目录
背景：
1.内核驱动模块配置
2.设备树配置
3.功能测试
4.bug修复
背景：
某个项目上使用RK3568的芯片，需要用到4路CAN接口进行通信，经过方案评审后决定使用RK3568自带的3路CAN外加一路spi转的CAN实现功能，在这个平台上进行CAN驱动的适配和测试。
1.内核驱动模块配置
根据官方sdk提供的驱动适配手册，芯片自带的CAN接口驱动文件在：
drivers/net/can/rockchip/rockchip_can.c
drivers/net/can/rockchip/rockchip_canfd.c
drivers/net/can/spi/mcp251x.c要启用该驱动，需要在SDK中配置使能内核的驱动模块。
需要注意的是，在make menuconfig配置使能后生成的config文件，在执行编译时会被默认配置刷掉，所以最终需要将配置同步到
kernel/arch/arm64/configs/rockchip_linux_defconfig2.设备树配置
根据官方指导手册配置CAN接口设备树rk3568-evb.dtsi
&can1 {assigned-clocks = <&cru CLK_CAN0>;assigned-clock-rates = <200000000>;pinctrl-names = "default";pinctrl-0 = <&can0m0_pins>;status = "disabled";
};&can0 {assigned-clocks = <&cru CLK_CAN1>;assigned-clock-rates = <200000000>;pinctrl-names = "default";pinctrl-0 = <&can1m1_pins>;status = "disabled";
};&can2 {assigned-clocks = <&cru CLK_CAN2>;assigned-clock-rates = <200000000>;pinctrl-names = "default";pinctrl-0 = <&can2m0_pins>;status = "disabled";
};由于我试用的设备树参照开发板模板，所以按照修改rk3568-evb1-ddr4-v10.dtsi修改修改添加CAN使能以及spi转CAN的mcp251x的设备树：
/ {mcp2515_reset: mcp2515_reset {label = "mcp2515_reset:ctrl";linux,default-trigger = "ir-power-click";default-state = "on";gpios = <&gpio3 RK_PA1 GPIO_ACTIVE_HIGH>;pinctrl-names = "default";pinctrl-0 = <&mcp2515_reset_pins>;};mcp251x_clk: mcp251x-clk {compatible = "fixed-clock";#clock-cells = <0>;clock-frequency = <16000000>; //根据MCP2515模块的硬件晶振设置 8MHz or 16MHz};};&can0 {status = "okay";//compatible = "rockchip,canfd-1.0";//compatible = "rockchip,can-2.0";compatible = "rockchip,rk3568-can-2.0";
};&can1 {status = "okay";//compatible = "rockchip,canfd-1.0";//compatible = "rockchip,can-2.0";compatible = "rockchip,rk3568-can-2.0";
};&can2 {status = "okay";//compatible = "rockchip,canfd-1.0";//compatible = "rockchip,can-2.0";compatible = "rockchip,rk3568-can-2.0";
};&spi2 {status = "okay";max-freq = <48000000>;dev-port = <0>;pinctrl-0 = <&spi2m1_pins &spi2m1_cs0>;
// pinctrl-1 = <&spi1m1_pins_hs &spi1m1_cs0_hs>;
// dma-names = "tx","rx";mcp2515: can@00 {status = "okay";compatible = "microchip,mcp2515";reg = <0x00>;clocks = <&mcp251x_clk>;interrupt-parent = <&gpio3>;interrupts = <RK_PB5 IRQ_TYPE_EDGE_FALLING>;//spi-max-frequency = <10000000>; //<1000000>; //<24000000>;pinctrl-names = "default";pinctrl-0 = <&mcp2515_irq1_pins>;poll_mode = <0>;enable_dma = <1>;//vdd-supply = <&mcp251x_vcc>;vdd-supply = <&vcc_3v3>;xceiver-supply = <&vcc_3v3>;};
};&pinctrl {mcp2515 {mcp2515_vcc3v3_en: mcp2515-vcc3v3-en {rockchip,pins = <0 RK_PC7 RK_FUNC_GPIO &pcfg_pull_none>;};mcp2515_irq1_pins: mcp2515-irq1-pins {rockchip,pins = <3 RK_PB5 RK_FUNC_GPIO &pcfg_pull_none>;};mcp2515_reset_pins: mcp2515-reset-pins {rockchip,pins = <3 RK_PA1 RK_FUNC_GPIO &pcfg_pull_none>;};};
};需要注意的是，mcp251x的驱动在官方的sdk中是没有包含的，需要自己添加一直，在调试过程中需要特别注意spi转CAN的芯片的IRQ中断配置，收发都会用到该中断引脚。驱动代码如下：
// SPDX-License-Identifier: GPL-2.0-only
/* CAN bus driver for Microchip 251x/25625 CAN Controller with SPI Interface** MCP2510 support and bug fixes by Christian Pellegrin* <chripell@evolware.org>** Copyright 2009 Christian Pellegrin EVOL S.r.l.** Copyright 2007 Raymarine UK, Ltd. All Rights Reserved.* Written under contract by:* Chris Elston, Katalix Systems, Ltd.** Based on Microchip MCP251x CAN controller driver written by* David Vrabel, Copyright 2006 Arcom Control Systems Ltd.** Based on CAN bus driver for the CCAN controller written by* - Sascha Hauer, Marc Kleine-Budde, Pengutronix* - Simon Kallweit, intefo AG* Copyright 2007*/#include <linux/bitfield.h>
#include <linux/can/core.h>
#include <linux/can/dev.h>
#include <linux/can/led.h>
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/freezer.h>
#include <linux/gpio.h>
#include <linux/gpio/driver.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/uaccess.h>/* SPI interface instruction set */
#define INSTRUCTION_WRITE 0x02
#define INSTRUCTION_READ 0x03
#define INSTRUCTION_BIT_MODIFY 0x05
#define INSTRUCTION_LOAD_TXB(n) (0x40 + 2 * (n))
#define INSTRUCTION_READ_RXB(n) (((n) == 0) ? 0x90 : 0x94)
#define INSTRUCTION_RESET 0xC0
#define RTS_TXB0 0x01
#define RTS_TXB1 0x02
#define RTS_TXB2 0x04
#define INSTRUCTION_RTS(n) (0x80 | ((n) & 0x07))/* MPC251x registers */
#define BFPCTRL 0x0c
# define BFPCTRL_B0BFM BIT(0)
# define BFPCTRL_B1BFM BIT(1)
# define BFPCTRL_BFM(n) (BFPCTRL_B0BFM << (n))
# define BFPCTRL_BFM_MASK GENMASK(1, 0)
# define BFPCTRL_B0BFE BIT(2)
# define BFPCTRL_B1BFE BIT(3)
# define BFPCTRL_BFE(n) (BFPCTRL_B0BFE << (n))
# define BFPCTRL_BFE_MASK GENMASK(3, 2)
# define BFPCTRL_B0BFS BIT(4)
# define BFPCTRL_B1BFS BIT(5)
# define BFPCTRL_BFS(n) (BFPCTRL_B0BFS << (n))
# define BFPCTRL_BFS_MASK GENMASK(5, 4)
#define TXRTSCTRL 0x0d
# define TXRTSCTRL_B0RTSM BIT(0)
# define TXRTSCTRL_B1RTSM BIT(1)
# define TXRTSCTRL_B2RTSM BIT(2)
# define TXRTSCTRL_RTSM(n) (TXRTSCTRL_B0RTSM << (n))
# define TXRTSCTRL_RTSM_MASK GENMASK(2, 0)
# define TXRTSCTRL_B0RTS BIT(3)
# define TXRTSCTRL_B1RTS BIT(4)
# define TXRTSCTRL_B2RTS BIT(5)
# define TXRTSCTRL_RTS(n) (TXRTSCTRL_B0RTS << (n))
# define TXRTSCTRL_RTS_MASK GENMASK(5, 3)
#define CANSTAT 0x0e
