| Message ID | 20170714214005.14967-2-stephen.boyd@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | [v2,1/3] mux: Add mux_control_get_optional() API | expand |
Generally looks like I imagined, but there are a few nits and some things that I'd like to do differently. Comments inline. Thanks! On 2017-07-14 23:40, Stephen Boyd wrote: > Sometimes drivers only use muxes under certain scenarios. For > example, the chipidea usb controller may be connected to a usb > switch on some platforms, and connected directly to a usb port on > others. The driver won't know one way or the other though, so add > a mux_control_get_optional() API that allows the driver to > differentiate errors getting the mux from there not being a mux > for the driver to use at all. > > Cc: Jonathan Cameron <jic23@kernel.org> > Cc: Philipp Zabel <p.zabel@pengutronix.de> > Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org> > --- > Documentation/driver-model/devres.txt | 1 + > drivers/mux/mux-core.c | 98 ++++++++++++++++++++++++++++------- > include/linux/mux/consumer.h | 4 ++ > 3 files changed, 83 insertions(+), 20 deletions(-) > > diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt > index 30e04f7a690d..4fdd3e63ff8b 100644 > --- a/Documentation/driver-model/devres.txt > +++ b/Documentation/driver-model/devres.txt > @@ -342,6 +342,7 @@ MUX > devm_mux_chip_alloc() > devm_mux_chip_register() > devm_mux_control_get() > + devm_mux_control_get_optional() > > PER-CPU MEM > devm_alloc_percpu() > diff --git a/drivers/mux/mux-core.c b/drivers/mux/mux-core.c > index 90b8995f07cb..a0e5bf16f02f 100644 > --- a/drivers/mux/mux-core.c > +++ b/drivers/mux/mux-core.c > @@ -289,6 +289,9 @@ EXPORT_SYMBOL_GPL(devm_mux_chip_register); > */ > unsigned int mux_control_states(struct mux_control *mux) > { > + if (!mux) > + return 0; > + I don't think this is appropriate. For this function, it might be ok, but... > return mux->states; > } > EXPORT_SYMBOL_GPL(mux_control_states); > @@ -338,6 +341,9 @@ int mux_control_select(struct mux_control *mux, unsigned int state) > { > int ret; > > + if (!mux) > + return 0; > + ...here and for other cases below it's very odd to return "ok", when -EINVAL or something seems much more appropriate. And if -EINVAL is returned here, the benefit of returning fake values for anything pretty much falls apart. I simply don't like it, and prefer if the consumer code is arranged to not call the mux functions when the optional get() does not find the mux. > ret = down_killable(&mux->lock); > if (ret < 0) > return ret; > @@ -370,6 +376,9 @@ int mux_control_try_select(struct mux_control *mux, unsigned int state) > { > int ret; > > + if (!mux) > + return 0; > + > if (down_trylock(&mux->lock)) > return -EBUSY; > > @@ -398,6 +407,9 @@ int mux_control_deselect(struct mux_control *mux) > { > int ret = 0; > > + if (!mux) > + return 0; > + > if (mux->idle_state != MUX_IDLE_AS_IS && > mux->idle_state != mux->cached_state) > ret = mux_control_set(mux, mux->idle_state); > @@ -422,14 +434,8 @@ static struct mux_chip *of_find_mux_chip_by_node(struct device_node *np) > return dev ? to_mux_chip(dev) : NULL; > } > > -/** > - * mux_control_get() - Get the mux-control for a device. > - * @dev: The device that needs a mux-control. > - * @mux_name: The name identifying the mux-control. > - * > - * Return: A pointer to the mux-control, or an ERR_PTR with a negative errno. > - */ > -struct mux_control *mux_control_get(struct device *dev, const char *mux_name) > +struct mux_control * > +__mux_control_get(struct device *dev, const char *mux_name, bool optional) > { > struct device_node *np = dev->of_node; > struct of_phandle_args args; > @@ -441,6 +447,8 @@ struct mux_control *mux_control_get(struct device *dev, const char *mux_name) > if (mux_name) { > index = of_property_match_string(np, "mux-control-names", > mux_name); > + if (index == -EINVAL && optional) > + return NULL; What about -ENODATA? And if an optional mux is found here, but lookup fails later in e.g. the of_parse_phandle_with_args call, then I think an error should be returned. Because that seems like an indication that DT specifies that there *should* be a mux, but then there isn't one. > if (index < 0) { > dev_err(dev, "mux