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Message-ID: <1b66dbcc-8fa9-5ad4-6f30-a397d0779cb2@grandegger.com>
Date: Mon, 4 Mar 2019 19:29:32 +0100
From: Wolfgang Grandegger <wg@...ndegger.com>
To: Dan Murphy <dmurphy@...com>, mkl@...gutronix.de,
davem@...emloft.net
Cc: linux-can@...r.kernel.org, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 4/4] can: tcan4x5x: Add tcan4x5x driver to the kernel
Hello Dan,
Am 01.03.19 um 19:50 schrieb Dan Murphy:
> Add the TCAN4x5x SPI CAN driver. This device uses the
> Bosch MCAN IP core along with a SPI interface map.
> Register to the MCAN common core code to manage the MCAN IP.
>
> This device has a special method to indicate a write/read
> operation on the data payload.
>
> Signed-off-by: Dan Murphy <dmurphy@...com>
> ---
>
> v6 - Updated Kconfig help and added REGMAP_SPI dependency, fixed coding style issues,
> removed setting GPIO high in wake routine, change -EIO to return ret in init and
> setup functions - https://lore.kernel.org/patchwork/patch/1042443/
>
> drivers/net/can/m_can/Kconfig | 9 +
> drivers/net/can/m_can/Makefile | 1 +
> drivers/net/can/m_can/tcan4x5x.c | 529 +++++++++++++++++++++++++++++++
> 3 files changed, 539 insertions(+)
> create mode 100644 drivers/net/can/m_can/tcan4x5x.c
>
> diff --git a/drivers/net/can/m_can/Kconfig b/drivers/net/can/m_can/Kconfig
> index f7119fd72df4..cf4f32765efa 100644
> --- a/drivers/net/can/m_can/Kconfig
> +++ b/drivers/net/can/m_can/Kconfig
> @@ -12,3 +12,12 @@ config CAN_M_CAN_PLATFORM
> Say Y here if you want support for IO Mapped Bosch M_CAN controller.
> This support is for devices that have the Bosch M_CAN controller
> IP embedded into the device and the IP is IO Mapped to the processor.
> +
> +config CAN_M_CAN_TCAN4X5X
> + depends on CAN_M_CAN
> + depends on REGMAP_SPI
> + tristate "TCAN4X5X M_CAN device"
> + ---help---
> + Say Y here if you want support for Texas Instruments TCAN4x5x
> + M_CAN controller. This device is a peripherial device that uses the
> + SPI bus for communication.
> diff --git a/drivers/net/can/m_can/Makefile b/drivers/net/can/m_can/Makefile
> index 057bbcdb3c74..e77f0eccff97 100644
> --- a/drivers/net/can/m_can/Makefile
> +++ b/drivers/net/can/m_can/Makefile
> @@ -4,3 +4,4 @@
>
> obj-$(CONFIG_CAN_M_CAN) += m_can.o
> obj-$(CONFIG_CAN_M_CAN_PLATFORM) += m_can_platform.o
> +obj-$(CONFIG_CAN_M_CAN_TCAN4X5X) += tcan4x5x.o
> diff --git a/drivers/net/can/m_can/tcan4x5x.c b/drivers/net/can/m_can/tcan4x5x.c
> new file mode 100644
> index 000000000000..a91b976bb522
> --- /dev/null
> +++ b/drivers/net/can/m_can/tcan4x5x.c
> @@ -0,0 +1,529 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// SPI to CAN driver for the Texas Instruments TCAN4x5x
> +// Copyright (C) 2018-19 Texas Instruments Incorporated - http://www.ti.com/
> +
> +#include <linux/regmap.h>
> +#include <linux/spi/spi.h>
> +
> +#include <linux/regulator/consumer.h>
> +#include <linux/gpio/consumer.h>
> +
> +#include "m_can.h"
> +
> +#define DEVICE_NAME "tcan4x5x"
> +#define TCAN4X5X_EXT_CLK_DEF 40000000
> +
> +#define TCAN4X5X_DEV_ID0 0x00
> +#define TCAN4X5X_DEV_ID1 0x04
> +#define TCAN4X5X_REV 0x08