#define CANCTRL 0x0f
# define CANCTRL_REQOP_MASK 0xe0
# define CANCTRL_REQOP_CONF 0x80
# define CANCTRL_REQOP_LISTEN_ONLY 0x60
# define CANCTRL_REQOP_LOOPBACK 0x40
# define CANCTRL_REQOP_SLEEP 0x20
# define CANCTRL_REQOP_NORMAL 0x00
# define CANCTRL_OSM 0x08
# define CANCTRL_ABAT 0x10
#define TEC 0x1c
#define REC 0x1d
#define CNF1 0x2a
# define CNF1_SJW_SHIFT 6
#define CNF2 0x29
# define CNF2_BTLMODE 0x80
# define CNF2_SAM 0x40
# define CNF2_PS1_SHIFT 3
#define CNF3 0x28
# define CNF3_SOF 0x08
# define CNF3_WAKFIL 0x04
# define CNF3_PHSEG2_MASK 0x07
#define CANINTE 0x2b
# define CANINTE_MERRE 0x80
# define CANINTE_WAKIE 0x40
# define CANINTE_ERRIE 0x20
# define CANINTE_TX2IE 0x10
# define CANINTE_TX1IE 0x08
# define CANINTE_TX0IE 0x04
# define CANINTE_RX1IE 0x02
# define CANINTE_RX0IE 0x01
#define CANINTF 0x2c
# define CANINTF_MERRF 0x80
# define CANINTF_WAKIF 0x40
# define CANINTF_ERRIF 0x20
# define CANINTF_TX2IF 0x10
# define CANINTF_TX1IF 0x08
# define CANINTF_TX0IF 0x04
# define CANINTF_RX1IF 0x02
# define CANINTF_RX0IF 0x01
# define CANINTF_RX (CANINTF_RX0IF | CANINTF_RX1IF)
# define CANINTF_TX (CANINTF_TX2IF | CANINTF_TX1IF | CANINTF_TX0IF)
# define CANINTF_ERR (CANINTF_ERRIF)
#define EFLG 0x2d
# define EFLG_EWARN 0x01
# define EFLG_RXWAR 0x02
# define EFLG_TXWAR 0x04
# define EFLG_RXEP 0x08
# define EFLG_TXEP 0x10
# define EFLG_TXBO 0x20
# define EFLG_RX0OVR 0x40
# define EFLG_RX1OVR 0x80
#define TXBCTRL(n) (((n) * 0x10) + 0x30 + TXBCTRL_OFF)
# define TXBCTRL_ABTF 0x40
# define TXBCTRL_MLOA 0x20
# define TXBCTRL_TXERR 0x10
# define TXBCTRL_TXREQ 0x08
#define TXBSIDH(n) (((n) * 0x10) + 0x30 + TXBSIDH_OFF)
# define SIDH_SHIFT 3
#define TXBSIDL(n) (((n) * 0x10) + 0x30 + TXBSIDL_OFF)
# define SIDL_SID_MASK 7
# define SIDL_SID_SHIFT 5
# define SIDL_EXIDE_SHIFT 3
# define SIDL_EID_SHIFT 16
# define SIDL_EID_MASK 3
#define TXBEID8(n) (((n) * 0x10) + 0x30 + TXBEID8_OFF)
#define TXBEID0(n) (((n) * 0x10) + 0x30 + TXBEID0_OFF)
#define TXBDLC(n) (((n) * 0x10) + 0x30 + TXBDLC_OFF)
# define DLC_RTR_SHIFT 6
#define TXBCTRL_OFF 0
#define TXBSIDH_OFF 1
#define TXBSIDL_OFF 2
#define TXBEID8_OFF 3
#define TXBEID0_OFF 4
#define TXBDLC_OFF 5
#define TXBDAT_OFF 6
#define RXBCTRL(n) (((n) * 0x10) + 0x60 + RXBCTRL_OFF)
# define RXBCTRL_BUKT 0x04
# define RXBCTRL_RXM0 0x20
# define RXBCTRL_RXM1 0x40
#define RXBSIDH(n) (((n) * 0x10) + 0x60 + RXBSIDH_OFF)
# define RXBSIDH_SHIFT 3
#define RXBSIDL(n) (((n) * 0x10) + 0x60 + RXBSIDL_OFF)
# define RXBSIDL_IDE 0x08
# define RXBSIDL_SRR 0x10
# define RXBSIDL_EID 3
# define RXBSIDL_SHIFT 5
#define RXBEID8(n) (((n) * 0x10) + 0x60 + RXBEID8_OFF)
#define RXBEID0(n) (((n) * 0x10) + 0x60 + RXBEID0_OFF)
#define RXBDLC(n) (((n) * 0x10) + 0x60 + RXBDLC_OFF)
# define RXBDLC_LEN_MASK 0x0f
# define RXBDLC_RTR 0x40
#define RXBCTRL_OFF 0
#define RXBSIDH_OFF 1
#define RXBSIDL_OFF 2
#define RXBEID8_OFF 3
#define RXBEID0_OFF 4
#define RXBDLC_OFF 5
#define RXBDAT_OFF 6
#define RXFSID(n) ((n < 3) ? 0 : 4)
#define RXFSIDH(n) ((n) * 4 + RXFSID(n))
#define RXFSIDL(n) ((n) * 4 + 1 + RXFSID(n))
#define RXFEID8(n) ((n) * 4 + 2 + RXFSID(n))
#define RXFEID0(n) ((n) * 4 + 3 + RXFSID(n))
#define RXMSIDH(n) ((n) * 4 + 0x20)
#define RXMSIDL(n) ((n) * 4 + 0x21)
#define RXMEID8(n) ((n) * 4 + 0x22)
#define RXMEID0(n) ((n) * 4 + 0x23)#define GET_BYTE(val, byte) \(((val) >> ((byte) * 8)) & 0xff)
#define SET_BYTE(val, byte) \(((val) & 0xff) << ((byte) * 8))/* Buffer size required for the largest SPI transfer (i.e., reading a* frame)*/
#define CAN_FRAME_MAX_DATA_LEN 8
#define SPI_TRANSFER_BUF_LEN (6 + CAN_FRAME_MAX_DATA_LEN)
#define CAN_FRAME_MAX_BITS 128#define TX_ECHO_SKB_MAX 1#define MCP251X_OST_DELAY_MS (5)#define DEVICE_NAME "mcp251x"static const struct can_bittiming_const mcp251x_bittiming_const = {.name = DEVICE_NAME,.tseg1_min = 3,.tseg1_max = 16,.tseg2_min = 2,.tseg2_max = 8,.sjw_max = 4,.brp_min = 1,.brp_max = 64,.brp_inc = 1,
};enum mcp251x_model {CAN_MCP251X_MCP2510 = 0x2510,CAN_MCP251X_MCP2515 = 0x2515,CAN_MCP251X_MCP25625 = 0x25625,
};struct mcp251x_priv {struct can_priv can;struct net_device *net;struct spi_device *spi;enum mcp251x_model model;struct mutex mcp_lock; /* SPI device lock */u8 *spi_tx_buf;u8 *spi_rx_buf;struct sk_buff *tx_skb;int tx_len;struct workqueue_struct *wq;struct work_struct tx_work;struct work_struct restart_work;int force_quit;int after_suspend;
#define AFTER_SUSPEND_UP 1
#define AFTER_SUSPEND_DOWN 2
#define AFTER_SUSPEND_POWER 4
#define AFTER_SUSPEND_RESTART 8int restart_tx;struct regulator *power;struct regulator *transceiver;struct clk *clk;
#ifdef CONFIG_GPIOLIBstruct gpio_chip gpio;u8 reg_bfpctrl;
#endif
};#define MCP251X_IS(_model) \
static inline int mcp251x_is_##_model(struct spi_device *spi) \
