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drivers: gpio: implement daisy chaining for BD8LB600FS

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This implements the daisy chain feature of the low side switch
BD8LB600FS. The daisy chaining is in hardware achieved via
connecting the MISO and MOSI lines of multiple instances of the IC
in a row. It is implemented in the driver through a variable number
of GPIOs on one instance. Therefore, one device tree instance of the
IC will handle multiple daisy chained physical instances.

Signed-off-by: Benedikt Schmidt <benedikt.schmidt@embedded-solutions.at>
This commit is contained in:
Benedikt Schmidt 2023-11-30 15:27:56 +01:00 committed by Anas Nashif
parent 2dc1cc712a
commit 7b55b99cac
2 changed files with 65 additions and 26 deletions
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81
drivers/gpio/gpio_bd8lb600fs.c
View file

@ -30,40 +30,61 @@ struct bd8lb600fs_config {
struct spi_dt_spec bus;
const struct gpio_dt_spec gpio_reset;
int gpios_count;
};
struct bd8lb600fs_drv_data {
/* gpio_driver_data needs to be first */
struct gpio_driver_data data;
uint8_t state; /* each bit is one output channel, bit 0 = channel 1, ... */
uint8_t configured; /* each bit defines if the output channel is configured, see state */
uint32_t state; /* each bit is one output channel, bit 0 = channel 1, ... */
uint32_t configured; /* each bit defines if the output channel is configured, see state */
struct k_mutex lock;
int instance_count_actual;
int gpios_count_actual;
};
static int write_state(const struct bd8lb600fs_config *config, uint8_t state)
static int write_state(const struct device *dev, uint32_t state)
{
LOG_DBG("writing state 0x%02X to BD8LB600FS", state);
const struct bd8lb600fs_config *config = dev->config;
struct bd8lb600fs_drv_data *drv_data = dev->data;
LOG_DBG("%s: writing state 0x%08X to BD8LB600FS", dev->name, state);
uint16_t state_converted = 0;
uint8_t buffer_tx[2];
const struct spi_buf tx_buf[] = {{
uint8_t buffer_tx[8];
const struct spi_buf tx_buf = {
.buf = buffer_tx,
.len = ARRAY_SIZE(buffer_tx),
}};
.len = drv_data->instance_count_actual * sizeof(state_converted),
};
const struct spi_buf_set tx = {
.buffers = tx_buf,
.count = ARRAY_SIZE(tx_buf),
.buffers = &tx_buf,
.count = 1,
};
for (size_t i = 0; i < 8; ++i) {
if ((state & BIT(i)) == 0) {
state_converted |= OUTPUT_OFF_WITH_OPEN_LOAD_DETECTION << (i * 2);
} else {
state_converted |= OUTPUT_ON << (i * 2);
memset(buffer_tx, 0x00, sizeof(buffer_tx));
for (size_t j = 0; j < drv_data->instance_count_actual; ++j) {
int instance_position = (drv_data->instance_count_actual - j - 1) * 2;
state_converted = 0;
for (size_t i = 0; i < 8; ++i) {
if ((state & BIT(i + j*8)) == 0) {
state_converted |= OUTPUT_OFF_WITH_OPEN_LOAD_DETECTION << (i * 2);
} else {
state_converted |= OUTPUT_ON << (i * 2);
}
}
LOG_DBG("%s: configuration for instance %i: %04X (position %i)",
dev->name,
j,
state_converted,
instance_position);
sys_put_be16(state_converted, buffer_tx + instance_position);
}
sys_put_be16(state_converted, buffer_tx);
LOG_HEXDUMP_DBG(buffer_tx, ARRAY_SIZE(buffer_tx), "configuration written out");
int result = spi_write_dt(&config->bus, &tx);
@ -77,7 +98,6 @@ static int write_state(const struct bd8lb600fs_config *config, uint8_t state)
static int bd8lb600fs_pin_configure(const struct device *dev, gpio_pin_t pin, gpio_flags_t flags)
{
const struct bd8lb600fs_config *config = dev->config;
struct bd8lb600fs_drv_data *drv_data = dev->data;
/* cannot execute a bus operation in an ISR context */
