arch/risc-v: Add LP I2C for esp32[-c6]

eren-terzioglu · xiaoxiang781216 · commit 8995226e0ab7 · 2025-07-09T12:18:06.000+08:00
Add LP I2C peripheral support for esp32c6

Signed-off-by: Eren Terzioglu &lt;eren.terzioglu@espressif.com&gt;
diff --git a/arch/risc-v/src/common/espressif/Kconfig b/arch/risc-v/src/common/espressif/Kconfig
@@ -384,6 +384,10 @@ config ESPRESSIF_I2C
 	bool
 	default n
 
+config ESPRESSIF_LPI2C
+	bool
+	default n
+
 config ESPRESSIF_I2C_PERIPH_MASTER_MODE
 	bool
 	depends on (ESPRESSIF_I2C0_MASTER_MODE || ESPRESSIF_I2C1_MASTER_MODE)
@@ -407,6 +411,14 @@ config ESPRESSIF_I2C1
 	select ESPRESSIF_I2C
 	select I2C
 
+config ESPRESSIF_LP_I2C0
+	bool "LP I2C 0"
+	default n
+	depends on ARCH_CHIP_ESP32C6
+	select ESPRESSIF_I2C
+	select ESPRESSIF_LPI2C
+	select I2C
+
 choice ESPRESSIF_I2C0_MODE
 	prompt "I2C0 Mode"
 	depends on ESPRESSIF_I2C0
@@ -2041,7 +2053,8 @@ if ESPRESSIF_I2C0
 
 config ESPRESSIF_I2C0_SCLPIN
 	int "I2C0 SCL Pin"
-	default 6
+	default 6 if !ESPRESSIF_LPI2C
+	default 23 if ESPRESSIF_LPI2C
 	range 0 21
 
 config ESPRESSIF_I2C0_SDAPIN
diff --git a/arch/risc-v/src/common/espressif/esp_i2c.c b/arch/risc-v/src/common/espressif/esp_i2c.c
@@ -64,11 +64,24 @@
 #if defined(CONFIG_ESPRESSIF_ESP32H2) || defined(CONFIG_ESPRESSIF_ESP32C6)
 #  include "soc/pcr_reg.h"
 #endif
+#if defined(CONFIG_ESPRESSIF_LP_I2C0)
+#  include "driver/rtc_io.h"
+#  include "hal/rtc_io_hal.h"
+#  include "io_mux.h"
+#  include "lp_core_i2c.h"
+#  include "soc/i2c_struct.h"
+#endif
 
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
 
+#if defined(CONFIG_ESPRESSIF_LP_I2C0)
+#  define ESP_LP_I2C0_ID     LP_I2C_NUM_0
+#else
+#  define ESP_LP_I2C0_ID     I2C_NUM_MAX
+#endif
+
 #ifdef CONFIG_ESPRESSIF_ESP32H2
 #  define SYSTEM_I2C_EXT0_CLK_EN PCR_I2C0_CLK_EN
 #  define SYSTEM_I2C_EXT0_RST    PCR_I2C0_RST_EN
@@ -251,6 +264,8 @@ struct esp_i2c_priv_s
 
   bool ready_read;             /* If I2C is ready for receiving data */
 
+  soc_module_clk_t clk_src;   /* Clock source */
+
   uint32_t clk_freq;           /* Current I2C Clock frequency */
 
   /* I2C trace support */
@@ -373,6 +388,7 @@ static struct esp_i2c_priv_s esp_i2c0_priv =
 #endif
   .error      = 0,
   .ready_read = false,
+  .clk_src    = I2C_CLK_SRC_DEFAULT,
   .clk_freq   = 0,
   .ctx = &i2c0_ctx
 };
@@ -424,11 +440,63 @@ static struct esp_i2c_priv_s esp_i2c1_priv =
 #endif
   .error      = 0,
   .ready_read = false,
+  .clk_src    = I2C_CLK_SRC_DEFAULT,
   .clk_freq   = 0,
   .ctx        = &i2c1_ctx
 };
 #endif /* CONFIG_ESPRESSIF_I2C1 */
 
