Date:	Tue, 28 Feb 2012 17:30:16 +0800
From:	Dong Aisheng <aisheng.dong@...escale.com>
To:	Stephen Warren <swarren@...dia.com>
CC:	Linus Walleij <linus.walleij@...ricsson.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	<B29396@...escale.com>, <s.hauer@...gutronix.de>,
	<dongas86@...il.com>, <shawn.guo@...aro.org>,
	<thomas.abraham@...aro.org>, <tony@...mide.com>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V2 1/2] pinctrl: Introduce PINCTRL_STATE_DEFAULT,
 define hogs as that state

On Mon, Feb 27, 2012 at 04:55:08PM -0700, Stephen Warren wrote:
> This provides a single centralized name for the default state.
> 
> Update PIN_MAP_* macros to use this state name, instead of requiring the
> user to pass a state name in.
> 
> With this change, hog entries in the mapping table are defined as those
> with state name PINCTRL_STATE_DEFAULT, i.e. all entries have the same
> name. This interacts badly with the nested iteration over mapping table
> entries in pinctrl_hog_maps() and pinctrl_hog_map() which would now
> attempt to claim each hog mapping table entry multiple times. Replacing
> the custom hog code with a simple pinctrl_get()/pinctrl_enable().
> 
> Update documentation and mapping tables to use this.
> 
> Signed-off-by: Stephen Warren <swarren@...dia.com>
> ---
The whole patch looks good to me.
A few trivial comments:

> v2: Added all the hogging rework now described above; hopefully will solve
> U300 runtime issues.
> ---
>  Documentation/pinctrl.txt       |    8 +-
>  arch/arm/mach-u300/core.c       |    6 +-
>  drivers/pinctrl/core.c          |  145 ++-------------------------------------
>  drivers/pinctrl/core.h          |    4 +-
>  include/linux/pinctrl/machine.h |   13 ++--
>  include/linux/pinctrl/pinctrl.h |    2 +
>  6 files changed, 26 insertions(+), 152 deletions(-)
> 
> diff --git a/Documentation/pinctrl.txt b/Documentation/pinctrl.txt
> index 5e314ce..6fe3232 100644
> --- a/Documentation/pinctrl.txt
> +++ b/Documentation/pinctrl.txt
> @@ -814,7 +814,7 @@ it even more compact which assumes you want to use pinctrl-foo and position
>  0 for mapping, for example:
>  
>  static struct pinctrl_map __initdata mapping[] = {
> -       PIN_MAP("I2CMAP", "pinctrl-foo", "i2c0", "foo-i2c.0"),
> +	PIN_MAP(PINCTRL_STATE_DEFAULT, "pinctrl-foo", "i2c0", "foo-i2c.0"),
It seemed Linus already applied your "re-order struct pinctrl_map".
This may need change a bit according to that patch.

>  
>  
> @@ -930,7 +930,7 @@ foo_probe()
>  	/* Allocate a state holder named "state" etc */
>  	struct pinctrl p;
>  
> -	p = pinctrl_get(&device, NULL);
> +	p = pinctrl_get(&device, PINCTRL_STATE_DEFAULT);
>  	if IS_ERR(p)
>  		return PTR_ERR(p);
>  	pinctrl_enable(p);
> @@ -989,7 +989,7 @@ of the pin controller itself, like this:
>  
>  {
>  	.dev_name = "pinctrl-foo",
> -	.name = "POWERMAP"
> +	.name = PINCTRL_STATE_DEFAULT,
>  	.ctrl_dev_name = "pinctrl-foo",
>  	.function = "power_func",
>  },
ditto

