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drivers: mipi_dbi: spi: add tearing effect support

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Add tearing effect support for better display synchronization. This
allows users to configure an external interrupt on falling/rising edges
of the gpio connected to the display controllers tearing effect pin.
See dt-bindings/mipi_dbi/mipi_dbi.h for details of how this works for
mipi_dbi display interfaces.

Signed-off-by: Christian Rask <christianrask2@gmail.com>
This commit is contained in:
Christian Rask
2025-06-11 21:32:13 +02:00
committed by Benjamin Cabé
parent 77e6ff8ad4
commit fe356031db
2 changed files with 153 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files

166
drivers/mipi_dbi/mipi_dbi_spi.c
View File

@@ -15,23 +15,6 @@
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(mipi_dbi_spi, CONFIG_MIPI_DBI_LOG_LEVEL);
struct mipi_dbi_spi_config {
/* SPI hardware used to send data */
const struct device *spi_dev;
/* Command/Data gpio */
const struct gpio_dt_spec cmd_data;
/* Reset GPIO */
const struct gpio_dt_spec reset;
/* Minimum transfer bits */
const uint8_t xfr_min_bits;
};
struct mipi_dbi_spi_data {
struct k_mutex lock;
/* Used for 3 wire mode */
uint16_t spi_byte;
};
/* Expands to 1 if the node does not have the `write-only` property */
#define MIPI_DBI_SPI_WRITE_ONLY_ABSENT(n) (!DT_INST_PROP(n, write_only)) |
@@ -42,6 +25,16 @@ struct mipi_dbi_spi_data {
#define MIPI_DBI_SPI_READ_REQUIRED DT_INST_FOREACH_STATUS_OKAY(MIPI_DBI_SPI_WRITE_ONLY_ABSENT) 0
uint32_t var = MIPI_DBI_SPI_READ_REQUIRED;
/* Expands to 1 if the node configures a gpio in the `te-gpios` property */
#define MIPI_DBI_SPI_TE_GPIOS_PRESENT(n) DT_INST_NODE_HAS_PROP(n, te_gpios) |
/* This macro will evaluate to 1 if any of the nodes with zephyr,mipi-dbi-spi
* has a `te-gpios` property. The intention here is to allow the entire
* configure_te and mipi_dbi_spi_te_cb functions to be optimized out when it
* is not needed.
*/
#define MIPI_DBI_SPI_TE_REQUIRED DT_INST_FOREACH_STATUS_OKAY(MIPI_DBI_SPI_TE_GPIOS_PRESENT) 0
/* Expands to 1 if the node does reflect the enum in `xfr-min-bits` property */
#define MIPI_DBI_SPI_XFR_8BITS(n) (DT_INST_STRING_UPPER_TOKEN(n, xfr_min_bits) \
== MIPI_DBI_SPI_XFR_8BIT) |
@@ -64,6 +57,53 @@ uint32_t var = MIPI_DBI_SPI_READ_REQUIRED;
*/
#define MIPI_DBI_DC_BIT BIT(8)
struct mipi_dbi_spi_config {
/* SPI hardware used to send data */
const struct device *spi_dev;
/* Command/Data gpio */
const struct gpio_dt_spec cmd_data;
/* Tearing Effect GPIO */
const struct gpio_dt_spec tearing_effect;
/* Reset GPIO */
const struct gpio_dt_spec reset;
/* Minimum transfer bits */
const uint8_t xfr_min_bits;
};
struct mipi_dbi_spi_data {
struct k_mutex lock;
#if MIPI_DBI_SPI_TE_REQUIRED
struct k_sem te_signal;
k_timeout_t te_delay;
atomic_t in_active_area;
struct gpio_callback te_cb_data;
#endif
/* Used for 3 wire mode */
uint16_t spi_byte;
};
#if MIPI_DBI_SPI_TE_REQUIRED
static void mipi_dbi_spi_te_cb(const struct device *dev,
struct gpio_callback *cb,
uint32_t pins)
{
ARG_UNUSED(dev);
ARG_UNUSED(pins);
struct mipi_dbi_spi_data *data = CONTAINER_OF(cb,
struct mipi_dbi_spi_data, te_cb_data);
/* Open frame window */
if (!atomic_cas(&data->in_active_area, 0, 1)) {
return;
}
k_sem_give(&data->te_signal);
}
#endif /* MIPI_DBI_SPI_TE_REQUIRED */
static inline int
mipi_dbi_spi_write_helper_3wire(const struct device *dev,
const struct mipi_dbi_config *dbi_config,
