lkml.org 
[lkml]   [2014]   [Jan]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] gpio: bcm281xx: Centralize register locking
Date
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>
---
drivers/gpio/gpio-bcm-kona.c | 82 +++++++++++++++++++++++++-----------------
1 file changed, 49 insertions(+), 33 deletions(-)

diff --git a/drivers/gpio/gpio-bcm-kona.c b/drivers/gpio/gpio-bcm-kona.c
index 233d088..3e51b62 100644
--- a/drivers/gpio/gpio-bcm-kona.c
+++ b/drivers/gpio/gpio-bcm-kona.c
@@ -80,22 +80,43 @@ 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)
@@ -110,7 +131,6 @@ 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));
@@ -127,7 +147,6 @@ 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);
}

@@ -143,7 +162,6 @@ 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));
@@ -154,32 +172,43 @@ 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;
@@ -198,7 +227,6 @@ 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;
@@ -210,7 +238,6 @@ 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;
@@ -233,7 +260,6 @@ 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;
@@ -257,7 +283,6 @@ 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;
@@ -272,7 +297,6 @@ 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;
@@ -281,6 +305,8 @@ 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,
@@ -303,13 +329,11 @@ 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);
}

@@ -326,13 +350,11 @@ 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);
}

@@ -349,13 +371,11 @@ 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);
}

@@ -367,7 +387,6 @@ 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;
@@ -394,14 +413,12 @@ 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;
@@ -424,7 +441,6 @@ 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)))))) {
@@ -444,8 +460,6 @@ 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);
}

@@ -531,10 +545,12 @@ 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);
}
}

--
1.7.9.5


\
 
 \ /
  Last update: 2014-01-22 01:41    [W:0.082 / U:1.812 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site