{ \struct mcp251x_priv *priv = spi_get_drvdata(spi); \return priv->model == CAN_MCP251X_MCP##_model; \
}MCP251X_IS(2510);static void mcp251x_clean(struct net_device *net)
{struct mcp251x_priv *priv = netdev_priv(net);if (priv->tx_skb || priv->tx_len)net->stats.tx_errors++;dev_kfree_skb(priv->tx_skb);if (priv->tx_len)can_free_echo_skb(priv->net, 0);priv->tx_skb = NULL;priv->tx_len = 0;
}/* Note about handling of error return of mcp251x_spi_trans: accessing* registers via SPI is not really different conceptually than using* normal I/O assembler instructions, although it's much more* complicated from a practical POV. So it's not advisable to always* check the return value of this function. Imagine that every* read{b,l}, write{b,l} and friends would be bracketed in "if ( < 0)* error();", it would be a great mess (well there are some situation* when exception handling C++ like could be useful after all). So we* just check that transfers are OK at the beginning of our* conversation with the chip and to avoid doing really nasty things* (like injecting bogus packets in the network stack).*/
static int mcp251x_spi_trans(struct spi_device *spi, int len)
{struct mcp251x_priv *priv = spi_get_drvdata(spi);struct spi_transfer t = {.tx_buf = priv->spi_tx_buf,.rx_buf = priv->spi_rx_buf,.len = len,.cs_change = 0,};struct spi_message m;int ret;spi_message_init(&m);spi_message_add_tail(&t, &m);ret = spi_sync(spi, &m);if (ret)dev_err(&spi->dev, "spi transfer failed: ret = %d\n", ret);return ret;
}static int mcp251x_spi_write(struct spi_device *spi, int len)
{struct mcp251x_priv *priv = spi_get_drvdata(spi);int ret;ret = spi_write(spi, priv->spi_tx_buf, len);if (ret)dev_err(&spi->dev, "spi write failed: ret = %d\n", ret);return ret;
}static u8 mcp251x_read_reg(struct spi_device *spi, u8 reg)
{struct mcp251x_priv *priv = spi_get_drvdata(spi);u8 val = 0;priv->spi_tx_buf[0] = INSTRUCTION_READ;priv->spi_tx_buf[1] = reg;if (spi->controller->flags & SPI_CONTROLLER_HALF_DUPLEX) {spi_write_then_read(spi, priv->spi_tx_buf, 2, &val, 1);} else {mcp251x_spi_trans(spi, 3);val = priv->spi_rx_buf[2];}return val;
}static void mcp251x_read_2regs(struct spi_device *spi, u8 reg, u8 *v1, u8 *v2)
{struct mcp251x_priv *priv = spi_get_drvdata(spi);priv->spi_tx_buf[0] = INSTRUCTION_READ;priv->spi_tx_buf[1] = reg;if (spi->controller->flags & SPI_CONTROLLER_HALF_DUPLEX) {u8 val[2] = { 0 };spi_write_then_read(spi, priv->spi_tx_buf, 2, val, 2);*v1 = val[0];*v2 = val[1];} else {mcp251x_spi_trans(spi, 4);*v1 = priv->spi_rx_buf[2];*v2 = priv->spi_rx_buf[3];}
}static void mcp251x_write_reg(struct spi_device *spi, u8 reg, u8 val)
{struct mcp251x_priv *priv = spi_get_drvdata(spi);priv->spi_tx_buf[0] = INSTRUCTION_WRITE;priv->spi_tx_buf[1] = reg;priv->spi_tx_buf[2] = val;mcp251x_spi_write(spi, 3);
}static void mcp251x_write_2regs(struct spi_device *spi, u8 reg, u8 v1, u8 v2)
{struct mcp251x_priv *priv = spi_get_drvdata(spi);priv->spi_tx_buf[0] = INSTRUCTION_WRITE;priv->spi_tx_buf[1] = reg;priv->spi_tx_buf[2] = v1;priv->spi_tx_buf[3] = v2;mcp251x_spi_write(spi, 4);
}static void mcp251x_write_bits(struct spi_device *spi, u8 reg,u8 mask, u8 val)
{struct mcp251x_priv *priv = spi_get_drvdata(spi);priv->spi_tx_buf[0] = INSTRUCTION_BIT_MODIFY;priv->spi_tx_buf[1] = reg;priv->spi_tx_buf[2] = mask;priv->spi_tx_buf[3] = val;mcp251x_spi_write(spi, 4);
}static u8 mcp251x_read_stat(struct spi_device *spi)
{return mcp251x_read_reg(spi, CANSTAT) & CANCTRL_REQOP_MASK;
}#define mcp251x_read_stat_poll_timeout(addr, val, cond, delay_us, timeout_us) \readx_poll_timeout(mcp251x_read_stat, addr, val, cond, \delay_us, timeout_us)#ifdef CONFIG_GPIOLIB
enum {MCP251X_GPIO_TX0RTS = 0, /* inputs */MCP251X_GPIO_TX1RTS,MCP251X_GPIO_TX2RTS,MCP251X_GPIO_RX0BF, /* outputs */MCP251X_GPIO_RX1BF,
};#define MCP251X_GPIO_INPUT_MASK \GENMASK(MCP251X_GPIO_TX2RTS, MCP251X_GPIO_TX0RTS)
#define MCP251X_GPIO_OUTPUT_MASK \GENMASK(MCP251X_GPIO_RX1BF, MCP251X_GPIO_RX0BF)static const char * const mcp251x_gpio_names[] = {[MCP251X_GPIO_TX0RTS] = "TX0RTS", /* inputs */[MCP251X_GPIO_TX1RTS] = "TX1RTS",[MCP251X_GPIO_TX2RTS] = "TX2RTS",[MCP251X_GPIO_RX0BF] = "RX0BF", /* outputs */[MCP251X_GPIO_RX1BF] = "RX1BF",
};static inline bool mcp251x_gpio_is_input(unsigned int offset)
{return offset <= MCP251X_GPIO_TX2RTS;
}static int mcp251x_gpio_request(struct gpio_chip *chip,unsigned int offset)
{struct mcp251x_priv *priv = gpiochip_get_data(chip);u8 val;/* nothing to be done for inputs */if (mcp251x_gpio_is_input(offset))return 0;val = BFPCTRL_BFE(offset - MCP251X_GPIO_RX0BF);mutex_lock(&priv->mcp_lock);mcp251x_write_bits(priv->spi, BFPCTRL, val, val);mutex_unlock(&priv->mcp_lock);priv->reg_bfpctrl |= val;return 0;
}static void mcp251x_gpio_free(struct gpio_chip *chip,unsigned int offset)
{struct mcp251x_priv *priv = gpiochip_get_data(chip);u8 val;/* nothing to be done for inputs */if (mcp251x_gpio_is_input(offset))return;val = BFPCTRL_BFE(offset - MCP251X_GPIO_RX0BF);mutex_lock(&priv->mcp_lock);mcp251x_write_bits(priv->spi, BFPCTRL, val, 0);mutex_unlock(&priv->mcp_lock);priv->reg_bfpctrl &= ~val;