> @@ -998,7 +998,7 @@ Since it may be common to request the core to hog a few always-applicable
>  mux settings on the primary pin controller, there is a convenience macro for
>  this:
>  
> -PIN_MAP_PRIMARY_SYS_HOG("POWERMAP", "pinctrl-foo", "power_func")
> +PIN_MAP_SYS_HOG("pinctrl-foo", "power_func")
>  
>  This gives the exact same result as the above construction.
>  
> diff --git a/arch/arm/mach-u300/core.c b/arch/arm/mach-u300/core.c
> index 336526a..c9050dd 100644
> --- a/arch/arm/mach-u300/core.c
> +++ b/arch/arm/mach-u300/core.c
> @@ -1569,9 +1569,9 @@ static struct platform_device dma_device = {
>  /* Pinmux settings */
>  static struct pinctrl_map __initdata u300_pinmux_map[] = {
>  	/* anonymous maps for chip power and EMIFs */
> -	PIN_MAP_SYS_HOG("POWER", "pinctrl-u300", "power"),
> -	PIN_MAP_SYS_HOG("EMIF0", "pinctrl-u300", "emif0"),
> -	PIN_MAP_SYS_HOG("EMIF1", "pinctrl-u300", "emif1"),
> +	PIN_MAP_SYS_HOG("pinctrl-u300", "power"),
> +	PIN_MAP_SYS_HOG("pinctrl-u300", "emif0"),
> +	PIN_MAP_SYS_HOG("pinctrl-u300", "emif1"),
>  	/* per-device maps for MMC/SD, SPI and UART */
>  	PIN_MAP("MMCSD", "pinctrl-u300", "mmc0", "mmci"),
>  	PIN_MAP("SPI", "pinctrl-u300", "spi0", "pl022"),
> diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
> index 376cede..f25307b 100644
> --- a/drivers/pinctrl/core.c
> +++ b/drivers/pinctrl/core.c
> @@ -44,18 +44,6 @@ struct pinctrl_maps {
>  	unsigned num_maps;
>  };
>  
> -/**
> - * struct pinctrl_hog - a list item to stash control hogs
> - * @node: pin control hog list node
> - * @map: map entry responsible for this hogging
> - * @pmx: the pin control hogged by this item
> - */
> -struct pinctrl_hog {
> -	struct list_head node;
> -	struct pinctrl_map const *map;
> -	struct pinctrl *p;
> -};
> -
>  /* Global list of pin control devices */
>  static DEFINE_MUTEX(pinctrldev_list_mutex);
>  static LIST_HEAD(pinctrldev_list);
> @@ -702,103 +690,6 @@ int pinctrl_register_mappings(struct pinctrl_map const *maps,
>  	return 0;
>  }
>  
> -/* Hog a single map entry and add to the hoglist */
> -static int pinctrl_hog_map(struct pinctrl_dev *pctldev,
> -			   struct pinctrl_map const *map)
> -{
> -	struct pinctrl_hog *hog;
> -	struct pinctrl *p;
> -	int ret;
> -
> -	hog = kzalloc(sizeof(*hog), GFP_KERNEL);
> -	if (!hog) {
> -		dev_err(pctldev->dev, "failed to alloc struct pinctrl_hog\n");
> -		return -ENOMEM;
> -	}
> -
> -	p = pinctrl_get_locked(pctldev->dev, map->name);
> -	if (IS_ERR(p)) {
> -		kfree(hog);
> -		dev_err(pctldev->dev,
> -			"could not get the %s pin control mapping for hogging\n",
> -			map->name);
> -		return PTR_ERR(p);
> -	}
> -
> -	ret = pinctrl_enable(p);
> -	if (ret) {
> -		pinctrl_put(p);
> -		kfree(hog);
> -		dev_err(pctldev->dev,
> -			"could not enable the %s pin control mapping for hogging\n",
> -			map->name);
> -		return ret;
> -	}
> -
> -	hog->map = map;
> -	hog->p = p;
> -
> -	dev_info(pctldev->dev, "hogged map %s, function %s\n", map->name,
> -		 map->function);
> -	list_add_tail(&hog->node, &pctldev->pinctrl_hogs);
> -
> -	return 0;
> -}
> -
> -/**
> - * pinctrl_hog_maps() - hog specific map entries on controller device
> - * @pctldev: the pin control device to hog entries on
> - *
> - * When the pin controllers are registered, there may be some specific pinmux
> - * map entries that need to be hogged, i.e. get+enabled until the system shuts
