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author | Aswath Govindraju <a-govindraju@ti.com> | 2022-01-07 08:44:25 +0100 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-02-04 15:47:11 +0100 |
commit | 84564481bc4520c47e7fe9c594c0523d81e6a97a (patch) | |
tree | 1385d09ee43714892b5a27e6a4c7282b94356b62 /drivers/mux/core.c | |
parent | b2fb28dedd39408268db38da98ef9c7d444623ab (diff) | |
download | linux-stable-84564481bc4520c47e7fe9c594c0523d81e6a97a.tar.gz linux-stable-84564481bc4520c47e7fe9c594c0523d81e6a97a.tar.bz2 linux-stable-84564481bc4520c47e7fe9c594c0523d81e6a97a.zip |
mux: Add support for reading mux state from consumer DT node
In some cases, we might need to provide the state of the mux to be set for
the operation of a given peripheral. Therefore, pass this information using
mux-states property.
Link: https://lore.kernel.org/lkml/20211123081222.27979-1-a-govindraju@ti.com
Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
Signed-off-by: Peter Rosin <peda@axentia.se> (minor edits)
Link: https://lore.kernel.org/r/aac25be8-9515-a980-f7cb-709938c84822@axentia.se
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/mux/core.c')
-rw-r--r-- | drivers/mux/core.c | 219 |
1 files changed, 198 insertions, 21 deletions
diff --git a/drivers/mux/core.c b/drivers/mux/core.c index 22f4709768d1..931fa8bd4962 100644 --- a/drivers/mux/core.c +++ b/drivers/mux/core.c @@ -29,6 +29,20 @@ */ #define MUX_CACHE_UNKNOWN MUX_IDLE_AS_IS +/** + * struct mux_state - Represents a mux controller state specific to a given + * consumer. + * @mux: Pointer to a mux controller. + * @state State of the mux to be selected. + * + * This structure is specific to the consumer that acquires it and has + * information specific to that consumer. + */ +struct mux_state { + struct mux_control *mux; + unsigned int state; +}; + static struct class mux_class = { .name = "mux", .owner = THIS_MODULE, @@ -341,7 +355,8 @@ static void mux_control_delay(struct mux_control *mux, unsigned int delay_us) * On successfully selecting the mux-control state, it will be locked until * there is a call to mux_control_deselect(). If the mux-control is already * selected when mux_control_select() is called, the caller will be blocked - * until mux_control_deselect() is called (by someone else). + * until mux_control_deselect() or mux_state_deselect() is called (by someone + * else). * * Therefore, make sure to call mux_control_deselect() when the operation is * complete and the mux-control is free for others to use, but do not call @@ -371,6 +386,30 @@ int mux_control_select_delay(struct mux_control *mux, unsigned int state, EXPORT_SYMBOL_GPL(mux_control_select_delay); /** + * mux_state_select_delay() - Select the given multiplexer state. + * @mstate: The mux-state to select. + * @delay_us: The time to delay (in microseconds) if the mux state is changed. + * + * On successfully selecting the mux-state, its mux-control will be locked + * until there is a call to mux_state_deselect(). If the mux-control is already + * selected when mux_state_select() is called, the caller will be blocked + * until mux_state_deselect() or mux_control_deselect() is called (by someone + * else). + * + * Therefore, make sure to call mux_state_deselect() when the operation is + * complete and the mux-control is free for others to use, but do not call + * mux_state_deselect() if mux_state_select() fails. + * + * Return: 0 when the mux-state has been selected or a negative + * errno on error. + */ +int mux_state_select_delay(struct mux_state *mstate, unsigned int delay_us) +{ + return mux_control_select_delay(mstate->mux, mstate->state, delay_us); +} +EXPORT_SYMBOL_GPL(mux_state_select_delay); + +/** * mux_control_try_select_delay() - Try to select the given multiplexer state. * @mux: The mux-control to request a change of state from. * @state: The new requested state. @@ -406,6 +445,27 @@ int mux_control_try_select_delay(struct mux_control *mux, unsigned int state, EXPORT_SYMBOL_GPL(mux_control_try_select_delay); /** + * mux_state_try_select_delay() - Try to select the given multiplexer state. + * @mstate: The mux-state to select. + * @delay_us: The time to delay (in microseconds) if the mux state is changed. + * + * On successfully selecting the mux-state, its mux-control will be locked + * until mux_state_deselect() is called. + * + * Therefore, make sure to call mux_state_deselect() when the operation is + * complete and the mux-control is free for others to use, but do not call + * mux_state_deselect() if mux_state_try_select() fails. + * + * Return: 0 when the mux-state has been selected or a negative errno on + * error. Specifically -EBUSY if the mux-control is contended. + */ +int mux_state_try_select_delay(struct mux_state *mstate, unsigned int delay_us) +{ + return mux_control_try_select_delay(mstate->mux, mstate->state, delay_us); +} +EXPORT_SYMBOL_GPL(mux_state_try_select_delay); + +/** * mux_control_deselect() - Deselect the previously selected multiplexer state. * @mux: The mux-control to deselect. * @@ -431,6 +491,24 @@ int mux_control_deselect(struct mux_control *mux) } EXPORT_SYMBOL_GPL(mux_control_deselect); +/** + * mux_state_deselect() - Deselect the previously selected multiplexer