| Message ID | 20210110190529.46135-6-tony@atomide.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Lost key-up interrupt handling for omap4-keypad | expand |
* Tony Lindgren <tony@atomide.com> [210110 19:08]: > --- a/drivers/input/keyboard/omap4-keypad.c > +++ b/drivers/input/keyboard/omap4-keypad.c > +/* > + * Errata ID i689 "1.32 Keyboard Key Up Event Can Be Missed". > + * Interrupt may not happen for key-up events. We must clear stuck > + * key-up events after the keyboard hardware has auto-idled. > + */ > +static int __maybe_unused omap4_keypad_runtime_suspend(struct device *dev) > +{ > + struct platform_device *pdev = to_platform_device(dev); > + struct omap4_keypad *keypad_data = platform_get_drvdata(pdev); > + u32 active; > + > + active = kbd_readl(keypad_data, OMAP4_KBD_STATEMACHINE); > + if (active) { > + pm_runtime_mark_last_busy(dev); > + return -EBUSY; > + } > + > + omap4_keypad_scan_keys(keypad_data, true); > + > + return 0; > +} So with the improvments done, here we need to replace the true above with 0 so when the hardware is idle we clear any stuck keys. Updated patch below. Regards, Tony 8< ----------------------- From tony Mon Sep 17 00:00:00 2001 From: Tony Lindgren <tony@atomide.com> Date: Thu, 17 Dec 2020 07:54:32 +0200 Subject: [PATCH] Input: omap4-keypad - implement errata check for lost key-up events We are still missing handling for errata i689 related issues for the case where we never see a key up interrupt for the last pressed key. To fix the issue, we must scan the key state again after the keyboard controller has idled to check if a key up event was missed. This is described in the omap4 silicon errata documentation for Errata ID i689 "1.32 Keyboard Key Up Event Can Be Missed": "When a key is released for a time shorter than the debounce time, in-between 2 key press (KP1 and KP2), the keyboard state machine will go to idle mode and will never detect the key release (after KP1, and also after KP2), and thus will never generate a new IRQ indicating the key release." We can use PM runtime autosuspend features to check the keyboard state after it enters idle. Cc: Arthur Demchenkov <spinal.by@gmail.com> Cc: Carl Philipp Klemm <philipp@uvos.xyz> Cc: Merlijn Wajer <merlijn@wizzup.org> Cc: Pavel Machek <pavel@ucw.cz> Cc: ruleh <ruleh@gmx.de> Cc: Sebastian Reichel <sre@kernel.org> Signed-off-by: Tony Lindgren <tony@atomide.com> --- drivers/input/keyboard/omap4-keypad.c | 30 +++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/drivers/input/keyboard/omap4-keypad.c b/drivers/input/keyboard/omap4-keypad.c --- a/drivers/input/keyboard/omap4-keypad.c +++ b/drivers/input/keyboard/omap4-keypad.c @@ -60,6 +60,8 @@ ((((dbms) * 1000) / ((1 << ((ptv) + 1)) * (1000000 / 32768))) - 1) #define OMAP4_VAL_DEBOUNCINGTIME_16MS \ OMAP4_KEYPAD_DEBOUNCINGTIME_MS(16, OMAP4_KEYPAD_PTV_DIV_128) +#define OMAP4_KEYPAD_AUTOIDLE_MS 50 /* Approximate measured time */ +#define OMAP4_KEYPAD_IDLE_CHECK_MS (OMAP4_KEYPAD_AUTOIDLE_MS / 2) enum { KBD_REVISION_OMAP4 = 0, @@ -306,6 +308,32 @@ static int omap4_keypad_check_revision(struct device *dev, return 0; } +/* + * Errata ID i689 "1.32 Keyboard Key Up Event Can Be Missed". + * Interrupt may not happen for key-up events. We must clear stuck + * key-up events after the keyboard hardware has auto-idled. + */ +static int __maybe_unused omap4_keypad_runtime_suspend(struct device *dev) +{ + struct platform_device *pdev = to_platform_device(dev); + struct omap4_keypad *keypad_data = platform_get_drvdata(pdev); + u32 active; + + active = kbd_readl(keypad_data, OMAP4_KBD_STATEMACHINE); + if (active) { + pm_runtime_mark_last_busy(dev); + return -EBUSY; + } + + omap4_keypad_scan_keys(keypad_data, 0); + + return 0; +} + +static const struct dev_pm_ops omap4_keypad_pm_ops = { + SET_RUNTIME_PM_OPS(omap4_keypad_runtime_suspend, NULL, NULL) +}; + static void omap4_disable_pm(void *d) { pm_runtime_dont_use_autosuspend(d); @@ -352,6 +380,7 @@ static int omap4_keypad_probe(struct platform_device *pdev) return PTR_ERR(keypad_data->base); pm_runtime_use_autosuspend(dev); + pm_runtime_set_autosuspend_delay(dev, OMAP4_KEYPAD_IDLE_CHECK_MS); pm_runtime_enable(dev); error = devm_add_action_or_reset(dev, omap4_disable_pm, dev); @@ -464,6 +493,7 @@ static struct platform_driver omap4_keypad_driver = { .driver = { .name = "omap4-keypad", .of_match_table = omap_keypad_dt_match, + .pm = &omap4_keypad_pm_ops, }, }; module_platform_driver(omap4_keypad_driver);