controller '%s' not found\n", > mux_name); > @@ -451,6 +459,8 @@ struct mux_control *mux_control_get(struct device *dev, const char *mux_name) > ret = of_parse_phandle_with_args(np, > "mux-controls", "#mux-control-cells", > index, &args); > + if (ret == -ENOENT && optional) > + return NULL; > if (ret) { > dev_err(dev, "%s: failed to get mux-control %s(%i)\n", > np->full_name, mux_name ?: "", index); > @@ -482,9 +492,35 @@ struct mux_control *mux_control_get(struct device *dev, const char *mux_name) > get_device(&mux_chip->dev); > return &mux_chip->mux[controller]; > } > + > +/** > + * mux_control_get() - Get the mux-control for a device. > + * @dev: The device that needs a mux-control. > + * @mux_name: The name identifying the mux-control. > + * > + * Return: A pointer to the mux-control, or an ERR_PTR with a negative errno. > + */ > +struct mux_control *mux_control_get(struct device *dev, const char *mux_name) > +{ > + return __mux_control_get(dev, mux_name, false); > +} > EXPORT_SYMBOL_GPL(mux_control_get); > > /** > + * mux_control_get_optional() - Get the optional mux-control for a device. > + * @dev: The device that needs a mux-control. > + * @mux_name: The name identifying the mux-control. > + * > + * Return: A pointer to the mux-control, or an ERR_PTR with a negative errno. You don't mention that NULL may be returned, or when. > + */ > +struct mux_control * > +mux_control_get_optional(struct device *dev, const char *mux_name) > +{ > + return __mux_control_get(dev, mux_name, true); > +} > +EXPORT_SYMBOL_GPL(mux_control_get_optional); > + > +/** > * mux_control_put() - Put away the mux-control for good. > * @mux: The mux-control to put away. > * > @@ -492,7 +528,8 @@ EXPORT_SYMBOL_GPL(mux_control_get); > */ > void mux_control_put(struct mux_control *mux) > { > - put_device(&mux->chip->dev); > + if (mux) > + put_device(&mux->chip->dev); Don't put it if you don't have it. > } > EXPORT_SYMBOL_GPL(mux_control_put); > > @@ -503,16 +540,8 @@ static void devm_mux_control_release(struct device *dev, void *res) > mux_control_put(mux); > } > > -/** > - * devm_mux_control_get() - Get the mux-control for a device, with resource > - * management. > - * @dev: The device that needs a mux-control. > - * @mux_name: The name identifying the mux-control. > - * > - * Return: Pointer to the mux-control, or an ERR_PTR with a negative errno. > - */ > -struct mux_control *devm_mux_control_get(struct device *dev, > - const char *mux_name) > +static struct mux_control * > +__devm_mux_control_get(struct device *dev, const char *mux_name, bool optional) > { > struct mux_control **ptr, *mux; > > @@ -520,7 +549,7 @@ struct mux_control *devm_mux_control_get(struct device *dev, > if (!ptr) > return ERR_PTR(-ENOMEM); > > - mux = mux_control_get(dev, mux_name); > + mux = __mux_control_get(dev, mux_name, optional); > if (IS_ERR(mux)) { > devres_free(ptr); > return mux; > @@ -531,8 +560,37 @@ struct mux_control *devm_mux_control_get(struct device *dev, > > return mux; > } > + > +/** > + * devm_mux_control_get() - Get the mux-control for a device, with resource > + * management. > + * @dev: The device that needs a mux-control. > + * @mux_name: The name identifying the mux-control. > + * > + * Return: Pointer to the mux-control, or an ERR_PTR with a negative errno. > + */ > +struct mux_control * > +devm_mux_control_get(struct device *dev, const char *mux_name) > +{ > + return __devm_mux_control_get(dev, mux_name, false); > +} > EXPORT_SYMBOL_GPL(devm_mux_control_get); > > +/** > + * devm_mux_control_get_optional() - Get the optional mux-control for a device, > + * with resource management. > + * @dev: The device that needs a mux-control. > + * @mux_name: The name identifying the mux-control. > + * > + * Return: Pointer to the mux-control, or an ERR_PTR with a negative errno. You don't mention that NULL may be returned, or when. Cheers, Peter > + */ > +struct mux_control * > +devm_mux_control_get_optional(struct device *dev, const char *mux_name) > +{ > + return __devm_mux_control_get(dev, mux_name, true); > +} > +EXPORT_SYMBOL_GPL(devm_mux_control_get_optional); > + > /* > * Using subsys_initcall instead of module_init here to try to ensure - for > * the non-modular case - that the subsystem is initialized when mux consumers > diff --git a/include/linux/mux/consumer.h b/include/linux/mux/consumer.h > index 5577e1b773c4..5e2aa046f032 100644 > --- a/include/linux/mux/consumer.h > +++ b/include/linux/mux/consumer.h > @@ -24,9 +24,13 @@ int __must_check mux_control_try_select(struct mux_control *mux, > int mux_control_deselect(struct mux_control *mux); > > struct mux_control *mux_control_get(struct device *dev, const char *mux_name); > +struct mux_control *mux_control_get_optional(struct device *dev, > + const char *mux_name); > void mux_control_put(struct mux_control *mux); > > struct mux_control *devm_mux_control_get(struct device *dev, > const char *mux_name); > +struct mux_control *devm_mux_control_get_optional(struct device *dev, > + const char *mux_name); > > #endif /* _LINUX_MUX_CONSUMER_H */ >
diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt index 30e04f7a690d..4fdd3e63ff8b 100644 --- a/Documentation/driver-model/devres.txt +++ b/Documentation/driver-model/devres.txt @@ -342,6 +342,7 @@ MUX devm_mux_chip_alloc() devm_mux_chip_register() devm_mux_control_get() + devm_mux_control_get_optional() PER-CPU MEM devm_alloc_percpu() diff --git a/drivers/mux/mux-core.c b/drivers/mux/mux-core.c index 90b8995f07cb..a0e5bf16f02f 100644 --- a/drivers/mux/mux-core.c +++ b/drivers/mux/mux-core.c @@ -289,6 +289,9 @@ EXPORT_SYMBOL_GPL(devm_mux_chip_register); */ unsigned int mux_control_states(struct mux_control *mux) { + if (!mux) + return 0; + return mux->states; } EXPORT_SYMBOL_GPL(mux_control_states); @@ -338,6 +341,9 @@ int mux_control_select(struct mux_control *mux, unsigned int state) { int ret; + if (!mux) + return 0; + ret = down_killable(&mux->lock); if (ret < 0) return ret; @@ -370,6 +376,9 @@ int mux_control_try_select(struct mux_control *mux, unsigned int state) { int ret; + if (!mux) + return 0; + if (down_trylock(&mux->lock)) return -EBUSY; @@ -398,6 +407,9 @@ int mux_control_deselect(struct mux_control *mux) { int ret = 0; + if (!mux) + return 0; + if (mux->idle_state != MUX_IDLE_AS_IS && mux->idle_state != mux->cached_state) ret = mux_control_set(mux, mux->idle_state); @@ -422,14 +434,8 @@ static struct mux_chip *of_find_mux_chip_by_node(struct device_node *np) return dev ? to_mux_chip(dev) : NULL; } -/** - * mux_control_get() - Get the mux-control for a device. - * @dev: The device that needs a mux-control. - * @mux_name: The name identifying the mux-control. - * - * Return: A pointer to the mux-control, or an ERR_PTR with a negative errno. - */ -struct mux_control *mux_control_get(struct device *dev, const char *mux_name) +struct mux_control * +__mux_control_get(struct device *dev, const char *mux_name, bool optional) { struct device_node *np = dev->of_node; struct of_phandle_args args; @@ -441,6 +447,8 @@ struct mux_control *mux_control_get(struct device *dev, const char *mux_name) if (mux_name) { index = of_property_match_string(np, "mux-control-names", mux_name); + if (index == -EINVAL && optional) + return NULL; if (index < 0) { dev_err(dev, "mux controller '%s' not found\n", mux_name); @@ -451,6 +459,8 @@ struct mux_control *mux_control_get(struct device *dev, const char *mux_name) ret = of_parse_phandle_with_args(np, "mux-controls", "#mux-control-cells", index, &args); + if (ret == -ENOENT && optional) + return NULL; if (ret) { dev_err(dev, "%s: failed to get mux-control %s(%i)\n", np->full_name, mux_name ?: "", index); @@ -482,9 +492,35 @@ struct mux_control *mux_control_get(struct device *dev, const char *mux_name) get_device(&mux_chip->dev); return &mux_chip->mux[controller]; } + +/** + * mux_control_get() - Get the mux-control for a device. + * @dev: The device that needs a mux-control. + * @mux_name: The name identifying the mux-control. + * + * Return: A pointer to the mux-control, or an ERR_PTR with a negative errno. + */ +struct mux_control *mux_control_get(struct device *dev, const char *mux_name) +{ + return __mux_control_get(dev, mux_name, false); +} EXPORT_SYMBOL_GPL(mux_control_get); /** + * mux_control_get_optional() - Get the optional mux-control for a device. + * @dev: The device that needs a mux-control. + * @mux_name: The name identifying the mux-control. + * + * Return: A