}static int mcp251x_gpio_get_direction(struct gpio_chip *chip,unsigned int offset)
{if (mcp251x_gpio_is_input(offset))return GPIOF_DIR_IN;return GPIOF_DIR_OUT;
}static int mcp251x_gpio_get(struct gpio_chip *chip, unsigned int offset)
{struct mcp251x_priv *priv = gpiochip_get_data(chip);u8 reg, mask, val;if (mcp251x_gpio_is_input(offset)) {reg = TXRTSCTRL;mask = TXRTSCTRL_RTS(offset);} else {reg = BFPCTRL;mask = BFPCTRL_BFS(offset - MCP251X_GPIO_RX0BF);}mutex_lock(&priv->mcp_lock);val = mcp251x_read_reg(priv->spi, reg);mutex_unlock(&priv->mcp_lock);return !!(val & mask);
}static int mcp251x_gpio_get_multiple(struct gpio_chip *chip,unsigned long *maskp, unsigned long *bitsp)
{struct mcp251x_priv *priv = gpiochip_get_data(chip);unsigned long bits = 0;u8 val;mutex_lock(&priv->mcp_lock);if (maskp[0] & MCP251X_GPIO_INPUT_MASK) {val = mcp251x_read_reg(priv->spi, TXRTSCTRL);val = FIELD_GET(TXRTSCTRL_RTS_MASK, val);bits |= FIELD_PREP(MCP251X_GPIO_INPUT_MASK, val);}if (maskp[0] & MCP251X_GPIO_OUTPUT_MASK) {val = mcp251x_read_reg(priv->spi, BFPCTRL);val = FIELD_GET(BFPCTRL_BFS_MASK, val);bits |= FIELD_PREP(MCP251X_GPIO_OUTPUT_MASK, val);}mutex_unlock(&priv->mcp_lock);bitsp[0] = bits;return 0;
}static void mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,int value)
{struct mcp251x_priv *priv = gpiochip_get_data(chip);u8 mask, val;mask = BFPCTRL_BFS(offset - MCP251X_GPIO_RX0BF);val = value ? mask : 0;mutex_lock(&priv->mcp_lock);mcp251x_write_bits(priv->spi, BFPCTRL, mask, val);mutex_unlock(&priv->mcp_lock);priv->reg_bfpctrl &= ~mask;priv->reg_bfpctrl |= val;
}static void
mcp251x_gpio_set_multiple(struct gpio_chip *chip,unsigned long *maskp, unsigned long *bitsp)
{struct mcp251x_priv *priv = gpiochip_get_data(chip);u8 mask, val;mask = FIELD_GET(MCP251X_GPIO_OUTPUT_MASK, maskp[0]);mask = FIELD_PREP(BFPCTRL_BFS_MASK, mask);val = FIELD_GET(MCP251X_GPIO_OUTPUT_MASK, bitsp[0]);val = FIELD_PREP(BFPCTRL_BFS_MASK, val);if (!mask)return;mutex_lock(&priv->mcp_lock);mcp251x_write_bits(priv->spi, BFPCTRL, mask, val);mutex_unlock(&priv->mcp_lock);priv->reg_bfpctrl &= ~mask;priv->reg_bfpctrl |= val;
}static void mcp251x_gpio_restore(struct spi_device *spi)
{struct mcp251x_priv *priv = spi_get_drvdata(spi);mcp251x_write_reg(spi, BFPCTRL, priv->reg_bfpctrl);
}static int mcp251x_gpio_setup(struct mcp251x_priv *priv)
{struct gpio_chip *gpio = &priv->gpio;if (!device_property_present(&priv->spi->dev, "gpio-controller"))return 0;/* gpiochip handles TX[0..2]RTS and RX[0..1]BF */gpio->label = priv->spi->modalias;gpio->parent = &priv->spi->dev;gpio->owner = THIS_MODULE;gpio->request = mcp251x_gpio_request;gpio->free = mcp251x_gpio_free;gpio->get_direction = mcp251x_gpio_get_direction;gpio->get = mcp251x_gpio_get;gpio->get_multiple = mcp251x_gpio_get_multiple;gpio->set = mcp251x_gpio_set;gpio->set_multiple = mcp251x_gpio_set_multiple;gpio->base = -1;gpio->ngpio = ARRAY_SIZE(mcp251x_gpio_names);gpio->names = mcp251x_gpio_names;gpio->can_sleep = true;
#ifdef CONFIG_OF_GPIOgpio->of_node = priv->spi->dev.of_node;
#endifreturn devm_gpiochip_add_data(&priv->spi->dev, gpio, priv);
}
#else
static inline void mcp251x_gpio_restore(struct spi_device *spi)
{
}static inline int mcp251x_gpio_setup(struct mcp251x_priv *priv)
{return 0;
}
#endifstatic void mcp251x_hw_tx_frame(struct spi_device *spi, u8 *buf,int len, int tx_buf_idx)
{struct mcp251x_priv *priv = spi_get_drvdata(spi);if (mcp251x_is_2510(spi)) {int i;for (i = 1; i < TXBDAT_OFF + len; i++)mcp251x_write_reg(spi, TXBCTRL(tx_buf_idx) + i,buf[i]);} else {memcpy(priv->spi_tx_buf, buf, TXBDAT_OFF + len);mcp251x_spi_write(spi, TXBDAT_OFF + len);}
}static void mcp251x_hw_tx(struct spi_device *spi, struct can_frame *frame,int tx_buf_idx)
{struct mcp251x_priv *priv = spi_get_drvdata(spi);u32 sid, eid, exide, rtr;u8 buf[SPI_TRANSFER_BUF_LEN];exide = (frame->can_id & CAN_EFF_FLAG) ? 1 : 0; /* Extended ID Enable */if (exide)sid = (frame->can_id & CAN_EFF_MASK) >> 18;elsesid = frame->can_id & CAN_SFF_MASK; /* Standard ID */eid = frame->can_id & CAN_EFF_MASK; /* Extended ID */rtr = (frame->can_id & CAN_RTR_FLAG) ? 1 : 0; /* Remote transmission */buf[TXBCTRL_OFF] = INSTRUCTION_LOAD_TXB(tx_buf_idx);buf[TXBSIDH_OFF] = sid >> SIDH_SHIFT;buf[TXBSIDL_OFF] = ((sid & SIDL_SID_MASK) << SIDL_SID_SHIFT) |(exide << SIDL_EXIDE_SHIFT) |((eid >> SIDL_EID_SHIFT) & SIDL_EID_MASK);buf[TXBEID8_OFF] = GET_BYTE(eid, 1);buf[TXBEID0_OFF] = GET_BYTE(eid, 0);buf[TXBDLC_OFF] = (rtr << DLC_RTR_SHIFT) | frame->can_dlc;memcpy(buf + TXBDAT_OFF, frame->data, frame->can_dlc);mcp251x_hw_tx_frame(spi, buf, frame->can_dlc, tx_buf_idx);/* use INSTRUCTION_RTS, to avoid "repeated frame problem" */priv->spi_tx_buf[0] = INSTRUCTION_RTS(1 << tx_buf_idx);mcp251x_spi_write(priv->spi, 1);
