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-rw-r--r--docs/configuration/i2c.md165
1 files changed, 82 insertions, 83 deletions
diff --git a/docs/configuration/i2c.md b/docs/configuration/i2c.md
index 7a6241e349..23406ad1e1 100644
--- a/docs/configuration/i2c.md
+++ b/docs/configuration/i2c.md
@@ -14,10 +14,10 @@ The following parameters control the behavior of the I2C library. [config.h]
defines a reasonable default value, but you may need to change the default value
for your board.
-- `CONFIG_I2C_CHIP_MAX_TRANSFER_SIZE <bytes>`
-- `CONFIG_I2C_NACK_RETRY_COUNT <count>`
-- `CONFIG_I2C_EXTRA_PACKET_SIZE <bytes>` - Only used on STM32 EC's if
- `CONFIG_HOSTCMD_I2C_ADDR_FLAGS` is defined.
+- `CONFIG_I2C_CHIP_MAX_TRANSFER_SIZE <bytes>`
+- `CONFIG_I2C_NACK_RETRY_COUNT <count>`
+- `CONFIG_I2C_EXTRA_PACKET_SIZE <bytes>` - Only used on STM32 EC's if
+ `CONFIG_HOSTCMD_I2C_ADDR_FLAGS` is defined.
## GPIOs and Alternate Pins
@@ -28,7 +28,7 @@ recovery actions using bit-banging without involvement by the EC-specific I2C
device driver.
You also need to define the alternate function assignment for all I2C pins using
-the `ALTERNATE()` macro. This step can be skipped for any pins that default to
+the `ALTERNATE()` macro. This step can be skipped for any pins that default to
I2C functionality.
Note that many I2C buses only support 1.8V operation. This is determined by I2C
@@ -42,12 +42,12 @@ macros.
## Data Structures
-- `const struct i2c_port_t i2c_ports[]` - This array should be defined in your
- baseboard.c or board.c file. This array defines the mapping of internal I2C
- port numbers used by the I2C library to the physical I2C ports connected to
- the EC.
-- `const unsigned int i2c_port_used = ARRAY_SIZE(i2c_ports)` - Defines the
- number of internal I2C ports accessible by the I2C library.
+- `const struct i2c_port_t i2c_ports[]` - This array should be defined in your
+ baseboard.c or board.c file. This array defines the mapping of internal I2C
+ port numbers used by the I2C library to the physical I2C ports connected to
+ the EC.
+- `const unsigned int i2c_port_used = ARRAY_SIZE(i2c_ports)` - Defines the
+ number of internal I2C ports accessible by the I2C library.
## Tasks
@@ -57,14 +57,14 @@ None required by this feature.
### Console Commands
-- `i2cscan` - Provides a quick look of all I2C devices found on all configured
- buses.
-- `i2cxfer` - Allows you to read and write individual registers on an I2C
- device.
+- `i2cscan` - Provides a quick look of all I2C devices found on all configured
+ buses.
+- `i2cxfer` - Allows you to read and write individual registers on an I2C
+ device.
-For runtime troubleshooting of an I2C device, enable and the [I2C
-tracing](../i2c-debugging.md) module to log all I2C transactions initiated by
-the EC code.
+For runtime troubleshooting of an I2C device, enable and the
+[I2C tracing](../i2c-debugging.md) module to log all I2C transactions initiated
+by the EC code.
## Example
@@ -72,8 +72,8 @@ The image below shows the I2C bus assignment for the Volteer reference board.
![I2C Example]
-The `gpio.inc` file for Volteer defines both `GPIO()` and `ALTERNATE()` entries for
-all I2C buses used in the design.
+The `gpio.inc` file for Volteer defines both `GPIO()` and `ALTERNATE()` entries
+for all I2C buses used in the design.
```c
/* I2C pins - Alternate function below configures I2C module on these pins */
@@ -101,17 +101,17 @@ ALTERNATE(PIN_MASK(B, BIT(3) | BIT(2)), 0, MODULE_I2C, 0)
The `i2c_ports[]` array requires the `.port` field to be assigned to an EC
chipset specific enumeration. For the NPCx7 I2C bus names are defined in
-[./chip/npcx/registers.h]. The Volteer `baseboard.h` file creates a mapping
-from the schematic net name to the NPCx7 I2C bus enumeration.
+[./chip/npcx/registers.h]. The Volteer `baseboard.h` file creates a mapping from
+the schematic net name to the NPCx7 I2C bus enumeration.
```c
#define CONFIG_I2C
-#define I2C_PORT_SENSOR NPCX_I2C_PORT0_0
-#define I2C_PORT_USB_C0 NPCX_I2C_PORT1_0
-#define I2C_PORT_USB_C1 NPCX_I2C_PORT2_0
-#define I2C_PORT_USB_1_MIX NPCX_I2C_PORT3_0
-#define I2C_PORT_POWER NPCX_I2C_PORT5_0
-#define I2C_PORT_EEPROM NPCX_I2C_PORT7_0
+#define I2C_PORT_SENSOR NPCX_I2C_PORT0_0
+#define I2C_PORT_USB_C0 NPCX_I2C_PORT1_0
+#define I2C_PORT_USB_C1 NPCX_I2C_PORT2_0
+#define I2C_PORT_USB_1_MIX NPCX_I2C_PORT3_0
+#define I2C_PORT_POWER NPCX_I2C_PORT5_0
+#define I2C_PORT_EEPROM NPCX_I2C_PORT7_0
```
The last piece for I2C configuration is to create the `i2c_ports[]` array using
@@ -120,56 +120,56 @@ the macros and enumerations added to `baseboard.h` and `gpio.inc`.
