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pinctrl: samsung: Decouple direction setting from pinctrl 

This patch makes the pinctrl-samsung driver configure GPIO direction on
its own, without using the pinctrl_gpio_direction_*() "helpers". The
rationale behind this change is as follows:
 - pinctrl-samsung does not need translation from GPIO namespace to
   pinctrl namespace to handle GPIO operations - GPIO chip and offset
   therein are enough to calculate necessary offsets and bit masks in
   constant time,
 - the pinctrl_gpio_direction_*() functions do not do anything useful
   other than translating the pin into pinctrl namespace and calling the
   .gpio_set_direction() from pinmux_ops of the controller,
 - the undesirable side effect of using those helpers is losing the
   ability to change GPIO direction in atomic context, because they
   explicitly use a mutex for synchronization,

Results of this patch are:
 - fixed warnings about scheduling while atomic in code that needs to
   set GPIO direction in atomic context (e.g. interrupt handler),
 - reduced overhead of bitbanging drivers that use gpio_direction_*(),
   e.g. i2c-gpio.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Tomasz Figa 2014-07-02 17:40:59 +02:00 committed by Linus Walleij
parent 0e93867527
commit 18c28caa17
1 changed files with 45 additions and 56 deletions
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101
drivers/pinctrl/pinctrl-samsung.c
View File

@ -333,57 +333,12 @@ static int samsung_pinmux_enable(struct pinctrl_dev *pctldev, unsigned selector,
return 0;
}
/*
* The calls to gpio_direction_output() and gpio_direction_input()
* leads to this function call (via the pinctrl_gpio_direction_{input|output}()
* function called from the gpiolib interface).
*/
static int samsung_pinmux_gpio_set_direction(struct pinctrl_dev *pctldev,
struct pinctrl_gpio_range *range, unsigned offset, bool input)
{
struct samsung_pin_bank_type *type;
struct samsung_pin_bank *bank;
struct samsung_pinctrl_drv_data *drvdata;
void __iomem *reg;
u32 data, pin_offset, mask, shift;
unsigned long flags;
bank = gc_to_pin_bank(range->gc);
type = bank->type;
drvdata = pinctrl_dev_get_drvdata(pctldev);
pin_offset = offset - bank->pin_base;
reg = drvdata->virt_base + bank->pctl_offset +
type->reg_offset[PINCFG_TYPE_FUNC];
mask = (1 << type->fld_width[PINCFG_TYPE_FUNC]) - 1;
shift = pin_offset * type->fld_width[PINCFG_TYPE_FUNC];
if (shift >= 32) {
/* Some banks have two config registers */
shift -= 32;
reg += 4;
}
spin_lock_irqsave(&bank->slock, flags);
data = readl(reg);
data &= ~(mask << shift);
if (!input)
data |= FUNC_OUTPUT << shift;
writel(data, reg);
spin_unlock_irqrestore(&bank->slock, flags);
return 0;
}
/* list of pinmux callbacks for the pinmux vertical in pinctrl core */
static const struct pinmux_ops samsung_pinmux_ops = {
.get_functions_count = samsung_get_functions_count,
.get_function_name = samsung_pinmux_get_fname,
.get_function_groups = samsung_pinmux_get_groups,
.enable = samsung_pinmux_enable,
.gpio_set_direction = samsung_pinmux_gpio_set_direction,
};
/* set or get the pin config settings for a specified pin */
@ -532,25 +487,59 @@ static int samsung_gpio_get(struct gpio_chip *gc, unsigned offset)
}
/*
* gpiolib gpio_direction_input callback function. The setting of the pin
* mux function as 'gpio input' will be handled by the pinctrl susbsystem
* interface.
* The calls to gpio_direction_output() and gpio_direction_input()
* leads to this function call.
*/
static int samsung_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
static int samsung_gpio_set_direction(struct gpio_chip *gc,
unsigned offset, bool input)
{
return pinctrl_gpio_direction_input(gc->base + offset);
struct samsung_pin_bank_type *type;
struct samsung_pin_bank *bank;
struct samsung_pinctrl_drv_data *drvdata;
void __iomem *reg;
u32 data, mask, shift;
unsigned long flags;
bank = gc_to_pin_bank(gc);
type = bank->type;
drvdata = bank->drvdata;
reg = drvdata->virt_base + bank->pctl_offset +
type->reg_offset[PINCFG_TYPE_FUNC];
mask = (1 << type->fld_width[PINCFG_TYPE_FUNC]) - 1;
shift = offset * type->fld_width[PINCFG_TYPE_FUNC];
if (shift >= 32) {
/* Some banks have two config registers */
shift -= 32;
reg += 4;
}
spin_lock_irqsave(&bank->slock, flags);
data = readl(reg);
data &= ~(mask << shift);
if (!input)
data |= FUNC_OUTPUT << shift;
writel(data, reg);
spin_unlock_irqrestore(&bank->slock, flags);
return 0;
}
/*
* gpiolib gpio_direction_output callback function. The setting of the pin
* mux function as 'gpio output' will be handled by the pinctrl susbsystem
* interface.
*/
/* gpiolib gpio_direction_input callback function. */
static int samsung_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
{
return samsung_gpio_set_direction(gc, offset, true);
}
/* gpiolib gpio_direction_output callback function. */
static int samsung_gpio_direction_output(struct gpio_chip *gc, unsigned offset,
int value)
{
samsung_gpio_set(gc, offset, value);
return pinctrl_gpio_direction_output(gc->base + offset);
return samsung_gpio_set_direction(gc, offset, false);
}
/*