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gpio: bcm281xx: Centralize register locking
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Rather than unlock/re-lock for every write access, unlock a GPIO when
it is requested and re-lock it when it is freed. As a result, the GPIO
helper functions no longer have to deal with unlocking and re-locking
the register.

In addition, only unlock a specific GPIO rather than unlocking the
entire GPIO bank as before.

Signed-off-by: Markus Mayer <markus.mayer@linaro.org>
Reviewed-by: Tim Kryger <tim.kryger@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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Markus Mayer authored and Linus Walleij committed Feb 6, 2014
1 parent d762bae commit bdb93c0
Showing 1 changed file with 49 additions and 33 deletions.
82 changes: 49 additions & 33 deletions drivers/gpio/gpio-bcm-kona.c
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Original file line number Diff line number Diff line change
Expand Up @@ -83,22 +83,43 @@ static inline struct bcm_kona_gpio *to_kona_gpio(struct gpio_chip *chip)
return container_of(chip, struct bcm_kona_gpio, gpio_chip);
}

static void bcm_kona_gpio_set_lockcode_bank(void __iomem *reg_base,
int bank_id, int lockcode)
static inline void bcm_kona_gpio_write_lock_regs(void __iomem *reg_base,
int bank_id, u32 lockcode)
{
writel(BCM_GPIO_PASSWD, reg_base + GPIO_GPPWR_OFFSET);
writel(lockcode, reg_base + GPIO_PWD_STATUS(bank_id));
}

static inline void bcm_kona_gpio_lock_bank(void __iomem *reg_base, int bank_id)
static void bcm_kona_gpio_lock_gpio(struct bcm_kona_gpio *kona_gpio,
unsigned gpio)
{
bcm_kona_gpio_set_lockcode_bank(reg_base, bank_id, LOCK_CODE);
u32 val;
unsigned long flags;
int bank_id = GPIO_BANK(gpio);

spin_lock_irqsave(&kona_gpio->lock, flags);

val = readl(kona_gpio->reg_base + GPIO_PWD_STATUS(bank_id));
val |= BIT(gpio);
bcm_kona_gpio_write_lock_regs(kona_gpio->reg_base, bank_id, val);

spin_unlock_irqrestore(&kona_gpio->lock, flags);
}

static inline void bcm_kona_gpio_unlock_bank(void __iomem *reg_base,
int bank_id)
static void bcm_kona_gpio_unlock_gpio(struct bcm_kona_gpio *kona_gpio,
unsigned gpio)
{
bcm_kona_gpio_set_lockcode_bank(reg_base, bank_id, UNLOCK_CODE);
u32 val;
unsigned long flags;
int bank_id = GPIO_BANK(gpio);

spin_lock_irqsave(&kona_gpio->lock, flags);

val = readl(kona_gpio->reg_base + GPIO_PWD_STATUS(bank_id));
val &= ~BIT(gpio);
bcm_kona_gpio_write_lock_regs(kona_gpio->reg_base, bank_id, val);

spin_unlock_irqrestore(&kona_gpio->lock, flags);
}

static void bcm_kona_gpio_set(struct gpio_chip *chip, unsigned gpio, int value)
Expand All @@ -113,7 +134,6 @@ static void bcm_kona_gpio_set(struct gpio_chip *chip, unsigned gpio, int value)
kona_gpio = to_kona_gpio(chip);
reg_base = kona_gpio->reg_base;
spin_lock_irqsave(&kona_gpio->lock, flags);
bcm_kona_gpio_unlock_bank(reg_base, bank_id);

/* determine the GPIO pin direction */
val = readl(reg_base + GPIO_CONTROL(gpio));
Expand All @@ -130,7 +150,6 @@ static void bcm_kona_gpio_set(struct gpio_chip *chip, unsigned gpio, int value)
writel(val, reg_base + reg_offset);

out:
bcm_kona_gpio_lock_bank(reg_base, bank_id);
spin_unlock_irqrestore(&kona_gpio->lock, flags);
}

Expand All @@ -146,7 +165,6 @@ static int bcm_kona_gpio_get(struct gpio_chip *chip, unsigned gpio)
kona_gpio = to_kona_gpio(chip);
reg_base = kona_gpio->reg_base;
spin_lock_irqsave(&kona_gpio->lock, flags);
bcm_kona_gpio_unlock_bank(reg_base, bank_id);