> +#define TCAN4X5X_STATUS 0x0C
> +#define TCAN4X5X_ERROR_STATUS 0x10
> +#define TCAN4X5X_CONTROL 0x14
> +
> +#define TCAN4X5X_CONFIG 0x800
> +#define TCAN4X5X_TS_PRESCALE 0x804
> +#define TCAN4X5X_TEST_REG 0x808
> +#define TCAN4X5X_INT_FLAGS 0x820
> +#define TCAN4X5X_MCAN_INT_REG 0x824
> +#define TCAN4X5X_INT_EN 0x830
> +
> +/* Interrupt bits */
> +#define TCAN4X5X_CANBUSTERMOPEN_INT_EN BIT(30)
> +#define TCAN4X5X_CANHCANL_INT_EN BIT(29)
> +#define TCAN4X5X_CANHBAT_INT_EN BIT(28)
> +#define TCAN4X5X_CANLGND_INT_EN BIT(27)
> +#define TCAN4X5X_CANBUSOPEN_INT_EN BIT(26)
> +#define TCAN4X5X_CANBUSGND_INT_EN BIT(25)
> +#define TCAN4X5X_CANBUSBAT_INT_EN BIT(24)
> +#define TCAN4X5X_UVSUP_INT_EN BIT(22)
> +#define TCAN4X5X_UVIO_INT_EN BIT(21)
> +#define TCAN4X5X_TSD_INT_EN BIT(19)
> +#define TCAN4X5X_ECCERR_INT_EN BIT(16)
> +#define TCAN4X5X_CANINT_INT_EN BIT(15)
> +#define TCAN4X5X_LWU_INT_EN BIT(14)
> +#define TCAN4X5X_CANSLNT_INT_EN BIT(10)
> +#define TCAN4X5X_CANDOM_INT_EN BIT(8)
> +#define TCAN4X5X_CANBUS_ERR_INT_EN BIT(5)
> +#define TCAN4X5X_BUS_FAULT BIT(4)
> +#define TCAN4X5X_MCAN_INT BIT(1)
> +#define TCAN4X5X_ENABLE_TCAN_INT (TCAN4X5X_MCAN_INT | \
> + TCAN4X5X_BUS_FAULT | \
> + TCAN4X5X_CANBUS_ERR_INT_EN | \
> + TCAN4X5X_CANINT_INT_EN)
> +
> +/* MCAN Interrupt bits */
> +#define TCAN4X5X_MCAN_IR_ARA BIT(29)
> +#define TCAN4X5X_MCAN_IR_PED BIT(28)
> +#define TCAN4X5X_MCAN_IR_PEA BIT(27)
> +#define TCAN4X5X_MCAN_IR_WD BIT(26)
> +#define TCAN4X5X_MCAN_IR_BO BIT(25)
> +#define TCAN4X5X_MCAN_IR_EW BIT(24)
> +#define TCAN4X5X_MCAN_IR_EP BIT(23)
> +#define TCAN4X5X_MCAN_IR_ELO BIT(22)
> +#define TCAN4X5X_MCAN_IR_BEU BIT(21)
> +#define TCAN4X5X_MCAN_IR_BEC BIT(20)
> +#define TCAN4X5X_MCAN_IR_DRX BIT(19)
> +#define TCAN4X5X_MCAN_IR_TOO BIT(18)
> +#define TCAN4X5X_MCAN_IR_MRAF BIT(17)
> +#define TCAN4X5X_MCAN_IR_TSW BIT(16)
> +#define TCAN4X5X_MCAN_IR_TEFL BIT(15)
> +#define TCAN4X5X_MCAN_IR_TEFF BIT(14)
> +#define TCAN4X5X_MCAN_IR_TEFW BIT(13)
> +#define TCAN4X5X_MCAN_IR_TEFN BIT(12)
> +#define TCAN4X5X_MCAN_IR_TFE BIT(11)
> +#define TCAN4X5X_MCAN_IR_TCF BIT(10)
> +#define TCAN4X5X_MCAN_IR_TC BIT(9)
> +#define TCAN4X5X_MCAN_IR_HPM BIT(8)
> +#define TCAN4X5X_MCAN_IR_RF1L BIT(7)
> +#define TCAN4X5X_MCAN_IR_RF1F BIT(6)
> +#define TCAN4X5X_MCAN_IR_RF1W BIT(5)
> +#define TCAN4X5X_MCAN_IR_RF1N BIT(4)
> +#define TCAN4X5X_MCAN_IR_RF0L BIT(3)
> +#define TCAN4X5X_MCAN_IR_RF0F BIT(2)
> +#define TCAN4X5X_MCAN_IR_RF0W BIT(1)
> +#define TCAN4X5X_MCAN_IR_RF0N BIT(0)
> +#define TCAN4X5X_ENABLE_MCAN_INT (TCAN4X5X_MCAN_IR_TC | \
> + TCAN4X5X_MCAN_IR_RF0N | \
> + TCAN4X5X_MCAN_IR_RF1N | \
> + TCAN4X5X_MCAN_IR_RF0F | \
> + TCAN4X5X_MCAN_IR_RF1F)
> +#define TCAN4X5X_MRAM_START 0x8000
> +#define TCAN4X5X_MCAN_OFFSET 0x1000
> +#define TCAN4X5X_MAX_REGISTER 0x8fff
> +
> +#define TCAN4X5X_CLEAR_ALL_INT 0xffffffff
> +#define TCAN4X5X_SET_ALL_INT 0xffffffff
> +
> +#define TCAN4X5X_WRITE_CMD (0x61 << 24)
> +#define TCAN4X5X_READ_CMD (0x41 << 24)
> +
> +#define TCAN4X5X_MODE_SEL_MASK (BIT(7) | BIT(6))
> +#define TCAN4X5X_MODE_SLEEP 0x00
> +#define TCAN4X5X_MODE_STANDBY BIT(6)
> +#define TCAN4X5X_MODE_NORMAL BIT(7)
> +
