linux/drivers/pinctrl/core.c, branch v4.5

drivers/pinctrl: Add the concept of an "init" state

2015-10-27T10:24:23Z

For pinctrl the "default" state is applied to pins before the driver's probe function is called. This is normally a sensible thing to do, but in some cases can cause problems. That's because the pins will change state before the driver is given a chance to program how those pins should behave. As an example you might have a regulator that is controlled by a PWM (output high = high voltage, output low = low voltage). The firmware might leave this pin as driven high. If we allow the driver core to reconfigure this pin as a PWM pin before the PWM's probe function runs then you might end up running at too low of a voltage while we probe. Let's introudce a new "init" state. If this is defined we'll set pinctrl to this state before probe and then "default" after probe (unless the driver explicitly changed states already). An alternative idea that was thought of was to use the pre-existing "sleep" or "idle" states and add a boolean property that we should start in that mode. This was not done because the "init" state is needed for correctness and those other states are only present (and only transitioned in to and out of) when (optional) power management is enabled. Changes in v3: - Moved declarations to pinctrl/devinfo.h - Fixed author/SoB Changes in v2: - Added comment to pinctrl_init_done() as per Linus W. Signed-off-by: Douglas Anderson Acked-by: Greg Kroah-Hartman Tested-by: Caesar Wang Signed-off-by: Linus Walleij

pinctrl: core: Warn about NULL gpio_chip in pinctrl_ready_for_gpio_range()

2015-09-14T07:13:43Z

If the gpio driver is confused about the numbers for gpio-ranges, pinctrl_ready_for_gpio_range() may get called with invalid GPIO causing a NULL pointer exception. Let's instead provide a warning that allows fixing the problem and return with error. Signed-off-by: Tony Lindgren Signed-off-by: Linus Walleij

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

2015-07-27T12:43:43Z

Use dev_err() rather than pr_err() to display the error message. (Besides, dev_err() is already used 7 lines below in this function.) Also, drop the redundant information "on %s" because dev_err() shows which device the message is related to. Signed-off-by: Masahiro Yamada Signed-off-by: Linus Walleij

Merge tag 'pinctrl-v4.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl

2015-06-25T02:21:02Z

Pull pin control updates from Linus Walleij: "Here is the bulk of pin control changes for the v4.2 series: Quite a lot of new SoC subdrivers and two new main drivers this time, apart from that business as usual. Details: Core functionality: - Enable exclusive pin ownership: it is possible to flag a pin controller so that GPIO and other functions cannot use a single pin simultaneously. New drivers: - NXP LPC18xx System Control Unit pin controller - Imagination Pistachio SoC pin controller New subdrivers: - Freescale i.MX7d SoC - Intel Sunrisepoint-H PCH - Renesas PFC R8A7793 - Renesas PFC R8A7794 - Mediatek MT6397, MT8127 - SiRF Atlas 7 - Allwinner A33 - Qualcomm MSM8660 - Marvell Armada 395 - Rockchip RK3368 Cleanups: - A big cleanup of the Marvell MVEBU driver rectifying it to correspond to reality - Drop platform device probing from the SH PFC driver, we are now a DT only shop for SuperH - Drop obsolte multi-platform check for SH PFC - Various janitorial: constification, grammar etc Improvements: - The AT91 GPIO portions now supports the set_multiple() feature - Split out SPI pins on the Xilinx Zynq - Support DTs without specific function nodes in the i.MX driver" * tag 'pinctrl-v4.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (99 commits) pinctrl: rockchip: add support for the rk3368 pinctrl: rockchip: generalize perpin driver-strength setting pinctrl: sh-pfc: r8a7794: add SDHI pin groups pinctrl: sh-pfc: r8a7794: add MMCIF pin groups pinctrl: sh-pfc: add R8A7794 PFC support pinctrl: make pinctrl_register() return proper error code pinctrl: mvebu: armada-39x: add support for Armada 395 variant pinctrl: mvebu: armada-39x: add missing SATA functions pinctrl: mvebu: armada-39x: add missing PCIe functions pinctrl: mvebu: armada-38x: add ptp functions pinctrl: mvebu: armada-38x: add ua1 functions pinctrl: mvebu: armada-38x: add nand functions pinctrl: mvebu: armada-38x: add sata functions pinctrl: mvebu: armada-xp: add dram functions pinctrl: mvebu: armada-xp: add nand rb function pinctrl: mvebu: armada-xp: add spi1 function pinctrl: mvebu: armada-39x: normalize ref clock naming pinctrl: mvebu: armada-xp: rename spi to spi0 pinctrl: mvebu: armada-370: align spi1 clock pin naming pinctrl: mvebu: armada-370: align VDD cpu-pd pin naming with datasheet ...

