Re: [PATCH] HID: i2c-hid: goodix: Tie the reset line to true state of the regulator

[Dan Carpenter <dan.carpenter@oracle.com>]

Hi Douglas,

url:    https://github.com/0day-ci/linux/commits/Douglas-Anderson/HID-i2c-hid-goodix-Tie-the-reset-line-to-true-state-of-the-regulator/20210617-102450
base:   https://git.kernel.org/pub/scm/linux/kernel/git/hid/hid.git for-next
config: i386-randconfig-m021-20210622 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

smatch warnings:
drivers/hid/i2c-hid/i2c-hid-of-goodix.c:151 i2c_hid_of_goodix_probe() warn: inconsistent returns '&ihid_goodix->regulator_mutex'.

vim +151 drivers/hid/i2c-hid/i2c-hid-of-goodix.c

c1ed18c11bdb80 Douglas Anderson 2021-01-15   95  static int i2c_hid_of_goodix_probe(struct i2c_client *client,
c1ed18c11bdb80 Douglas Anderson 2021-01-15   96  				   const struct i2c_device_id *id)
c1ed18c11bdb80 Douglas Anderson 2021-01-15   97  {
c1ed18c11bdb80 Douglas Anderson 2021-01-15   98  	struct i2c_hid_of_goodix *ihid_goodix;
2b87ff72c696bc Douglas Anderson 2021-06-11   99  	int ret;
c1ed18c11bdb80 Douglas Anderson 2021-01-15  100  	ihid_goodix = devm_kzalloc(&client->dev, sizeof(*ihid_goodix),
c1ed18c11bdb80 Douglas Anderson 2021-01-15  101  				   GFP_KERNEL);
c1ed18c11bdb80 Douglas Anderson 2021-01-15  102  	if (!ihid_goodix)
c1ed18c11bdb80 Douglas Anderson 2021-01-15  103  		return -ENOMEM;
c1ed18c11bdb80 Douglas Anderson 2021-01-15  104  
2b87ff72c696bc Douglas Anderson 2021-06-11  105  	mutex_init(&ihid_goodix->regulator_mutex);
2b87ff72c696bc Douglas Anderson 2021-06-11  106  
c1ed18c11bdb80 Douglas Anderson 2021-01-15  107  	ihid_goodix->ops.power_up = goodix_i2c_hid_power_up;
c1ed18c11bdb80 Douglas Anderson 2021-01-15  108  	ihid_goodix->ops.power_down = goodix_i2c_hid_power_down;
c1ed18c11bdb80 Douglas Anderson 2021-01-15  109  
c1ed18c11bdb80 Douglas Anderson 2021-01-15  110  	/* Start out with reset asserted */
c1ed18c11bdb80 Douglas Anderson 2021-01-15  111  	ihid_goodix->reset_gpio =
c1ed18c11bdb80 Douglas Anderson 2021-01-15  112  		devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);
c1ed18c11bdb80 Douglas Anderson 2021-01-15  113  	if (IS_ERR(ihid_goodix->reset_gpio))
c1ed18c11bdb80 Douglas Anderson 2021-01-15  114  		return PTR_ERR(ihid_goodix->reset_gpio);
c1ed18c11bdb80 Douglas Anderson 2021-01-15  115  
c1ed18c11bdb80 Douglas Anderson 2021-01-15  116  	ihid_goodix->vdd = devm_regulator_get(&client->dev, "vdd");
c1ed18c11bdb80 Douglas Anderson 2021-01-15  117  	if (IS_ERR(ihid_goodix->vdd))
c1ed18c11bdb80 Douglas Anderson 2021-01-15  118  		return PTR_ERR(ihid_goodix->vdd);
c1ed18c11bdb80 Douglas Anderson 2021-01-15  119  
c1ed18c11bdb80 Douglas Anderson 2021-01-15  120  	ihid_goodix->timings = device_get_match_data(&client->dev);
c1ed18c11bdb80 Douglas Anderson 2021-01-15  121  
2b87ff72c696bc Douglas Anderson 2021-06-11  122  	/*
2b87ff72c696bc Douglas Anderson 2021-06-11  123  	 * We need to control the "reset" line in lockstep with the regulator
2b87ff72c696bc Douglas Anderson 2021-06-11  124  	 * actually turning on an off instead of just when we make the request.
2b87ff72c696bc Douglas Anderson 2021-06-11  125  	 * This matters if the regulator is shared with another consumer.
2b87ff72c696bc Douglas Anderson 2021-06-11  126  	 * - If the regulator is off then we must assert reset. The reset
2b87ff72c696bc Douglas Anderson 2021-06-11  127  	 *   line is active low and on some boards it could cause a current
2b87ff72c696bc Douglas Anderson 2021-06-11  128  	 *   leak if left high.
2b87ff72c696bc Douglas Anderson 2021-06-11  129  	 * - If the regulator is on then we don't want reset asserted for very
2b87ff72c696bc Douglas Anderson 2021-06-11  130  	 *   long. Holding the controller in reset apparently draws extra
2b87ff72c696bc Douglas Anderson 2021-06-11  131  	 *   power.
2b87ff72c696bc Douglas Anderson 2021-06-11  132  	 */
2b87ff72c696bc Douglas Anderson 2021-06-11  133  	mutex_lock(&ihid_goodix->regulator_mutex);
                                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2b87ff72c696bc Douglas Anderson 2021-06-11  134  	ihid_goodix->nb.notifier_call = ihid_goodix_vdd_notify;
2b87ff72c696bc Douglas Anderson 2021-06-11  135  	ret = regulator_register_notifier(ihid_goodix->vdd, &ihid_goodix->nb);
2b87ff72c696bc Douglas Anderson 2021-06-11  136  	if (ret)
2b87ff72c696bc Douglas Anderson 2021-06-11  137  		return dev_err_probe(&client->dev, ret,
2b87ff72c696bc Douglas Anderson 2021-06-11  138  			"regulator notifier request failed\n");
                                                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Drop the lock before returning?

2b87ff72c696bc Douglas Anderson 2021-06-11  139  
2b87ff72c696bc Douglas Anderson 2021-06-11  140  	/*
2b87ff72c696bc Douglas Anderson 2021-06-11  141  	 * If someone else is holding the regulator on (or the regulator is
2b87ff72c696bc Douglas Anderson 2021-06-11  142  	 * an always-on one) we might never be told to deassert reset. Do it
2b87ff72c696bc Douglas Anderson 2021-06-11  143  	 * now. Here we'll assume that someone else might have _just
2b87ff72c696bc Douglas Anderson 2021-06-11  144  	 * barely_ turned the regulator on so we'll do the full
2b87ff72c696bc Douglas Anderson 2021-06-11  145  	 * "post_power_delay" just in case.
2b87ff72c696bc Douglas Anderson 2021-06-11  146  	 */
2b87ff72c696bc Douglas Anderson 2021-06-11  147  	if (ihid_goodix->reset_gpio && regulator_is_enabled(ihid_goodix->vdd))
2b87ff72c696bc Douglas Anderson 2021-06-11  148  		goodix_i2c_hid_deassert_reset(ihid_goodix, true);
2b87ff72c696bc Douglas Anderson 2021-06-11  149  	mutex_unlock(&ihid_goodix->regulator_mutex);
2b87ff72c696bc Douglas Anderson 2021-06-11  150  
c1ed18c11bdb80 Douglas Anderson 2021-01-15 @151  	return i2c_hid_core_probe(client, &ihid_goodix->ops, 0x0001);
c1ed18c11bdb80 Douglas Anderson 2021-01-15  152  }

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