Re: [RFC PATCH] da9052_tsi: remove fifo and use delayed work

From: Dmitry Torokhov
Date: Fri Aug 12 2011 - 03:26:59 EST


Hi Michael,

On Tue, Aug 09, 2011 at 03:59:32PM +0200, Michael Grzeschik wrote:
> Remove the coordinate fifo and check for penup with a delayed work,
> instead of a watching kernel thread.
>

Yes, this looks much better. A few comments below.

> Issues:
> Sometimes there are well defined jitter values on the x-axys this must
> be more investigated. Hint: DA9052_TSI_CONT_A_REG holds some time Adjust
> values for TSI_SKIP and TSI_DELAY, which might have to be properly
> aligned to the touch events.
>
> Signed-off-by: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx>
> ---
> drivers/input/touchscreen/da9052_tsi.c | 245 ++++++++------------------------
> 1 files changed, 61 insertions(+), 184 deletions(-)
>
> diff --git a/drivers/input/touchscreen/da9052_tsi.c b/drivers/input/touchscreen/da9052_tsi.c
> index 91e051a..91d489f 100755
> --- a/drivers/input/touchscreen/da9052_tsi.c
> +++ b/drivers/input/touchscreen/da9052_tsi.c
> @@ -15,47 +15,24 @@
> #include <linux/input.h>
> #include <linux/delay.h>
> #include <linux/platform_device.h>
> -#include <linux/freezer.h>
> +#include <linux/sched.h>
> #include <linux/kthread.h>

That can be dropped too I think.

> -#include <linux/kfifo.h>
>
> #include <linux/mfd/da9052/reg.h>
> #include <linux/mfd/da9052/da9052.h>
>
> -#define DA9052_ACTIVE 1
> -#define DA9052_INACTIVE 0
> -
> -#define DA9052_TSI_FIFOSIZE 640
> -
> -enum {
> - DA9052_PEN_IDLE,
> - DA9052_PEN_DOWN,
> - DA9052_PEN_UP
> -};
> -
> struct da9052_tsi_reg {
> u16 x;
> u16 y;
> };
>
> -struct tsi_thread_type {
> - u8 pid;
> - u8 state;
> - struct completion notifier;
> - struct task_struct *thread_task;
> -};
> -
> struct da9052_tsi {
> struct da9052 *da9052;
> struct input_dev *dev;
> - struct tsi_thread_type tsi_pen_state_thread;
> - struct tsi_thread_type tsi_filter_thread;
> - struct kfifo fifo;
> - struct kfifo fifo_buf;
> u8 pen_up_detect_interval;
> u32 zero_data_cnt;
> u32 valid_penup_count;

Above 2 are not used.

> - u8 pen_state;
> + struct delayed_work work;
> int irq_pendwn;
> int irq_datardy;
> };
> @@ -71,6 +48,48 @@ static inline int da9052_ts_stop(struct da9052_tsi *tsi)
> return da9052_clear_bits(tsi->da9052, DA9052_TSI_CONT_A_REG, 1 << 0);
> }
>
> +static void da9052_work(struct work_struct *work)
> +{
> + struct da9052_tsi *tsi = container_of(work, struct da9052_tsi, work.work);
> + struct da9052 *da9052 = tsi->da9052;
> + int ret;
> + uint8_t _v;
> + u16 down;
> +
> + ret = da9052_reg_read(tsi->da9052, DA9052_TSI_LSB_REG);
> + if (ret < 0)
> + return;
> +
> + _v = (uint8_t) ret;
> + down = ((_v & 0x40) >> 6);
> +
> + if (!down) {
> + tsi->da9052->events_mask |= DA9052_E_TSI_READY;
> + tsi->da9052->events_mask &= ~DA9052_E_PEN_DOWN;
> +
> + /* Mask TSI_READY event and unmask PEN_DOWN event*/
> + ret = da9052_reg_update(tsi->da9052, DA9052_IRQ_MASK_B_REG, 0x40, 0x80);
> + if (ret < 0)
> + return;

There is no good way to handle da9052_reg_update() failure so don't.

> +
> + input_report_abs(tsi->dev, ABS_PRESSURE, 0);

No fake pressure events please.

