From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: [PATCH] gpio: gpio-omap: take pm_runtime usage while IRQs are claimed Date: Mon, 8 Apr 2019 12:45:06 -0700 Message-ID: <20190408194506.25821-1-tony@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Linus Walleij , Bartosz Golaszewski Cc: Tero Kristo , Grygorii Strashko , Aaro Koskinen , Keerthy , Peter Ujfalusi , linux-gpio@vger.kernel.org, Russell King , linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org List-Id: linux-omap@vger.kernel.org From: Russell King Commit b764a5863fd8 ("gpio: omap: Remove custom PM calls and use cpu_pm instead") moved interrupt using GPIO banks to idle with cpu_pm in order to drop the use of pm_runtime_irq_safe() in a later patch. The GPIO banks with no interrupts claimed are still being idled based on PM runtime calls. However this caused a regression for am437x suspend for rtc+ddr idle mode as reported by Keerthy . The fix to this is: Bump the pm_runtime usage count while interrupts are in use, rather than failing the pm_runtime callbacks. The logic here is a little non-obvious - the calling order will be: omap_gpio_irq_bus_lock() (optionally) raw_spin_lock_irqsave(desc->lock) omap_gpio_irq_startup() (optionally) raw_spin_unlock_irqrestore(desc->lock) gpio_irq_bus_sync_unlock() As the irq_startup method may be called with interrupts disabled, we must not use pm_runtime_get() here, so as the bus lock takes an initial pm reference count us, use pm_runtime_get_if_in_use() which will merely increment the use count. Cc: Aaro Koskinen Cc: Grygorii Strashko Cc: Keerthy Cc: Peter Ujfalusi Cc: Tero Kristo Fixes: b764a5863fd8 ("gpio: omap: Remove custom PM calls and use cpu_pm instead") Reported-by: Keerthy Signed-off-by: Russell King [tony@atomide.com: updated patch description for regression fix] Signed-off-by: Tony Lindgren --- AFAIK this is only needed with patches heading to v5.2, so this is based on Linux next. We can always backport as needed. --- drivers/gpio/gpio-omap.c | 23 +++++++---------------- 1 file changed, 7 insertions(+), 16 deletions(-) diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c --- a/drivers/gpio/gpio-omap.c +++ b/drivers/gpio/gpio-omap.c @@ -811,6 +811,9 @@ static unsigned int omap_gpio_irq_startup(struct irq_data *d) unsigned long flags; unsigned offset = d->hwirq; + /* Take a reference on the runtime PM to prevent RPM suspends */ + WARN_ON(pm_runtime_get_if_in_use(bank->chip.parent) == 0); + raw_spin_lock_irqsave(&bank->lock, flags); if (!LINE_USED(bank->mod_usage, offset)) @@ -844,6 +847,8 @@ static void omap_gpio_irq_shutdown(struct irq_data *d) omap_clear_gpio_debounce(bank, offset); omap_disable_gpio_module(bank, offset); raw_spin_unlock_irqrestore(&bank->lock, flags); + + pm_runtime_put(bank->chip.parent); } static void omap_gpio_irq_bus_lock(struct irq_data *data) @@ -1719,40 +1724,26 @@ static int __maybe_unused omap_gpio_runtime_suspend(struct device *dev) { struct gpio_bank *bank = dev_get_drvdata(dev); unsigned long flags; - int error = 0; raw_spin_lock_irqsave(&bank->lock, flags); - /* Must be idled only by CPU_CLUSTER_PM_ENTER? */ - if (bank->irq_usage) { - error = -EBUSY; - goto unlock; - } omap_gpio_idle(bank, true); bank->is_suspended = true; -unlock: raw_spin_unlock_irqrestore(&bank->lock, flags); - return error; + return 0; } static int __maybe_unused omap_gpio_runtime_resume(struct device *dev) { struct gpio_bank *bank = dev_get_drvdata(dev); unsigned long flags; - int error = 0; raw_spin_lock_irqsave(&bank->lock, flags); - /* Must be unidled only by CPU_CLUSTER_PM_ENTER? */ - if (bank->irq_usage) { - error = -EBUSY; - goto unlock; - } omap_gpio_unidle(bank); bank->is_suspended = false; -unlock: raw_spin_unlock_irqrestore(&bank->lock, flags); - return error; + return 0; } static const struct dev_pm_ops gpio_pm_ops = { -- 2.21.0