+#ifdef CONFIG_ESPRESSIF_LP_I2C0
+i2c_hal_context_t lp_i2c0_ctx =
+{
+  0
+};
+
+/* I2C device structure */
+
+static const struct esp_i2c_config_s esp_lp_i2c0_config =
+{
+  .clk_freq   = I2C_CLK_FREQ_DEF,
+  .scl_pin    = 7,
+  .sda_pin    = 6,
+#ifndef CONFIG_I2C_POLLED
+  .periph     = ETS_LP_I2C_INTR_SOURCE,
+  .irq        = ESP_IRQ_LP_I2C,
+#endif
+  .clk_bit    = SYSTEM_I2C_EXT0_CLK_EN,
+  .rst_bit    = SYSTEM_I2C_EXT0_RST,
+  .scl_insig  = 0,
+  .scl_outsig = 0,
+  .sda_insig  = 0,
+  .sda_outsig = 0
+};
+
+static struct esp_i2c_priv_s esp_lp_i2c0_priv =
+{
+  .ops        = &esp_i2c_ops,
+  .id         = LP_I2C_NUM_0,
+  .module     = PERIPH_LP_I2C0_MODULE,
+  .config     = &esp_lp_i2c0_config,
+  .refs       = 0,
+  .lock       = NXMUTEX_INITIALIZER,
+#ifndef CONFIG_I2C_POLLED
+  .sem_isr    = SEM_INITIALIZER(0),
+#endif
+  .i2cstate   = I2CSTATE_IDLE,
+  .msgv       = NULL,
+  .msgid      = 0,
+  .bytes      = 0,
+#ifndef CONFIG_I2C_POLLED
+  .cpuint     = -ENOMEM,
+#endif
+  .error      = 0,
+  .ready_read = false,
+  .clk_src    = LP_I2C_SCLK_DEFAULT,
+  .clk_freq   = 0,
+  .ctx        = &lp_i2c0_ctx
+};
+#endif /* CONFIG_ESPRESSIF_LP_I2C0 */
+
 /* Trace events strings */
 
 #ifdef CONFIG_I2C_TRACE
@@ -718,25 +786,64 @@ static void esp_i2c_sendstop(struct esp_i2c_priv_s *priv)
 static void esp_i2c_init_clock(struct esp_i2c_priv_s *priv,
                                uint32_t bus_freq)
 {
-  uint32_t src_clk_frequency;
+  uint32_t src_clk_frequency = 0;
 
   if (bus_freq == priv->clk_freq)
     {
       return ;
     }
 
-  i2c_clock_source_t src_clk = I2C_CLK_SRC_DEFAULT;
-  esp_clk_tree_src_get_freq_hz((soc_module_clk_t)src_clk,
-                               ESP_CLK_TREE_SRC_FREQ_PRECISION_CACHED,
+  esp_clk_tree_src_get_freq_hz(priv->clk_src,
+                               ESP_CLK_TREE_SRC_FREQ_PRECISION_APPROX,
                                &src_clk_frequency);
   i2c_hal_set_bus_timing(priv->ctx, priv->config->clk_freq,
-                         src_clk, src_clk_frequency);
+                         priv->clk_src, src_clk_frequency);
   i2c_hal_master_set_scl_timeout_val(priv->ctx, SCL_TIMEOUT_VAL_US,
                                      src_clk_frequency);
+
+#ifdef CONFIG_ESPRESSIF_LPI2C
+  PERIPH_RCC_ATOMIC()
+    {
+      lp_i2c_ll_set_source_clk(priv->ctx->dev, priv->clk_src);
+    }
+#endif
+
   i2c_ll_update(priv->ctx->dev);
   priv->clk_freq = bus_freq;
 }
 
+#ifdef CONFIG_ESPRESSIF_LPI2C
+/****************************************************************************
+ * Name: esp_lp_i2c_config_io
+ *
+ * Description:
+ *   Configures LP I2C pin.
+ *
+ * Parameters:
+ *   priv      - Pointer to the private driver struct.
+ *   pin       - Pin number to configure.
+ *
+ * Return Value:
+ *   None.
+ *
+ ****************************************************************************/
+
+static void esp_lp_i2c_config_io(const struct esp_i2c_priv_s *priv,
+                                 int8_t pin)
+{
+  int lp_pin = rtc_io_num_map[pin];
+
+  DEBUGASSERT(lp_pin != -1);
+
+  rtc_gpio_set_level(pin, 1);
+  rtc_gpio_init(pin);
+
+  rtc_gpio_set_direction(pin, RTC_GPIO_MODE_INPUT_OUTPUT_OD);
+  rtc_gpio_pulldown_dis(pin);
+  rtc_gpio_pullup_en(pin);
+}
+#endif /* CONFIG_ESPRESSIF_LPI2C */
+
 /****************************************************************************
  * Name: esp_i2c_init
  *
@@ -752,22 +859,53 @@ static void esp_i2c_init(struct esp_i2c_priv_s *priv)
 {
   const struct esp_i2c_config_s *config = priv->config;
 
-  /* Configure GPIO signals for I2C SCL and SDA pins */
+  if (priv->id < ESP_LP_I2C0_ID)
+    {
+      /* Configure GPIO signals for I2C SCL and SDA pins */
+
+      esp_gpiowrite(config->scl_pin, 1);
+      esp_gpiowrite(config->sda_pin, 1);
 
