From c899afedf168b6735911997d8366b7f23e7e59bc Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Wed, 4 Jan 2012 22:18:42 -0800 Subject: [PATCH] Input: ucb1400_ts - convert to threaded IRQ Instead of manually create and handler kernel thread switch to threaded IRQ and let kernel IRQ core manage thread for us. Acked-by: Marek Vasut Signed-off-by: Dmitry Torokhov --- drivers/input/touchscreen/ucb1400_ts.c | 235 ++++++++++++++++----------------- include/linux/ucb1400.h | 6 +- 2 files changed, 115 insertions(+), 126 deletions(-) diff --git a/drivers/input/touchscreen/ucb1400_ts.c b/drivers/input/touchscreen/ucb1400_ts.c index 36ff154..5162f4e 100644 --- a/drivers/input/touchscreen/ucb1400_ts.c +++ b/drivers/input/touchscreen/ucb1400_ts.c @@ -20,24 +20,24 @@ #include #include -#include #include +#include +#include #include #include #include -#include -#include -#include #include +#define UCB1400_TS_POLL_PERIOD 10 /* ms */ + static int adcsync; static int ts_delay = 55; /* us */ static int ts_delay_pressure; /* us */ /* Switch to interrupt mode. */ -static void ucb1400_ts_mode_int(struct snd_ac97 *ac97) +static void ucb1400_ts_mode_int(struct ucb1400_ts *ucb) { - ucb1400_reg_write(ac97, UCB_TS_CR, + ucb1400_reg_write(ucb->ac97, UCB_TS_CR, UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW | UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND | UCB_TS_CR_MODE_INT); @@ -53,7 +53,9 @@ static unsigned int ucb1400_ts_read_pressure(struct ucb1400_ts *ucb) UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW | UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND | UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA); + udelay(ts_delay_pressure); + return ucb1400_adc_read(ucb->ac97, UCB_ADC_INP_TSPY, adcsync); } @@ -127,26 +129,26 @@ static unsigned int ucb1400_ts_read_yres(struct ucb1400_ts *ucb) return ucb1400_adc_read(ucb->ac97, 0, adcsync); } -static int ucb1400_ts_pen_up(struct snd_ac97 *ac97) +static int ucb1400_ts_pen_up(struct ucb1400_ts *ucb) { - unsigned short val = ucb1400_reg_read(ac97, UCB_TS_CR); + unsigned short val = ucb1400_reg_read(ucb->ac97, UCB_TS_CR); return val & (UCB_TS_CR_TSPX_LOW | UCB_TS_CR_TSMX_LOW); } -static void ucb1400_ts_irq_enable(struct snd_ac97 *ac97) +static void ucb1400_ts_irq_enable(struct ucb1400_ts *ucb) { - ucb1400_reg_write(ac97, UCB_IE_CLEAR, UCB_IE_TSPX); - ucb1400_reg_write(ac97, UCB_IE_CLEAR, 0); - ucb1400_reg_write(ac97, UCB_IE_FAL, UCB_IE_TSPX); + ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, UCB_IE_TSPX); + ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0); + ucb1400_reg_write(ucb->ac97, UCB_IE_FAL, UCB_IE_TSPX); } -static void ucb1400_ts_irq_disable(struct snd_ac97 *ac97) +static void ucb1400_ts_irq_disable(struct ucb1400_ts *ucb) { - ucb1400_reg_write(ac97, UCB_IE_FAL, 0); + ucb1400_reg_write(ucb->ac97, UCB_IE_FAL, 0); } -static void ucb1400_ts_evt_add(struct input_dev *idev, u16 pressure, u16 x, u16 y) +static void ucb1400_ts_report_event(struct input_dev *idev, u16 pressure, u16 x, u16 y) { input_report_abs(idev, ABS_X, x); input_report_abs(idev, ABS_Y, y); @@ -162,7 +164,7 @@ static void ucb1400_ts_event_release(struct input_dev *idev) input_sync(idev); } -static void ucb1400_handle_pending_irq(struct ucb1400_ts *ucb) +static void ucb1400_clear_pending_irq(struct ucb1400_ts *ucb) { unsigned int isr; @@ -171,32 +173,34 @@ static void ucb1400_handle_pending_irq(struct ucb1400_ts *ucb) ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0); if (isr & UCB_IE_TSPX) - ucb1400_ts_irq_disable(ucb->ac97); + ucb1400_ts_irq_disable(ucb); else - dev_dbg(&ucb->ts_idev->dev, "ucb1400: unexpected IE_STATUS = %#x\n", isr); - enable_irq(ucb->irq); + dev_dbg(&ucb->ts_idev->dev, + "ucb1400: unexpected IE_STATUS = %#x\n", isr); } -static int ucb1400_ts_thread(void *_ucb) +/* + * A restriction with interrupts exists when using the ucb1400, as + * the codec read/write routines may