Input: rotary_encoder - add support for REL_* axes

The rotary encoder driver only supports returning input events
for ABS_* axes, this adds support for REL_* axes.  The relative
axis input event is reported as -1 for each counter-clockwise
step and +1 for each clockwise step.

The ability to clamp the position of ABS_* axes between 0 and
a maximum of "steps" has also been added.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
This commit is contained in:
H Hartley Sweeten 2009-04-17 20:12:35 -07:00 committed by Dmitry Torokhov
parent 3f3e7c6e13
commit bd3ce65560
3 changed files with 51 additions and 21 deletions

View File

@ -67,7 +67,12 @@ data with it.
struct rotary_encoder_platform_data is declared in
include/linux/rotary-encoder.h and needs to be filled with the number of
steps the encoder has and can carry information about externally inverted
signals (because of used invertig buffer or other reasons).
signals (because of an inverting buffer or other reasons). The encoder
can be set up to deliver input information as either an absolute or relative
axes. For relative axes the input event returns +/-1 for each step. For
absolute axes the position of the encoder can either roll over between zero
and the number of steps or will clamp at the maximum and zero depending on
the configuration.
Because GPIO to IRQ mapping is platform specific, this information must
be given in seperately to the driver. See the example below.
@ -85,6 +90,8 @@ be given in seperately to the driver. See the example below.
static struct rotary_encoder_platform_data my_rotary_encoder_info = {
.steps = 24,
.axis = ABS_X,
.relative_axis = false,
.rollover = false,
.gpio_a = GPIO_ROTARY_A,
.gpio_b = GPIO_ROTARY_B,
.inverted_a = 0,

View File

@ -26,13 +26,17 @@
#define DRV_NAME "rotary-encoder"
struct rotary_encoder {
unsigned int irq_a;
unsigned int irq_b;
unsigned int pos;
unsigned int armed;
unsigned int dir;
struct input_dev *input;
struct rotary_encoder_platform_data *pdata;
unsigned int axis;
unsigned int pos;
unsigned int irq_a;
unsigned int irq_b;
bool armed;
unsigned char dir; /* 0 - clockwise, 1 - CCW */
};
static irqreturn_t rotary_encoder_irq(int irq, void *dev_id)
@ -53,21 +57,32 @@ static irqreturn_t rotary_encoder_irq(int irq, void *dev_id)
if (!encoder->armed)
break;
if (pdata->relative_axis) {
input_report_rel(encoder->input, pdata->axis,
encoder->dir ? -1 : 1);
} else {
unsigned int pos = encoder->pos;
if (encoder->dir) {
/* turning counter-clockwise */
encoder->pos += pdata->steps;
encoder->pos--;
encoder->pos %= pdata->steps;
if (pdata->rollover)
pos += pdata->steps;
if (pos)
pos--;
} else {
/* turning clockwise */
encoder->pos++;
encoder->pos %= pdata->steps;
if (pdata->rollover || pos < pdata->steps)
pos++;
}
if (pdata->rollover)
pos %= pdata->steps;
encoder->pos = pos;
input_report_abs(encoder->input, pdata->axis,
encoder->pos);
}
input_report_abs(encoder->input, pdata->axis, encoder->pos);
input_sync(encoder->input);
encoder->armed = 0;
encoder->armed = false;
break;
case 0x1:
@ -77,7 +92,7 @@ static irqreturn_t rotary_encoder_irq(int irq, void *dev_id)
break;
case 0x3:
encoder->armed = 1;
encoder->armed = true;
break;
}
@ -113,9 +128,15 @@ static int __devinit rotary_encoder_probe(struct platform_device *pdev)
input->name = pdev->name;
input->id.bustype = BUS_HOST;
input->dev.parent = &pdev->dev;
if (pdata->relative_axis) {
input->evbit[0] = BIT_MASK(EV_REL);
input->relbit[0] = BIT_MASK(pdata->axis);
} else {
input->evbit[0] = BIT_MASK(EV_ABS);
input_set_abs_params(encoder->input,
pdata->axis, 0, pdata->steps, 0, 1);
}
err = input_register_device(input);
if (err) {

View File

@ -8,6 +8,8 @@ struct rotary_encoder_platform_data {
unsigned int gpio_b;
unsigned int inverted_a;
unsigned int inverted_b;
bool relative_axis;
bool rollover;
};
#endif /* __ROTARY_ENCODER_H__ */