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i2c: rk3x: Add "suspended" flag to forbid access I2C bus during suspend/resume noirq

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Add "suspended" flag in suspend_noirq()/resume_noirq() callback
to prevent new i2c job started, and use i2c_lock_adapter() to wait
for current i2c transfer finished.

If any i2c client try to access I2C after suspend_noirq() or
before resume_noirq() callback, return the error, and they
should fix it, not to start i2c access at this moment.

Change-Id: Idd1142058d10547d085895a498201c2ade6b9e96
Signed-off-by: David Wu <david.wu@rock-chips.com>
This commit is contained in:
David Wu
2018-05-02 15:26:52 +08:00
committed by Tao Huang
parent 91842c9d8b
commit ffc12e054c
1 changed files with 32 additions and 2 deletions
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34
drivers/i2c/busses/i2c-rk3x.c
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@@ -223,6 +223,7 @@ struct rk3x_i2c {
enum rk3x_i2c_state state;
unsigned int processed;
int error;
unsigned int suspended:1;
struct notifier_block i2c_restart_nb;
};
@@ -1058,6 +1059,9 @@ static int rk3x_i2c_xfer(struct i2c_adapter *adap,
int ret = 0;
int i;
if (i2c->suspended)
return -EACCES;
spin_lock_irqsave(&i2c->lock, flags);
clk_enable(i2c->clk);
@@ -1152,12 +1156,35 @@ static int rk3x_i2c_restart_notify(struct notifier_block *this,
return NOTIFY_DONE;
}
static __maybe_unused int rk3x_i2c_resume(struct device *dev)
static __maybe_unused int rk3x_i2c_suspend_noirq(struct device *dev)
{
struct rk3x_i2c *i2c = dev_get_drvdata(dev);
/*
* Below code is needed only to ensure that there are no
* activities on I2C bus. if at this moment any driver
* is trying to use I2C bus - this may cause i2c timeout.
*
* So forbid access to I2C device using i2c->suspended flag.
*/
i2c_lock_adapter(&i2c->adap);
i2c->suspended = 1;
i2c_unlock_adapter(&i2c->adap);
return 0;
}
static __maybe_unused int rk3x_i2c_resume_noirq(struct device *dev)
{
struct rk3x_i2c *i2c = dev_get_drvdata(dev);
rk3x_i2c_adapt_div(i2c, clk_get_rate(i2c->clk));
/* Allow access to I2C bus */
i2c_lock_adapter(&i2c->adap);
i2c->suspended = 0;
i2c_unlock_adapter(&i2c->adap);
return 0;
}
@@ -1398,7 +1425,10 @@ static int rk3x_i2c_remove(struct platform_device *pdev)
return 0;
}
static SIMPLE_DEV_PM_OPS(rk3x_i2c_pm_ops, NULL, rk3x_i2c_resume);
const static struct dev_pm_ops rk3x_i2c_pm_ops = {
SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(rk3x_i2c_suspend_noirq,
rk3x_i2c_resume_noirq)
};
static struct platform_driver rk3x_i2c_driver = {
.probe = rk3x_i2c_probe,