sleep while waiting for codec + * access completion and uses semaphores for access control to the + * AC97 bus. Therefore the driver is forced to use threaded interrupt + * handler. + */ +static irqreturn_t ucb1400_irq(int irqnr, void *devid) { - struct ucb1400_ts *ucb = _ucb; - struct task_struct *tsk = current; - int valid = 0; - struct sched_param param = { .sched_priority = 1 }; + struct ucb1400_ts *ucb = devid; + unsigned int x, y, p; + bool penup; - sched_setscheduler(tsk, SCHED_FIFO, ¶m); + if (unlikely(irqnr != ucb->irq)) + return IRQ_NONE; - set_freezable(); - while (!kthread_should_stop()) { - unsigned int x, y, p; - long timeout; + ucb1400_clear_pending_irq(ucb); - ucb->ts_restart = 0; + /* Start with a small delay before checking pendown state */ + msleep(UCB1400_TS_POLL_PERIOD); - if (ucb->irq_pending) { - ucb->irq_pending = 0; - ucb1400_handle_pending_irq(ucb); - } + while (!ucb->stopped && !(penup = ucb1400_ts_pen_up(ucb))) { ucb1400_adc_enable(ucb->ac97); x = ucb1400_ts_read_xpos(ucb); @@ -204,91 +208,62 @@ static int ucb1400_ts_thread(void *_ucb) p = ucb1400_ts_read_pressure(ucb); ucb1400_adc_disable(ucb->ac97); - /* Switch back to interrupt mode. */ - ucb1400_ts_mode_int(ucb->ac97); - - msleep(10); - - if (ucb1400_ts_pen_up(ucb->ac97)) { - ucb1400_ts_irq_enable(ucb->ac97); - - /* - * If we spat out a valid sample set last time, - * spit out a "pen off" sample here. - */ - if (valid) { - ucb1400_ts_event_release(ucb->ts_idev); - valid = 0; - } - - timeout = MAX_SCHEDULE_TIMEOUT; - } else { - valid = 1; - ucb1400_ts_evt_add(ucb->ts_idev, p, x, y); - timeout = msecs_to_jiffies(10); - } + ucb1400_ts_report_event(ucb->ts_idev, p, x, y); - wait_event_freezable_timeout(ucb->ts_wait, - ucb->irq_pending || ucb->ts_restart || - kthread_should_stop(), timeout); + wait_event_timeout(ucb->ts_wait, ucb->stopped, + msecs_to_jiffies(UCB1400_TS_POLL_PERIOD)); } - /* Send the "pen off" if we are stopping with the pen still active */ - if (valid) - ucb1400_ts_event_release(ucb->ts_idev); + ucb1400_ts_event_release(ucb->ts_idev); - ucb->ts_task = NULL; - return 0; + if (!ucb->stopped) { + /* Switch back to interrupt mode. */ + ucb1400_ts_mode_int(ucb); + ucb1400_ts_irq_enable(ucb); + } + + return IRQ_HANDLED; } -/* - * A restriction with interrupts exists when using the ucb1400, as - * the codec read/write routines may sleep while waiting for codec - * access completion and uses semaphores for access control to the - * AC97 bus. A complete codec read cycle could take anywhere from - * 60 to 100uSec so we *definitely* don't want to spin inside the - * interrupt handler waiting for codec access. So, we handle the - * interrupt by scheduling a RT kernel thread to run in process - * context instead of interrupt context. - */ -static irqreturn_t ucb1400_hard_irq(int irqnr, void *devid) +static void ucb1400_ts_stop(struct ucb1400_ts *ucb) { - struct ucb1400_ts *ucb = devid; + /* Signal IRQ thread to stop polling and disable the handler. */ + ucb->stopped = true; + mb(); + wake_up(&ucb->ts_wait); + disable_irq(ucb->irq); - if (irqnr == ucb->irq) { - disable_irq_nosync(ucb->irq); - ucb->irq_pending = 1; - wake_up(&ucb->ts_wait); - return IRQ_HANDLED; - } - return IRQ_NONE; + ucb1400_ts_irq_disable(ucb); + ucb1400_reg_write(ucb->ac97, UCB_TS_CR, 0); +} + +/* Must be called with ts->lock held */ +static void ucb1400_ts_start(struct ucb1400_ts *ucb) +{ + /* Tell IRQ thread that it may poll the device. */ + ucb->stopped = false; + mb(); + + ucb1400_ts_mode_int(ucb); + ucb1400_ts_irq_enable(ucb); + + enable_irq(ucb->irq); } static int ucb1400_ts_open(struct input_dev *idev) { struct ucb1400_ts *ucb = input_get_drvdata(idev); - int ret = 0; - - BUG_ON(ucb->ts_task); - ucb->ts_task = kthread_run(ucb1400_ts_thread, ucb, "UCB1400_ts"); - if (IS_ERR(ucb->ts_task)) { - ret = PTR_ERR(ucb->ts_task); - ucb->ts_task = NULL; - } + ucb1400_ts_start(ucb); - return