0045-RP2040-add-I2C-peripheral-support.patch

From 0ea81c670f830055473ebdca39bddfb112bb7a9f Mon Sep 17 00:00:00 2001
From: Alexander Entinger <cto@lxrobotics.com>
Date: Tue, 16 Feb 2021 06:29:59 +0100
Subject: [PATCH 45/87] RP2040: add I2C peripheral support

---
 .../TARGET_RP2040/i2c_api.c                   | 88 +++++++++++++++++++
 .../TARGET_RP2040/objects.h                   |  1 +
 targets/targets.json                          |  1 +
 3 files changed, 90 insertions(+)
 create mode 100644 targets/TARGET_RASPBERRYPI/TARGET_RP2040/i2c_api.c

diff --git a/targets/TARGET_RASPBERRYPI/TARGET_RP2040/i2c_api.c b/targets/TARGET_RASPBERRYPI/TARGET_RP2040/i2c_api.c
new file mode 100644
index 0000000000..210279b3b0
--- /dev/null
+++ b/targets/TARGET_RASPBERRYPI/TARGET_RP2040/i2c_api.c
@@ -0,0 +1,88 @@
+/******************************************************************************
+ * INCLUDE
+ ******************************************************************************/
+
+#include "mbed_assert.h"
+#include "i2c_api.h"
+#include "pinmap.h"
+#include "PeripheralPins.h"
+
+/******************************************************************************
+ * CONST
+ ******************************************************************************/
+
+static unsigned int const DEFAULT_I2C_BAUDRATE = 100 * 1000; /* 100 kHz */
+
+/******************************************************************************
+ * FUNCTION DEFINITION
+ ******************************************************************************/
+
+void i2c_init(i2c_t *obj, PinName sda, PinName scl)
+{
+    /* Verify if both pins belong to the same I2C peripheral. */
+    I2CName const i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA);
+    I2CName const i2c_scl = (I2CName)pinmap_peripheral(scl, PinMap_I2C_SCL);
+    MBED_ASSERT(i2c_sda == i2c_scl);
+
+    /* Obtain the pointer to the I2C hardware instance. */
+    obj->dev = (i2c_inst_t *)pinmap_function(sda, PinMap_I2C_SDA);
+    obj->baudrate = DEFAULT_I2C_BAUDRATE;
+
+    /* Initialize the I2C module. */
+    _i2c_init(obj->dev, obj->baudrate);
+
+    /* Configure GPIO for I2C as alternate function. */
+    gpio_set_function(sda, GPIO_FUNC_I2C);
+    gpio_set_function(scl, GPIO_FUNC_I2C);
+
+    /* Enable pull-ups for I2C pins. */
+    gpio_pull_up(sda);
+    gpio_pull_up(scl);
+}
+
+void i2c_frequency(i2c_t *obj, int hz)
+{
+    obj->baudrate = i2c_set_baudrate(obj->dev, hz);
+}
+
+int i2c_read(i2c_t *obj, int address, char *data, int length, int stop)
+{
+    int const bytes_read = i2c_read_blocking(obj->dev,
+                                             (uint8_t)address,
+                                             (uint8_t *)data,
+                                             (size_t)length,
+                                             /* nostop = */(stop == 0));
+    if (bytes_read < 0)
+        return I2C_ERROR_NO_SLAVE;
+    else
+        return bytes_read;
+}
+
+int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop)
+{
+    int const bytes_written = i2c_write_blocking(obj->dev,
+                                                 address,
+                                                 (const uint8_t *)data,
+                                                 (size_t)length,
+                                                 /* nostop = */(stop == 0));
+    if (bytes_written < 0)
+        return I2C_ERROR_NO_SLAVE;
+    else
+        return bytes_written;
+}
+
+void i2c_reset(i2c_t *obj)
+{
+    i2c_deinit(obj->dev);
+    _i2c_init(obj->dev, obj->baudrate);
+}
+
+const PinMap *i2c_master_sda_pinmap()
+{
+    return PinMap_I2C_SDA;
+}
+
+const PinMap *i2c_master_scl_pinmap()
+{
+    return PinMap_I2C_SCL;
+}
diff --git a/targets/TARGET_RASPBERRYPI/TARGET_RP2040/objects.h b/targets/TARGET_RASPBERRYPI/TARGET_RP2040/objects.h
index 16dab0daaf..061cee5908 100644
--- a/targets/TARGET_RASPBERRYPI/TARGET_RP2040/objects.h
+++ b/targets/TARGET_RASPBERRYPI/TARGET_RP2040/objects.h
@@ -94,6 +94,7 @@ struct serial_s {
 
 struct i2c_s {
     i2c_inst_t * dev;
+    unsigned int baudrate;
 };
 
 struct spi_s {
diff --git a/targets/targets.json b/targets/targets.json
index 748038db91..909e5746a7 100644
--- a/targets/targets.json
+++ b/targets/targets.json
@@ -8377,6 +8377,7 @@
         },
         "device_has": [
             "ANALOGIN",
+            "I2C",
             "PORT_IN",
             "PORT_OUT",
             "SERIAL",
-- 
2.30.2