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drivers: can: esp32_twai: add support for newer MCUs

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Newer ESP32 series MCUs like the ESP32-C3 contain some register changes
incompatible to the original ESP32 and the SJA1000.

The additions in this commit consider these changes and fix the
incompatibilities in the TWAI front-end for the SJA1000 driver.

Signed-off-by: Martin Jäger <martin@libre.solar>
This commit is contained in:
Martin Jäger 2022-10-06 13:46:54 +02:00 committed by Carles Cufí
parent 9326d113a2
commit 2a035f775b
2 changed files with 167 additions and 12 deletions
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167
drivers/can/can_esp32_twai.c
View file

@ -1,5 +1,6 @@
/*
* Copyright (c) 2022 Henrik Brix Andersen <henrik@brixandersen.dk>
* Copyright (c) 2022 Martin Jäger <martin@libre.solar>
*
* SPDX-License-Identifier: Apache-2.0
*/
@ -18,12 +19,62 @@
LOG_MODULE_REGISTER(can_esp32_twai, CONFIG_CAN_LOG_LEVEL);
/*
* Newer ESP32-series MCUs like ESP32-C3 and ESP32-S2 have some slightly different registers
* compared to the original ESP32, which is fully compatible with the SJA1000 controller.
*
* The names with TWAI_ prefixes from Espressif reference manuals are used for these incompatible
* registers.
*/
#ifndef CONFIG_SOC_ESP32
/* TWAI_BUS_TIMING_0_REG is incompatible with CAN_SJA1000_BTR0 */
#define TWAI_BUS_TIMING_0_REG (6U)
#define TWAI_BAUD_PRESC_MASK GENMASK(12, 0)
#define TWAI_SYNC_JUMP_WIDTH_MASK GENMASK(15, 14)
#define TWAI_BAUD_PRESC_PREP(brp) FIELD_PREP(TWAI_BAUD_PRESC_MASK, brp)
#define TWAI_SYNC_JUMP_WIDTH_PREP(sjw) FIELD_PREP(TWAI_SYNC_JUMP_WIDTH_MASK, sjw)
/*
* TWAI_BUS_TIMING_1_REG is compatible with CAN_SJA1000_BTR1, but needed here for the custom
* set_timing() function.
*/
#define TWAI_BUS_TIMING_1_REG (7U)
#define TWAI_TIME_SEG1_MASK GENMASK(3, 0)
#define TWAI_TIME_SEG2_MASK GENMASK(6, 4)
#define TWAI_TIME_SAMP BIT(7)
#define TWAI_TIME_SEG1_PREP(seg1) FIELD_PREP(TWAI_TIME_SEG1_MASK, seg1)
#define TWAI_TIME_SEG2_PREP(seg2) FIELD_PREP(TWAI_TIME_SEG2_MASK, seg2)
/* TWAI_CLOCK_DIVIDER_REG is incompatible with CAN_SJA1000_CDR */
#define TWAI_CLOCK_DIVIDER_REG (31U)
#define TWAI_CD_MASK GENMASK(7, 0)
#define TWAI_CLOCK_OFF BIT(8)
/*
* Further incompatible registers currently not used by the driver:
* - TWAI_STATUS_REG has new bit 8: TWAI_MISS_ST
* - TWAI_INT_RAW_REG has new bit 8: TWAI_BUS_STATE_INT_ST
* - TWAI_INT_ENA_REG has new bit 8: TWAI_BUS_STATE_INT_ENA
*/
#else
/* Redefinitions of the SJA1000 CDR bits to simplify driver config */
#define TWAI_CD_MASK GENMASK(2, 0)
#define TWAI_CLOCK_OFF BIT(3)
#endif /* !CONFIG_SOC_ESP32 */
struct can_esp32_twai_config {
mm_reg_t base;
const struct pinctrl_dev_config *pcfg;
const struct device *clock_dev;
const clock_control_subsys_t clock_subsys;
int irq_source;
#ifndef CONFIG_SOC_ESP32
/* 32-bit variant of output clock divider register required for non-ESP32 MCUs */