> + input_report_key(tsi->dev, BTN_TOUCH, 1);
> + input_sync(tsi->dev);
> + } else {
> + da9052->events_mask |= DA9052_E_PEN_DOWN;
> + da9052->events_mask &= ~DA9052_E_TSI_READY;
> +
> + /* Mask PEN_DOWN event and unmask TSI_READY event*/
> + ret = da9052_reg_update(da9052, DA9052_IRQ_MASK_B_REG, 0x80, 0x40);
> + if (ret < 0)
> + return;

Why do we need to do the masking again? Just re-schedule the work.

> +
> + /* start polling for touch_det to detect release */
> + schedule_delayed_work(&tsi->work, HZ / 50);
> + }
> +
> +}
> +
> static irqreturn_t da9052_ts_pendwn_irq(int irq, void *data)
> {
> struct da9052_tsi *tsi = (struct da9052_tsi *)data;
> @@ -86,7 +105,10 @@ static irqreturn_t da9052_ts_pendwn_irq(int irq, void *data)
> return IRQ_NONE;
>
> da9052_ts_start(tsi);
> - tsi->pen_state = DA9052_PEN_DOWN;
> +
> + input_report_abs(tsi->dev, ABS_PRESSURE, 1023);
> + input_report_key(tsi->dev, BTN_TOUCH, 0);
> + input_sync(tsi->dev);
>
> return IRQ_HANDLED;
> }
> @@ -118,7 +140,10 @@ static int da9052_ts_read(struct da9052_tsi *tsi)
> co_ord.x = ((_x << 2) & 0x3fc) | (_v & 0x3);
> co_ord.y = ((_y << 2) & 0x3fc) | ((_v & 0xc) >> 2);
>
> - ret = kfifo_in(&tsi->fifo, &co_ord, sizeof(struct da9052_tsi_reg));
> + input_report_abs(tsi->dev, ABS_X, co_ord.x);
> + input_report_abs(tsi->dev, ABS_Y, co_ord.y);
> + input_report_abs(tsi->dev, ABS_PRESSURE, 1023);
> + input_sync(tsi->dev);
>
> return 0;
> }
> @@ -135,131 +160,10 @@ static irqreturn_t da9052_ts_datardy_irq(int irq, void *data)
> return IRQ_NONE;
> }
>

[skip[

> + /* start polling for touch_det to detect release */
> + schedule_delayed_work(&tsi->work, HZ / 50);
>

What if da9052_ts_datardy_irq() never comes? You should schedule from
pendown IRQ handler.

> - return 0;
> + return IRQ_HANDLED;
> }
>

...

> -
> + cancel_delayed_work(&tsi->work);

cancel_delayed_work_sync()

There are a few other changes in the patch below, however I can't
compile it since the rest of the MFD code is not in mainline nor in
linux-next.

Thanks.

--
Dmitry


Input: da9052 - misc fixes

From: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>

Signed-off-by: Dmitry Torokhov <dtor@xxxxxxx>
---

drivers/input/touchscreen/da9052_tsi.c | 210 +++++++++++++++-----------------
1 files changed, 96 insertions(+), 114 deletions(-)


diff --git a/drivers/input/touchscreen/da9052_tsi.c b/drivers/input/touchscreen/da9052_tsi.c
index 0445d88..095999e 100644
--- a/drivers/input/touchscreen/da9052_tsi.c
+++ b/drivers/input/touchscreen/da9052_tsi.c
@@ -15,7 +15,6 @@
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/sched.h>
-#include <linux/kthread.h>

#include <linux/mfd/da9052/reg.h>
#include <linux/mfd/da9052/da9052.h>
@@ -26,23 +25,20 @@ struct da9052_tsi_reg {
};

struct da9052_tsi {
- struct da9052 *da9052;
+ struct da9052 *da9052;
struct input_dev *dev;
- u8 pen_up_detect_interval;
- u32 zero_data_cnt;
- u32 valid_penup_count;
struct delayed_work work;
int irq_pendwn;
int irq_datardy;
};

-static inline int da9052_ts_start(struct da9052_tsi *tsi)
+static int da9052_ts_start(struct da9052_tsi *tsi)
{
return da9052_reg_update(tsi->da9052, DA9052_TSI_CONT_A_REG,
1 << 0, 1 << 0);
}