> - * down.
> - */
> -static int pinctrl_hog_maps(struct pinctrl_dev *pctldev)
> -{
> -	struct device *dev = pctldev->dev;
> -	const char *devname = dev_name(dev);
> -	int ret;
> -	struct pinctrl_maps *maps_node;
> -	int i;
> -	struct pinctrl_map const *map;
> -
> -	INIT_LIST_HEAD(&pctldev->pinctrl_hogs);
> -
> -	mutex_lock(&pinctrl_maps_mutex);
> -	for_each_maps(maps_node, i, map) {
> -		if (!strcmp(map->ctrl_dev_name, devname) &&
> -		    !strcmp(map->dev_name, devname)) {
> -			/* OK time to hog! */
> -			ret = pinctrl_hog_map(pctldev, map);
> -			if (ret) {
> -				mutex_unlock(&pinctrl_maps_mutex);
> -				return ret;
> -			}
> -		}
> -	}
> -	mutex_unlock(&pinctrl_maps_mutex);
> -
> -	return 0;
> -}
> -
> -/**
> - * pinctrl_unhog_maps() - unhog specific map entries on controller device
> - * @pctldev: the pin control device to unhog entries on
> - */
> -static void pinctrl_unhog_maps(struct pinctrl_dev *pctldev)
> -{
> -	struct list_head *node, *tmp;
> -
> -	list_for_each_safe(node, tmp, &pctldev->pinctrl_hogs) {
> -		struct pinctrl_hog *hog =
> -			list_entry(node, struct pinctrl_hog, node);
> -		pinctrl_disable(hog->p);
> -		pinctrl_put(hog->p);
> -		list_del(node);
> -		kfree(hog);
> -	}
> -}
> -
>  #ifdef CONFIG_DEBUG_FS
>  
>  static int pinctrl_pins_show(struct seq_file *s, void *what)
> @@ -889,19 +780,6 @@ static int pinctrl_gpioranges_show(struct seq_file *s, void *what)
>  	return 0;
>  }
>  
> -static int pinmux_hogs_show(struct seq_file *s, void *what)
> -{
> -	struct pinctrl_dev *pctldev = s->private;
> -	struct pinctrl_hog *hog;
> -
> -	seq_puts(s, "Pin control map hogs held by device\n");
> -
> -	list_for_each_entry(hog, &pctldev->pinctrl_hogs, node)
> -		seq_printf(s, "%s\n", hog->map->name);
> -
> -	return 0;
> -}
> -
>  static int pinctrl_devices_show(struct seq_file *s, void *what)
>  {
>  	struct pinctrl_dev *pctldev;
> @@ -988,11 +866,6 @@ static int pinctrl_gpioranges_open(struct inode *inode, struct file *file)
>  	return single_open(file, pinctrl_gpioranges_show, inode->i_private);
>  }
>  
> -static int pinmux_hogs_open(struct inode *inode, struct file *file)
> -{
> -	return single_open(file, pinmux_hogs_show, inode->i_private);
> -}
> -
>  static int pinctrl_devices_open(struct inode *inode, struct file *file)
>  {
>  	return single_open(file, pinctrl_devices_show, NULL);
> @@ -1029,13 +902,6 @@ static const struct file_operations pinctrl_gpioranges_ops = {
>  	.release	= single_release,
>  };
>  
> -static const struct file_operations pinmux_hogs_ops = {
> -	.open		= pinmux_hogs_open,
> -	.read		= seq_read,
> -	.llseek		= seq_lseek,
> -	.release	= single_release,
> -};
> -
>  static const struct file_operations pinctrl_devices_ops = {
>  	.open		= pinctrl_devices_open,
>  	.read		= seq_read,
> @@ -1078,8 +944,6 @@ static void pinctrl_init_device_debugfs(struct pinctrl_dev *pctldev)
>  			    device_root, pctldev, &pinctrl_groups_ops);
>  	debugfs_create_file("gpio-ranges", S_IFREG | S_IRUGO,
>  			    device_root, pctldev, &pinctrl_gpioranges_ops);
> -	debugfs_create_file("pinmux-hogs", S_IFREG | S_IRUGO,
> -			    device_root, pctldev, &pinmux_hogs_ops);
I see you remove the pinnmux-hogs sysfs file here.
I guess you may want to merge it into pinctrl-maps sysfs file since
they're almost same(only difference is device name).

