Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-27 14:41:39 +00:00
Code Issues Packages Projects Releases Wiki Activity

Input: eeti_ts - read hardware state once after wakeup

Browse Source 
For systems in which the touch IRQ is acting as wakeup source, and that do
not support level-driven interrupts, the interrupt controller might not
latch the GPIO IRQ during sleep. In such cases, the interrupt will never
occur again after resume, hence the touch screen appears dead.

To fix this, check for the assertion of the attn gpio, and read form the
controller once in the resume path to read the hardware status and
to arm the IRQ again.

Introduce a mutex to guard eeti_ts_read() against parallel invocations
from different contexts.

Signed-off-by: Daniel Mack <daniel@zonque.org>
Reported-by: Sven Neumann <Sven.Neumann@teufel.de>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Daniel Mack 2019-05-06 20:03:46 -07:00 committed by Dmitry Torokhov
parent 7f7a020836
commit b283d0c353
1 changed files with 56 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

71
drivers/input/touchscreen/eeti_ts.c
View File

@ -41,6 +41,7 @@ struct eeti_ts {
struct input_dev *input;
struct gpio_desc *attn_gpio;
struct touchscreen_properties props;
struct mutex mutex;
bool running;
};
@ -75,42 +76,80 @@ static void eeti_ts_report_event(struct eeti_ts *eeti, u8 *buf)
input_sync(eeti->input);
}
static int eeti_ts_read(struct eeti_ts *eeti)
{
int len, error;
char buf[6];
len = i2c_master_recv(eeti->client, buf, sizeof(buf));
if (len != sizeof(buf)) {
error = len < 0 ? len : -EIO;
dev_err(&eeti->client->dev,
"failed to read touchscreen data: %d\n",
error);
return error;
}
/* Motion packet */
if (buf[0] & 0x80)
eeti_ts_report_event(eeti, buf);
return 0;
}
static irqreturn_t eeti_ts_isr(int irq, void *dev_id)
{
struct eeti_ts *eeti = dev_id;
int len;
int error;
char buf[6];
mutex_lock(&eeti->mutex);
do {
len = i2c_master_recv(eeti->client, buf, sizeof(buf));
if (len != sizeof(buf)) {
error = len < 0 ? len : -EIO;
dev_err(&eeti->client->dev,
"failed to read touchscreen data: %d\n",
error);
/*
* If we have attention GPIO, trust it. Otherwise we'll read
* once and exit. We assume that in this case we are using
* level triggered interrupt and it will get raised again
* if/when there is more data.
*/
if (eeti->attn_gpio &&
!gpiod_get_value_cansleep(eeti->attn_gpio)) {
break;
}
if (buf[0] & 0x80) {
/* Motion packet */
eeti_ts_report_event(eeti, buf);
}
} while (eeti->running &&
eeti->attn_gpio && gpiod_get_value_cansleep(eeti->attn_gpio));
error = eeti_ts_read(eeti);
if (error)
break;
} while (eeti->running && eeti->attn_gpio);
mutex_unlock(&eeti->mutex);
return IRQ_HANDLED;
}
static void eeti_ts_start(struct eeti_ts *eeti)
{
mutex_lock(&eeti->mutex);
eeti->running = true;
wmb();
enable_irq(eeti->client->irq);
/*
* Kick the controller in case we are using edge interrupt and
* we missed our edge while interrupt was disabled. We expect
* the attention GPIO to be wired in this case.
*/
if (eeti->attn_gpio && gpiod_get_value_cansleep(eeti->attn_gpio))
eeti_ts_read(eeti);
mutex_unlock(&eeti->mutex);
}
static void eeti_ts_stop(struct eeti_ts *eeti)
{
/*
* Not locking here, just setting a flag and expect that the
* interrupt thread will notice the flag eventually.
*/
eeti->running = false;
wmb();
disable_irq(eeti->client->irq);
@ -153,6 +192,8 @@ static int eeti_ts_probe(struct i2c_client *client,
return -ENOMEM;
}
mutex_init(&eeti->mutex);
input = devm_input_allocate_device(dev);
if (!input) {
dev_err(dev, "Failed to allocate input device.\n");