pointer to the mux-control, or an ERR_PTR with a negative errno. + */ +struct mux_control * +mux_control_get_optional(struct device *dev, const char *mux_name) +{ + return __mux_control_get(dev, mux_name, true); +} +EXPORT_SYMBOL_GPL(mux_control_get_optional); + +/** * mux_control_put() - Put away the mux-control for good. * @mux: The mux-control to put away. * @@ -492,7 +528,8 @@ EXPORT_SYMBOL_GPL(mux_control_get); */ void mux_control_put(struct mux_control *mux) { - put_device(&mux->chip->dev); + if (mux) + put_device(&mux->chip->dev); } EXPORT_SYMBOL_GPL(mux_control_put); @@ -503,16 +540,8 @@ static void devm_mux_control_release(struct device *dev, void *res) mux_control_put(mux); } -/** - * devm_mux_control_get() - Get the mux-control for a device, with resource - * management. - * @dev: The device that needs a mux-control. - * @mux_name: The name identifying the mux-control. - * - * Return: Pointer to the mux-control, or an ERR_PTR with a negative errno. - */ -struct mux_control *devm_mux_control_get(struct device *dev, - const char *mux_name) +static struct mux_control * +__devm_mux_control_get(struct device *dev, const char *mux_name, bool optional) { struct mux_control **ptr, *mux; @@ -520,7 +549,7 @@ struct mux_control *devm_mux_control_get(struct device *dev, if (!ptr) return ERR_PTR(-ENOMEM); - mux = mux_control_get(dev, mux_name); + mux = __mux_control_get(dev, mux_name, optional); if (IS_ERR(mux)) { devres_free(ptr); return mux; @@ -531,8 +560,37 @@ struct mux_control *devm_mux_control_get(struct device *dev, return mux; } + +/** + * devm_mux_control_get() - Get the mux-control for a device, with resource + * management. + * @dev: The device that needs a mux-control. + * @mux_name: The name identifying the mux-control. + * + * Return: Pointer to the mux-control, or an ERR_PTR with a negative errno. + */ +struct mux_control * +devm_mux_control_get(struct device *dev, const char *mux_name) +{ + return __devm_mux_control_get(dev, mux_name, false); +} EXPORT_SYMBOL_GPL(devm_mux_control_get); +/** + * devm_mux_control_get_optional() - Get the optional mux-control for a device, + * with resource management. + * @dev: The device that needs a mux-control. + * @mux_name: The name identifying the mux-control. + * + * Return: Pointer to the mux-control, or an ERR_PTR with a negative errno. + */ +struct mux_control * +devm_mux_control_get_optional(struct device *dev, const char *mux_name) +{ + return __devm_mux_control_get(dev, mux_name, true); +} +EXPORT_SYMBOL_GPL(devm_mux_control_get_optional); + /* * Using subsys_initcall instead of module_init here to try to ensure - for * the non-modular case - that the subsystem is initialized when mux consumers diff --git a/include/linux/mux/consumer.h b/include/linux/mux/consumer.h index 5577e1b773c4..5e2aa046f032 100644 --- a/include/linux/mux/consumer.h +++ b/include/linux/mux/consumer.h @@ -24,9 +24,13 @@ int __must_check mux_control_try_select(struct mux_control *mux, int mux_control_deselect(struct mux_control *mux); struct mux_control *mux_control_get(struct device *dev, const char *mux_name); +struct mux_control *mux_control_get_optional(struct device *dev, + const char *mux_name); void mux_control_put(struct mux_control *mux); struct mux_control *devm_mux_control_get(struct device *dev, const char *mux_name); +struct mux_control *devm_mux_control_get_optional(struct device *dev, + const char *mux_name); #endif /* _LINUX_MUX_CONSUMER_H */
Sometimes drivers only use muxes under certain scenarios. For example, the chipidea usb controller may be connected to a usb switch on some platforms, and connected directly to a usb port on others. The driver won't know one way or the other though, so add a mux_control_get_optional() API that allows the driver to differentiate errors getting the mux from there not being a mux for the driver to use at all. Cc: Jonathan Cameron <jic23@kernel.org> Cc: Philipp Zabel <p.zabel@pengutronix.de> Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org> --- Documentation/driver-model/devres.txt | 1 + drivers/mux/mux-core.c | 98 ++++++++++++++++++++++++++++------- include/linux/mux/consumer.h | 4 ++ 3 files changed, 83 insertions(+), 20 deletions(-) -- 2.10.0.297.gf6727b0