}static void mcp251x_hw_rx_frame(struct spi_device *spi, u8 *buf,int buf_idx)
{struct mcp251x_priv *priv = spi_get_drvdata(spi);if (mcp251x_is_2510(spi)) {int i, len;for (i = 1; i < RXBDAT_OFF; i++)buf[i] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + i);len = get_can_dlc(buf[RXBDLC_OFF] & RXBDLC_LEN_MASK);for (; i < (RXBDAT_OFF + len); i++)buf[i] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + i);} else {priv->spi_tx_buf[RXBCTRL_OFF] = INSTRUCTION_READ_RXB(buf_idx);if (spi->controller->flags & SPI_CONTROLLER_HALF_DUPLEX) {spi_write_then_read(spi, priv->spi_tx_buf, 1,priv->spi_rx_buf,SPI_TRANSFER_BUF_LEN);memcpy(buf + 1, priv->spi_rx_buf,SPI_TRANSFER_BUF_LEN - 1);} else {mcp251x_spi_trans(spi, SPI_TRANSFER_BUF_LEN);memcpy(buf, priv->spi_rx_buf, SPI_TRANSFER_BUF_LEN);}}
}static void mcp251x_hw_rx(struct spi_device *spi, int buf_idx)
{struct mcp251x_priv *priv = spi_get_drvdata(spi);struct sk_buff *skb;struct can_frame *frame;u8 buf[SPI_TRANSFER_BUF_LEN];skb = alloc_can_skb(priv->net, &frame);if (!skb) {dev_err(&spi->dev, "cannot allocate RX skb\n");priv->net->stats.rx_dropped++;return;}mcp251x_hw_rx_frame(spi, buf, buf_idx);if (buf[RXBSIDL_OFF] & RXBSIDL_IDE) {/* Extended ID format */frame->can_id = CAN_EFF_FLAG;frame->can_id |=/* Extended ID part */SET_BYTE(buf[RXBSIDL_OFF] & RXBSIDL_EID, 2) |SET_BYTE(buf[RXBEID8_OFF], 1) |SET_BYTE(buf[RXBEID0_OFF], 0) |/* Standard ID part */(((buf[RXBSIDH_OFF] << RXBSIDH_SHIFT) |(buf[RXBSIDL_OFF] >> RXBSIDL_SHIFT)) << 18);/* Remote transmission request */if (buf[RXBDLC_OFF] & RXBDLC_RTR)frame->can_id |= CAN_RTR_FLAG;} else {/* Standard ID format */frame->can_id =(buf[RXBSIDH_OFF] << RXBSIDH_SHIFT) |(buf[RXBSIDL_OFF] >> RXBSIDL_SHIFT);if (buf[RXBSIDL_OFF] & RXBSIDL_SRR)frame->can_id |= CAN_RTR_FLAG;}/* Data length */frame->can_dlc = get_can_dlc(buf[RXBDLC_OFF] & RXBDLC_LEN_MASK);memcpy(frame->data, buf + RXBDAT_OFF, frame->can_dlc);priv->net->stats.rx_packets++;priv->net->stats.rx_bytes += frame->can_dlc;can_led_event(priv->net, CAN_LED_EVENT_RX);netif_rx_ni(skb);
}static void mcp251x_hw_sleep(struct spi_device *spi)
{mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_SLEEP);
}/* May only be called when device is sleeping! */
static int mcp251x_hw_wake(struct spi_device *spi)
{u8 value;int ret;/* Force wakeup interrupt to wake device, but don't execute IST */disable_irq(spi->irq);mcp251x_write_2regs(spi, CANINTE, CANINTE_WAKIE, CANINTF_WAKIF);/* Wait for oscillator startup timer after wake up */mdelay(MCP251X_OST_DELAY_MS);/* Put device into config mode */mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_CONF);/* Wait for the device to enter config mode */ret = mcp251x_read_stat_poll_timeout(spi, value, value == CANCTRL_REQOP_CONF,MCP251X_OST_DELAY_MS * 1000,USEC_PER_SEC);if (ret) {dev_err(&spi->dev, "MCP251x didn't enter in config mode\n");return ret;}/* Disable and clear pending interrupts */mcp251x_write_2regs(spi, CANINTE, 0x00, 0x00);enable_irq(spi->irq);return 0;
}static netdev_tx_t mcp251x_hard_start_xmit(struct sk_buff *skb,struct net_device *net)
{struct mcp251x_priv *priv = netdev_priv(net);struct spi_device *spi = priv->spi;if (priv->tx_skb || priv->tx_len) {dev_warn(&spi->dev, "hard_xmit called while tx busy\n");return NETDEV_TX_BUSY;}if (can_dropped_invalid_skb(net, skb))return NETDEV_TX_OK;netif_stop_queue(net);priv->tx_skb = skb;queue_work(priv->wq, &priv->tx_work);return NETDEV_TX_OK;
}static int mcp251x_do_set_mode(struct net_device *net, enum can_mode mode)
{struct mcp251x_priv *priv = netdev_priv(net);switch (mode) {case CAN_MODE_START:mcp251x_clean(net);/* We have to delay work since SPI I/O may sleep */priv->can.state = CAN_STATE_ERROR_ACTIVE;priv->restart_tx = 1;if (priv->can.restart_ms == 0)priv->after_suspend = AFTER_SUSPEND_RESTART;queue_work(priv->wq, &priv->restart_work);break;default:return -EOPNOTSUPP;}return 0;
}static int mcp251x_set_normal_mode(struct spi_device *spi)
{struct mcp251x_priv *priv = spi_get_drvdata(spi);u8 value;int ret;/* Enable interrupts */mcp251x_write_reg(spi, CANINTE,CANINTE_ERRIE | CANINTE_TX2IE | CANINTE_TX1IE |CANINTE_TX0IE | CANINTE_RX1IE | CANINTE_RX0IE);if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) {/* Put device into loopback mode */mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_LOOPBACK);} else if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) {/* Put device into listen-only mode */mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_LISTEN_ONLY);} else {/* Put device into normal mode */mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_NORMAL);/* Wait for the device to enter normal mode */ret = mcp251x_read_stat_poll_timeout(spi, value, value == 0,MCP251X_OST_DELAY_MS * 1000,USEC_PER_SEC);if (ret) {dev_err(&spi->dev, "MCP251x didn't enter in normal mode\n");return ret;}}priv->can.state = CAN_STATE_ERROR_ACTIVE;return 0;