ret; + return 0; } static void ucb1400_ts_close(struct input_dev *idev) { struct ucb1400_ts *ucb = input_get_drvdata(idev); - if (ucb->ts_task) - kthread_stop(ucb->ts_task); - - ucb1400_ts_irq_disable(ucb->ac97); - ucb1400_reg_write(ucb->ac97, UCB_TS_CR, 0); + ucb1400_ts_stop(ucb); } #ifndef NO_IRQ @@ -342,11 +317,11 @@ static int __devinit ucb1400_ts_detect_irq(struct ucb1400_ts *ucb) return 0; } -static int __devinit ucb1400_ts_probe(struct platform_device *dev) +static int __devinit ucb1400_ts_probe(struct platform_device *pdev) { + struct ucb1400_ts *ucb = pdev->dev.platform_data; int error, x_res, y_res; u16 fcsr; - struct ucb1400_ts *ucb = dev->dev.platform_data; ucb->ts_idev = input_allocate_device(); if (!ucb->ts_idev) { @@ -362,21 +337,13 @@ static int __devinit ucb1400_ts_probe(struct platform_device *dev) goto err_free_devs; } } + printk(KERN_DEBUG "UCB1400: found IRQ %d\n", ucb->irq); init_waitqueue_head(&ucb->ts_wait); - error = request_irq(ucb->irq, ucb1400_hard_irq, IRQF_TRIGGER_RISING, - "UCB1400", ucb); - if (error) { - printk(KERN_ERR "ucb1400: unable to grab irq%d: %d\n", - ucb->irq, error); - goto err_free_devs; - } - printk(KERN_DEBUG "UCB1400: found IRQ %d\n", ucb->irq); - input_set_drvdata(ucb->ts_idev, ucb); - ucb->ts_idev->dev.parent = &dev->dev; + ucb->ts_idev->dev.parent = &pdev->dev; ucb->ts_idev->name = "UCB1400 touchscreen interface"; ucb->ts_idev->id.vendor = ucb1400_reg_read(ucb->ac97, AC97_VENDOR_ID1); @@ -404,6 +371,17 @@ static int __devinit ucb1400_ts_probe(struct platform_device *dev) input_set_abs_params(ucb->ts_idev, ABS_Y, 0, y_res, 0, 0); input_set_abs_params(ucb->ts_idev, ABS_PRESSURE, 0, 0, 0, 0); + ucb1400_ts_stop(ucb); + + error = request_threaded_irq(ucb->irq, NULL, ucb1400_irq, + IRQF_TRIGGER_RISING | IRQF_ONESHOT, + "UCB1400", ucb); + if (error) { + printk(KERN_ERR "ucb1400: unable to grab irq%d: %d\n", + ucb->irq, error); + goto err_free_devs; + } + error = input_register_device(ucb->ts_idev); if (error) goto err_free_irq; @@ -418,9 +396,9 @@ err: return error; } -static int __devexit ucb1400_ts_remove(struct platform_device *dev) +static int __devexit ucb1400_ts_remove(struct platform_device *pdev) { - struct ucb1400_ts *ucb = dev->dev.platform_data; + struct ucb1400_ts *ucb = pdev->dev.platform_data; free_irq(ucb->irq, ucb); input_unregister_device(ucb->ts_idev); @@ -429,24 +407,37 @@ static int __devexit ucb1400_ts_remove(struct platform_device *dev) } #ifdef CONFIG_PM_SLEEP +static int ucb1400_ts_suspend(struct device *dev) +{ + struct ucb1400_ts *ucb = dev->platform_data; + struct input_dev *idev = ucb->ts_idev; + + mutex_lock(&idev->mutex); + + if (idev->users) + ucb1400_ts_start(ucb); + + mutex_unlock(&idev->mutex); + return 0; +} + static int ucb1400_ts_resume(struct device *dev) { struct ucb1400_ts *ucb = dev->platform_data; + struct input_dev *idev = ucb->ts_idev; - if (ucb->ts_task) { - /* - * Restart the TS thread to ensure the - * TS interrupt mode is set up again - * after sleep. - */ - ucb->ts_restart = 1; - wake_up(&ucb->ts_wait); - } + mutex_lock(&idev->mutex); + + if (idev->users) + ucb1400_ts_stop(ucb); + + mutex_unlock(&idev->mutex); return 0; } #endif -static SIMPLE_DEV_PM_OPS(ucb1400_ts_pm_ops, NULL, ucb1400_ts_resume); +static SIMPLE_DEV_PM_OPS(ucb1400_ts_pm_ops, + ucb1400_ts_suspend, ucb1400_ts_resume); static struct platform_driver ucb1400_ts_driver = { .probe = ucb1400_ts_probe, diff --git a/include/linux/ucb1400.h b/include/linux/ucb1400.h index 5c75153f..d21b33c 100644 --- a/include/linux/ucb1400.h +++ b/include/linux/ucb1400.h @@ -96,13 +96,11 @@ struct ucb1400_gpio { struct ucb1400_ts { struct input_dev *ts_idev; - struct task_struct *ts_task; int id; - wait_queue_head_t ts_wait; - unsigned int ts_restart:1; int irq; - unsigned int irq_pending; /* not bit field shared */ struct snd_ac97 *ac97; + wait_queue_head_t ts_wait; + bool stopped; }; struct ucb1400 { -- 2.7.4