From f5346668150c37094b42cc2d07ec5fd1451eb980 Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Wed, 27 Apr 2011 23:08:34 -0700 Subject: Input: wm831x-ts - fix races with IRQ management If the WM831x pen down and data IRQs run in parallel it is possible for the data and pen down IRQs to deadlock themselves as one is part way through disabling its operation while the other is part way through enabling. Fix this by always disabling the pen down interrupt while data is active and vice versa. When a changeover is required we disable the IRQ that is to be stopped then schedule work that will enable the new IRQ. We need to handle the data flow in the data IRQ as the readback from the device needs to be ordered correctly with the IRQ for robust operation. This also fixes an issue when using the built in IRQs due to enable_irq() not being valid from interrupt context on an interrupt controller with bus operations like the built in IRQ controller - this issue may also have affected other interrupt controllers. We can't rely on having the data and pen down IRQs available via GPIOs on the CPU on every system. Signed-off-by: Mark Brown Signed-off-by: Dmitry Torokhov --- drivers/input/touchscreen/wm831x-ts.c | 54 +++++++++++++++++++++++++++++++---- 1 file changed, 49 insertions(+), 5 deletions(-) (limited to 'drivers/input') diff --git a/drivers/input/touchscreen/wm831x-ts.c b/drivers/input/touchscreen/wm831x-ts.c index 6ae054f8e0aa..b9373012b3e6 100644 --- a/drivers/input/touchscreen/wm831x-ts.c +++ b/drivers/input/touchscreen/wm831x-ts.c @@ -68,8 +68,23 @@ struct wm831x_ts { unsigned int pd_irq; bool pressure; bool pen_down; + struct work_struct pd_data_work; }; +static void wm831x_pd_data_work(struct work_struct *work) +{ + struct wm831x_ts *wm831x_ts = + container_of(work, struct wm831x_ts, pd_data_work); + + if (wm831x_ts->pen_down) { + enable_irq(wm831x_ts->data_irq); + dev_dbg(wm831x_ts->wm831x->dev, "IRQ PD->DATA done\n"); + } else { + enable_irq(wm831x_ts->pd_irq); + dev_dbg(wm831x_ts->wm831x->dev, "IRQ DATA->PD done\n"); + } +} + static irqreturn_t wm831x_ts_data_irq(int irq, void *irq_data) { struct wm831x_ts *wm831x_ts = irq_data; @@ -110,6 +125,9 @@ static irqreturn_t wm831x_ts_data_irq(int irq, void *irq_data) } if (!wm831x_ts->pen_down) { + /* Switch from data to pen down */ + dev_dbg(wm831x->dev, "IRQ DATA->PD\n"); + disable_irq_nosync(wm831x_ts->data_irq); /* Don't need data any more */ @@ -128,6 +146,8 @@ static irqreturn_t wm831x_ts_data_irq(int irq, void *irq_data) ABS_PRESSURE, 0); input_report_key(wm831x_ts->input_dev, BTN_TOUCH, 0); + + schedule_work(&wm831x_ts->pd_data_work); } input_sync(wm831x_ts->input_dev); @@ -141,6 +161,11 @@ static irqreturn_t wm831x_ts_pen_down_irq(int irq, void *irq_data) struct wm831x *wm831x = wm831x_ts->wm831x; int ena = 0; + if (wm831x_ts->pen_down) + return IRQ_HANDLED; + + disable_irq_nosync(wm831x_ts->pd_irq); + /* Start collecting data */ if (wm831x_ts->pressure) ena |= WM831X_TCH_Z_ENA; @@ -156,7 +181,10 @@ static irqreturn_t wm831x_ts_pen_down_irq(int irq, void *irq_data) WM831X_TCHPD_EINT, WM831X_TCHPD_EINT); wm831x_ts->pen_down = true; - enable_irq(wm831x_ts->data_irq); + + /* Switch from pen down to data */ + dev_dbg(wm831x->dev, "IRQ PD->DATA\n"); + schedule_work(&wm831x_ts->pd_data_work); return IRQ_HANDLED; } @@ -182,13 +210,28 @@ static void wm831x_ts_input_close(struct input_dev *idev) struct wm831x_ts *wm831x_ts = input_get_drvdata(idev); struct wm831x *wm831x = wm831x_ts->wm831x; + /* Shut the controller down, disabling all other functionality too */ wm831x_set_bits(wm831x, WM831X_TOUCH_CONTROL_1, - WM831X_TCH_ENA | WM831X_TCH_CVT_ENA | - WM831X_TCH_X_ENA | WM831X_TCH_Y_ENA | - WM831X_TCH_Z_ENA, 0); + WM831X_TCH_ENA | WM831X_TCH_X_ENA | + WM831X_TCH_Y_ENA | WM831X_TCH_Z_ENA, 0); - if (wm831x_ts->pen_down) + /* Make sure any pending IRQs are done, the above will prevent + * new ones firing. + */ + synchronize_irq(wm831x_ts->data_irq); + synchronize_irq(wm831x_ts->pd_irq); + + /* Make sure the IRQ completion work is