}static int mcp251x_do_set_bittiming(struct net_device *net)
{struct mcp251x_priv *priv = netdev_priv(net);struct can_bittiming *bt = &priv->can.bittiming;struct spi_device *spi = priv->spi;mcp251x_write_reg(spi, CNF1, ((bt->sjw - 1) << CNF1_SJW_SHIFT) |(bt->brp - 1));mcp251x_write_reg(spi, CNF2, CNF2_BTLMODE |(priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES ?CNF2_SAM : 0) |((bt->phase_seg1 - 1) << CNF2_PS1_SHIFT) |(bt->prop_seg - 1));mcp251x_write_bits(spi, CNF3, CNF3_PHSEG2_MASK,(bt->phase_seg2 - 1));dev_dbg(&spi->dev, "CNF: 0x%02x 0x%02x 0x%02x\n",mcp251x_read_reg(spi, CNF1),mcp251x_read_reg(spi, CNF2),mcp251x_read_reg(spi, CNF3));return 0;
}static int mcp251x_setup(struct net_device *net, struct spi_device *spi)
{mcp251x_do_set_bittiming(net);mcp251x_write_reg(spi, RXBCTRL(0),RXBCTRL_BUKT | RXBCTRL_RXM0 | RXBCTRL_RXM1);mcp251x_write_reg(spi, RXBCTRL(1),RXBCTRL_RXM0 | RXBCTRL_RXM1);return 0;
}static int mcp251x_hw_reset(struct spi_device *spi)
{struct mcp251x_priv *priv = spi_get_drvdata(spi);u8 value;int ret;/* Wait for oscillator startup timer after power up */mdelay(MCP251X_OST_DELAY_MS);priv->spi_tx_buf[0] = INSTRUCTION_RESET;ret = mcp251x_spi_write(spi, 1);if (ret)return ret;/* Wait for oscillator startup timer after reset */mdelay(MCP251X_OST_DELAY_MS);/* Wait for reset to finish */ret = mcp251x_read_stat_poll_timeout(spi, value, value == CANCTRL_REQOP_CONF,MCP251X_OST_DELAY_MS * 1000,USEC_PER_SEC);if (ret)dev_err(&spi->dev, "MCP251x didn't enter in conf mode after reset\n");return ret;
}static int mcp251x_hw_probe(struct spi_device *spi)
{u8 ctrl;int ret;ret = mcp251x_hw_reset(spi);if (ret)return ret;ctrl = mcp251x_read_reg(spi, CANCTRL);dev_dbg(&spi->dev, "CANCTRL 0x%02x\n", ctrl);/* Check for power up default value */if ((ctrl & 0x17) != 0x07)return -ENODEV;return 0;
}static int mcp251x_power_enable(struct regulator *reg, int enable)
{if (IS_ERR_OR_NULL(reg))return 0;if (enable)return regulator_enable(reg);elsereturn regulator_disable(reg);
}static int mcp251x_stop(struct net_device *net)
{struct mcp251x_priv *priv = netdev_priv(net);struct spi_device *spi = priv->spi;close_candev(net);priv->force_quit = 1;free_irq(spi->irq, priv);mutex_lock(&priv->mcp_lock);/* Disable and clear pending interrupts */mcp251x_write_2regs(spi, CANINTE, 0x00, 0x00);mcp251x_write_reg(spi, TXBCTRL(0), 0);mcp251x_clean(net);mcp251x_hw_sleep(spi);mcp251x_power_enable(priv->transceiver, 0);priv->can.state = CAN_STATE_STOPPED;mutex_unlock(&priv->mcp_lock);can_led_event(net, CAN_LED_EVENT_STOP);return 0;
}static void mcp251x_error_skb(struct net_device *net, int can_id, int data1)
{struct sk_buff *skb;struct can_frame *frame;skb = alloc_can_err_skb(net, &frame);if (skb) {frame->can_id |= can_id;frame->data[1] = data1;netif_rx_ni(skb);} else {netdev_err(net, "cannot allocate error skb\n");}
}static void mcp251x_tx_work_handler(struct work_struct *ws)
{struct mcp251x_priv *priv = container_of(ws, struct mcp251x_priv,tx_work);struct spi_device *spi = priv->spi;struct net_device *net = priv->net;struct can_frame *frame;mutex_lock(&priv->mcp_lock);if (priv->tx_skb) {if (priv->can.state == CAN_STATE_BUS_OFF) {mcp251x_clean(net);} else {frame = (struct can_frame *)priv->tx_skb->data;if (frame->can_dlc > CAN_FRAME_MAX_DATA_LEN)frame->can_dlc = CAN_FRAME_MAX_DATA_LEN;mcp251x_hw_tx(spi, frame, 0);priv->tx_len = 1 + frame->can_dlc;can_put_echo_skb(priv->tx_skb, net, 0);priv->tx_skb = NULL;}}mutex_unlock(&priv->mcp_lock);
}static void mcp251x_restart_work_handler(struct work_struct *ws)
{struct mcp251x_priv *priv = container_of(ws, struct mcp251x_priv,restart_work);struct spi_device *spi = priv->spi;struct net_device *net = priv->net;mutex_lock(&priv->mcp_lock);if (priv->after_suspend) {if (priv->after_suspend & AFTER_SUSPEND_POWER) {mcp251x_hw_reset(spi);mcp251x_setup(net, spi);mcp251x_gpio_restore(spi);} else {mcp251x_hw_wake(spi);}priv->force_quit = 0;if (priv->after_suspend & AFTER_SUSPEND_RESTART) {mcp251x_set_normal_mode(spi);} else if (priv->after_suspend & AFTER_SUSPEND_UP) {netif_device_attach(net);mcp251x_clean(net);mcp251x_set_normal_mode(spi);netif_wake_queue(net);} else {mcp251x_hw_sleep(spi);}priv->after_suspend = 0;}if (priv->restart_tx) {priv->restart_tx = 0;mcp251x_write_reg(spi, TXBCTRL(0), 0);mcp251x_clean(net);netif_wake_queue(net);mcp251x_error_skb(net, CAN_ERR_RESTARTED, 0);}mutex_unlock(&priv->mcp_lock);
}static irqreturn_t mcp251x_can_ist(int irq, void *dev_id)