> +#define TCAN4X5X_SW_RESET BIT(2)
> +
> +#define TCAN4X5X_MCAN_CONFIGURED BIT(5)
> +#define TCAN4X5X_WATCHDOG_EN BIT(3)
> +#define TCAN4X5X_WD_60_MS_TIMER 0
> +#define TCAN4X5X_WD_600_MS_TIMER BIT(28)
> +#define TCAN4X5X_WD_3_S_TIMER BIT(29)
> +#define TCAN4X5X_WD_6_S_TIMER (BIT(28) | BIT(29))
> +
> +struct tcan4x5x_priv {
> + struct regmap *regmap;
> + struct spi_device *spi;
> + struct mutex tcan4x5x_lock; /* SPI device lock */
> +
> + struct m_can_classdev *mcan_dev;
> +
> + struct gpio_desc *reset_gpio;
> + struct gpio_desc *interrupt_gpio;
> + struct gpio_desc *device_wake_gpio;
> + struct gpio_desc *device_state_gpio;
> + struct regulator *power;
> +
> + /* Register based ip */
> + int mram_start;
> + int reg_offset;
> +};
> +
> +static struct can_bittiming_const tcan4x5x_bittiming_const = {
> + .name = DEVICE_NAME,
> + .tseg1_min = 2,
> + .tseg1_max = 31,
> + .tseg2_min = 2,
> + .tseg2_max = 16,
> + .sjw_max = 16,
> + .brp_min = 1,
> + .brp_max = 32,
> + .brp_inc = 1,
> +};
> +
> +static struct can_bittiming_const tcan4x5x_data_bittiming_const = {
> + .name = DEVICE_NAME,
> + .tseg1_min = 1,
> + .tseg1_max = 32,
> + .tseg2_min = 1,
> + .tseg2_max = 16,
> + .sjw_max = 16,
> + .brp_min = 1,
> + .brp_max = 32,
> + .brp_inc = 1,
> +};
> +
> +static void tcan4x5x_check_wake(struct tcan4x5x_priv *priv)
> +{
> + int wake_state = 0;
> +
> + if (priv->device_state_gpio)
> + wake_state = gpiod_get_value(priv->device_state_gpio);
> +
> + if (priv->device_wake_gpio && wake_state) {
> + gpiod_set_value(priv->device_wake_gpio, 0);
> + usleep_range(5, 50);
> + gpiod_set_value(priv->device_wake_gpio, 1);
> + }
> +}
> +
> +static int regmap_spi_gather_write(void *context, const void *reg,
> + size_t reg_len, const void *val,
> + size_t val_len)
> +{
> + struct device *dev = context;
> + struct spi_device *spi = to_spi_device(dev);
> + struct spi_message m;
> + u32 addr;
> + struct spi_transfer t[2] = {
> + { .tx_buf = &addr, .len = reg_len, .cs_change = 0,},
> + { .tx_buf = val, .len = val_len, },
> + };
> +
> + addr = TCAN4X5X_WRITE_CMD | (*((u16 *)reg) << 8) | val_len >> 3;
> +
> + spi_message_init(&m);
> + spi_message_add_tail(&t[0], &m);
> + spi_message_add_tail(&t[1], &m);
> +
> + return spi_sync(spi, &m);
> +}
> +
> +static int tcan4x5x_regmap_write(void *context, const void *data, size_t count)
> +{
> + u16 *reg = (u16 *)(data);
> + const u32 *val = data + 4;
> +
> + return regmap_spi_gather_write(context, reg, 4, val, count);
> +}
> +
> +static int regmap_spi_async_write(void *context,
> + const void *reg, size_t reg_len,
> + const void *val, size_t val_len,
> + struct regmap_async *a)
> +{
> + return -ENOTSUPP;
> +}
> +
> +static struct regmap_async *regmap_spi_async_alloc(void)
> +{
> + return NULL;
> +}
> +
> +static int tcan4x5x_regmap_read(void *context,
> + const void *reg, size_t reg_size,
> + void *val, size_t val_size)
> +{
> + struct device *dev = context;
> + struct spi_device *spi = to_spi_device(dev);
> +
> + u32 addr = TCAN4X5X_READ_CMD | (*((u16 *)reg) << 8) | val_size >> 2;
> +
> + return spi_write_then_read(spi, &addr, reg_size, (u32 *)val, val_size);
> +}
> +
> +static struct regmap_bus tcan4x5x_bus = {