/* determine the GPIO pin direction */
val = readl(reg_base + GPIO_CONTROL(gpio));
Expand All @@ -157,32 +175,43 @@ static int bcm_kona_gpio_get(struct gpio_chip *chip, unsigned gpio)
GPIO_IN_STATUS(bank_id) : GPIO_OUT_STATUS(bank_id);
val = readl(reg_base + reg_offset);

bcm_kona_gpio_lock_bank(reg_base, bank_id);
spin_unlock_irqrestore(&kona_gpio->lock, flags);

/* return the specified bit status */
return !!(val & BIT(bit));
}

static int bcm_kona_gpio_request(struct gpio_chip *chip, unsigned gpio)
{
struct bcm_kona_gpio *kona_gpio = to_kona_gpio(chip);

bcm_kona_gpio_unlock_gpio(kona_gpio, gpio);
return 0;
}

static void bcm_kona_gpio_free(struct gpio_chip *chip, unsigned gpio)
{
struct bcm_kona_gpio *kona_gpio = to_kona_gpio(chip);

bcm_kona_gpio_lock_gpio(kona_gpio, gpio);
}

static int bcm_kona_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
{
struct bcm_kona_gpio *kona_gpio;
void __iomem *reg_base;
u32 val;
unsigned long flags;
int bank_id = GPIO_BANK(gpio);

kona_gpio = to_kona_gpio(chip);
reg_base = kona_gpio->reg_base;
spin_lock_irqsave(&kona_gpio->lock, flags);
bcm_kona_gpio_unlock_bank(reg_base, bank_id);

val = readl(reg_base + GPIO_CONTROL(gpio));
val &= ~GPIO_GPCTR0_IOTR_MASK;
val |= GPIO_GPCTR0_IOTR_CMD_INPUT;
writel(val, reg_base + GPIO_CONTROL(gpio));

bcm_kona_gpio_lock_bank(reg_base, bank_id);
spin_unlock_irqrestore(&kona_gpio->lock, flags);

return 0;
Expand All @@ -201,7 +230,6 @@ static int bcm_kona_gpio_direction_output(struct gpio_chip *chip,
kona_gpio = to_kona_gpio(chip);
reg_base = kona_gpio->reg_base;
spin_lock_irqsave(&kona_gpio->lock, flags);
bcm_kona_gpio_unlock_bank(reg_base, bank_id);

val = readl(reg_base + GPIO_CONTROL(gpio));
val &= ~GPIO_GPCTR0_IOTR_MASK;
Expand All @@ -213,7 +241,6 @@ static int bcm_kona_gpio_direction_output(struct gpio_chip *chip,
val |= BIT(bit);
writel(val, reg_base + reg_offset);

bcm_kona_gpio_lock_bank(reg_base, bank_id);
spin_unlock_irqrestore(&kona_gpio->lock, flags);

return 0;
Expand All @@ -236,7 +263,6 @@ static int bcm_kona_gpio_set_debounce(struct gpio_chip *chip, unsigned gpio,
void __iomem *reg_base;
u32 val, res;
unsigned long flags;
int bank_id = GPIO_BANK(gpio);

kona_gpio = to_kona_gpio(chip);
reg_base = kona_gpio->reg_base;
Expand All @@ -260,7 +286,6 @@ static int bcm_kona_gpio_set_debounce(struct gpio_chip *chip, unsigned gpio,

/* spin lock for read-modify-write of the GPIO register */
spin_lock_irqsave(&kona_gpio->lock, flags);
bcm_kona_gpio_unlock_bank(reg_base, bank_id);

val = readl(reg_base + GPIO_CONTROL(gpio));
val &= ~GPIO_GPCTR0_DBR_MASK;
Expand All @@ -275,7 +300,6 @@ static int bcm_kona_gpio_set_debounce(struct gpio_chip *chip, unsigned gpio,

writel(val, reg_base + GPIO_CONTROL(gpio));

bcm_kona_gpio_lock_bank(reg_base, bank_id);
spin_unlock_irqrestore(&kona_gpio->lock, flags);

return 0;
Expand All @@ -284,6 +308,8 @@ static int bcm_kona_gpio_set_debounce(struct gpio_chip *chip, unsigned gpio,
static struct gpio_chip template_chip = {
.label = "bcm-kona-gpio",
.owner = THIS_MODULE,
.request = bcm_kona_gpio_request,
.free = bcm_kona_gpio_free,
.direction_input = bcm_kona_gpio_direction_input,
.get = bcm_kona_gpio_get,
.direction_output = bcm_kona_gpio_direction_output,
Expand All @@ -306,13 +332,11 @@ static void bcm_kona_gpio_irq_ack(struct irq_data *d)
kona_gpio = irq_data_get_irq_chip_data(d);
reg_base = kona_gpio->reg_base;
spin_lock_irqsave(&kona_gpio->lock, flags);
bcm_kona_gpio_unlock_bank(reg_base, bank_id);

val = readl(reg_base + GPIO_INT_STATUS(bank_id));
val |= BIT(bit);
writel(val, reg_base + GPIO_INT_STATUS(bank_id));

bcm_kona_gpio_lock_bank(reg_base, bank_id);
spin_unlock_irqrestore(&kona_gpio->lock, flags);
}

