diff options
| author | Hans de Goede <hdegoede@redhat.com> | 2017-01-22 17:14:08 +0100 |
|---|---|---|
| committer | Thierry Reding <thierry.reding@gmail.com> | 2017-01-30 09:36:42 +0100 |
| commit | b526a314263ea217b8fa9758dca5dc245fd49997 (patch) | |
| tree | 33bc36f29bee3acf277fded5b5d30513d16bfd53 | |
| parent | 69efb3439ccf2ce72e01edde05d2c63d624e251e (diff) | |
pwm: Try to load modules during pwm_get()
Add a module name string to the pwm_lookup struct and if specified try
to load the module using request_module() if pwmchip_find_by_name() is
unable to find the PWM chip.
This is a last resort to work around drivers that can't - and can't be
made to - deal with deferred probe.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
[thierry.reding@gmail.com: rename new macro, reword commit message]
[thierry.reding@gmail.com: add comment explaining use-case]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
| -rw-r--r-- | drivers/pwm/core.c | 14 | ||||
| -rw-r--r-- | include/linux/pwm.h | 23 |
2 files changed, 29 insertions, 8 deletions
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 799c4fb4cc2f..a0860b30bd93 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -765,6 +765,7 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id) unsigned int best = 0; struct pwm_lookup *p, *chosen = NULL; unsigned int match; + int err; /* look up via DT first */ if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node) @@ -825,6 +826,19 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id) return ERR_PTR(-ENODEV); chip = pwmchip_find_by_name(chosen->provider); + + /* + * If the lookup entry specifies a module, load the module and retry + * the PWM chip lookup. This can be used to work around driver load + * ordering issues if driver's can't be made to properly support the + * deferred probe mechanism. + */ + if (!chip && chosen->module) { + err = request_module(chosen->module); + if (err == 0) + chip = pwmchip_find_by_name(chosen->provider); + } + if (!chip) return ERR_PTR(-EPROBE_DEFER); diff --git a/include/linux/pwm.h b/include/linux/pwm.h index eae215ef1b2c..08fad7c6a471 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -603,18 +603,25 @@ struct pwm_lookup { const char *con_id; unsigned int period; enum pwm_polarity polarity; + const char *module; /* optional, may be NULL */ }; -#define PWM_LOOKUP(_provider, _index, _dev_id, _con_id, _period, _polarity) \ - { \ - .provider = _provider, \ - .index = _index, \ - .dev_id = _dev_id, \ - .con_id = _con_id, \ - .period = _period, \ - .polarity = _polarity \ +#define PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, \ + _period, _polarity, _module) \ + { \ + .provider = _provider, \ + .index = _index, \ + .dev_id = _dev_id, \ + .con_id = _con_id, \ + .period = _period, \ + .polarity = _polarity, \ + .module = _module, \ } +#define PWM_LOOKUP(_provider, _index, _dev_id, _con_id, _period, _polarity) \ + PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, _period, \ + _polarity, NULL) + #if IS_ENABLED(CONFIG_PWM) void pwm_add_table(struct pwm_lookup *table, size_t num); void pwm_remove_table(struct pwm_lookup *table, size_t num); |