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Commit 19cfcafd authored by Bartosz Golaszewski's avatar Bartosz Golaszewski Committed by Wolfram Sang
Browse files

i2c: davinci: fix the cpufreq transition 



i2c_davinci_cpufreq_transition() is implemented in a way that will
block if it ever gets called while no transfer is in progress.

Not only that, but reinit_completion() is never called for xfr_complete.

Use the fact that cpufreq uses an srcu_notifier (running in process
context) for transitions and that the bus_lock is taken during the call
to master_xfer() and simplify the code by removing the transfer
completion entirely and protecting i2c_davinci_cpufreq_transition()
with i2c_lock/unlock_adapter().

Reported-by: default avatarDavid Lechner <david@lechnology.com>
Signed-off-by: default avatarBartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: default avatarSekhar Nori <nsekhar@ti.com>
Tested-by: default avatarDavid Lechner <david@lechnology.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 5bacb56b

drivers/i2c/busses/i2c-davinci.c

+4 −8
Original line number Diff line number Diff line
@@ -139,7 +139,6 @@ struct davinci_i2c_dev { 
	u8			terminate;

	struct i2c_adapter	adapter;

#ifdef CONFIG_CPU_FREQ

	struct completion	xfr_complete;

	struct notifier_block	freq_transition;

#endif

	struct davinci_i2c_platform_data *pdata;
@@ -567,9 +566,6 @@ i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) 
	}



	ret = num;

#ifdef CONFIG_CPU_FREQ

	complete(&dev->xfr_complete);

#endif



out:

	pm_runtime_mark_last_busy(dev->dev);
@@ -717,13 +713,15 @@ static int i2c_davinci_cpufreq_transition(struct notifier_block *nb, 
	struct davinci_i2c_dev *dev;



	dev = container_of(nb, struct davinci_i2c_dev, freq_transition);



	i2c_lock_adapter(&dev->adapter);

	if (val == CPUFREQ_PRECHANGE) {

		wait_for_completion(&dev->xfr_complete);

		davinci_i2c_reset_ctrl(dev, 0);

	} else if (val == CPUFREQ_POSTCHANGE) {

		i2c_davinci_calc_clk_dividers(dev);

		davinci_i2c_reset_ctrl(dev, 1);

	}

	i2c_unlock_adapter(&dev->adapter);



	return 0;

}
@@ -790,9 +788,7 @@ static int davinci_i2c_probe(struct platform_device *pdev) 
	}



	init_completion(&dev->cmd_complete);

#ifdef CONFIG_CPU_FREQ

	init_completion(&dev->xfr_complete);

#endif



	dev->dev = &pdev->dev;

	dev->irq = irq;

	dev->pdata = dev_get_platdata(&pdev->dev);