spi->dev, "spi_sync --> %d\n",
+ error);
+ packet->ignore = true;
+ return;
+ }
+
+ /*
+ * Last message is power down request, no need to convert
+ * or filter the value.
+ */
+ if (msg_idx == ts->msg_count - 1)
+ break;
+
+ error = ads7846_filter_one(ts, msg_idx);
+ if (error == -EAGAIN) {
+ continue;
+ } else if (error) {
+ packet->ignore = true;
+ msg_idx = ts->msg_count - 1;
+ } else {
+ msg_idx++;
+ }
+ }
+}
+
static void ads7846_read_state(struct ads7846 *ts)
{
struct ads7846_packet *packet = ts->packet;
@@ -947,7 +1005,7 @@ static irqreturn_t ads7846_irq(int irq, void *handle)
while (!ts->stopped && get_pendown_state(ts)) {
/* pen is down, continue with the measurement */
- ads7846_read_state(ts);
+ ts->read_state(ts);
if (!ts->stopped)
ads7846_report_state(ts);
@@ -1035,6 +1093,102 @@ static int ads7846_setup_pendown(struct spi_device *spi,
return 0;
}
+/*
+ * Set up the transfers to read touchscreen state; this assumes we
+ * use formula #2 for pressure, not #3.
+ */
+static int ads7846_halfd_spi_msg(struct ads7846 *ts,
+ const struct ads7846_platform_data *pdata)
+{
+ struct spi_message *m = ts->msg;
+ struct spi_transfer *x = ts->xfer;
+ struct ads7846_packet *packet = ts->packet;
+ int vref = pdata->keep_vref_on;
+ unsigned int offset = 0;
+ unsigned int cmd_idx, b;
+ size_t size = 0;
+
+ if (pdata->settle_delay_usecs)
+ packet->count = 2;
+ else
+ packet->count = 1;
+
+ if (ts->model == 7846)
+ packet->cmds = 5; /* x, y, z1, z2, pwdown */
+ else
+ packet->cmds = 3; /* x, y, pwdown */
+
+ for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
+ struct ads7846_buf_layout *l = &packet->l[cmd_idx];
+ unsigned int max_count;
+
+ if (cmd_idx == packet->cmds - 1) {
+ cmd_idx = ADS7846_PWDOWN;
+ max_count = 1;
+ } else {
+ max_count = packet->count;
+ }
+
+ l->offset = offset;
+ offset += max_count;
+ l->count = max_count;
+ l->skip = 0;
+ size += sizeof(*packet->rx) * max_count;
+ }
+
+ /* We use two transfers per command. */
+ if (ARRAY_SIZE(ts->xfer) < offset * 2)
+ return -ENOMEM;
+
+ packet->rx = devm_kzalloc(&ts->spi->dev, size, GFP_KERNEL);
+ if (!packet->rx)
+ return -ENOMEM;
+
+ if (ts->model == 7873) {
+ /*
+ * The AD7873 is almost identical to the ADS7846
+ * keep VREF off during differential/ratiometric
+ * conversion modes.
+ */
+ ts->model = 7846;
+ vref = 0;
+ }
+
+ ts->msg_count = 0;
+
+ for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
+ struct ads7846_buf_layout *l = &packet->l[cmd_idx];
+ u8 cmd;
+
+ ts->msg_count++;
+ spi_message_init(m);
+ m->context = ts;
+
+ if (cmd_idx == packet->cmds - 1)
+ cmd_idx = ADS7846_PWDOWN;
+
+ cmd = ads7846_get_cmd(cmd_idx, vref);
+
+ for (b = 0; b < l->count; b++) {
+ packet->rx[l->offset + b].cmd = cmd;
+ x->tx_buf = &packet->rx[l->offset + b].cmd;
+ x->len = 1;
+ spi_message_add_tail(x, m);
+ x++;
+ x->rx_buf = &packet->rx[l->offset + b].data;
+ x->len = 2;
+ if (b < l->count - 1 && l->count > 1) {
+ x->delay.value = pdata->settle_delay_usecs;
+ x->delay.unit = SPI_DELAY_UNIT_USECS;
+ }
+ spi_message_add_tail(x, m);
+ x++;
+ }
+ m++;
+ }
+ return 0;
+}
+
/*
* Set up the transfers to read touchscreen state; this assumes we
* use formula #2 for pressure, not #3.
@@ -1249,6 +1403,14 @@ static int ads7846_probe(struct spi_device *spi)
if (!ts)
return -ENOMEM;
+ if (spi->controller->flags & SPI_CONTROLLER_HALF_DUPLEX) {
+ ts->setup_spi_msg = ads7846_halfd_spi_msg;
+ ts->read_state = ads7846_halfd_read_state;
+ } else {
+ ts->setup_spi_msg = ads7846_setup_spi_msg;
+ ts->read_state = ads7846_read_state;
+ }
+
packet = devm_kzalloc(dev, sizeof(struct ads7846_packet), GFP_KERNEL);
if (!packet)
return -ENOMEM;
@@ -1343,7 +1505,9 @@ static int ads7846_probe(struct spi_device *spi)
ts->core_prop.swap_x_y = true;
}
- ads7846_setup_spi_msg(ts, pdata);
+ err = ts->setup_spi_msg(ts, pdata);
+ if (err)
+ return err;
ts->reg = devm_regulator_get(dev, "vcc");
if (IS_ERR(ts->reg)) {
--
2.39.2
