| Message ID | 20160517140803.078e3f5e@bbrezillon (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, May 17, 2016 at 02:08:03PM +0200, Boris Brezillon wrote: > Hi Thierry, > > On Tue, 17 May 2016 13:00:05 +0200 > Thierry Reding <thierry.reding@gmail.com> wrote: > > > On Tue, May 17, 2016 at 11:12:32AM +0200, Boris Brezillon wrote: > > > The PWM device exposed by the HLCDC IP is configured with an inverted > > > polarity by default. Registering the PWM chip with the normal polarity > > > was not a problem before commit 42e8992c58d4 ("pwm: Add core > > > infrastructure to allow atomic updates") because the ->set_polarity() > > > hook was called no matter the current polarity state, but this is no longer > > > the case. > > > > > > Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> > > > Fixes: 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates") > > > > That's not technically correct, because it's the driver that has the > > bug. The core change merely exposes it. How about if I sort this into > > the pwm-atomic branch and reword the commit message accordingly? That > > way things should all stay bisectible. > > > > Then again, given the breakage caused by the pwm_args patch I suppose > > it doesn't matter much because that's part of a stable branch that I > > can't rebase. > > If I understood correctly, you plan to rebase your pwm-atomic branch to > insert this commit before commit 42e8992c58d4 ("pwm: Add core > infrastructure to allow atomic updates"). > > Could you consider taking the following commit (or something similar if > you already have a fix) as the first commit of your pwm-atomic branch? > > Sorry for the mess around the introduction of pwm_args and pwm_state > (that's not an excuse, but I've reworked this series so many time that I > forgot to check bisectibility on the last versions :-(). > > --- > From ad73fa3a56c7320979425d64ab54c09b9d83d4cf Mon Sep 17 00:00:00 2001 > From: Boris Brezillon <boris.brezillon@free-electrons.com> > Date: Tue, 17 May 2016 13:55:02 +0200 > Subject: [PATCH] pwm: Fix pwm_apply_args() call sites > > pwm_apply_args() is supposed to initialize a PWM device according to the > arguments provided by the DT or the PWM lookup, but this function was > called inside pwm_device_request(), which in turn was called before the > core had a chance to initialize the pwm->args fields. > > Fix that by calling pwm_apply_args directly in pwm_get() and of_pwm_get() > after initializing pwm->args field. > > This commit also fixes an invalid pointer dereference introduced by > commit e39c0df1be5a ("pwm: Introduce the pwm_args concept"). > > Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> > Fixes: e39c0df1be5a ("pwm: Introduce the pwm_args concept") > --- > drivers/pwm/core.c | 27 +++++++++++++++++---------- > 1 file changed, 17 insertions(+), 10 deletions(-) This looks good to me. However I can't easily apply this because git gets confused by the existing headers. Also manually copying out the patch yields patch corruption that I don't exactly know how to fix. I think you can inline patches by using a scissor mark (--- >8 ---) instead of the signature separator (---). Or you can attach the patch with "Content-Disposition: inline". Rather than putting this into the pwm-atomic branch, I'll probably stick it into the pwm-args branch on top of the existing patch. Technically only the existing patch needs to be stable, so the branch can still evolve. Thierry
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 680fbc7..22cf395 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -128,13 +128,6 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label) set_bit(PWMF_REQUESTED, &pwm->flags); pwm->label = label; - /* - * FIXME: This should be removed once all PWM users properly make use - * of struct pwm_args to initialize the PWM device. As long as this is - * here, the PWM state and hardware state can get out of sync. - */ - pwm_apply_args(pwm); - return 0; } @@ -627,6 +620,13 @@ struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id) pwm->label = con_id; + /* + * FIXME: This should be removed once all PWM users properly make use + * of struct pwm_args to initialize the PWM device. As long as this is + * here, the PWM state and hardware state can get out of sync. + */ + pwm_apply_args(pwm); + put: of_node_put(args.np); @@ -754,13 +754,20 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id) if (!chip) goto out; - pwm->args.period = chosen->period; - pwm->args.polarity = chosen->polarity; - pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id); if (IS_ERR(pwm)) goto out; + pwm->args.period = chosen->period; + pwm->args.polarity = chosen->polarity; + + /* + * FIXME: This should be removed once all PWM users properly make use + * of struct pwm_args to initialize the PWM device. As long as this is + * here, the PWM state and hardware state can get out of sync. + */ + pwm_apply_args(pwm); + out: mutex_unlock(&pwm_lookup_lock); return pwm;