-static inline int da9052_ts_stop(struct da9052_tsi *tsi)
+static int da9052_ts_stop(struct da9052_tsi *tsi)
{
return da9052_clear_bits(tsi->da9052, DA9052_TSI_CONT_A_REG, 1 << 0);
}
@@ -63,51 +59,43 @@ static void da9052_work(struct work_struct *work)
down = ((_v & 0x40) >> 6);

if (!down) {
+ input_report_key(tsi->dev, BTN_TOUCH, 0);
+ input_sync(tsi->dev);
+
+ da9052_ts_stop(tsi);
+
tsi->da9052->events_mask |= DA9052_E_TSI_READY;
tsi->da9052->events_mask &= ~DA9052_E_PEN_DOWN;

/* Mask TSI_READY event and unmask PEN_DOWN event*/
- ret = da9052_reg_update(tsi->da9052, DA9052_IRQ_MASK_B_REG, 0x40, 0x80);
- if (ret < 0)
- return;
-
- input_report_abs(tsi->dev, ABS_PRESSURE, 0);
- input_report_key(tsi->dev, BTN_TOUCH, 1);
- input_sync(tsi->dev);
+ da9052_reg_update(tsi->da9052, DA9052_IRQ_MASK_B_REG, 0x40, 0x80);
} else {
- da9052->events_mask |= DA9052_E_PEN_DOWN;
- da9052->events_mask &= ~DA9052_E_TSI_READY;
-
- /* Mask PEN_DOWN event and unmask TSI_READY event*/
- ret = da9052_reg_update(da9052, DA9052_IRQ_MASK_B_REG, 0x80, 0x40);
- if (ret < 0)
- return;
-
- /* start polling for touch_det to detect release */
+ /* keep polling to detect release */
schedule_delayed_work(&tsi->work, HZ / 50);
}
-
}

static irqreturn_t da9052_ts_pendwn_irq(int irq, void *data)
{
- struct da9052_tsi *tsi = (struct da9052_tsi *)data;
+ struct da9052_tsi *tsi = data;
struct da9052 *da9052 = tsi->da9052;
int ret;

+ input_report_key(tsi->dev, BTN_TOUCH, 1);
+ input_sync(tsi->dev);
+
da9052->events_mask |= DA9052_E_PEN_DOWN;
da9052->events_mask &= ~DA9052_E_TSI_READY;

- /* Mask PEN_DOWN event and unmask TSI_READY event*/
+ /* Mask PEN_DOWN event and unmask TSI_READY event */
ret = da9052_reg_update(da9052, DA9052_IRQ_MASK_B_REG, 0x80, 0x40);
if (ret < 0)
return IRQ_NONE;

da9052_ts_start(tsi);

- input_report_abs(tsi->dev, ABS_PRESSURE, 1023);
- input_report_key(tsi->dev, BTN_TOUCH, 0);
- input_sync(tsi->dev);
+ /* start polling for touch_det to detect release */
+ schedule_delayed_work(&tsi->work, HZ / 50);

return IRQ_HANDLED;
}
@@ -141,7 +129,6 @@ static int da9052_ts_read(struct da9052_tsi *tsi)

input_report_abs(tsi->dev, ABS_X, co_ord.x);
input_report_abs(tsi->dev, ABS_Y, co_ord.y);
- input_report_abs(tsi->dev, ABS_PRESSURE, 1023);
input_sync(tsi->dev);

return 0;
@@ -149,23 +136,20 @@ static int da9052_ts_read(struct da9052_tsi *tsi)

static irqreturn_t da9052_ts_datardy_irq(int irq, void *data)
{
- struct da9052_tsi *tsi = (struct da9052_tsi *)data;
- int ret;
+ struct da9052_tsi *tsi = data;
+ int error;

- ret = da9052_ts_read(tsi);
- if (ret) {
+ error = da9052_ts_read(tsi);
+ if (error) {
dev_err(tsi->da9052->dev,
- "Failed to read TSI co-ordinate, %d\n", ret);
+ "Failed to read TSI co-ordinate, error: %d\n", error);
return IRQ_NONE;
}

- /* start polling for touch_det to detect release */
- schedule_delayed_work(&tsi->work, HZ / 50);
-
return IRQ_HANDLED;
}

-static int da9052_ts_configure_gpio(struct da9052 *da9052)
+static int __devinit da9052_ts_configure_gpio(struct da9052 *da9052)
{
int ret;

@@ -181,26 +165,22 @@ static int da9052_ts_configure_gpio(struct da9052 *da9052)
if (ret < 0)
return -EIO;