On Mon, Jan 11, 2021 at 08:10:18AM +0200, Tony Lindgren wrote: > * Tony Lindgren <tony@atomide.com> [210110 19:08]: > > --- a/drivers/input/keyboard/omap4-keypad.c > > +++ b/drivers/input/keyboard/omap4-keypad.c > > +/* > > + * Errata ID i689 "1.32 Keyboard Key Up Event Can Be Missed". > > + * Interrupt may not happen for key-up events. We must clear stuck > > + * key-up events after the keyboard hardware has auto-idled. > > + */ > > +static int __maybe_unused omap4_keypad_runtime_suspend(struct device *dev) > > +{ > > + struct platform_device *pdev = to_platform_device(dev); > > + struct omap4_keypad *keypad_data = platform_get_drvdata(pdev); > > + u32 active; > > + > > + active = kbd_readl(keypad_data, OMAP4_KBD_STATEMACHINE); > > + if (active) { > > + pm_runtime_mark_last_busy(dev); > > + return -EBUSY; > > + } > > + > > + omap4_keypad_scan_keys(keypad_data, true); > > + > > + return 0; > > +} > > So with the improvments done, here we need to replace the true above with 0 > so when the hardware is idle we clear any stuck keys. Updated patch below. Applied, thank you.
Hi! > We are still missing handling for errata i689 related issues for the > case where we never see a key up interrupt for the last pressed key. > > To fix the issue, we must scan the key state again after the keyboard > controller has idled to check if a key up event was missed. This is > described in the omap4 silicon errata documentation for Errata ID i689 > "1.32 Keyboard Key Up Event Can Be Missed": > > "When a key is released for a time shorter than the debounce time, > in-between 2 key press (KP1 and KP2), the keyboard state machine will go > to idle mode and will never detect the key release (after KP1, and also > after KP2), and thus will never generate a new IRQ indicating the key > release." > > We can use PM runtime autosuspend features to check the keyboard state > after it enters idle. I thought about this and... is it reasonable? Autosuspend is now required for correct operation. But autosuspend is optional feature, configurable by user, and may not be available depending on .config. Do we need some other solution? Pavel
* Pavel Machek <pavel@ucw.cz> [210111 08:34]: > Hi! > > > We are still missing handling for errata i689 related issues for the > > case where we never see a key up interrupt for the last pressed key. > > > > To fix the issue, we must scan the key state again after the keyboard > > controller has idled to check if a key up event was missed. This is > > described in the omap4 silicon errata documentation for Errata ID i689 > > "1.32 Keyboard Key Up Event Can Be Missed": > > > > "When a key is released for a time shorter than the debounce time, > > in-between 2 key press (KP1 and KP2), the keyboard state machine will go > > to idle mode and will never detect the key release (after KP1, and also > > after KP2), and thus will never generate a new IRQ indicating the key > > release." > > > > We can use PM runtime autosuspend features to check the keyboard state > > after it enters idle. > > I thought about this and... is it reasonable? > > Autosuspend is now required for correct operation. But autosuspend is > optional feature, configurable by user, and may not be available > depending on .config. Well suspending hardware that has (lost) events pending is wrong. So we need to do this delayed hardware check at least when runtime suspending the device. > Do we need some other solution? Not sure if other places make sense to do this check as we