uint32_t cdr32;
#endif /* !CONFIG_SOC_ESP32 */
};
static uint8_t can_esp32_twai_read_reg(const struct device *dev, uint8_t reg)
@ -44,6 +95,70 @@ static void can_esp32_twai_write_reg(const struct device *dev, uint8_t reg, uint
sys_write32(val & 0xFF, addr);
}
#ifndef CONFIG_SOC_ESP32
/*
* Required for newer ESP32-series MCUs which violate the original SJA1000 8-bit register size.
*/
static void can_esp32_twai_write_reg32(const struct device *dev, uint8_t reg, uint32_t val)
{
const struct can_sja1000_config *sja1000_config = dev->config;
const struct can_esp32_twai_config *twai_config = sja1000_config->custom;
mm_reg_t addr = twai_config->base + reg * sizeof(uint32_t);
sys_write32(val, addr);
}
/*
* Custom implementation instead of can_sja1000_set_timing required because TWAI_BUS_TIMING_0_REG
* is incompatible with CAN_SJA1000_BTR0.
*/
static int can_esp32_twai_set_timing(const struct device *dev, const struct can_timing *timing)
{
struct can_sja1000_data *data = dev->data;
uint8_t btr0;
uint8_t btr1;
uint8_t sjw;
__ASSERT_NO_MSG(timing->sjw == CAN_SJW_NO_CHANGE ||
(timing->sjw >= 0x1 && timing->sjw <= 0x4));
__ASSERT_NO_MSG(timing->prop_seg == 0);
__ASSERT_NO_MSG(timing->phase_seg1 >= 0x1 && timing->phase_seg1 <= 0x10);
__ASSERT_NO_MSG(timing->phase_seg2 >= 0x1 && timing->phase_seg2 <= 0x8);
__ASSERT_NO_MSG(timing->prescaler >= 0x1 && timing->prescaler <= 0x2000);
if (data->started) {
return -EBUSY;
}
k_mutex_lock(&data->mod_lock, K_FOREVER);
if (timing->sjw == CAN_SJW_NO_CHANGE) {
sjw = data->sjw;
} else {
sjw = timing->sjw;
data->sjw = timing->sjw;
}
btr0 = TWAI_BAUD_PRESC_PREP(timing->prescaler - 1) |
TWAI_SYNC_JUMP_WIDTH_PREP(sjw - 1);
btr1 = TWAI_TIME_SEG1_PREP(timing->phase_seg1 - 1) |
TWAI_TIME_SEG2_PREP(timing->phase_seg2 - 1);
if ((data->mode & CAN_MODE_3_SAMPLES) != 0) {
btr1 |= TWAI_TIME_SAMP;
}
can_esp32_twai_write_reg32(dev, TWAI_BUS_TIMING_0_REG, btr0);
can_esp32_twai_write_reg32(dev, TWAI_BUS_TIMING_1_REG, btr1);
k_mutex_unlock(&data->mod_lock);
return 0;
}
#endif /* !CONFIG_SOC_ESP32 */
static int can_esp32_twai_get_core_clock(const struct device *dev, uint32_t *rate)
{
ARG_UNUSED(dev);
@ -90,6 +205,18 @@ static int can_esp32_twai_init(const struct device *dev)
return err;
}
#ifndef CONFIG_SOC_ESP32
/*
* TWAI_CLOCK_DIVIDER_REG is incompatible with CAN_SJA1000_CDR for non-ESP32 MCUs
* - TWAI_CD has length of 8 bits instead of 3 bits
* - TWAI_CLOCK_OFF at BIT(8) instead of BIT(3)
* - TWAI_EXT_MODE bit missing (always "extended" = PeliCAN mode)
*
* Overwrite with 32-bit register variant configured via devicetree.
*/
can_esp32_twai_write_reg32(dev, TWAI_CLOCK_DIVIDER_REG, twai_config->cdr32);
#endif /* !CONFIG_SOC_ESP32 */
esp_intr_alloc(twai_config->irq_source, 0, can_esp32_twai_isr, (void *)dev, NULL);
return 0;
@ -100,7 +227,11 @@ const struct can_driver_api can_esp32_twai_driver_api = {
.start = can_sja1000_start,
.stop = can_sja1000_stop,
