drivers/ft5x06: use a const pointer to params instead of a copy

There is no need to copy the configuration parameter set to the device descriptor. A const pointer to the configuration parameter set in ROM is sufficient. It saves some 16 byte of RAM.

drivers/ft5x06/ft5x06.c

@@ -34,14 +34,17 @@
 #define ENABLE_DEBUG    0
 #include "debug.h"
 
-#define FT5X06_BUS              (dev->params.i2c)
-#define FT5X06_ADDR             (dev->params.addr)
+#define FT5X06_BUS              (dev->params->i2c)
+#define FT5X06_ADDR             (dev->params->addr)
 
 #define FT5X06_RESET_DELAY_MS   (200)
 
 int ft5x06_init(ft5x06_t *dev, const ft5x06_params_t *params, ft5x06_event_cb_t cb, void *arg)
 {
-    dev->params = *params;
+    assert(dev);
+    assert(params);
+
+    dev->params = params;
 
     /* Wait at least 200ms after power up before accessing registers */
     ztimer_sleep(ZTIMER_MSEC, FT5X06_RESET_DELAY_MS);
@@ -54,7 +57,7 @@ int ft5x06_init(ft5x06_t *dev, const ft5x06_params_t *params, ft5x06_event_cb_t
         return -EPROTO;
     }
 
-    if (dev->params.type == FT5X06_TYPE_FT6X06 || dev->params.type == FT5X06_TYPE_FT6X36) {
+    if (dev->params->type == FT5X06_TYPE_FT6X06 || dev->params->type == FT5X06_TYPE_FT6X36) {
         if ((vendor_id != FT5X06_VENDOR_ID_2) && (vendor_id != FT5X06_VENDOR_ID_3)) {
             DEBUG("[ft5x06] init: invalid vendor ID: '0x%02x' (expected: 0x%02x or 0x%02x)\n",
                   vendor_id, FT5X06_VENDOR_ID_2, FT5X06_VENDOR_ID_3);
@@ -70,16 +73,16 @@ int ft5x06_init(ft5x06_t *dev, const ft5x06_params_t *params, ft5x06_event_cb_t
     }
 
     /* Auto-calibrate if needed */
-    if (dev->params.type == FT5X06_TYPE_FT5606|| dev->params.type == FT5X06_TYPE_FT5X16 ||
-        dev->params.type == FT5X06_TYPE_FT5X06I) {
+    if (dev->params->type == FT5X06_TYPE_FT5606|| dev->params->type == FT5X06_TYPE_FT5X16 ||
+        dev->params->type == FT5X06_TYPE_FT5X06I) {
         DEBUG("[ft5x06] init: enable device auto-calibration\n");
         i2c_write_reg(FT5X06_BUS, FT5X06_ADDR, FT5X06_G_AUTO_CLB_MODE_REG, 0, 0);
     }
 
     /* Configure interrupt */
-    if (gpio_is_valid(dev->params.int_pin)) {
+    if (gpio_is_valid(dev->params->int_pin)) {
         DEBUG("[ft5x06] init: configuring touchscreen interrupt\n");
-        gpio_init_int(dev->params.int_pin, GPIO_IN, GPIO_RISING, cb, arg);
+        gpio_init_int(dev->params->int_pin, GPIO_IN, GPIO_RISING, cb, arg);
         i2c_write_reg(FT5X06_BUS, FT5X06_ADDR, FT5X06_G_MODE_REG, FT5X06_G_MODE_INTERRUPT_TRIGGER & 0x01, 0);
     }
 
@@ -98,6 +101,9 @@ static const uint8_t touch_reg_map[FT5X06_TOUCHES_COUNT_MAX] = {
 
 int ft5x06_read_touch_positions(const ft5x06_t *dev, ft5x06_touch_position_t *positions, size_t len)
 {
+    assert(dev);
+    assert(positions);
+
     i2c_acquire(FT5X06_BUS);
     for (uint8_t touch = 0; touch < len; touch++) {
         uint8_t regs[4];
@@ -116,6 +122,9 @@ int ft5x06_read_touch_positions(const ft5x06_t *dev, ft5x06_touch_position_t *po
 
 int ft5x06_read_touch_count(const ft5x06_t *dev, uint8_t *count)
 {
+    assert(dev);
+    assert(count);
+
     i2c_acquire(FT5X06_BUS);
     i2c_read_reg(FT5X06_BUS, FT5X06_ADDR, FT5X06_TD_STATUS_REG, count, 0);
     i2c_release(FT5X06_BUS);
@@ -130,6 +139,9 @@ int ft5x06_read_touch_count(const ft5x06_t *dev, uint8_t *count)
 
 int ft5x06_read_touch_gesture(const ft5x06_t *dev, ft5x06_touch_gesture_t *gesture)
 {
+    assert(dev);
+    assert(gesture);
+
     uint8_t gesture_id = 0;
     i2c_acquire(FT5X06_BUS);
     i2c_read_reg(FT5X06_BUS, FT5X06_ADDR, FT5X06_GESTURE_ID_REG, &gesture_id, 0);

drivers/ft5x06/ft5x06_internal.c

@@ -20,7 +20,7 @@
 #include "ft5x06_internal.h"
 
 uint8_t ft5x06_get_touches_count_max(const ft5x06_t *dev) {
-    if (dev->params.type == FT5X06_TYPE_FT6X06 || dev->params.type == FT5X06_TYPE_FT6X36) {
+    if (dev->params->type == FT5X06_TYPE_FT6X06 || dev->params->type == FT5X06_TYPE_FT6X36) {
         return FT6XX6_TOUCHES_COUNT_MAX;
     }
     else {

drivers/ft5x06/ft5x06_touch_dev.c

@@ -37,7 +37,7 @@ uint16_t _ft5x06_height(const touch_dev_t *touch_dev)
     const ft5x06_t *dev = (const ft5x06_t *)touch_dev;
     assert(dev);
 
-    return dev->params.ymax;
+    return dev->params->ymax;
 }
 
 uint16_t _ft5x06_width(const touch_dev_t *touch_dev)
@@ -45,7 +45,7 @@ uint16_t _ft5x06_width(const touch_dev_t *touch_dev)
     const ft5x06_t *dev = (const ft5x06_t *)touch_dev;
     assert(dev);
 
-    return dev->params.xmax;
+    return dev->params->xmax;
 }
 
 uint8_t _ft5x06_touches(const touch_dev_t *touch_dev, touch_t *touches, size_t len)
@@ -69,8 +69,8 @@ void _ft5x06_set_event_callback(const touch_dev_t *touch_dev, touch_event_cb_t c
     ft5x06_t *dev = (ft5x06_t *)touch_dev;
     assert(dev);
 
-    if (gpio_is_valid(dev->params.int_pin)) {
-        gpio_init_int(dev->params.int_pin, GPIO_IN, GPIO_RISING, cb, arg);
+    if (gpio_is_valid(dev->params->int_pin)) {
+        gpio_init_int(dev->params->int_pin, GPIO_IN, GPIO_RISING, cb, arg);
     }
 }
 

drivers/include/ft5x06.h

@@ -101,9 +101,9 @@ typedef struct {
  */
 typedef struct {
 #ifdef MODULE_TOUCH_DEV
-    touch_dev_t *dev;       /**< Pointer to the generic touch device */
+    touch_dev_t *dev;               /**< Pointer to the generic touch device */
 #endif
-    ft5x06_params_t params; /**< Initialization parameters */
+    const ft5x06_params_t *params;  /**< Initialization parameters */
 } ft5x06_t;
 
 /**