-  esp_gpiowrite(config->scl_pin, 1);
-  esp_gpiowrite(config->sda_pin, 1);
+      esp_configgpio(config->scl_pin, INPUT_PULLUP | OUTPUT_OPEN_DRAIN);
+      esp_gpio_matrix_out(config->scl_pin, config->scl_outsig, 0, 0);
+      esp_gpio_matrix_in(config->scl_pin, config->scl_insig, 0);
 
-  esp_configgpio(config->scl_pin, INPUT_PULLUP | OUTPUT_OPEN_DRAIN);
-  esp_gpio_matrix_out(config->scl_pin, config->scl_outsig, 0, 0);
-  esp_gpio_matrix_in(config->scl_pin, config->scl_insig, 0);
+      esp_configgpio(config->sda_pin, INPUT_PULLUP | OUTPUT_OPEN_DRAIN);
+      esp_gpio_matrix_out(config->sda_pin, config->sda_outsig, 0, 0);
+      esp_gpio_matrix_in(config->sda_pin, config->sda_insig, 0);
 
-  esp_configgpio(config->sda_pin, INPUT_PULLUP | OUTPUT_OPEN_DRAIN);
-  esp_gpio_matrix_out(config->sda_pin, config->sda_outsig, 0, 0);
-  esp_gpio_matrix_in(config->sda_pin, config->sda_insig, 0);
+      /* Enable I2C hardware */
 
-  /* Enable I2C hardware */
+      periph_module_enable(priv->module);
+    }
+#ifdef CONFIG_ESPRESSIF_LPI2C
+  else
+    {
+      PERIPH_RCC_ATOMIC()
+        {
+          /* Enable LP I2C bus clock */
+
+          lp_i2c_ll_enable_bus_clock(priv->id - LP_I2C_NUM_0, true);
+
+          /* Reset LP I2C register */
+
+          lp_i2c_ll_reset_register(priv->id - LP_I2C_NUM_0);
+        }
+
+      esp_lp_i2c_config_io(priv, config->scl_pin);
+      esp_lp_i2c_config_io(priv, config->sda_pin);
+      const i2c_signal_conn_t *p_i2c_pin = &i2c_periph_signal[priv->id];
+#if !SOC_LP_GPIO_MATRIX_SUPPORTED
+      rtc_gpio_iomux_func_sel(config->sda_pin, p_i2c_pin->iomux_func);
+      rtc_gpio_iomux_func_sel(config->scl_pin, p_i2c_pin->iomux_func);
+#else
+      /* ToDo: Add LP I2C for LP GPIO Matrix
+       * supported devices (e.g ESP32-P4)
+       */
 
-  periph_module_enable(priv->module);
+#endif /* SOC_LP_GPIO_MATRIX_SUPPORTED */
+    }
+#endif
 
   i2c_hal_init(priv->ctx, priv->id);
 
@@ -783,6 +921,17 @@ static void esp_i2c_init(struct esp_i2c_priv_s *priv)
 
   i2c_ll_master_set_filter(priv->ctx->dev, I2C_FILTER_CYC_NUM_DEF);
 
+#ifdef CONFIG_ESPRESSIF_LPI2C
+  /* Enable internal open-drain mode for I2C IO lines */
+
+  priv->ctx->dev->ctr.sda_force_out = 0;
+  priv->ctx->dev->ctr.scl_force_out = 0;
+
+  /* Configure the I2C master to send a NACK when the Rx FIFO count is full */
+
+  i2c_ll_master_rx_full_ack_level(priv->ctx->dev, 1);
+#endif
+
   /* Initialize I2C bus clock */
 
   esp_i2c_init_clock(priv, config->clk_freq);
@@ -1531,6 +1680,11 @@ struct i2c_master_s *esp_i2cbus_initialize(int port)
     case ESPRESSIF_I2C1:
       priv = &esp_i2c1_priv;
       break;
+#endif
+#ifdef CONFIG_ESPRESSIF_LP_I2C0
+    case ESPRESSIF_LP_I2C0:
+      priv = &esp_lp_i2c0_priv;
+      break;
 #endif
     default:
       return NULL;
diff --git a/arch/risc-v/src/common/espressif/esp_i2c.h b/arch/risc-v/src/common/espressif/esp_i2c.h
@@ -49,6 +49,10 @@
 #  define ESPRESSIF_I2C1 1
 #endif
 
+#ifdef CONFIG_ESPRESSIF_LP_I2C0
+#  define ESPRESSIF_LP_I2C0 2
+#endif
+
 /****************************************************************************
  * Public Function Prototypes
  ****************************************************************************/
diff --git a/arch/risc-v/src/common/espressif/esp_i2c_slave.c b/arch/risc-v/src/common/espressif/esp_i2c_slave.c
@@ -540,7 +540,7 @@ static void esp_i2c_slave_init(struct esp_i2c_priv_s *priv)
 
