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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: David Lechner <david@lechnology.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Sekhar Nori <nsekhar@ti.com>
Tested-by: David Lechner <david@lechnology.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Bartosz Golaszewski 2018-01-22 15:42:58 +01:00 committed by Wolfram Sang
parent 5bacb56b2b
commit 19cfcafd7f
1 changed files with 4 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/i2c/busses/i2c-davinci.c
View File

@ -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);