```c
/* I2C port map configuration */
const struct i2c_port_t i2c_ports[] = {
- {
- .name = "sensor",
- .port = I2C_PORT_SENSOR,
- .kbps = 400,
- .scl = GPIO_EC_I2C0_SENSOR_SCL,
- .sda = GPIO_EC_I2C0_SENSOR_SDA,
- .flags = 0,
- },
- {
- .name = "usb_c0",
- .port = I2C_PORT_USB_C0,
- /*
- * I2C buses used for PD communication must be set for 400 kbps
- * or greater. Set to the maximum speed supported by all devices.
- */
- .kbps = 1000,
- .scl = GPIO_EC_I2C1_USB_C0_SCL,
- .sda = GPIO_EC_I2C1_USB_C0_SDA,
- },
- {
- .name = "usb_c1",
- .port = I2C_PORT_USB_C1,
- /*
- * I2C buses used for PD communication must be set for 400 kbps
- * or greater. Set to the maximum speed supported by all devices.
- */
- .scl = GPIO_EC_I2C2_USB_C1_SCL,
- .sda = GPIO_EC_I2C2_USB_C1_SDA,
- },
- {
- .name = "usb_1_mix",
- .port = I2C_PORT_USB_1_MIX,
- .kbps = 100,
- .scl = GPIO_EC_I2C3_USB_1_MIX_SCL,
- .sda = GPIO_EC_I2C3_USB_1_MIX_SDA,
- },
- {
- .name = "power",
- .port = I2C_PORT_POWER,
- .kbps = 100,
- .scl = GPIO_EC_I2C5_POWER_SCL,
- .sda = GPIO_EC_I2C5_POWER_SDA,
- },
- {
- .name = "eeprom",
- .port = I2C_PORT_EEPROM,
- .kbps = 400,
- .scl = GPIO_EC_I2C7_EEPROM_SCL,
- .sda = GPIO_EC_I2C7_EEPROM_SDA,
- },
+ {
+ .name = "sensor",
+ .port = I2C_PORT_SENSOR,
+ .kbps = 400,
+ .scl = GPIO_EC_I2C0_SENSOR_SCL,
+ .sda = GPIO_EC_I2C0_SENSOR_SDA,
+ .flags = 0,
+ },
+ {
+ .name = "usb_c0",
+ .port = I2C_PORT_USB_C0,
+ /*
+ * I2C buses used for PD communication must be set for 400 kbps
+ * or greater. Set to the maximum speed supported by all devices.
+ */
+ .kbps = 1000,
+ .scl = GPIO_EC_I2C1_USB_C0_SCL,
+ .sda = GPIO_EC_I2C1_USB_C0_SDA,
+ },
+ {
+ .name = "usb_c1",
+ .port = I2C_PORT_USB_C1,
+ /*
+ * I2C buses used for PD communication must be set for 400 kbps
+ * or greater. Set to the maximum speed supported by all devices.
+ */
+ .scl = GPIO_EC_I2C2_USB_C1_SCL,
+ .sda = GPIO_EC_I2C2_USB_C1_SDA,
+ },
+ {
+ .name = "usb_1_mix",
+ .port = I2C_PORT_USB_1_MIX,
+ .kbps = 100,
+ .scl = GPIO_EC_I2C3_USB_1_MIX_SCL,
+ .sda = GPIO_EC_I2C3_USB_1_MIX_SDA,
+ },
+ {
+ .name = "power",
+ .port = I2C_PORT_POWER,
+ .kbps = 100,
+ .scl = GPIO_EC_I2C5_POWER_SCL,
+ .sda = GPIO_EC_I2C5_POWER_SDA,
+ },
+ {
+ .name = "eeprom",
+ .port = I2C_PORT_EEPROM,
+ .kbps = 400,
+ .scl = GPIO_EC_I2C7_EEPROM_SCL,
+ .sda = GPIO_EC_I2C7_EEPROM_SDA,
+ },
};
const unsigned int i2c_ports_used = ARRAY_SIZE(i2c_ports);
```
@@ -184,19 +184,18 @@ different speeds based on the BOARD_VERSION in [CBI]. For example board version
operation. `I2C_PORT_FLAG_DYNAMIC_SPEED` is not used to change the I2C bus
frequency on the fly depending on the addressed slave device.
-An example of changing the I2C bus frequency from the [Kodama
-board](../../board/kodama/board.c) is shown below.
+An example of changing the I2C bus frequency from the
+[Kodama board](../../board/kodama/board.c) is shown below.
```c
static void board_i2c_init(void)
{
- if (board_get_version() < 2)
- i2c_set_freq(1, I2C_FREQ_100KHZ);
+ if (board_get_version() < 2)
+ i2c_set_freq(1, I2C_FREQ_100KHZ);
}
DECLARE_HOOK(HOOK_INIT, board_i2c_init, HOOK_PRIO_INIT_I2C);
```
-
[config.h]: ../new_board_checklist.md#config_h
[./chip/npcx/registers.h]: ../../chip/npcx/registers.h
[./include/i2c.h]: ../../include/i2c.h
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