- return ret;
+ return 0;
}

-static int __init da9052_ts_enable_device(struct da9052_tsi *tsi)
+static int __devinit da9052_ts_enable_device(struct da9052_tsi *tsi)
{
- ssize_t ret;
struct da9052 *da9052 = tsi->da9052;
+ int error;

- ret = da9052_ts_configure_gpio(tsi->da9052);
- if (ret < 0)
- return ret;
+ error = da9052_ts_configure_gpio(tsi->da9052);
+ if (error)
+ return error;

ret = da9052_reg_update(tsi->da9052, DA9052_TSI_CONT_A_REG, 0xFC, 0xC0);
if (ret < 0)
return ret;

- tsi->valid_penup_count = 5;
-
- tsi->zero_data_cnt = 0;
-
/* Measure TSI sample every 1ms */
ret = da9052_reg_update(tsi->da9052, DA9052_ADC_CONT_REG,
1 << 6, 1 << 6);
@@ -220,43 +200,49 @@ static int __init da9052_ts_enable_device(struct da9052_tsi *tsi)
if (ret < 0)
return ret;

- /*Supply TSIRef thru LD09 */
+ /* Supply TSIRef thru LD09 */
ret = da9052_reg_write(tsi->da9052, DA9052_LDO9_REG, 0x59);
+ if (ret < 0)
+ return ret;

- return ret;
+ return 0;
}

-static s32 __devinit da9052_ts_probe(struct platform_device *pdev)
+static int __devinit da9052_ts_probe(struct platform_device *pdev)
{
+ struct da9052 *da9052 = platform_get_drvdata(pdev->dev.parent);
struct da9052_tsi *tsi;
struct input_dev *input_dev;
- struct da9052 *da9052;
- int ret;
-
- da9052 = dev_get_drvdata(pdev->dev.parent);
+ int irq_pendown, irq_datardy;
+ int error;
+
+ irq_pendwn = platform_get_irq_byname(pdev, "PENDWN");
+ irq_datardy = platform_get_irq_byname(pdev, "TSIRDY");
+ if (irq_pendown < 0 || irq_datardy < 0) {
+ dev_err(da9052->dev, "Unable to determine device interrupts\n");
+ return -ENXIO;
+ }

tsi = kzalloc(sizeof(struct da9052_tsi), GFP_KERNEL);
- if (!tsi)
- return -ENOMEM;
-
input_dev = input_allocate_device();
- if (!input_dev) {
- dev_err(tsi->da9052->dev,
- "failed to allocate input device\n");
+ if (!tsi || !input_dev) {
+ dev_err(da9052->dev, "failed to allocate memory\n");
ret = -ENOMEM;
- goto err_mem;
+ goto err_free_mem;
}

tsi->da9052 = da9052;
- tsi->pen_up_detect_interval = 5;
- platform_set_drvdata(pdev, tsi);
+ tsi->dev = input_dev;
+ tsi->irq_pendown = irq_pendwn;
+ tsi->irq_datadry = irq_datardy;
+ INIT_DELAYED_WORK(&tsi->work, da9052_work);

+ input_dev->name = "Dialog DA9052 TouchScreen Driver";
input_dev->id.version = 0x0101;
input_dev->id.vendor = 0x15B6;
input_dev->id.product = 0x9052;
input_dev->id.bustype = BUS_RS232;
- input_dev->name = "Dialog DA9052 TouchScreen Driver";
- input_dev->dev.parent = &pdev->dev;
+ input_dev->dev.parent = &pdev->dev;
__set_bit(EV_ABS, input_dev->evbit);
__set_bit(EV_KEY, input_dev->evbit);
__set_bit(BTN_TOUCH, input_dev->keybit);
@@ -265,85 +251,81 @@ static s32 __devinit da9052_ts_probe(struct platform_device *pdev)

input_set_abs_params(input_dev, ABS_X, 0, 1023, 0, 0);
input_set_abs_params(input_dev, ABS_Y, 0, 1023, 0, 0);
- input_set_abs_params(input_dev, ABS_PRESSURE, 0, 1023, 0, 0);

- tsi->dev = input_dev;
input_set_drvdata(input_dev, tsi);
- ret = input_register_device(tsi->dev);
- if (ret)
- goto err_mem;

