linux-toradex.git/drivers/pinctrl/pinmux.c, branch v4.4.95

pinctrl: join lines that can be a single line within 80 columns

2015-09-14T07:13:43+00:00

There is no reason to break a line shorter than 80 columns.

Signed-off-by: Masahiro Yamada 
Signed-off-by: Linus Walleij

pinctrl: use dev_err() to show message in pinmux_func_name_to_selector()

2015-07-27T12:44:33+00:00

Use dev_err() rather than pr_err() to display the error message.

pinctrl_dev_get_name(pctldev) is no longer necessary because
dev_err() shows which device the message is related to.

Signed-off-by: Masahiro Yamada 
Signed-off-by: Linus Walleij

pinctrl: don't print unavailable function groups

2015-06-10T08:44:05+00:00

There is no reason to try to print groups associated to a function if
get_function_groups returns an error. Moreover, it can lead to a NULL
pointer dereference error.

Signed-off-by: Ludovic Desroches 
Signed-off-by: Linus Walleij

pinctrl: improve debugfs for strict controllers

2015-05-28T08:14:21+00:00

If we know we are using a strict pin controller (one that cannot
mix device functions+group use and GPIO) we can be a bit more
specific in debugfs, just print either device-function-group
or GPIO consumer for the pin. Let's do that to be helpful.

Cc: Sonic Zhang 
Signed-off-by: Linus Walleij

pinctrl: move strict option to pinmux_ops

2015-05-06T12:45:19+00:00

While the pinmux_ops are ideally just a vtable for pin mux
calls, the "strict" setting belongs so intuitively with the
pin multiplexing that we should move it here anyway. Putting
it in the top pinctrl_desc makes no sense.

Cc: Sonic Zhang 
Signed-off-by: Linus Walleij

pinctrl: allow exlusive GPIO/mux pin allocation

2015-05-06T12:45:19+00:00

Disallow simultaneous use of the the GPIO and peripheral mux
functions by setting a flag "strict" in struct pinctrl_desc.

The blackfin pinmux and gpio controller doesn't allow user to
set up a pin for both GPIO and peripheral function. So, add flag
strict in struct pinctrl_desc to check both gpio_owner and
mux_owner before approving the pin request.

v2-changes:
- if strict flag is set, check gpio_owner and mux_onwer in if and
  else clause

v3-changes:
- add kerneldoc for this struct
- augment Documentation/pinctrl.txt

Signed-off-by: Sonic Zhang 
Signed-off-by: Linus Walleij

pinctrl: clean up after enable refactoring

2014-09-04T08:05:07+00:00

commit 2243a87d90b42eb38bc281957df3e57c712b5e56
"pinctrl: avoid duplicated calling enable_pinmux_setting for a pin"
removed the .disable callback from the struct pinmux_ops,
making the .enable() callback the only remaining callback.

However .enable() is a bad name as it seems to imply that a
muxing can also be disabled. Rename the callback to .set_mux()
and also take this opportunity to clean out any remaining
mentions of .disable() from the documentation.

Acked-by: Stephen Warren 
Acked-by: Bjorn Andersson 
Acked-by: Fan Wu 
Signed-off-by: Linus Walleij

pinctrl: avoid duplicated calling enable_pinmux_setting for a pin

2014-07-11T12:08:26+00:00

What the patch does:
1. Call pinmux_disable_setting ahead of pinmux_enable_setting
  each time pinctrl_select_state is called
2. Remove the HW disable operation in pinmux_disable_setting function.
3. Remove the disable ops in struct pinmux_ops
4. Remove all the disable ops users in current code base.

Notes:
1. Great thanks for the suggestion from Linus, Tony Lindgren and
   Stephen Warren and Everyone that shared comments on this patch.
2. The patch also includes comment fixes from Stephen Warren.

The reason why we do this:
1. To avoid duplicated calling of the enable_setting operation
   without disabling operation inbetween which will let the pin
   descriptor desc->mux_usecount increase monotonously.
2. The HW pin disable operation is not useful for any of the
   existing platforms.
   And this can be used to avoid the HW glitch after using the
   item #1 modification.