Expand All @@ -329,13 +353,11 @@ static void bcm_kona_gpio_irq_mask(struct irq_data *d)
kona_gpio = irq_data_get_irq_chip_data(d);
reg_base = kona_gpio->reg_base;
spin_lock_irqsave(&kona_gpio->lock, flags);
bcm_kona_gpio_unlock_bank(reg_base, bank_id);

val = readl(reg_base + GPIO_INT_MASK(bank_id));
val |= BIT(bit);
writel(val, reg_base + GPIO_INT_MASK(bank_id));

bcm_kona_gpio_lock_bank(reg_base, bank_id);
spin_unlock_irqrestore(&kona_gpio->lock, flags);
}

Expand All @@ -352,13 +374,11 @@ static void bcm_kona_gpio_irq_unmask(struct irq_data *d)
kona_gpio = irq_data_get_irq_chip_data(d);
reg_base = kona_gpio->reg_base;
spin_lock_irqsave(&kona_gpio->lock, flags);
bcm_kona_gpio_unlock_bank(reg_base, bank_id);

val = readl(reg_base + GPIO_INT_MSKCLR(bank_id));
val |= BIT(bit);
writel(val, reg_base + GPIO_INT_MSKCLR(bank_id));

bcm_kona_gpio_lock_bank(reg_base, bank_id);
spin_unlock_irqrestore(&kona_gpio->lock, flags);
}

Expand All @@ -370,7 +390,6 @@ static int bcm_kona_gpio_irq_set_type(struct irq_data *d, unsigned int type)
u32 lvl_type;
u32 val;
unsigned long flags;
int bank_id = GPIO_BANK(gpio);

kona_gpio = irq_data_get_irq_chip_data(d);
reg_base = kona_gpio->reg_base;
Expand All @@ -397,14 +416,12 @@ static int bcm_kona_gpio_irq_set_type(struct irq_data *d, unsigned int type)
}

spin_lock_irqsave(&kona_gpio->lock, flags);
bcm_kona_gpio_unlock_bank(reg_base, bank_id);

val = readl(reg_base + GPIO_CONTROL(gpio));
val &= ~GPIO_GPCTR0_ITR_MASK;
val |= lvl_type << GPIO_GPCTR0_ITR_SHIFT;
writel(val, reg_base + GPIO_CONTROL(gpio));

bcm_kona_gpio_lock_bank(reg_base, bank_id);
spin_unlock_irqrestore(&kona_gpio->lock, flags);

return 0;
Expand All @@ -427,7 +444,6 @@ static void bcm_kona_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
*/
reg_base = bank->kona_gpio->reg_base;
bank_id = bank->id;
bcm_kona_gpio_unlock_bank(reg_base, bank_id);

while ((sta = readl(reg_base + GPIO_INT_STATUS(bank_id)) &
(~(readl(reg_base + GPIO_INT_MASK(bank_id)))))) {
Expand All @@ -447,8 +463,6 @@ static void bcm_kona_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
}
}

bcm_kona_gpio_lock_bank(reg_base, bank_id);

chained_irq_exit(chip, desc);
}

Expand Down Expand Up @@ -534,10 +548,12 @@ static void bcm_kona_gpio_reset(struct bcm_kona_gpio *kona_gpio)
reg_base = kona_gpio->reg_base;
/* disable interrupts and clear status */
for (i = 0; i < kona_gpio->num_bank; i++) {
bcm_kona_gpio_unlock_bank(reg_base, i);
/* Unlock the entire bank first */
bcm_kona_gpio_write_lock_regs(kona_gpio, i, UNLOCK_CODE);
writel(0xffffffff, reg_base + GPIO_INT_MASK(i));
writel(0xffffffff, reg_base + GPIO_INT_STATUS(i));
bcm_kona_gpio_lock_bank(reg_base, i);
/* Now re-lock the bank */
bcm_kona_gpio_write_lock_regs(kona_gpio, i, LOCK_CODE);
}
}

Expand Down

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