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pinctrl: stm32: add suspend/resume management
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During power sequence, GPIO hardware registers could be lost if the power
supply is switched off. Each device using pinctrl API is in charge of
managing pins during suspend/resume sequences. But for pins used as gpio or
irq stm32 pinctrl driver has to save the hardware configuration.

Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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@atorgue @linusw
atorgue authored and linusw committed May 24, 2019
1 parent b672a87 commit e2f3cf1
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Showing 2 changed files with 134 additions and 0 deletions.
132 changes: 132 additions & 0 deletions drivers/pinctrl/stm32/pinctrl-stm32.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,18 @@
#define STM32_GPIO_AFRL 0x20
#define STM32_GPIO_AFRH 0x24

/* custom bitfield to backup pin status */
#define STM32_GPIO_BKP_MODE_SHIFT 0
#define STM32_GPIO_BKP_MODE_MASK GENMASK(1, 0)
#define STM32_GPIO_BKP_ALT_SHIFT 2
#define STM32_GPIO_BKP_ALT_MASK GENMASK(5, 2)
#define STM32_GPIO_BKP_SPEED_SHIFT 6
#define STM32_GPIO_BKP_SPEED_MASK GENMASK(7, 6)
#define STM32_GPIO_BKP_PUPD_SHIFT 8
#define STM32_GPIO_BKP_PUPD_MASK GENMASK(9, 8)
#define STM32_GPIO_BKP_TYPE 10
#define STM32_GPIO_BKP_VAL 11

#define STM32_GPIO_PINS_PER_BANK 16
#define STM32_GPIO_IRQ_LINE 16

Expand Down Expand Up @@ -79,6 +91,7 @@ struct stm32_gpio_bank {
struct irq_domain *domain;
u32 bank_nr;
u32 bank_ioport_nr;
u32 pin_backup[STM32_GPIO_PINS_PER_BANK];
};

struct stm32_pinctrl {
Expand Down Expand Up @@ -133,11 +146,50 @@ static inline u32 stm32_gpio_get_alt(u32 function)
return 0;
}

static void stm32_gpio_backup_value(struct stm32_gpio_bank *bank,
u32 offset, u32 value)
{
bank->pin_backup[offset] &= ~BIT(STM32_GPIO_BKP_VAL);
bank->pin_backup[offset] |= value << STM32_GPIO_BKP_VAL;
}

static void stm32_gpio_backup_mode(struct stm32_gpio_bank *bank, u32 offset,
u32 mode, u32 alt)
{
bank->pin_backup[offset] &= ~(STM32_GPIO_BKP_MODE_MASK |
STM32_GPIO_BKP_ALT_MASK);
bank->pin_backup[offset] |= mode << STM32_GPIO_BKP_MODE_SHIFT;
bank->pin_backup[offset] |= alt << STM32_GPIO_BKP_ALT_SHIFT;
}

static void stm32_gpio_backup_driving(struct stm32_gpio_bank *bank, u32 offset,
u32 drive)
{
bank->pin_backup[offset] &= ~BIT(STM32_GPIO_BKP_TYPE);
bank->pin_backup[offset] |= drive << STM32_GPIO_BKP_TYPE;
}

static void stm32_gpio_backup_speed(struct stm32_gpio_bank *bank, u32 offset,
u32 speed)
{
bank->pin_backup[offset] &= ~STM32_GPIO_BKP_SPEED_MASK;
bank->pin_backup[offset] |= speed << STM32_GPIO_BKP_SPEED_SHIFT;
}

static void stm32_gpio_backup_bias(struct stm32_gpio_bank *bank, u32 offset,
u32 bias)
{
bank->pin_backup[offset] &= ~STM32_GPIO_BKP_PUPD_MASK;
bank->pin_backup[offset] |= bias << STM32_GPIO_BKP_PUPD_SHIFT;
}

/* GPIO functions */

static inline void __stm32_gpio_set(struct stm32_gpio_bank *bank,
unsigned offset, int value)
{
stm32_gpio_backup_value(bank, offset, value);

if (!value)
offset += STM32_GPIO_PINS_PER_BANK;