In the following case, the issue can be reproduced:
1. There is a driver that need to switch pin state dynamically,
   e.g. between "sleep" and "default" state
2. The pin setting configuration in a DTS node may be like this:

  component a {
	pinctrl-names = "default", "sleep";
	pinctrl-0 = <&a_grp_setting &c_grp_setting>;
	pinctrl-1 = <&b_grp_setting &c_grp_setting>;
  }

  The "c_grp_setting" config node is totally identical, maybe like
  following one:

  c_grp_setting: c_grp_setting {
	pinctrl-single,pins = ;
  }

3. When switching the pin state in the following official pinctrl
   sequence:
	pin = pinctrl_get();
	state = pinctrl_lookup_state(wanted_state);
	pinctrl_select_state(state);
	pinctrl_put();

Test Result:
1. The switch is completed as expected, that is: the device's
   pin configuration is changed according to the description in the
   "wanted_state" group setting
2. The "desc->mux_usecount" of the corresponding pins in "c_group"
   is increased without being decreased, because the "desc" is for
   each physical pin while the setting is for each setting node
   in the DTS.
   Thus, if the "c_grp_setting" in pinctrl-0 is not disabled ahead
   of enabling "c_grp_setting" in pinctrl-1, the desc->mux_usecount
   will keep increasing without any chance to be decreased.

According to the comments in the original code, only the setting,
in old state but not in new state, will be "disabled" (calling
pinmux_disable_setting), which is correct logic but not intact. We
still need consider case that the setting is in both old state
and new state. We can do this in the following two ways:

1. Avoid to "enable"(calling pinmux_enable_setting) the "same pin
   setting" repeatedly
2. "Disable"(calling pinmux_disable_setting) the "same pin setting",
   actually two setting instances, ahead of enabling them.

Analysis:
1. The solution #2 is better because it can avoid too much
   iteration.
2. If we disable all of the settings in the old state and one of
   the setting(s) exist in the new state, the pins mux function
   change may happen when some SoC vendors defined the
   "pinctrl-single,function-off"
   in their DTS file.
   old_setting => disabled_setting => new_setting.
3. In the pinmux framework, when a pin state is switched, the
   setting in the old state should be marked as "disabled".

Conclusion:
1. To Remove the HW disabling operation to above the glitch mentioned
   above.
2. Handle the issue mentioned above by disabling all of the settings
   in old state and then enable the all of the settings in new state.

Signed-off-by: Fan Wu 
Acked-by: Stephen Warren 
Acked-by: Patrice Chotard 
Acked-by: Heiko Stuebner 
Acked-by: Maxime Coquelin 
Signed-off-by: Linus Walleij

pinctrl: allows not to define the get_group_pins operation

2014-04-22T12:47:02+00:00

When using a group only pinctrl driver, which does not have any
information on the pins it is useless to define a get_group_pins
always returning an empty list of pins.

When not using get_group_pin[1], a driver must implement it so
pins = NULL and num_pins = 0. This patch makes it the default
behaviour if not defined in the pinctrl driver when used in
pinmux enable and disable funtions and in pinctrl_groups_show.

It also adds a check in pinctrl_get_group_pins and return -EINVAL if
not defined. This function is called in the gpiolib when adding when
pingroup range. It cannot be used if no group is defined, so this seams
reasonable.

[1] get_group_pin(struct pinctrl_dev *pctldev,
		  unsigned selector,
		  const unsigned **pins,
		  unsigned *num_pins);

Signed-off-by: Antoine TÃ©nart 
Signed-off-by: Linus Walleij

pinctrl: remove minor dead code

2013-11-04T12:07:05+00:00

This removes a test whether the 'desc' variable is NULL.
This possibility has already been eliminated by the
below test earlier in the loop:

                if (desc == NULL) {
                        dev_warn(pctldev->dev,
                                 "could not get pin desc for pin %d\n",
                                 pins[i]);
                        continue;
                }

Found with Coverity: CID #1090078

Signed-off-by: Michael Opdenacker 
Signed-off-by: Linus Walleij