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drivers: gpio_pca95xx: guard read/write with semaphore

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Since the GPIO expander is a I2C device, any read/write to
the registers has high latency. Therefore, semaphore is
introduced to prevent multiple threads to manipulate
the GPIOs at the same time.

Also make sure that we are not doing I2C transactions
within ISRs.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>
This commit is contained in:
Daniel Leung 2019-11-04 11:46:41 -08:00 • committed by Carles Cufí
commit b2e1058ca3
1 changed files with 75 additions and 5 deletions
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80
drivers/gpio/gpio_pca95xx.c
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@ -75,6 +75,8 @@ struct gpio_pca95xx_drv_data {
u16_t pud_en;
u16_t pud_sel;
} reg_cache;
struct k_sem lock;
};
/**
@ -380,6 +382,8 @@ static int gpio_pca95xx_config(struct device *dev, int access_op,
u32_t pin, int flags)
{
int ret;
struct gpio_pca95xx_drv_data * const drv_data =
(struct gpio_pca95xx_drv_data * const)dev->driver_data;
#if (CONFIG_GPIO_LOG_LEVEL >= LOG_LEVEL_DEBUG)
const struct gpio_pca95xx_config * const config =
@ -399,6 +403,13 @@ static int gpio_pca95xx_config(struct device *dev, int access_op,
return -ENOTSUP;
}
/* Can't do I2C bus operations from an ISR */
if (k_is_in_isr()) {
return -EWOULDBLOCK;
}
k_sem_take(&drv_data->lock, K_FOREVER);
ret = setup_pin_dir(dev, access_op, pin, flags);
if (ret) {
LOG_ERR("PCA95XX[0x%X]: error setting pin direction (%d)",
@ -414,6 +425,7 @@ static int gpio_pca95xx_config(struct device *dev, int access_op,
}
done:
k_sem_give(&drv_data->lock);
return ret;
}
@ -432,9 +444,18 @@ static int gpio_pca95xx_write(struct device *dev, int access_op,
{
struct gpio_pca95xx_drv_data * const drv_data =
(struct gpio_pca95xx_drv_data * const)dev->driver_data;
u16_t reg_out = drv_data->reg_cache.output;
u16_t reg_out;
int ret;
/* Can't do I2C bus operations from an ISR */
if (k_is_in_isr()) {
return -EWOULDBLOCK;
}
k_sem_take(&drv_data->lock, K_FOREVER);
reg_out = drv_data->reg_cache.output;
/* Invert input value for pins configurated as active low. */
switch (access_op) {
case GPIO_ACCESS_BY_PIN:
@ -455,6 +476,7 @@ static int gpio_pca95xx_write(struct device *dev, int access_op,
ret = update_output_regs(dev, reg_out);
done:
k_sem_give(&drv_data->lock);
return ret;
}
@ -471,9 +493,18 @@ done:
static int gpio_pca95xx_read(struct device *dev, int access_op,
u32_t pin, u32_t *value)
{
struct gpio_pca95xx_drv_data * const drv_data =
(struct gpio_pca95xx_drv_data * const)dev->driver_data;
u16_t buf;
int ret;
/* Can't do I2C bus operations from an ISR */
if (k_is_in_isr()) {
return -EWOULDBLOCK;
}
k_sem_take(&drv_data->lock, K_FOREVER);
ret = read_port_regs(dev, REG_INPUT_PORT0, &buf);
if (ret != 0) {
goto done;
@ -492,14 +523,24 @@ static int gpio_pca95xx_read(struct device *dev, int access_op,
}
done:
k_sem_give(&drv_data->lock);
return ret;
}
static int gpio_pca95xx_port_get_raw(struct device *dev, u32_t *value)
{
struct gpio_pca95xx_drv_data * const drv_data =
(struct gpio_pca95xx_drv_data * const)dev->driver_data;
u16_t buf;
int ret;
/* Can't do I2C bus operations from an ISR */
if (k_is_in_isr()) {
return -EWOULDBLOCK;
}
k_sem_take(&drv_data->lock, K_FOREVER);
ret = read_port_regs(dev, REG_INPUT_PORT0, &buf);
if (ret != 0) {
goto done;
@ -508,6 +549,7 @@ static int gpio_pca95xx_port_get_raw(struct device *dev, u32_t *value)
*value = buf;
done:
k_sem_give(&drv_data->lock);
return ret;
}
@ -516,11 +558,24 @@ static int gpio_pca95xx_port_set_masked_raw(struct device *dev,
{
struct gpio_pca95xx_drv_data * const drv_data =
(struct gpio_pca95xx_drv_data * const)dev->driver_data;
u16_t reg_out = drv_data->reg_cache.output;
u16_t reg_out;
int ret;
/* Can't do I2C bus operations from an ISR */
if (k_is_in_isr()) {
return -EWOULDBLOCK;
}
k_sem_take(&drv_data->lock, K_FOREVER);
reg_out = drv_data->reg_cache.output;
reg_out = (reg_out & ~mask) | (mask & value);
return update_output_regs(dev, reg_out);
ret = update_output_regs(dev, reg_out);
k_sem_give(&drv_data->lock);
return ret;
}
static int gpio_pca95xx_port_set_bits_raw(struct device *dev, u32_t mask)
@ -537,11 +592,24 @@ static int gpio_pca95xx_port_toggle_bits(struct device *dev, u32_t mask)
{
struct gpio_pca95xx_drv_data * const drv_data =
(struct gpio_pca95xx_drv_data * const)dev->driver_data;
u16_t reg_out = drv_data->reg_cache.output;
u16_t reg_out;
int ret;
/* Can't do I2C bus operations from an ISR */
if (k_is_in_isr()) {
return -EWOULDBLOCK;
}
k_sem_take(&drv_data->lock, K_FOREVER);
reg_out = drv_data->reg_cache.output;
reg_out ^= mask;
return update_output_regs(dev, reg_out);
ret = update_output_regs(dev, reg_out);
k_sem_give(&drv_data->lock);
return ret;
}
static int gpio_pca95xx_pin_interrupt_configure(struct device *dev,
@ -585,6 +653,8 @@ static int gpio_pca95xx_init(struct device *dev)
}
drv_data->i2c_master = i2c_master;
k_sem_init(&drv_data->lock, 1, 1);
return 0;
}