{struct mcp251x_priv *priv = dev_id;struct spi_device *spi = priv->spi;struct net_device *net = priv->net;mutex_lock(&priv->mcp_lock);while (!priv->force_quit) {enum can_state new_state;u8 intf, eflag;u8 clear_intf = 0;int can_id = 0, data1 = 0;mcp251x_read_2regs(spi, CANINTF, &intf, &eflag);/* mask out flags we don't care about */intf &= CANINTF_RX | CANINTF_TX | CANINTF_ERR;/* receive buffer 0 */if (intf & CANINTF_RX0IF) {mcp251x_hw_rx(spi, 0);/* Free one buffer ASAP* (The MCP2515/25625 does this automatically.)*/if (mcp251x_is_2510(spi))mcp251x_write_bits(spi, CANINTF,CANINTF_RX0IF, 0x00);}/* receive buffer 1 */if (intf & CANINTF_RX1IF) {mcp251x_hw_rx(spi, 1);/* The MCP2515/25625 does this automatically. */if (mcp251x_is_2510(spi))clear_intf |= CANINTF_RX1IF;}/* any error or tx interrupt we need to clear? */if (intf & (CANINTF_ERR | CANINTF_TX))clear_intf |= intf & (CANINTF_ERR | CANINTF_TX);if (clear_intf)mcp251x_write_bits(spi, CANINTF, clear_intf, 0x00);if (eflag & (EFLG_RX0OVR | EFLG_RX1OVR))mcp251x_write_bits(spi, EFLG, eflag, 0x00);/* Update can state */if (eflag & EFLG_TXBO) {new_state = CAN_STATE_BUS_OFF;can_id |= CAN_ERR_BUSOFF;} else if (eflag & EFLG_TXEP) {new_state = CAN_STATE_ERROR_PASSIVE;can_id |= CAN_ERR_CRTL;data1 |= CAN_ERR_CRTL_TX_PASSIVE;} else if (eflag & EFLG_RXEP) {new_state = CAN_STATE_ERROR_PASSIVE;can_id |= CAN_ERR_CRTL;data1 |= CAN_ERR_CRTL_RX_PASSIVE;} else if (eflag & EFLG_TXWAR) {new_state = CAN_STATE_ERROR_WARNING;can_id |= CAN_ERR_CRTL;data1 |= CAN_ERR_CRTL_TX_WARNING;} else if (eflag & EFLG_RXWAR) {new_state = CAN_STATE_ERROR_WARNING;can_id |= CAN_ERR_CRTL;data1 |= CAN_ERR_CRTL_RX_WARNING;} else {new_state = CAN_STATE_ERROR_ACTIVE;}/* Update can state statistics */switch (priv->can.state) {case CAN_STATE_ERROR_ACTIVE:if (new_state >= CAN_STATE_ERROR_WARNING &&new_state <= CAN_STATE_BUS_OFF)priv->can.can_stats.error_warning++;case CAN_STATE_ERROR_WARNING:if (new_state >= CAN_STATE_ERROR_PASSIVE &&new_state <= CAN_STATE_BUS_OFF)priv->can.can_stats.error_passive++;break;default:break;}priv->can.state = new_state;if (intf & CANINTF_ERRIF) {/* Handle overflow counters */if (eflag & (EFLG_RX0OVR | EFLG_RX1OVR)) {if (eflag & EFLG_RX0OVR) {net->stats.rx_over_errors++;net->stats.rx_errors++;}if (eflag & EFLG_RX1OVR) {net->stats.rx_over_errors++;net->stats.rx_errors++;}can_id |= CAN_ERR_CRTL;data1 |= CAN_ERR_CRTL_RX_OVERFLOW;}mcp251x_error_skb(net, can_id, data1);}if (priv->can.state == CAN_STATE_BUS_OFF) {if (priv->can.restart_ms == 0) {priv->force_quit = 1;priv->can.can_stats.bus_off++;can_bus_off(net);mcp251x_hw_sleep(spi);break;}}if (intf == 0)break;if (intf & CANINTF_TX) {net->stats.tx_packets++;net->stats.tx_bytes += priv->tx_len - 1;can_led_event(net, CAN_LED_EVENT_TX);if (priv->tx_len) {can_get_echo_skb(net, 0);priv->tx_len = 0;}netif_wake_queue(net);}}mutex_unlock(&priv->mcp_lock);return IRQ_HANDLED;
}static int mcp251x_open(struct net_device *net)
{struct mcp251x_priv *priv = netdev_priv(net);struct spi_device *spi = priv->spi;unsigned long flags = 0;int ret;ret = open_candev(net);if (ret) {dev_err(&spi->dev, "unable to set initial baudrate!\n");return ret;}mutex_lock(&priv->mcp_lock);mcp251x_power_enable(priv->transceiver, 1);priv->force_quit = 0;priv->tx_skb = NULL;priv->tx_len = 0;if (!dev_fwnode(&spi->dev))flags = IRQF_TRIGGER_FALLING;ret = request_threaded_irq(spi->irq, NULL, mcp251x_can_ist,flags | IRQF_ONESHOT, dev_name(&spi->dev),priv);if (ret) {dev_err(&spi->dev, "failed to acquire irq %d\n", spi->irq);goto out_close;}ret = mcp251x_hw_wake(spi);if (ret)goto out_free_irq;ret = mcp251x_setup(net, spi);if (ret)goto out_free_irq;ret = mcp251x_set_normal_mode(spi);if (ret)goto out_free_irq;can_led_event(net, CAN_LED_EVENT_OPEN);netif_wake_queue(net);mutex_unlock(&priv->mcp_lock);return 0;out_free_irq:free_irq(spi->irq, priv);mcp251x_hw_sleep(spi);
out_close:mcp251x_power_enable(priv->transceiver, 0);close_candev(net);mutex_unlock(&priv->mcp_lock);return ret;
}static const struct net_device_ops mcp251x_netdev_ops = {.ndo_open = mcp251x_open,.ndo_stop = mcp251x_stop,.ndo_start_xmit = mcp251x_hard_start_xmit,.ndo_change_mtu = can_change_mtu,
};static const struct of_device_id mcp251x_of_match[] = {{.compatible = "microchip,mcp2510",.data = (void *)CAN_MCP251X_MCP2510,},{.compatible = "microchip,mcp2515",.data = (void *)CAN_MCP251X_MCP2515,},{.compatible = "microchip,mcp25625",.data = (void *)CAN_MCP251X_MCP25625,},{ }
};
MODULE_DEVICE_TABLE(of, mcp251x_of_match);static const struct spi_device_id mcp251x_id_table[] = {{.name = "mcp2510",.driver_data = (kernel_ulong_t)CAN_MCP251X_MCP2510,},{.name = "mcp2515",.driver_data = (kernel_ulong_t)CAN_MCP251X_MCP2515,},{.name = "mcp25625",.driver_data = (kernel_ulong_t)CAN_MCP251X_MCP25625,},{ }
};
MODULE_DEVICE_TABLE(spi, mcp251x_id_table);static int mcp251x_can_probe(struct spi_device *spi)