- INIT_DELAYED_WORK(&tsi->work, da9052_work);
-
- tsi->irq_pendwn = platform_get_irq_byname(pdev, "PENDWN");
- ret = request_threaded_irq(tsi->da9052->irq_base + tsi->irq_pendwn,
- NULL, da9052_ts_pendwn_irq,
- IRQF_TRIGGER_LOW | IRQF_ONESHOT,
- "PENDWN", tsi);
- if (ret < 0) {
- dev_err(tsi->da9052->dev,
+ error = request_threaded_irq(tsi->da9052->irq_base + tsi->irq_pendwn,
+ NULL, da9052_ts_pendwn_irq,
+ IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+ "PENDWN", tsi);
+ if (error) {
+ dev_err(da9052->dev,
"Failed to register %s IRQ %d, error = %d\n", "PENDWN",
- tsi->da9052->irq_base + tsi->irq_pendwn, ret);
+ tsi->da9052->irq_base + tsi->irq_pendwn, error);
goto err_input;
}

- tsi->irq_datardy = platform_get_irq_byname(pdev, "TSIRDY");
- ret = request_threaded_irq(tsi->da9052->irq_base + tsi->irq_datardy,
- NULL, da9052_ts_datardy_irq,
- IRQF_TRIGGER_LOW | IRQF_ONESHOT,
- "TSIRDY", tsi);
- if (ret < 0) {
- dev_err(tsi->da9052->dev,
+ error = request_threaded_irq(tsi->da9052->irq_base + tsi->irq_datardy,
+ NULL, da9052_ts_datardy_irq,
+ IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+ "TSIRDY", tsi);
+ if (error) {
+ dev_err(da9052->dev,
"Failed to register %s IRQ %d, error = %d\n", "TSIRDY",
- tsi->da9052->irq_base + tsi->irq_datardy, ret);
- goto err_input;
+ tsi->da9052->irq_base + tsi->irq_datardy, error);
+ goto err_free_pendown;
}

- ret = da9052_ts_enable_device(tsi);
- if (ret < 0)
- goto err_input;
+ error = da9052_ts_enable_device(tsi);
+ if (error) {
+ dev_err(da9052->dev,
+ "Failed to enable device, error: %d\n", error);
+ goto err_free_datardy;
+ }

+ error = input_register_device(tsi->dev);
+ if (error)
+ goto err_free_datardy;
+
+ platform_set_drvdata(pdev, tsi);
return 0;

-err_input:
+err_free_pendown:
+ free_irq(tsi->da9052->irq_base + tsi->irq_pendwn, tsi);
+err_free_datardy:
+ free_irq(tsi->da9052->irq_base + tsi->irq_datardy, tsi);
+err_free_mem:
input_free_device(input_dev);
-err_mem:
kfree(tsi);
- return ret;
+ return error;
}

static int __devexit da9052_ts_remove(struct platform_device *pdev)
{
struct da9052_tsi *tsi = platform_get_drvdata(pdev);
- s32 ret;

- ret = da9052_clear_bits(tsi->da9052, DA9052_TSI_CONT_A_REG, 1 << 0);
- if (ret < 0)
- return ret;
+ da9052_ts_stop(tsi);
+ da9052_reg_write(tsi->da9052, DA9052_LDO9_REG, 0x19);

- ret = da9052_reg_write(tsi->da9052, DA9052_LDO9_REG, 0x19);
- if (ret < 0)
- return ret;
+ free_irq(tsi->da9052->irq_base + tsi->irq_pendwn, tsi);
+ free_irq(tsi->da9052->irq_base + tsi->irq_datardy, tsi);

- free_irq(tsi->da9052->irq_base + tsi->irq_pendwn, NULL);
- free_irq(tsi->da9052->irq_base + tsi->irq_datardy, NULL);
+ cancel_delayed_work_sync(&tsi->work);

- cancel_delayed_work(&tsi->work);
input_unregister_device(tsi->dev);
+ kfree(tsi);

platform_set_drvdata(pdev, NULL);

- kfree(tsi);
-
return 0;
}

static struct platform_driver da9052_tsi_driver = {
- .probe = da9052_ts_probe,
- .remove = __devexit_p(da9052_ts_remove),
- .driver = {
- .name = "da9052-tsi",
- .owner = THIS_MODULE,
+ .probe = da9052_ts_probe,
+ .remove = __devexit_p(da9052_ts_remove),
+ .driver = {
+ .name = "da9052-tsi",
+ .owner = THIS_MODULE,
},
};

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