pinctrl: make pinctrl_register() return proper error code

2015-06-10T12:49:52Z

Currently, pinctrl_register() just returns NULL on error, so the callers can not know the exact reason of the failure. Some of the pinctrl drivers return -EINVAL, some -ENODEV, and some -ENOMEM on error of pinctrl_register(), although the error code might be different from the real cause of the error. This commit reworks pinctrl_register() to return the appropriate error code and modifies all of the pinctrl drivers to use IS_ERR() for the error checking and PTR_ERR() for getting the error code. Signed-off-by: Masahiro Yamada Acked-by: Patrice Chotard Acked-by: Thierry Reding Acked-by: Heiko Stuebner Tested-by: Mika Westerberg Acked-by: Mika Westerberg Acked-by: Lee Jones Acked-by: Sören Brinkmann Acked-by: Laurent Pinchart Acked-by: Ray Jui Acked-by: Antoine Tenart Acked-by: Hongzhou Yang Acked-by: Wei Chen Signed-off-by: Linus Walleij

pinctrl: fix confusing debug message in pinctrl_register_map()

2015-06-02T11:32:20Z

There are two types for pinctrl maps: pinmux and pinconfig This debug message shows the number of maps of both types. The string "pinmux map" is not precise. Let's say "pinctrl map" instead. Signed-off-by: Masahiro Yamada [also fixed %d -> %u] Signed-off-by: Linus Walleij

pinctrl: Grammar s/used in as/used as/

2015-05-12T11:17:41Z

Signed-off-by: Geert Uytterhoeven Signed-off-by: Linus Walleij

pinctrl: Don't just pretend to protect pinctrl_maps, do it for real

2015-05-06T14:24:28Z

Way back, when the world was a simpler place and there was no war, no evil, and no kernel bugs, there was just a single pinctrl lock. That was how the world was when (57291ce pinctrl: core device tree mapping table parsing support) was written. In that case, there were instances where the pinctrl mutex was already held when pinctrl_register_map() was called, hence a "locked" parameter was passed to the function to indicate that the mutex was already locked (so we shouldn't lock it again). A few years ago in (42fed7b pinctrl: move subsystem mutex to pinctrl_dev struct), we switched to a separate pinctrl_maps_mutex. ...but (oops) we forgot to re-think about the whole "locked" parameter for pinctrl_register_map(). Basically the "locked" parameter appears to still refer to whether the bigger pinctrl_dev mutex is locked, but we're using it to skip locks of our (now separate) pinctrl_maps_mutex. That's kind of a bad thing(TM). Probably nobody noticed because most of the calls to pinctrl_register_map happen at boot time and we've got synchronous device probing. ...and even cases where we're asynchronous don't end up actually hitting the race too often. ...but after banging my head against the wall for a bug that reproduced 1 out of 1000 reboots and lots of looking through kgdb, I finally noticed this. Anyway, we can now safely remove the "locked" parameter and go back to a war-free, evil-free, and kernel-bug-free world. Fixes: 42fed7ba44e4 ("pinctrl: move subsystem mutex to pinctrl_dev struct") Signed-off-by: Doug Anderson Signed-off-by: Linus Walleij

pinctrl: Fix two deadlocks

2015-01-14T13:20:33Z

This patch is to fix two deadlock cases. Deadlock 1: CPU #1 pinctrl_register-> pinctrl_get -> create_pinctrl (Holding lock pinctrl_maps_mutex) -> get_pinctrl_dev_from_devname (Trying to acquire lock pinctrldev_list_mutex) CPU #0 pinctrl_unregister (Holding lock pinctrldev_list_mutex) -> pinctrl_put ->> pinctrl_free -> pinctrl_dt_free_maps -> pinctrl_unregister_map (Trying to acquire lock pinctrl_maps_mutex) Simply to say CPU#1 is holding lock A and trying to acquire lock B, CPU#0 is holding lock B and trying to acquire lock A. Deadlock 2: CPU #3 pinctrl_register-> pinctrl_get -> create_pinctrl (Holding lock pinctrl_maps_mutex) -> get_pinctrl_dev_from_devname (Trying to acquire lock pinctrldev_list_mutex) CPU #2 pinctrl_unregister (Holding lock pctldev->mutex) -> pinctrl_put ->> pinctrl_free -> pinctrl_dt_free_maps -> pinctrl_unregister_map (Trying to acquire lock pinctrl_maps_mutex) CPU #0 tegra_gpio_request (Holding lock pinctrldev_list_mutex) -> pinctrl_get_device_gpio_range (Trying to acquire lock pctldev->mutex) Simply to say CPU#3 is holding lock A and trying to acquire lock D, CPU#2 is holding lock B and trying to acquire lock A, CPU#0 is holding lock D and trying to acquire lock B. Cc: Stable Signed-off-by: Jim Lin Signed-off-by: Linus Walleij

pinctrl: avoid duplicated calling enable_pinmux_setting for a pin

2014-07-11T12:08:26Z

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