   /* Enable I2C hardware */
 
-  periph_module_enable(i2c_periph_signal[priv->id].module);
+  periph_module_enable(PERIPH_I2C0_MODULE);
 
   i2c_hal_init(priv->ctx, priv->id);
 
@@ -551,7 +551,7 @@ static void esp_i2c_slave_init(struct esp_i2c_priv_s *priv)
   /* Initialize I2C Slave */
 
   i2c_hal_slave_init(priv->ctx);
-  i2c_ll_slave_tx_auto_start_en(priv->ctx->dev, true);
+  i2c_ll_slave_enable_auto_start(priv->ctx->dev, true);
   i2c_ll_set_source_clk(priv->ctx->dev, I2C_CLK_SRC_DEFAULT);
   i2c_ll_set_slave_addr(priv->ctx->dev, priv->addr, false);
   i2c_ll_set_rxfifo_full_thr(priv->ctx->dev, I2C_FIFO_FULL_THRESH_VAL);
@@ -583,7 +583,7 @@ static void esp_i2c_slave_deinit(struct esp_i2c_priv_s *priv)
   const struct esp_i2c_config_s *config = priv->config;
 
   i2c_hal_deinit(priv->ctx);
-  periph_module_disable(i2c_periph_signal[priv->id].module);
+  periph_module_disable(PERIPH_I2C0_MODULE);
 }
 
 /****************************************************************************
diff --git a/arch/risc-v/src/esp32c6/hal_esp32c6.mk b/arch/risc-v/src/esp32c6/hal_esp32c6.mk
@@ -212,6 +212,7 @@ CHIP_CSRCS += chip$(DELIM)$(ESP_HAL_3RDPARTY_REPO)$(DELIM)components$(DELIM)soc$
 CHIP_CSRCS += chip$(DELIM)$(ESP_HAL_3RDPARTY_REPO)$(DELIM)components$(DELIM)soc$(DELIM)$(CHIP_SERIES)$(DELIM)rtc_io_periph.c
 CHIP_CSRCS += chip$(DELIM)$(ESP_HAL_3RDPARTY_REPO)$(DELIM)components$(DELIM)soc$(DELIM)$(CHIP_SERIES)$(DELIM)temperature_sensor_periph.c
 CHIP_CSRCS += chip$(DELIM)$(ESP_HAL_3RDPARTY_REPO)$(DELIM)components$(DELIM)soc$(DELIM)${CHIP_SERIES}$(DELIM)uart_periph.c
+CHIP_CSRCS += chip$(DELIM)$(ESP_HAL_3RDPARTY_REPO)$(DELIM)components$(DELIM)ulp$(DELIM)lp_core$(DELIM)lp_core_i2c.c
 
 CHIP_CSRCS += chip$(DELIM)$(ESP_HAL_3RDPARTY_REPO)$(DELIM)nuttx$(DELIM)src$(DELIM)components$(DELIM)esp_driver_gpio$(DELIM)src$(DELIM)gpio.c
 CHIP_CSRCS += chip$(DELIM)$(ESP_HAL_3RDPARTY_REPO)$(DELIM)nuttx$(DELIM)src$(DELIM)components$(DELIM)esp_driver_gpio$(DELIM)src$(DELIM)rtc_io.c
diff --git a/boards/risc-v/esp32c6/common/src/esp_board_i2c.c b/boards/risc-v/esp32c6/common/src/esp_board_i2c.c
@@ -160,5 +160,9 @@ int board_i2c_init(void)
   ret = i2c_slave_driver_init(ESPRESSIF_I2C0_SLAVE, I2C0_SLAVE_ADDR);
 #endif
 
+#ifdef CONFIG_ESPRESSIF_LP_I2C0
+  ret = i2c_driver_init(ESPRESSIF_LP_I2C0);
+#endif
+
   return ret;
 }

Original file line number	Diff line number	Diff line change
`@@ -160,5 +160,9 @@ int board_i2c_init(void)`
`160`	`160`	`ret = i2c_slave_driver_init(ESPRESSIF_I2C0_SLAVE, I2C0_SLAVE_ADDR);`
`161`	`161`	`#endif`
`162`	`162`
	`163`	`+#ifdef CONFIG_ESPRESSIF_LP_I2C0`
	`164`	`+ ret = i2c_driver_init(ESPRESSIF_LP_I2C0);`
	`165`	`+#endif`
	`166`	`+`
`163`	`167`	`return ret;`
`164`	`168`	`}`