quiesced */ + flush_work_sync(&wm831x_ts->pd_data_work); + + /* If we ended up with the pen down then make sure we revert back + * to pen detection state for the next time we start up. + */ + if (wm831x_ts->pen_down) { disable_irq(wm831x_ts->data_irq); + enable_irq(wm831x_ts->pd_irq); + wm831x_ts->pen_down = false; + } } static __devinit int wm831x_ts_probe(struct platform_device *pdev) @@ -212,6 +255,7 @@ static __devinit int wm831x_ts_probe(struct platform_device *pdev) wm831x_ts->wm831x = wm831x; wm831x_ts->input_dev = input_dev; + INIT_WORK(&wm831x_ts->pd_data_work, wm831x_pd_data_work); /* * If we have a direct IRQ use it, otherwise use the interrupt -- cgit v1.2.1 From acad9853b95df6a3887f52e0ec88e4a77119ee28 Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Wed, 27 Apr 2011 23:08:51 -0700 Subject: Input: wm831x-ts - allow IRQ flags to be specified This allows maximum flexibility for configuring the direct GPIO based interrupts. Signed-off-by: Mark Brown Signed-off-by: Dmitry Torokhov --- drivers/input/touchscreen/wm831x-ts.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) (limited to 'drivers/input') diff --git a/drivers/input/touchscreen/wm831x-ts.c b/drivers/input/touchscreen/wm831x-ts.c index b9373012b3e6..78e8705df20d 100644 --- a/drivers/input/touchscreen/wm831x-ts.c +++ b/drivers/input/touchscreen/wm831x-ts.c @@ -241,7 +241,7 @@ static __devinit int wm831x_ts_probe(struct platform_device *pdev) struct wm831x_pdata *core_pdata = dev_get_platdata(pdev->dev.parent); struct wm831x_touch_pdata *pdata = NULL; struct input_dev *input_dev; - int error; + int error, irqf; if (core_pdata) pdata = core_pdata->touch; @@ -314,9 +314,14 @@ static __devinit int wm831x_ts_probe(struct platform_device *pdev) wm831x_set_bits(wm831x, WM831X_TOUCH_CONTROL_1, WM831X_TCH_RATE_MASK, 6); + if (pdata && pdata->data_irqf) + irqf = pdata->data_irqf; + else + irqf = IRQF_TRIGGER_HIGH; + error = request_threaded_irq(wm831x_ts->data_irq, NULL, wm831x_ts_data_irq, - IRQF_ONESHOT, + irqf | IRQF_ONESHOT, "Touchscreen data", wm831x_ts); if (error) { dev_err(&pdev->dev, "Failed to request data IRQ %d: %d\n", @@ -325,9 +330,14 @@ static __devinit int wm831x_ts_probe(struct platform_device *pdev) } disable_irq(wm831x_ts->data_irq); + if (pdata && pdata->pd_irqf) + irqf = pdata->pd_irqf; + else + irqf = IRQF_TRIGGER_HIGH; + error = request_threaded_irq(wm831x_ts->pd_irq, NULL, wm831x_ts_pen_down_irq, - IRQF_ONESHOT, + irqf | IRQF_ONESHOT, "Touchscreen pen down", wm831x_ts); if (error) { dev_err(&pdev->dev, "Failed to request pen down IRQ %d: %d\n", -- cgit v1.2.1 From bf283707d5fb174ec09215ae19860ad04ba7b67a Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Wed, 27 Apr 2011 23:09:26 -0700 Subject: Input: wm831x-ts - move BTN_TOUCH reporting to data transfer Don't report BTN_TOUCH until we've got data as some less robust applications can be confused by getting a touch event by itself and it doesn't seem unreasonable for them to expect coordinates along with a touch. Signed-off-by: Mark Brown Signed-off-by: Dmitry Torokhov --- drivers/input/touchscreen/wm831x-ts.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'drivers/input') diff --git a/drivers/input/touchscreen/wm831x-ts.c b/drivers/input/touchscreen/wm831x-ts.c index 78e8705df20d..9175d49d2546 100644 --- a/drivers/input/touchscreen/wm831x-ts.c +++ b/drivers/input/touchscreen/wm831x-ts.c @@ -148,6 +148,8 @@ static irqreturn_t wm831x_ts_data_irq(int irq, void *irq_data) input_report_key(wm831x_ts->input_dev, BTN_TOUCH, 0); schedule_work(&wm831x_ts->pd_data_work); + } else { + input_report_key(wm831x_ts->input_dev, BTN_TOUCH, 1); } input_sync(wm831x_ts->input_dev); @@ -174,9 +176,6 @@ static irqreturn_t wm831x_ts_pen_down_irq(int irq, void *irq_data) WM831X_TCH_X_ENA | WM831X_TCH_Y_ENA | WM831X_TCH_Z_ENA, WM831X_TCH_X_ENA | WM831X_TCH_Y_ENA | ena); - input_report_key(wm831x_ts->input_dev, BTN_TOUCH, 1); - input_sync(wm831x_ts->input_dev); - wm831x_set_bits(wm831x, WM831X_INTERRUPT_STATUS_1, WM831X_TCHPD_EINT, WM831X_TCHPD_EINT); -- cgit v1.2.1