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| 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 /drivers/pwm | |
| parent | 69efb3439ccf2ce72e01edde05d2c63d624e251e (diff) | |
| download | linux-b526a314263ea217b8fa9758dca5dc245fd49997.tar.gz linux-b526a314263ea217b8fa9758dca5dc245fd49997.tar.bz2 linux-b526a314263ea217b8fa9758dca5dc245fd49997.zip | |
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>
Diffstat (limited to 'drivers/pwm')
| -rw-r--r-- | drivers/pwm/core.c | 14 |
1 files changed, 14 insertions, 0 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); |