Do you think if we can add a special flag for that type of map in sysfs
(e.g. a "Hog" flag behind the regular map debug info)?
Then users do not need to check device's name to see if it's a hogged function.

(Anyway, it should be in another patch)

>  	pinmux_init_device_debugfs(device_root, pctldev);
>  	pinconf_init_device_debugfs(device_root, pctldev);
>  }
> @@ -1188,7 +1052,9 @@ struct pinctrl_dev *pinctrl_register(struct pinctrl_desc *pctldesc,
>  	mutex_lock(&pinctrldev_list_mutex);
>  	list_add_tail(&pctldev->node, &pinctrldev_list);
>  	mutex_unlock(&pinctrldev_list_mutex);
> -	pinctrl_hog_maps(pctldev);
> +	pctldev->p = pinctrl_get(pctldev->dev, PINCTRL_STATE_DEFAULT);
> +	if (!IS_ERR(pctldev->p))
> +		pinctrl_enable(pctldev->p);
This change looks good to me.

>  	pinctrl_init_device_debugfs(pctldev);
>  
>  	return pctldev;
> @@ -1211,7 +1077,10 @@ void pinctrl_unregister(struct pinctrl_dev *pctldev)
>  		return;
>  
>  	pinctrl_remove_device_debugfs(pctldev);
> -	pinctrl_unhog_maps(pctldev);
> +	if (!IS_ERR(pctldev->p)) {
> +		pinctrl_disable(pctldev->p);
> +		pinctrl_put(pctldev->p);
> +	}
>  	/* TODO: check that no pinmuxes are still active? */
>  	mutex_lock(&pinctrldev_list_mutex);
>  	list_del(&pctldev->node);
> diff --git a/drivers/pinctrl/core.h b/drivers/pinctrl/core.h
> index 7551611..2981b73 100644
> --- a/drivers/pinctrl/core.h
> +++ b/drivers/pinctrl/core.h
> @@ -27,7 +27,7 @@ struct pinctrl_gpio_range;
>   * @owner: module providing the pin controller, used for refcounting
>   * @driver_data: driver data for drivers registering to the pin controller
>   *	subsystem
> - * @pinctrl_hogs: list of pin control maps hogged by this device
> + * @p: result of pinctrl_get() for this device
>   * @device_root: debugfs root for this device
>   */
>  struct pinctrl_dev {
> @@ -39,7 +39,7 @@ struct pinctrl_dev {
>  	struct device *dev;
>  	struct module *owner;
>  	void *driver_data;
> -	struct list_head pinctrl_hogs;
> +	struct pinctrl *p;
>  #ifdef CONFIG_DEBUG_FS
>  	struct dentry *device_root;
>  #endif
> diff --git a/include/linux/pinctrl/machine.h b/include/linux/pinctrl/machine.h
> index 73fbb27..20e9735 100644
> --- a/include/linux/pinctrl/machine.h
> +++ b/include/linux/pinctrl/machine.h
> @@ -12,6 +12,8 @@
>  #ifndef __LINUX_PINCTRL_MACHINE_H
>  #define __LINUX_PINCTRL_MACHINE_H
>  
> +#include "pinctrl.h"
> +
>  /**
>   * struct pinctrl_map - boards/machines shall provide this map for devices
>   * @dev_name: the name of the device using this specific mapping, the name
> @@ -49,17 +51,18 @@ struct pinctrl_map {
>   * Convenience macro to map a system function onto a certain pinctrl device,
>   * to be hogged by the pin control core until the system shuts down.
>   */
> -#define PIN_MAP_SYS_HOG(a, b, c) \
> -	{ .name = a, .ctrl_dev_name = b, .dev_name = b, .function = c, }
> +#define PIN_MAP_SYS_HOG(a, b) \
> +	{ .name = PINCTRL_STATE_DEFAULT, .ctrl_dev_name = a, .dev_name = a, \
> +	  .function = b, }
>  
>  /*
>   * Convenience macro to map a system function onto a certain pinctrl device
>   * using a specified group, to be hogged by the pin control core until the
>   * system shuts down.
>   */
> -#define PIN_MAP_SYS_HOG_GROUP(a, b, c, d)		\
> -	{ .name = a, .ctrl_dev_name = b, .dev_name = b, .function = c, \
> -	  .group = d, }
> +#define PIN_MAP_SYS_HOG_GROUP(a, b, c) \
> +	{ .name = PINCTRL_STATE_DEFAULT, .ctrl_dev_name = a, .dev_name = a, \
> +	  .function = b, .group = c, }
>  

In your v1 patch, we discussed about the possible requirement of different state
support for hog functions(it seemed still no conclusion, right?).
If we decide to support it, i'd suggest change here macro a bit to align with
the exist PIN_MAP macro like:

#define PIN_MAP_SYS_HOG_DEFAULT(a, b) \
	{ .name = PINCTRL_STATE_DEFAULT, .ctrl_dev_name = a, .dev_name = a, \
	.function = b, }

#define PIN_MAP_SYS_HOG_GROUP_DEFAULT(a, b, c) \
	{ .name = PINCTRL_STATE_DEFAULT, .ctrl_dev_name = a, .dev_name = a, \
	.function = b, .group = c, }
And reserve the original PIN_MAP_SYS_HOG for users to add the state name as they
want.

However, since this is still undetermined, i'm also ok if you want to use this
macro first.

Acked-by: Dong Aisheng <dong.aisheng@...aro.org>

Regards
Dong Aisheng

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