From: Grygorii Strashko <grygorii.strashko@ti.com> To: Baolin Wang <baolin.wang@linaro.org>, <wsa@the-dreams.de> Cc: <broonie@kernel.org>, <linux-i2c@vger.kernel.org>, <linux-kernel@vger.kernel.org> Subject: Re: [PATCH 1/2] i2c: sprd: Prevent i2c accesses after suspend is called Date: Mon, 9 Apr 2018 15:56:52 -0500 [thread overview] Message-ID: <557074eb-e988-8ff5-bec0-c85bb9dcb8ec@ti.com> (raw) In-Reply-To: <99031524fa147e72451d26f54b24f36093c0d3fa.1523255712.git.baolin.wang@linaro.org> On 04/09/2018 01:40 AM, Baolin Wang wrote: > Add one flag to indicate if the i2c controller has been in suspend state, > which can prevent i2c accesses after i2c controller is suspended following > system suspend. This usually indicates some bigger problem - there should be no i2c access to the I2C driver once it's suspended. But if happens - it means suspend dependencies between drivers are broken or there some scheduling primitives are not disabled properly. (possible sources - kthreads, delayed works, timers or even threaded irqs) > > Signed-off-by: Baolin Wang <baolin.wang@linaro.org> > --- > drivers/i2c/busses/i2c-sprd.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/drivers/i2c/busses/i2c-sprd.c b/drivers/i2c/busses/i2c-sprd.c > index 25fcc3c..2fdad63 100644 > --- a/drivers/i2c/busses/i2c-sprd.c > +++ b/drivers/i2c/busses/i2c-sprd.c > @@ -86,6 +86,7 @@ struct sprd_i2c { > u32 count; > int irq; > int err; > + bool is_suspended; > }; > > static void sprd_i2c_set_count(struct sprd_i2c *i2c_dev, u32 count) > @@ -283,6 +284,9 @@ static int sprd_i2c_master_xfer(struct i2c_adapter *i2c_adap, > struct sprd_i2c *i2c_dev = i2c_adap->algo_data; > int im, ret; > > + if (i2c_dev->is_suspended) > + return -EBUSY; > + > ret = pm_runtime_get_sync(i2c_dev->dev); > if (ret < 0) > return ret; > @@ -586,11 +590,23 @@ static int sprd_i2c_remove(struct platform_device *pdev) > > static int __maybe_unused sprd_i2c_suspend_noirq(struct device *pdev) > { > + struct sprd_i2c *i2c_dev = dev_get_drvdata(pdev); > + > + i2c_lock_adapter(&i2c_dev->adap); > + i2c_dev->is_suspended = true; > + i2c_unlock_adapter(&i2c_dev->adap); > + > return pm_runtime_force_suspend(pdev); > } > > static int __maybe_unused sprd_i2c_resume_noirq(struct device *pdev) > { > + struct sprd_i2c *i2c_dev = dev_get_drvdata(pdev); > + > + i2c_lock_adapter(&i2c_dev->adap); > + i2c_dev->is_suspended = false; > + i2c_unlock_adapter(&i2c_dev->adap); > + > return pm_runtime_force_resume(pdev); > } > > -- regards, -grygorii
WARNING: multiple messages have this Message-ID (diff)
From: Grygorii Strashko <grygorii.strashko@ti.com> To: Baolin Wang <baolin.wang@linaro.org>, wsa@the-dreams.de Cc: broonie@kernel.