@ -85,7 +105,7 @@ static int bd8lb600fs_pin_configure(const struct device *dev, gpio_pin_t pin, gp
return -EWOULDBLOCK;
}
if (pin > 7) {
if (pin >= drv_data->gpios_count_actual) {
LOG_ERR("invalid pin number %i", pin);
return -EINVAL;
}
@ -130,7 +150,7 @@ static int bd8lb600fs_pin_configure(const struct device *dev, gpio_pin_t pin, gp
WRITE_BIT(drv_data->configured, pin, 1);
int result = write_state(config, drv_data->state);
int result = write_state(dev, drv_data->state);
k_mutex_unlock(&drv_data->lock);
@ -145,7 +165,6 @@ static int bd8lb600fs_port_get_raw(const struct device *dev, uint32_t *value)
static int bd8lb600fs_port_set_masked_raw(const struct device *dev, uint32_t mask, uint32_t value)
{
const struct bd8lb600fs_config *config = dev->config;
struct bd8lb600fs_drv_data *drv_data = dev->data;
/* cannot execute a bus operation in an ISR context */
@ -156,7 +175,7 @@ static int bd8lb600fs_port_set_masked_raw(const struct device *dev, uint32_t mas
k_mutex_lock(&drv_data->lock, K_FOREVER);
drv_data->state = (drv_data->state & ~mask) | (mask & value);
int result = write_state(config, drv_data->state);
int result = write_state(dev, drv_data->state);
k_mutex_unlock(&drv_data->lock);
@ -175,7 +194,6 @@ static int bd8lb600fs_port_clear_bits_raw(const struct device *dev, uint32_t mas
static int bd8lb600fs_port_toggle_bits(const struct device *dev, uint32_t mask)
{
const struct bd8lb600fs_config *config = dev->config;
struct bd8lb600fs_drv_data *drv_data = dev->data;
/* cannot execute a bus operation in an ISR context */
@ -186,7 +204,7 @@ static int bd8lb600fs_port_toggle_bits(const struct device *dev, uint32_t mask)
k_mutex_lock(&drv_data->lock, K_FOREVER);
drv_data->state ^= mask;
int result = write_state(config, drv_data->state);
int result = write_state(dev, drv_data->state);
k_mutex_unlock(&drv_data->lock);
@ -219,6 +237,22 @@ static int bd8lb600fs_init(const struct device *dev)
return result;
}
drv_data->instance_count_actual = config->gpios_count / 8;
if (config->gpios_count % 8 != 0) {
LOG_ERR("%s: number of GPIOs %i is not a multiple of 8",
dev->name, config->gpios_count);
return -EINVAL;
}
if (drv_data->instance_count_actual > 4) {
LOG_ERR("%s: only a maximum of 4 devices are supported for the daisy chaining",
dev->name);
return -EINVAL;
}
drv_data->gpios_count_actual = drv_data->instance_count_actual * 8;
result = gpio_pin_configure_dt(&config->gpio_reset, GPIO_OUTPUT_ACTIVE);
if (result != 0) {
@ -242,6 +276,7 @@ static int bd8lb600fs_init(const struct device *dev)
.bus = SPI_DT_SPEC_INST_GET( \
inst, SPI_OP_MODE_MASTER | SPI_MODE_CPHA | SPI_WORD_SET(8), 0), \
.gpio_reset = GPIO_DT_SPEC_GET_BY_IDX(DT_DRV_INST(inst), reset_gpios, 0), \
.gpios_count = DT_INST_PROP(inst, ngpios), \
}; \
\
static struct bd8lb600fs_drv_data bd8lb600fs_##inst##_drvdata = { \

10
dts/bindings/gpio/rohm,bd8lb600fs.yaml
View file

@ -6,6 +6,8 @@
description: |
This is a representation of the Rohm BD8LB600FS SPI Gpio Expander.
Multiple instances may be daisy chained, which can be configured
via the number of supported GPIOs.
compatible: "rohm,bd8lb600fs"
@ -18,13 +20,15 @@ properties:
ngpios:
type: int
required: true
const: 8
description: Number of gpios supported
description: |
Number of pins for the expander. This must be a multiple of 8.
The number of pins also defines how many devices are daisy chained.
Set to 8 for one instance without daisy chaining.
reset-gpios:
type: phandle-array
required: true
description: "GPIO for reset"
description: GPIO for reset
gpio-cells:
- pin