Expand Down Expand Up @@ -620,6 +672,8 @@ static int stm32_pmx_set_mode(struct stm32_gpio_bank *bank,
if (pctl->hwlock)
hwspin_unlock(pctl->hwlock);

stm32_gpio_backup_mode(bank, pin, mode, alt);

unlock:
spin_unlock_irqrestore(&bank->lock, flags);
clk_disable(bank->clk);
Expand Down Expand Up @@ -732,6 +786,8 @@ static int stm32_pconf_set_driving(struct stm32_gpio_bank *bank,
if (pctl->hwlock)
hwspin_unlock(pctl->hwlock);

stm32_gpio_backup_driving(bank, offset, drive);

unlock:
spin_unlock_irqrestore(&bank->lock, flags);
clk_disable(bank->clk);
Expand Down Expand Up @@ -784,6 +840,8 @@ static int stm32_pconf_set_speed(struct stm32_gpio_bank *bank,
if (pctl->hwlock)
hwspin_unlock(pctl->hwlock);

stm32_gpio_backup_speed(bank, offset, speed);

unlock:
spin_unlock_irqrestore(&bank->lock, flags);
clk_disable(bank->clk);
Expand Down Expand Up @@ -836,6 +894,8 @@ static int stm32_pconf_set_bias(struct stm32_gpio_bank *bank,
if (pctl->hwlock)
hwspin_unlock(pctl->hwlock);

stm32_gpio_backup_bias(bank, offset, bias);

unlock:
spin_unlock_irqrestore(&bank->lock, flags);
clk_disable(bank->clk);
Expand Down Expand Up @@ -1369,3 +1429,75 @@ int stm32_pctl_probe(struct platform_device *pdev)

return 0;
}

static int __maybe_unused stm32_pinctrl_restore_gpio_regs(
struct stm32_pinctrl *pctl, u32 pin)
{
const struct pin_desc *desc = pin_desc_get(pctl->pctl_dev, pin);
u32 val, alt, mode, offset = stm32_gpio_pin(pin);
struct pinctrl_gpio_range *range;
struct stm32_gpio_bank *bank;
bool pin_is_irq;
int ret;

range = pinctrl_find_gpio_range_from_pin(pctl->pctl_dev, pin);
if (!range)
return 0;

pin_is_irq = gpiochip_line_is_irq(range->gc, offset);

if (!desc || (!pin_is_irq && !desc->gpio_owner))
return 0;

bank = gpiochip_get_data(range->gc);

alt = bank->pin_backup[offset] & STM32_GPIO_BKP_ALT_MASK;
alt >>= STM32_GPIO_BKP_ALT_SHIFT;
mode = bank->pin_backup[offset] & STM32_GPIO_BKP_MODE_MASK;
mode >>= STM32_GPIO_BKP_MODE_SHIFT;

ret = stm32_pmx_set_mode(bank, offset, mode, alt);
if (ret)
return ret;

if (mode == 1) {
val = bank->pin_backup[offset] & BIT(STM32_GPIO_BKP_VAL);
val = val >> STM32_GPIO_BKP_VAL;
__stm32_gpio_set(bank, offset, val);
}

val = bank->pin_backup[offset] & BIT(STM32_GPIO_BKP_TYPE);
val >>= STM32_GPIO_BKP_TYPE;
ret = stm32_pconf_set_driving(bank, offset, val);
if (ret)
return ret;

val = bank->pin_backup[offset] & STM32_GPIO_BKP_SPEED_MASK;
val >>= STM32_GPIO_BKP_SPEED_SHIFT;
ret = stm32_pconf_set_speed(bank, offset, val);
if (ret)
return ret;

val = bank->pin_backup[offset] & STM32_GPIO_BKP_PUPD_MASK;
val >>= STM32_GPIO_BKP_PUPD_SHIFT;
ret = stm32_pconf_set_bias(bank, offset, val);
if (ret)
return ret;

if (pin_is_irq)
regmap_field_write(pctl->irqmux[offset], bank->bank_ioport_nr);

return 0;
}

int __maybe_unused stm32_pinctrl_resume(struct device *dev)
{
struct stm32_pinctrl *pctl = dev_get_drvdata(dev);
struct stm32_pinctrl_group *g = pctl->groups;
int i;

for (i = g->pin; i < g->pin + pctl->ngroups; i++)
stm32_pinctrl_restore_gpio_regs(pctl, i);

return 0;
}
2 changes: 2 additions & 0 deletions drivers/pinctrl/stm32/pinctrl-stm32.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -65,5 +65,7 @@ struct stm32_gpio_bank;
int stm32_pctl_probe(struct platform_device *pdev);
void stm32_pmx_get_mode(struct stm32_gpio_bank *bank,
int pin, u32 *mode, u32 *alt);
int stm32_pinctrl_resume(struct device *dev);

#endif /* __PINCTRL_STM32_H */

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