state. + * @mstate: The mux-state to deselect. + * + * It is required that a single call is made to mux_state_deselect() for + * each and every successful call made to either of mux_state_select() or + * mux_state_try_select(). + * + * Return: 0 on success and a negative errno on error. An error can only + * occur if the mux has an idle state. Note that even if an error occurs, the + * mux-control is unlocked and is thus free for the next access. + */ +int mux_state_deselect(struct mux_state *mstate) +{ + return mux_control_deselect(mstate->mux); +} +EXPORT_SYMBOL_GPL(mux_state_deselect); + /* Note this function returns a reference to the mux_chip dev. */ static struct mux_chip *of_find_mux_chip_by_node(struct device_node *np) { @@ -441,14 +519,17 @@ 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. +/* + * mux_get() - Get the mux-control for a device. * @dev: The device that needs a mux-control. * @mux_name: The name identifying the mux-control. + * @state: Pointer to where the requested state is returned, or NULL when + * the required multiplexer states are handled by other means. * * 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) +static struct mux_control *mux_get(struct device *dev, const char *mux_name, + unsigned int *state) { struct device_node *np = dev->of_node; struct of_phandle_args args; @@ -458,8 +539,12 @@ struct mux_control *mux_control_get(struct device *dev, const char *mux_name) int ret; if (mux_name) { - index = of_property_match_string(np, "mux-control-names", - mux_name); + if (state) + index = of_property_match_string(np, "mux-state-names", + mux_name); + else + index = of_property_match_string(np, "mux-control-names", + mux_name); if (index < 0) { dev_err(dev, "mux controller '%s' not found\n", mux_name); @@ -467,12 +552,17 @@ 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 (state) + ret = of_parse_phandle_with_args(np, + "mux-states", "#mux-state-cells", + index, &args); + else + ret = of_parse_phandle_with_args(np, + "mux-controls", "#mux-control-cells", + index, &args); if (ret) { - dev_err(dev, "%pOF: failed to get mux-control %s(%i)\n", - np, mux_name ?: "", index); + dev_err(dev, "%pOF: failed to get mux-%s %s(%i)\n", + np, state ? "state" : "control", mux_name ?: "", index); return ERR_PTR(ret); } @@ -481,17 +571,35 @@ struct mux_control *mux_control_get(struct device *dev, const char *mux_name) if (!mux_chip) return ERR_PTR(-EPROBE_DEFER); - if (args.args_count > 1 || - (!args.args_count && (mux_chip->controllers > 1))) { - dev_err(dev, "%pOF: wrong #mux-control-cells for %pOF\n", - np, args.np); - put_device(&mux_chip->dev); - return ERR_PTR(-EINVAL); - } - controller = 0; - if (args.args_count) - controller = args.args[0]; + if (state) { + if (args.args_count > 2 || args.args_count == 0 || + (args.args_count < 2 && mux_chip->controllers > 1)) { + dev_err(dev, "%pOF: wrong #mux-state-cells for %pOF\n", + np, args.np); + put_device(&mux_chip->dev); + return ERR_PTR(-EINVAL); + } + + if (args.args_count == 2) { + controller = args.args[0]; + *state = args.args[1]; + } else { + *state = args.args[0]; + } + + } else { + if (args.args_count > 1 || + (!args.args_count && mux_chip->controllers > 1)) { + dev_err(dev, "%pOF: wrong #mux-control-cells for %pOF\n", + np, args.np); + put_device(&mux_chip->dev); + return ERR_PTR(-EINVAL); + } + + if (args.args_count) + controller = args.args[0]; + } if (controller >= mux_chip->controllers) { dev_err(dev, "%pOF: bad mux controller %u specified in %pOF\n", @@ -502,6 +610,18 @@ struct mux_control *mux_control_get(struct device *dev, const char *mux_name) 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_get(dev, mux_name, NULL); +} EXPORT_SYMBOL_GPL(mux_control_get); /** @@ -554,6 +674,63 @@ struct mux_control *devm_mux_control_get(struct device *dev, EXPORT_SYMBOL_GPL(devm_mux_control_get); /* + * mux_state_put() - Put away the mux-state for good. + * @mstate: The mux-state to put away. + * + * mux_state_put() reverses the effects of mux_state_get(). + */ +static void mux_state_put(struct mux_state *mstate) +{ + mux_control_put(mstate->mux); + kfree(mstate); +} + +static void devm_mux_state_release(struct device *dev, void *res) +{ + struct mux_state *mstate = *(struct mux_state **)res; + + mux_state_put(mstate); +} + +/** + * devm_mux_state_get() - Get the mux-state 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-state, or an ERR_PTR with a negative errno. + */ +struct mux_state *devm_mux_state_get(struct device *dev, + const char *mux_name) +{ + struct mux_state **ptr, *mstate; + struct mux_control *mux_ctrl; + int state; + + mstate = devm_kzalloc(dev, sizeof(struct mux_state), GFP_KERNEL); + if (!mstate) + return ERR_PTR(-ENOMEM); + + ptr = devres_alloc(devm_mux_state_release, sizeof(*ptr), GFP_KERNEL); + if (!ptr) + return ERR_PTR(-ENOMEM); + + mux_ctrl = mux_get(dev, mux_name, &state); + if (IS_ERR(mux_ctrl)) { + devres_free(ptr); + return (struct mux_state *)mux_ctrl; + } + + mstate->mux = mux_ctrl; + mstate->state = state; + *ptr = mstate; + devres_add(dev, ptr); + + return mstate; +} +EXPORT_SYMBOL_GPL(devm_mux_state_get); + +/* * 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 * and mux controllers start to use it. |