need to wait about 50ms for hardware to autoidle, and only then check if there are events pending, and then clear the pending events. The PM runtime suspend function seems like a natural place to do this. If PM runtime autosuspend is disabled, the issue with last pressed key getting stuck sometimes can still happen like it did earlier. That issue has always been there for past 10 or so years and nobody else bothered to fix it so I'm not too worried about it. With this series we already fix the bigger issue anyways where rapidly pressing the keys would have the previous key stuck. Like rapid pressing of shift shift j would produce an upper case J instead of j. Naturally there is nothing stopping us from adding additional other places to call omap4_keypad_scan_keys() as needed now though if you have some good ideas for that :) Regards, Tony
diff --git a/drivers/input/keyboard/omap4-keypad.c b/drivers/input/keyboard/omap4-keypad.c --- a/drivers/input/keyboard/omap4-keypad.c +++ b/drivers/input/keyboard/omap4-keypad.c @@ -60,6 +60,8 @@ ((((dbms) * 1000) / ((1 << ((ptv) + 1)) * (1000000 / 32768))) - 1) #define OMAP4_VAL_DEBOUNCINGTIME_16MS \ OMAP4_KEYPAD_DEBOUNCINGTIME_MS(16, OMAP4_KEYPAD_PTV_DIV_128) +#define OMAP4_KEYPAD_AUTOIDLE_MS 50 /* Approximate measured time */ +#define OMAP4_KEYPAD_IDLE_CHECK_MS (OMAP4_KEYPAD_AUTOIDLE_MS / 2) enum { KBD_REVISION_OMAP4 = 0, @@ -312,6 +314,32 @@ static int omap4_keypad_check_revision(struct device *dev, return 0; } +/* + * Errata ID i689 "1.32 Keyboard Key Up Event Can Be Missed". + * Interrupt may not happen for key-up events. We must clear stuck + * key-up events after the keyboard hardware has auto-idled. + */ +static int __maybe_unused omap4_keypad_runtime_suspend(struct device *dev) +{ + struct platform_device *pdev = to_platform_device(dev); + struct omap4_keypad *keypad_data = platform_get_drvdata(pdev); + u32 active; + + active = kbd_readl(keypad_data, OMAP4_KBD_STATEMACHINE); + if (active) { + pm_runtime_mark_last_busy(dev); + return -EBUSY; + } + + omap4_keypad_scan_keys(keypad_data, true); + + return 0; +} + +static const struct dev_pm_ops omap4_keypad_pm_ops = { + SET_RUNTIME_PM_OPS(omap4_keypad_runtime_suspend, NULL, NULL) +}; + static void omap4_disable_pm(void *d) { pm_runtime_dont_use_autosuspend(d); @@ -358,6 +386,7 @@ static int omap4_keypad_probe(struct platform_device *pdev) return PTR_ERR(keypad_data->base); pm_runtime_use_autosuspend(dev); + pm_runtime_set_autosuspend_delay(dev, OMAP4_KEYPAD_IDLE_CHECK_MS); pm_runtime_enable(dev); error = devm_add_action_or_reset(dev, omap4_disable_pm, dev); @@ -470,6 +499,7 @@ static struct platform_driver omap4_keypad_driver = { .driver = { .name = "omap4-keypad", .of_match_table = omap_keypad_dt_match, + .pm = &omap4_keypad_pm_ops, }, }; module_platform_driver(omap4_keypad_driver);
We are still missing handling for errata i689 related issues for the case where we never see a key up interrupt for the last pressed key. To fix the issue, we must scan the key state again after the keyboard controller has idled to check if a key up event was missed. This is described in the omap4 silicon errata documentation for Errata ID i689 "1.32 Keyboard Key Up Event Can Be Missed": "When a key is released for a time shorter than the debounce time, in-between 2 key press (KP1 and KP2), the keyboard state machine will go to idle mode and will never detect the key release (after KP1, and also after KP2), and thus will never generate a new IRQ indicating the key release." We can use PM runtime autosuspend features to check the keyboard state after it enters idle. Cc: Arthur Demchenkov <spinal.by@gmail.com> Cc: Carl Philipp Klemm <philipp@uvos.xyz> Cc: Merlijn Wajer <merlijn@wizzup.org> Cc: Pavel Machek <pavel@ucw.cz> Cc: ruleh <ruleh@gmx.de> Cc: Sebastian Reichel <sre@kernel.org> Signed-off-by: Tony Lindgren <tony@atomide.com> --- drivers/input/keyboard/omap4-keypad.c | 30 +++++++++++++++++++++++++++ 1 file changed, 30 insertions(+)