> + .write = tcan4x5x_regmap_write,
> + .gather_write = regmap_spi_gather_write,
> + .async_write = regmap_spi_async_write,
> + .async_alloc = regmap_spi_async_alloc,
> + .read = tcan4x5x_regmap_read,
> + .read_flag_mask = 0x00,
> + .reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
> + .val_format_endian_default = REGMAP_ENDIAN_NATIVE,
> +};
> +
> +static u32 tcan4x5x_read_reg(struct m_can_classdev *m_can_class, int reg)
> +{
> + struct tcan4x5x_priv *priv = (struct tcan4x5x_priv *)m_can_class->device_data;
> + u32 val;
> +
> + tcan4x5x_check_wake(priv);
> +
> + regmap_read(priv->regmap, priv->reg_offset + reg, &val);
> +
> + return val;
> +}
> +
> +static u32 tcan4x5x_read_fifo(struct m_can_classdev *m_can_class,
> + int addr_offset)
> +{
> + struct tcan4x5x_priv *priv = (struct tcan4x5x_priv *)m_can_class->device_data;
> + u32 val;
> +
> + tcan4x5x_check_wake(priv);
> +
> + regmap_read(priv->regmap, priv->mram_start + addr_offset, &val);
> +
> + return val;
> +}
> +
> +static int tcan4x5x_write_reg(struct m_can_classdev *m_can_class,
> + int reg, int val)
> +{
> + struct tcan4x5x_priv *priv = (struct tcan4x5x_priv *)m_can_class->device_data;
> +
> + tcan4x5x_check_wake(priv);
> +
> + return regmap_write(priv->regmap, priv->reg_offset + reg, val);
> +}
> +
> +static int tcan4x5x_write_fifo(struct m_can_classdev *m_can_class,
> + int addr_offset, int val)
> +{
> + struct tcan4x5x_priv *priv = (struct tcan4x5x_priv *)m_can_class->device_data;
> +
> + tcan4x5x_check_wake(priv);
> +
> + return regmap_write(priv->regmap, priv->mram_start + addr_offset, val);
> +}
> +
> +static int tcan4x5x_power_enable(struct regulator *reg, int enable)
> +{
> + if (IS_ERR_OR_NULL(reg))
> + return 0;
> +
> + if (enable)
> + return regulator_enable(reg);
> + else
> + return regulator_disable(reg);
> +}
> +
> +static int tcan4x5x_write_tcan_reg(struct m_can_classdev *m_can_class,
> + int reg, int val)
> +{
> + struct tcan4x5x_priv *priv = (struct tcan4x5x_priv *)m_can_class->device_data;
> +
> + tcan4x5x_check_wake(priv);
> +
> + return regmap_write(priv->regmap, reg, val);
> +}
> +
> +static int tcan4x5x_clear_interrupts(struct m_can_classdev *class_dev)
> +{
> + struct tcan4x5x_priv *tcan4x5x = (struct tcan4x5x_priv *)class_dev->device_data;
> + int ret;
> +
> + tcan4x5x_check_wake(tcan4x5x);
> +
> + ret = tcan4x5x_write_tcan_reg(class_dev, TCAN4X5X_STATUS,
> + TCAN4X5X_CLEAR_ALL_INT);
> + if (ret)
> + return ret;
> +
> + ret = tcan4x5x_write_tcan_reg(class_dev, TCAN4X5X_MCAN_INT_REG,
> + TCAN4X5X_ENABLE_MCAN_INT);
> + if (ret)
> + return ret;
> +
> + ret = tcan4x5x_write_tcan_reg(class_dev, TCAN4X5X_INT_FLAGS,
> + TCAN4X5X_CLEAR_ALL_INT);
> + if (ret)
> + return ret;
> +
> + ret = tcan4x5x_write_tcan_reg(class_dev, TCAN4X5X_ERROR_STATUS,
> + TCAN4X5X_CLEAR_ALL_INT);
> + if (ret)
> + return ret;
> +
> + return ret;
> +}
Hm, handling the interrupt seems to be a quite heavy operation. How does
the device and system digest small messages (dlc=0) coming in at a very
high rate?
Any chance to optimize accesses be reading more than on word?
Wolfgang.
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