.set_mode = can_sja1000_set_mode,
#ifdef CONFIG_SOC_ESP32
.set_timing = can_sja1000_set_timing,
#else
.set_timing = can_esp32_twai_set_timing,
#endif /* CONFIG_SOC_ESP32 */
.send = can_sja1000_send,
.add_rx_filter = can_sja1000_add_rx_filter,
.remove_rx_filter = can_sja1000_remove_rx_filter,
@ -113,13 +244,40 @@ const struct can_driver_api can_esp32_twai_driver_api = {
.recover = can_sja1000_recover,
#endif /* !CONFIG_CAN_AUTO_BUS_OFF_RECOVERY */
.timing_min = CAN_SJA1000_TIMING_MIN_INITIALIZER,
#ifdef CONFIG_SOC_ESP32
.timing_max = CAN_SJA1000_TIMING_MAX_INITIALIZER,
#else
/* larger prescaler allowed for newer ESP32-series MCUs */
.timing_max = {
.sjw = 0x4,
.prop_seg = 0x0,
.phase_seg1 = 0x10,
.phase_seg2 = 0x8,
.prescaler = 0x2000,
}
#endif /* CONFIG_SOC_ESP32 */
};
#ifdef CONFIG_SOC_ESP32
#define TWAI_CLKOUT_DIVIDER_MAX (14)
#define TWAI_CDR32_INIT(inst)
#else
#define TWAI_CLKOUT_DIVIDER_MAX (490)
#define TWAI_CDR32_INIT(inst) .cdr32 = CAN_ESP32_TWAI_DT_CDR_INST_GET(inst)
#endif /* CONFIG_SOC_ESP32 */
#define CAN_ESP32_TWAI_ASSERT_CLKOUT_DIVIDER(inst) \
BUILD_ASSERT(COND_CODE_0(DT_INST_NODE_HAS_PROP(inst, clkout_divider), (1), \
(DT_INST_PROP(inst, clkout_divider) == 1 || \
(DT_INST_PROP(inst, clkout_divider) % 2 == 0 && \
DT_INST_PROP(inst, clkout_divider) / 2 <= TWAI_CLKOUT_DIVIDER_MAX))), \
"TWAI clkout-divider from dts invalid")
#define CAN_ESP32_TWAI_DT_CDR_INST_GET(inst) \
COND_CODE_1(DT_INST_NODE_HAS_PROP(inst, clkout_divider), \
(UTIL_CAT(CAN_SJA1000_CDR_CD_DIV, DT_INST_PROP(inst, clkout_divider))), \
(CAN_SJA1000_CDR_CLOCK_OFF))
COND_CODE_1(DT_INST_PROP(inst, clkout_divider) == 1, (TWAI_CD_MASK), \
((DT_INST_PROP(inst, clkout_divider)) / 2 - 1)), \
(TWAI_CLOCK_OFF))
#define CAN_ESP32_TWAI_INIT(inst) \
PINCTRL_DT_INST_DEFINE(inst); \
@ -130,12 +288,15 @@ const struct can_driver_api can_esp32_twai_driver_api = {
.clock_subsys = (clock_control_subsys_t)DT_INST_CLOCKS_CELL(inst, offset), \
.pcfg = PINCTRL_DT_INST_DEV_CONFIG_GET(inst), \
.irq_source = DT_INST_IRQN(inst), \
TWAI_CDR32_INIT(inst) \
}; \
CAN_ESP32_TWAI_ASSERT_CLKOUT_DIVIDER(inst); \
static const struct can_sja1000_config can_sja1000_config_##inst = \
CAN_SJA1000_DT_CONFIG_INST_GET(inst, &can_esp32_twai_config_##inst, \
can_esp32_twai_read_reg, can_esp32_twai_write_reg, \
CAN_SJA1000_OCR_OCMODE_BIPHASE, \
CAN_ESP32_TWAI_DT_CDR_INST_GET(inst)); \
COND_CODE_0(IS_ENABLED(CONFIG_SOC_ESP32), (0), \
(CAN_ESP32_TWAI_DT_CDR_INST_GET(inst)))); \
\
static struct can_sja1000_data can_sja1000_data_##inst = \
CAN_SJA1000_DATA_INITIALIZER(NULL); \

12
dts/bindings/can/espressif,esp32-twai.yaml
View file

@ -26,14 +26,8 @@ properties:
clkout-divider:
type: int
required: false
enum:
- 1
- 2
- 4
- 6
- 8
- 10
- 12
- 14
description: |
Clock divider for the CLKOUT signal. If not set, the CLKOUT signal is turned off.
Valid values are 1 or any even number from 2 to 14 for ESP32 and 2 to 490 for newer
Espressif MCUs like ESP32-C3.