{const void *match = device_get_match_data(&spi->dev);struct net_device *net;struct mcp251x_priv *priv;struct clk *clk;u32 freq;int ret;clk = devm_clk_get_optional(&spi->dev, NULL);if (IS_ERR(clk))return PTR_ERR(clk);freq = clk_get_rate(clk);if (freq == 0)device_property_read_u32(&spi->dev, "clock-frequency", &freq);/* Sanity check */if (freq < 1000000 || freq > 25000000)return -ERANGE;/* Allocate can/net device */net = alloc_candev(sizeof(struct mcp251x_priv), TX_ECHO_SKB_MAX);if (!net)return -ENOMEM;ret = clk_prepare_enable(clk);if (ret)goto out_free;net->netdev_ops = &mcp251x_netdev_ops;net->flags |= IFF_ECHO;priv = netdev_priv(net);priv->can.bittiming_const = &mcp251x_bittiming_const;priv->can.do_set_mode = mcp251x_do_set_mode;priv->can.clock.freq = freq / 2;priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES |CAN_CTRLMODE_LOOPBACK | CAN_CTRLMODE_LISTENONLY;if (match)priv->model = (enum mcp251x_model)match;elsepriv->model = spi_get_device_id(spi)->driver_data;priv->net = net;priv->clk = clk;spi_set_drvdata(spi, priv);/* Configure the SPI bus */spi->bits_per_word = 8;if (mcp251x_is_2510(spi))spi->max_speed_hz = spi->max_speed_hz ? : 5 * 1000 * 1000;elsespi->max_speed_hz = spi->max_speed_hz ? : 10 * 1000 * 1000;ret = spi_setup(spi);if (ret)goto out_clk;priv->power = devm_regulator_get_optional(&spi->dev, "vdd");priv->transceiver = devm_regulator_get_optional(&spi->dev, "xceiver");if ((PTR_ERR(priv->power) == -EPROBE_DEFER) ||(PTR_ERR(priv->transceiver) == -EPROBE_DEFER)) {ret = -EPROBE_DEFER;goto out_clk;}ret = mcp251x_power_enable(priv->power, 1);if (ret)goto out_clk;priv->wq = alloc_workqueue("mcp251x_wq", WQ_FREEZABLE | WQ_MEM_RECLAIM,0);if (!priv->wq) {ret = -ENOMEM;goto out_clk;}INIT_WORK(&priv->tx_work, mcp251x_tx_work_handler);INIT_WORK(&priv->restart_work, mcp251x_restart_work_handler);priv->spi = spi;mutex_init(&priv->mcp_lock);priv->spi_tx_buf = devm_kzalloc(&spi->dev, SPI_TRANSFER_BUF_LEN,GFP_KERNEL);if (!priv->spi_tx_buf) {ret = -ENOMEM;goto error_probe;}priv->spi_rx_buf = devm_kzalloc(&spi->dev, SPI_TRANSFER_BUF_LEN,GFP_KERNEL);if (!priv->spi_rx_buf) {ret = -ENOMEM;goto error_probe;}SET_NETDEV_DEV(net, &spi->dev);/* Here is OK to not lock the MCP, no one knows about it yet */ret = mcp251x_hw_probe(spi);if (ret) {if (ret == -ENODEV)dev_err(&spi->dev, "Cannot initialize MCP%x. Wrong wiring?\n",priv->model);goto error_probe;}mcp251x_hw_sleep(spi);ret = register_candev(net);if (ret)goto error_probe;devm_can_led_init(net);ret = mcp251x_gpio_setup(priv);if (ret)goto error_probe;netdev_info(net, "MCP%x successfully initialized.\n", priv->model);return 0;error_probe:destroy_workqueue(priv->wq);priv->wq = NULL;mcp251x_power_enable(priv->power, 0);out_clk:clk_disable_unprepare(clk);out_free:free_candev(net);dev_err(&spi->dev, "Probe failed, err=%d\n", -ret);return ret;
}static int mcp251x_can_remove(struct spi_device *spi)
{struct mcp251x_priv *priv = spi_get_drvdata(spi);struct net_device *net = priv->net;unregister_candev(net);mcp251x_power_enable(priv->power, 0);destroy_workqueue(priv->wq);priv->wq = NULL;clk_disable_unprepare(priv->clk);free_candev(net);return 0;
}static int __maybe_unused mcp251x_can_suspend(struct device *dev)
{struct spi_device *spi = to_spi_device(dev);struct mcp251x_priv *priv = spi_get_drvdata(spi);struct net_device *net = priv->net;priv->force_quit = 1;disable_irq(spi->irq);/* Note: at this point neither IST nor workqueues are running.* open/stop cannot be called anyway so locking is not needed*/if (netif_running(net)) {netif_device_detach(net);mcp251x_hw_sleep(spi);mcp251x_power_enable(priv->transceiver, 0);priv->after_suspend = AFTER_SUSPEND_UP;} else {priv->after_suspend = AFTER_SUSPEND_DOWN;}mcp251x_power_enable(priv->power, 0);priv->after_suspend |= AFTER_SUSPEND_POWER;return 0;
}static int __maybe_unused mcp251x_can_resume(struct device *dev)
{struct spi_device *spi = to_spi_device(dev);struct mcp251x_priv *priv = spi_get_drvdata(spi);if (priv->after_suspend & AFTER_SUSPEND_POWER)mcp251x_power_enable(priv->power, 1);if (priv->after_suspend & AFTER_SUSPEND_UP)mcp251x_power_enable(priv->transceiver, 1);if (priv->after_suspend & (AFTER_SUSPEND_POWER | AFTER_SUSPEND_UP))queue_work(priv->wq, &priv->restart_work);elsepriv->after_suspend = 0;priv->force_quit = 0;enable_irq(spi->irq);return 0;
}static SIMPLE_DEV_PM_OPS(mcp251x_can_pm_ops, mcp251x_can_suspend,mcp251x_can_resume);static struct spi_driver mcp251x_can_driver = {.driver = {.name = DEVICE_NAME,.of_match_table = mcp251x_of_match,.pm = &mcp251x_can_pm_ops,},.id_table = mcp251x_id_table,.probe = mcp251x_can_probe,.remove = mcp251x_can_remove,
};
module_spi_driver(mcp251x_can_driver);MODULE_AUTHOR("Chris Elston <celston@katalix.com>, ""Christian Pellegrin <chripell@evolware.org>");
MODULE_DESCRIPTION("Microchip 251x/25625 CAN driver");
MODULE_LICENSE("GPL v2");
3.功能测试
使用 candump 和 cansend 工具进行收发报文测试即可，将工具push到/system/bin/目录下执行。工具可以在 官方 或者 github 下载。
#在收发端关闭can0设备
ip link set can0 down
#在收发端设置比特率为250Kbps
ip link set can0 type can bitrate 250000
#在收发端打开can0设备
ip link set can0 up
#在接收端执行candump,阻塞等待报文
candump can0
#在发送端执行cansend，发送报文
cansend can0 123#1122334455667788 4.bug修复
瑞芯微原生的CAN接口在使用中遇到如下问题，经过调试进行了修复和规避
- CAN拓展帧发送时偶发标准帧问题
- 发送接收数据时总线错误帧多的问题
- 规避了错误帧中断过多导致的系统卡顿问题
- 支持CAN2.0协议标准数据帧收发
驱动代码参考：https://download.csdn.net/download/qq_28643619/88403793
开发板技术参考：3. CAN 使用 — Firefly Wiki