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] i2c: sprd: Prevent i2c accesses after suspend is called Date: Mon, 9 Apr 2018 15:56:52 -0500 [thread overview] Message-ID: <557074eb-e988-8ff5-bec0-c85bb9dcb8ec@ti.com> (raw) In-Reply-To: <99031524fa147e72451d26f54b24f36093c0d3fa.1523255712.git.baolin.wang@linaro.org> On 04/09/2018 01:40 AM, Baolin Wang wrote: > Add one flag to indicate if the i2c controller has been in suspend state, > which can prevent i2c accesses after i2c controller is suspended following > system suspend. This usually indicates some bigger problem - there should be no i2c access to the I2C driver once it's suspended. But if happens - it means suspend dependencies between drivers are broken or there some scheduling primitives are not disabled properly. (possible sources - kthreads, delayed works, timers or even threaded irqs) > > Signed-off-by: Baolin Wang <baolin.wang@linaro.org> > --- > drivers/i2c/busses/i2c-sprd.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/drivers/i2c/busses/i2c-sprd.c b/drivers/i2c/busses/i2c-sprd.c > index 25fcc3c..2fdad63 100644 > --- a/drivers/i2c/busses/i2c-sprd.c > +++ b/drivers/i2c/busses/i2c-sprd.c > @@ -86,6 +86,7 @@ struct sprd_i2c { > u32 count; > int irq; > int err; > + bool is_suspended; > }; > > static void sprd_i2c_set_count(struct sprd_i2c *i2c_dev, u32 count) > @@ -283,6 +284,9 @@ static int sprd_i2c_master_xfer(struct i2c_adapter *i2c_adap, > struct sprd_i2c *i2c_dev = i2c_adap->algo_data; > int im, ret; > > + if (i2c_dev->is_suspended) > + return -EBUSY; > + > ret = pm_runtime_get_sync(i2c_dev->dev); > if (ret < 0) > return ret; > @@ -586,11 +590,23 @@ static int sprd_i2c_remove(struct platform_device *pdev) > > static int __maybe_unused sprd_i2c_suspend_noirq(struct device *pdev) > { > + struct sprd_i2c *i2c_dev = dev_get_drvdata(pdev); > + > + i2c_lock_adapter(&i2c_dev->adap); > + i2c_dev->is_suspended = true; > + i2c_unlock_adapter(&i2c_dev->adap); > + > return pm_runtime_force_suspend(pdev); > } > > static int __maybe_unused sprd_i2c_resume_noirq(struct device *pdev) > { > + struct sprd_i2c *i2c_dev = dev_get_drvdata(pdev); > + > + i2c_lock_adapter(&i2c_dev->adap); > + i2c_dev->is_suspended = false; > + i2c_unlock_adapter(&i2c_dev->adap); > + > return pm_runtime_force_resume(pdev); > } > > -- regards, -grygorii
next prev parent reply other threads:[~2018-04-09 20:57 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-04-09 6:40 [PATCH 1/2] i2c: sprd: Prevent i2c accesses after suspend is called Baolin Wang 2018-04-09 6:40 ` [PATCH 2/2] i2c: sprd: Fix the i2c count issue Baolin Wang 2018-04-27 12:14 ` Wolfram Sang 2018-04-09 20:56 ` Grygorii Strashko [this message] 2018-04-09 20:56 ` [PATCH 1/2] i2c: sprd: Prevent i2c accesses after suspend is called Grygorii Strashko 2018-04-10 8:08 ` Baolin Wang 2018-04-27 12:14 ` Wolfram Sang 2018-05-02 3:27 ` Baolin Wang 2018-05-02 5:23 ` Wolfram Sang 2018-05-02 5:48 ` Baolin Wang 2018-05-03 16:26 ` Grygorii Strashko 2018-05-03 16:26 ` Grygorii Strashko 2018-05-04 12:24 ` I2C PM overhaul needed? (Re: [PATCH 1/2] i2c: sprd: Prevent i2c accesses after suspend is called) Wolfram Sang 2018-05-05 1:54 ` Mark Brown 2018-05-05 8:32 ` Wolfram Sang 2018-05-09 8:18 ` Mark Brown 2018-05-07 17:48 ` Grygorii Strashko 2018-05-07 17:48 ` Grygorii Strashko 2018-05-08 16:32 ` Wolfram Sang 2018-05-08 18:31 ` Peter Rosin 2018-05-11 15:14 ` Grygorii Strashko 2018-05-11 15:14 ` Grygorii Strashko
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