| Message ID | 20210611092847.1.I358cae5e33f742765fd38485d6ddf1a4a978644d@changeid (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Jiri Kosina |
| Headers | show |
| Series | HID: i2c-hid: goodix: Tie the reset line to true state of the regulator | expand |
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 }
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Hi, On Tue, Jun 22, 2021 at 1:49 AM Dan Carpenter <dan.carpenter@oracle.com> wrote: > > 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? Thank you for catching that. Fixed in v2: https://lore.kernel.org/r/20210625081818.v2.1.I358cae5e33f742765fd38485d6ddf1a4a978644d@changeid/ -Doug
diff --git a/drivers/hid/i2c-hid/i2c-hid-of-goodix.c b/drivers/hid/i2c-hid/i2c-hid-of-goodix.c index ee0225982a82..c13ea29c7911 100644 --- a/drivers/hid/i2c-hid/i2c-hid-of-goodix.c +++ b/drivers/hid/i2c-hid/i2c-hid-of-goodix.c @@ -26,28 +26,29 @@ struct i2c_hid_of_goodix { struct i2chid_ops ops; struct regulator *vdd; + struct notifier_block nb; + struct mutex regulator_mutex; struct gpio_desc *reset_gpio; const struct goodix_i2c_hid_timing_data *timings; }; -static int goodix_i2c_hid_power_up(struct i2chid_ops *ops) +static void goodix_i2c_hid_deassert_reset(struct i2c_hid_of_goodix *ihid_goodix, + bool regulator_just_turned_on) { - struct i2c_hid_of_goodix *ihid_goodix = - container_of(ops, struct i2c_hid_of_goodix, ops); - int ret; - - ret = regulator_enable(ihid_goodix->vdd); - if (ret) - return ret; - - if (ihid_goodix->timings->post_power_delay_ms) + if (regulator_just_turned_on && ihid_goodix->timings->post_power_delay_ms) msleep(ihid_goodix->timings->post_power_delay_ms); gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 0); if (ihid_goodix->timings->post_gpio_reset_delay_ms) msleep(ihid_goodix->timings->post_gpio_reset_delay_ms); +} - return 0; +static int goodix_i2c_hid_power_up(struct i2chid_ops *ops) +{ + struct i2c_hid_of_goodix *ihid_goodix = + container_of(ops, struct i2c_hid_of_goodix, ops); + + return regulator_enable(ihid_goodix->vdd); } static void goodix_i2c_hid_power_down(struct i2chid_ops *ops) @@ -55,20 +56,54 @@ static void goodix_i2c_hid_power_down(struct i2chid_ops *ops) struct i2c_hid_of_goodix *ihid_goodix = container_of(ops, struct i2c_hid_of_goodix, ops); - gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1); regulator_disable(ihid_goodix->vdd); } +static int ihid_goodix_vdd_notify(struct notifier_block *nb, + unsigned long event, + void *ignored) +{ + struct i2c_hid_of_goodix *ihid_goodix = + container_of(nb, struct i2c_hid_of_goodix, nb); + int ret = NOTIFY_OK; + + mutex_lock(&ihid_goodix->regulator_mutex); + + switch (event) { + case REGULATOR_EVENT_PRE_DISABLE: + gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1); + break; + + case REGULATOR_EVENT_ENABLE: + goodix_i2c_hid_deassert_reset(ihid_goodix, true); + break; + + case REGULATOR_EVENT_ABORT_DISABLE: + goodix_i2c_hid_deassert_reset(ihid_goodix, false); + break; + + default: + ret = NOTIFY_DONE; + break; + } + + mutex_unlock(&ihid_goodix->regulator_mutex); + + return ret; +} + static int i2c_hid_of_goodix_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct i2c_hid_of_goodix *ihid_goodix; - + int ret; ihid_goodix = devm_kzalloc(&client->dev, sizeof(*ihid_goodix), GFP_KERNEL); if (!ihid_goodix) return -ENOMEM; + mutex_init(&ihid_goodix->regulator_mutex); + ihid_goodix->ops.power_up = goodix_i2c_hid_power_up; ihid_goodix->ops.power_down = goodix_i2c_hid_power_down; @@ -84,6 +119,35 @@ static int i2c_hid_of_goodix_probe(struct i2c_client *client, ihid_goodix->timings = device_get_match_data(&client->dev); + /* + * We need to control the "reset" line in lockstep with the regulator + * actually turning on an off instead of just when we make the request. + * This matters if the regulator is shared with another consumer. + * - If the regulator is off then we must assert reset. The reset + * line is active low and on some boards it could cause a current + * leak if left high. + * - If the regulator is on then we don't want reset asserted for very + * long. Holding the controller in reset apparently draws extra + * power. + */ + mutex_lock(&ihid_goodix->regulator_mutex); + ihid_goodix->nb.notifier_call = ihid_goodix_vdd_notify; + ret = regulator_register_notifier(ihid_goodix->vdd, &ihid_goodix->nb); + if (ret) + return dev_err_probe(&client->dev, ret, + "regulator notifier request failed\n"); + + /* + * If someone else is holding the regulator on (or the regulator is + * an always-on one) we might never be told to deassert reset. Do it + * now. Here we'll assume that someone else might have _just + * barely_ turned the regulator on so we'll do the full + * "post_power_delay" just in case. + */ + if (ihid_goodix->reset_gpio && regulator_is_enabled(ihid_goodix->vdd)) + goodix_i2c_hid_deassert_reset(ihid_goodix, true); + mutex_unlock(&ihid_goodix->regulator_mutex); + return i2c_hid_core_probe(client, &ihid_goodix->ops, 0x0001); }
The regulator for the touchscreen could be: * A dedicated regulator just for the touchscreen. * A regulator shared with something else in the system. * An always-on regulator. How we want the "reset" line to behave depends a bit on which of those three cases we're in. Currently the code is written with the assumption that it has a dedicated regulator, but that's not really guaranteed to be the case. The problem we run into is that if we leave the touchscreen powered on (because someone else is requesting the regulator or it's an always-on regulator) and we assert reset then we apparently burn an extra 67 mW of power. That's not great. Let's instead tie the control of the reset line to the true state of the regulator as reported by regulator notifiers. If we have an always-on regulator our notifier will never be called. If we have a shared regulator then our notifier will be called when the touchscreen is truly turned on or truly turned off. Using notifiers like this nicely handles all the cases without resorting to hacks like pretending that there is no "reset" GPIO if we have an always-on regulator. NOTE: if the regulator is on a shared line it's still possible that things could be a little off. Specifically, this case is not handled even after this patch: 1. Suspend goodix (send "sleep", goodix stops requesting regulator on) 2. Other regulator user turns off (regulator fully turns off). 3. Goodix driver gets notified and asserts reset. 4. Other regulator user turns on. 5. Goodix driver gets notified and deasserts reset. 6. Nobody resumes goodix. With that set of steps we'll have reset deasserted but we will have lost the results of the I2C_HID_PWR_SLEEP from the suspend path. That means we might be in higher power than we could be even if the goodix driver thinks things are suspended. Presumably, however, we're still in better shape than if we were asserting "reset" the whole time. If somehow the above situation is actually affecting someone and we want to do better we can deal with it when we have a real use case. Signed-off-by: Douglas Anderson <dianders@chromium.org> --- drivers/hid/i2c-hid/i2c-hid-of-goodix.c | 90 +++++++++++++++++++++---- 1 file changed, 77 insertions(+), 13 deletions(-)