feat(ads1256): 添加 EMI 防护与寄存器自恢复机制

CS 引脚加内部上拉防止干扰误触发；新增 ads1256_recover() 在检测到
寄存器被改写时重写关键配置并验证恢复。

inc/ads1256.h

@@ -12,3 +12,4 @@ void ads1256_sync_wakeup(void);
 int ads1256_hwreset(void);
 int32_t ads1256_read_data(void);
 void ads1256_write_cmd(uint8_t cmd);
+int ads1256_recover(int max_retries);

src/ads1256.c

@@ -179,7 +179,8 @@ int32_t ads1256_read_data(void) {
  */
 int ads1256_init(void) {
     /* GPIO */
-    gpio_pin_configure_dt(&cs_spec, GPIO_OUTPUT_INACTIVE);
+    /* CS 加内部上拉：EMI 干扰时维持高电平，阻止 ADS1256 误收命令 */
+    gpio_pin_configure_dt(&cs_spec, GPIO_OUTPUT_INACTIVE | GPIO_PULL_UP);
     gpio_pin_configure_dt(&reset_spec, GPIO_OUTPUT_INACTIVE);
     gpio_pin_configure_dt(&drdy_spec, GPIO_INPUT);
 
@@ -248,3 +249,30 @@ int ads1256_init(void) {
     LOG_INF("ADS1256 initialized (BUFEN=1, PGA=64, 3750SPS)");
     return 0;
 }
+
+/**
+ * @brief EMI 恢复：重写关键寄存器并验证，用于马达干扰后自恢复。
+ *
+ * @param max_retries 最大重试次数，每次间隔 20ms。
+ *
+ * @retval 0 恢复成功。
+ * @retval -EIO 达到最大重试次数仍未恢复。
+ */
+int ads1256_recover(int max_retries) {
+    for (int i = 0; i < max_retries; i++) {
+        ads1256_write_reg(REG_STATUS, 0x06);
+        ads1256_write_reg(REG_ADCON, 0x07);
+        ads1256_write_reg(REG_DRATE, 0xC0);
+        ads1256_sync_wakeup();
+        k_msleep(20);
+
+        uint8_t adcon = ads1256_read_reg(REG_ADCON);
+        uint8_t drate = ads1256_read_reg(REG_DRATE);
+        if (adcon == 0x07 && drate == 0xC0) {
+            LOG_WRN("ADS1256 recovered after %d retries", i + 1);
+            return 0;
+        }
+    }
+    LOG_ERR("ADS1256 recovery failed after %d retries", max_retries);
+    return -EIO;
+}