@@ -323,8 +363,32 @@ static int mipi_dbi_spi_write_display(const struct device *dev,
{
ARG_UNUSED(pixfmt);
return mipi_dbi_spi_write_helper(dev, dbi_config, false, 0x0,
framebuf, desc->buf_size);
int ret = 0;
#if MIPI_DBI_SPI_TE_REQUIRED
struct mipi_dbi_spi_data *data = dev->data;
/* Wait for TE signal, otherwise transferring can begin */
if (!atomic_get(&data->in_active_area)) {
ret = k_sem_take(&data->te_signal, K_FOREVER);
if (ret < 0) {
return ret;
}
k_sleep(data->te_delay);
}
#endif
ret = mipi_dbi_spi_write_helper(dev, dbi_config, false, 0x0,
framebuf, desc->buf_size);
#if MIPI_DBI_SPI_TE_REQUIRED
/* End of frame reset */
if (!desc->frame_incomplete) {
atomic_set(&data->in_active_area, 0);
}
#endif
return ret;
}
#if MIPI_DBI_SPI_READ_REQUIRED
@@ -507,6 +571,66 @@ static int mipi_dbi_spi_release(const struct device *dev,
return spi_release(config->spi_dev, &dbi_config->config);
}
#if MIPI_DBI_SPI_TE_REQUIRED
static int mipi_dbi_spi_configure_te(const struct device *dev,
uint8_t edge,
k_timeout_t delay_us)
{
const struct mipi_dbi_spi_config *config = dev->config;
struct mipi_dbi_spi_data *data = dev->data;
int ret = 0;
if (edge == MIPI_DBI_TE_NO_EDGE) {
/* No configuration */
return 0;
}
if (!mipi_dbi_has_pin(&config->tearing_effect)) {
return -ENOTSUP;
}
if (!gpio_is_ready_dt(&config->tearing_effect)) {
return -ENODEV;
}
ret = gpio_pin_configure_dt(&config->tearing_effect, GPIO_INPUT);
if (ret < 0) {
LOG_ERR("Could not configure Tearing Effect GPIO (%d)", ret);
return ret;
}
if (edge == MIPI_DBI_TE_RISING_EDGE) {
ret = gpio_pin_interrupt_configure_dt(&config->tearing_effect,
GPIO_INT_EDGE_RISING);
} else if (edge == MIPI_DBI_TE_FALLING_EDGE) {
ret = gpio_pin_interrupt_configure_dt(&config->tearing_effect,
GPIO_INT_EDGE_FALLING);
}
if (ret < 0) {
LOG_ERR("Could not configure Tearing Effect GPIO EXT interrupt (%d)", ret);
return ret;
}
gpio_init_callback(&data->te_cb_data, mipi_dbi_spi_te_cb,
BIT(config->tearing_effect.pin));
ret = gpio_add_callback(config->tearing_effect.port,
&data->te_cb_data);
if (ret < 0) {
LOG_ERR("Could not add Tearing Effect GPIO callback (%d)", ret);
return ret;
}
data->te_delay = delay_us;
atomic_set(&data->in_active_area, 0);
k_sem_init(&data->te_signal, 0, 1);
return ret;
}
#endif /* MIPI_DBI_SPI_TE_REQUIRED */
static int mipi_dbi_spi_init(const struct device *dev)
{
const struct mipi_dbi_spi_config *config = dev->config;
@@ -553,6 +677,9 @@ static DEVICE_API(mipi_dbi, mipi_dbi_spi_driver_api) = {
#if MIPI_DBI_SPI_READ_REQUIRED
.command_read = mipi_dbi_spi_command_read,
#endif
#if MIPI_DBI_SPI_TE_REQUIRED
.configure_te = mipi_dbi_spi_configure_te,
#endif
};
#define MIPI_DBI_SPI_INIT(n) \
@@ -561,6 +688,7 @@ static DEVICE_API(mipi_dbi, mipi_dbi_spi_driver_api) = {
.spi_dev = DEVICE_DT_GET( \
DT_INST_PHANDLE(n, spi_dev)), \
.cmd_data = GPIO_DT_SPEC_INST_GET_OR(n, dc_gpios, {}), \
.tearing_effect = GPIO_DT_SPEC_INST_GET_OR(n, te_gpios, {}), \
.reset = GPIO_DT_SPEC_INST_GET_OR(n, reset_gpios, {}), \
.xfr_min_bits = DT_INST_STRING_UPPER_TOKEN(n, xfr_min_bits) \
}; \

6
dts/bindings/mipi-dbi/zephyr,mipi-dbi-spi.yaml
View File

@@ -22,6 +22,12 @@ properties:
Data/command gpio pin. Required when using 4 wire SPI mode (Mode C1).
Set to low when sending a command, or high when sending data.
te-gpios:
type: phandle-array
description: |
Tearing Effect GPIO pin. Set to high when the display is blanking
(i.e., not actively reading pixels from its RAM).
reset-gpios:
type: phandle-array
description: |