>From a173c9ea843a85d83e003894c03a9378c20d6862 Mon Sep 17 00:00:00 2001 From: Wen Wang <wen.w.wang@xxxxxxxxx> Date: Thu, 23 Apr 2009 16:16:25 +0800 Subject: [PATCH] Moorestown I2C controller driver Signed-off-by: Wen Wang <wen.w.wang@xxxxxxxxx> --- drivers/i2c/busses/Kconfig | 10 + drivers/i2c/busses/Makefile | 1 + drivers/i2c/busses/i2c-mrst.c | 973 +++++++++++++++++++++++++++++++++++++++++ drivers/i2c/busses/i2c-mrst.h | 279 ++++++++++++ drivers/i2c/i2c-boardinfo.c | 36 +- 5 files changed, 1288 insertions(+), 11 deletions(-) create mode 100644 drivers/i2c/busses/i2c-mrst.c create mode 100755 drivers/i2c/busses/i2c-mrst.h diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index a48c8ae..cfd3528 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -738,4 +738,14 @@ config SCx200_ACB This support is also available as a module. If so, the module will be called scx200_acb. +config I2C_MRST + tristate "Intel Moorestown I2C Controller" + depends on PCI && GPIOLIB + default y + help + If you say yes to this option, support will be included for the Intel + Moorestown chipset I2C controller. + This driver can also be built as a module. If so, the module + will be called i2c-mrst. + endmenu diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index 776acb6..e11fd0f 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -69,6 +69,7 @@ obj-$(CONFIG_I2C_SIBYTE) += i2c-sibyte.o obj-$(CONFIG_I2C_STUB) += i2c-stub.o obj-$(CONFIG_SCx200_ACB) += scx200_acb.o obj-$(CONFIG_SCx200_I2C) += scx200_i2c.o +obj-$(CONFIG_I2C_MRST) += i2c-mrst.o ifeq ($(CONFIG_I2C_DEBUG_BUS),y) EXTRA_CFLAGS += -DDEBUG diff --git a/drivers/i2c/busses/i2c-mrst.c b/drivers/i2c/busses/i2c-mrst.c new file mode 100644 index 0000000..c93ff30 --- /dev/null +++ b/drivers/i2c/busses/i2c-mrst.c @@ -0,0 +1,973 @@ +/* + * Support for Moorestown I2C controller + * + * Copyright (c) 2009 Intel Corporation. + * Copyright (c) 2009 Synopsys. Inc. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, version + * 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT ANY + * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS + * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more + * details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., 51 + * Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. + * + */ + +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/version.h> +#include <linux/kernel.h> +#include <linux/err.h> +#include <linux/slab.h> +#include <linux/stat.h> +#include <linux/types.h> +#include <linux/delay.h> +#include <linux/i2c.h> +#include <linux/init.h> +#include <linux/pci.h> +#include <linux/gpio.h> + +#include <linux/io.h> + +#include "i2c-mrst.h" + +#define MAX_T_POLL_COUNT 4000 /* FIXME */ +#define DEF_BAR 0 +#define VERSION "Version 0.5" + +#define mrst_i2c_read(reg) __raw_readl(reg) +#define mrst_i2c_write(reg, val) __raw_writel((val), (reg)) + +static int speed_mode = STANDARD; +module_param(speed_mode, int, S_IRUGO); + +/** + * mrst_i2c_register_board_info - Register I2C device info + * @dev: struct pointer to pci_dev + * @busnum: Bus number to register + * + * Return Value: + * 0 success + * -ENOMEM if fail to allocate memory + * -ENODEV if fail to detect the address of I2C device info table + * + * Moorestown I2C device info table is initialized by firmware and the address + * pointer is filled into I2C controller PCI config space BAR 1. + * + * Driver will read this table from memory and register this device table into + * I2C core. + */ +static int mrst_i2c_register_board_info(struct pci_dev *dev, int busnum) +{ + struct mrst_i2c_private *mrst = (struct mrst_i2c_private *) + pci_get_drvdata(dev); + int err; + unsigned short addr, irq, host; + char *name = NULL; + struct i2c_board_info *info = NULL; + unsigned int addr_off, irq_off, name_off, data_off, host_off; + unsigned int table_len, block_num, block = 0; + int i, j; + unsigned int start, len; + void __iomem *base = NULL, *ptr = NULL; + + /* Determine the address of the I2C device info table area */ + start = pci_resource_start(dev, 1); + len = pci_resource_len(dev, 1); + if (!start || len <= 0) { + err = -ENODEV; + return err; + } + + err = pci_request_region(dev, 1, "mrst_i2c"); + if (err) { + dev_err(&dev->dev, "Failed to request I2C region " + "0x%1x-0x%Lx\n", start, + (unsigned long long)pci_resource_end(dev, 1)); + return err; + } + + ptr = ioremap(start, len); + if (!ptr) { + dev_err(&dev->dev, "I/O memory remapping failed\n"); + err = -ENOMEM; + goto err0; + } + + /* + * Detect if an old firmware is used. + * Newer firmware is using two levels pointer to the device info table + */ + if (len == 8) { + start = ioread32(ptr); + len = ioread32(ptr + 4); + iounmap(ptr); + base = ioremap(start, len); + } else + base = ptr; + + /* Initialization */ + name = kzalloc(sizeof(char) * NAME_LENGTH, GFP_KERNEL); + if (name == NULL) { + err = -ENOMEM; + goto err1; + } + + info = kzalloc(sizeof(struct i2c_board_info), GFP_KERNEL); + if (info == NULL) { + dev_err(&dev->dev, + "Can't allocate interface for i2c_board_info\n"); + err = -ENOMEM; + goto err2; + } + + /* Get I2C info table length */ + table_len = ioread32(base + I2C_INFO_TABLE_LENGTH); + + /* Calculate the number of I2C device */ + block_num = (table_len - HEAD_LENGTH)/BLOCK_LENGTH; + if (!block_num) + /* No I2C device info */ + goto err3; + + /* Initialize mrst_i2c_info array */ + mrst->mrst_i2c_info = kzalloc(sizeof(struct i2c_board_info) * + block_num, GFP_KERNEL); + if (mrst->mrst_i2c_info == NULL) { + dev_err(&dev->dev, + "Can't allocate interface for i2c_board_info\n"); + err = -ENOMEM; + goto err3; + } + + mrst->data = kzalloc(sizeof(*mrst->data) * block_num, GFP_KERNEL); + if (mrst->data == NULL) { + dev_err(&dev->dev, + "Can't allocate interface for per device data\n"); + err = -ENOMEM; + goto err4; + } + + for (i = 0; i < block_num; i++) { + /* I2C device info block offsets */ + host_off = I2C_INFO_DEV_BLOCK + BLOCK_LENGTH * i; + addr_off = I2C_INFO_DEV_BLOCK + BLOCK_LENGTH * i + I2C_DEV_ADDR; + irq_off = I2C_INFO_DEV_BLOCK + BLOCK_LENGTH * i + I2C_DEV_IRQ; + name_off = I2C_INFO_DEV_BLOCK + BLOCK_LENGTH * i + I2C_DEV_NAME; + data_off = I2C_INFO_DEV_BLOCK + BLOCK_LENGTH * i + I2C_DEV_INFO; + + /* Read PCI config table */ + host = ioread16(base + host_off); + if (host != busnum) + continue; + addr = ioread16(base + addr_off); + irq = ioread16(base + irq_off); + for (j = 0; j < NAME_LENGTH; j++) + name[j] = ioread8(base + name_off + j); + + for (j = 0; j < INFO_LENGTH; j++) + mrst->data[i][j] = ioread8(base + data_off + j); + dev_dbg(&dev->dev, "I2C device info table: name = %s, address =" + " %x\n", name, addr); + + /* Fill in i2c_board_info struct */ + memcpy(info->type, name, NAME_LENGTH); + info->platform_data = mrst->data[i]; + info->addr = addr; + info->irq = irq; + + /* Add to mrst_i2c_info array */ + memcpy(mrst->mrst_i2c_info + block, info, + sizeof(struct i2c_board_info)); + block++; + } + + /* Register i2c board info */ + err = i2c_register_board_info(busnum, mrst->mrst_i2c_info, block); + goto err3; + +/* Clean up */ +err4: + kfree(mrst->mrst_i2c_info); +err3: + kfree(info); +err2: + kfree(name); +err1: + iounmap(base); +err0: + pci_release_region(dev, 1); + return err; +} + +/** + * mrst_i2c_disable - Disable I2C controller + * @adap: struct pointer to i2c_adapter + * + * Return Value: + * 0 success + * -EBUSY if device is busy + * -ETIMEOUT if i2c cannot be disabled within the given time + * + * I2C bus state should be checked prior to disabling the hardware. If bus is + * not in idle state, an errno is returned. Write "0" to IC_ENABLE to disable + * I2C controller. + */ +static int mrst_i2c_disable(struct i2c_adapter *adap) +{ + struct mrst_i2c_private *i2c = + (struct mrst_i2c_private *)i2c_get_adapdata(adap); + + int count = 0; + + /* Check if device is busy */ + dev_dbg(&adap->dev, "mrst i2c disable\n"); + while (mrst_i2c_read(i2c->base + IC_STATUS) & 0x1) { + dev_dbg(&adap->dev, "i2c is busy, count is %d\n", count); + if (count++ > 10000) + return -EBUSY; + } + + /* Set IC_ENABLE to 0 */ + mrst_i2c_write(i2c->base + IC_ENABLE, 0); + + /* Disable all interupts */ + mrst_i2c_write(i2c->base + IC_INTR_MASK, 0x0000); + + /* Clear all interrupts */ + mrst_i2c_read(i2c->base + IC_CLR_INTR); + + return 0; +} + +/** + * mrst_i2c_hwinit - Initiate the I2C hardware registers. This function will + * be called in mrst_i2c_probe() before device registration. + * @dev: pci device struct pointer + * + * Return Values: + * 0 success + * -EBUSY i2c cannot be disabled + * -ETIMEDOUT i2c cannot be disabled + * -EFAULT If APB data width is not 32-bit wide + * + * I2C should be disabled prior to other register operation. If failed, an + * errno is returned. Mask and Clear all interrpts, this should be done at + * first. Set common registers which will not be modified during normal + * transfers, including: controll register, FIFO threshold and clock freq. + * Check APB data width at last. + */ +static int __devinit mrst_i2c_hwinit(struct pci_dev *dev) +{ + struct mrst_i2c_private *i2c = + (struct mrst_i2c_private *)pci_get_drvdata(dev); + int err = 0; + + /* Disable i2c first */ + err = mrst_i2c_disable(i2c->adap); + if (err) + return err; + + /* Disable all interupts */ + mrst_i2c_write(i2c->base + IC_INTR_MASK, 0x0000); + + /* Clear all interrupts */ + mrst_i2c_read(i2c->base + IC_CLR_INTR); + + /* + * Setup clock frequency and speed mode + * Enable restart condition, + * enable master FSM, disable slave FSM, + * use target address when initiating transfer + */ + switch (speed_mode) { + case STANDARD: + mrst_i2c_write(i2c->base + IC_CON, + SLV_DIS | RESTART | STANDARD_MODE | MASTER_EN); + mrst_i2c_write(i2c->base + IC_SS_SCL_HCNT, 0x75); + mrst_i2c_write(i2c->base + IC_SS_SCL_LCNT, 0x7c); + break; + case FAST: + mrst_i2c_write(i2c->base + IC_CON, + SLV_DIS | RESTART | FAST_MODE | MASTER_EN); + mrst_i2c_write(i2c->base + IC_SS_SCL_HCNT, 0x15); + mrst_i2c_write(i2c->base + IC_SS_SCL_LCNT, 0x21); + break; + case HIGH: + mrst_i2c_write(i2c->base + IC_CON, + SLV_DIS | RESTART | HIGH_MODE | MASTER_EN); + mrst_i2c_write(i2c->base + IC_SS_SCL_HCNT, 0x7); + mrst_i2c_write(i2c->base + IC_SS_SCL_LCNT, 0xE); + break; + default: + ; + } + + /* Set tranmit & receive FIFO threshold to zero */ + mrst_i2c_write(i2c->base + IC_RX_TL, 0x3); + mrst_i2c_write(i2c->base + IC_TX_TL, 0x3); + + mrst_i2c_write(i2c->base + IC_ENABLE, 1); + + return err; +} + +/** + * mrst_i2c_func - Return the supported three I2C operations. + * @adapter: i2c_adapter struct pointer + */ +static u32 mrst_i2c_func(struct i2c_adapter *adapter) +{ + return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | I2C_FUNC_SMBUS_EMUL; +} + +/** + * mrst_i2c_invalid_address - To check if the address in i2c message is + * correct. + * @p: i2c_msg struct pointer + * + * Return Values: + * 0 if the address is valid + * 1 if the address is invalid + */ +static inline int mrst_i2c_invalid_address(const struct i2c_msg *p) +{ + int ret = ((p->addr > 0x3ff) || (!(p->flags & I2C_M_TEN) + && (p->addr > 0x7f))); + return ret; +} + +/** + * mrst_i2c_address_neq - To check if the addresses for different i2c messages + * are equal. + * @p1: first i2c_msg + * @p2: second i2c_msg + * + * Return Values: + * 0 if addresse are equal + * 1 if not equal + * + * Within a single transfer, I2C client may need to send its address more + * than one time. So a check for the address equation is needed. + */ +static inline int mrst_i2c_address_neq(const struct i2c_msg *p1, + const struct i2c_msg *p2) +{ + int ret = ((p1->addr != p2->addr) || ((p1->flags & (I2C_M_TEN)) + != ((p2->flags) & (I2C_M_TEN)))); + return ret; +} + +/** + * mrst_i2c_abort - To handle transfer abortions and print error messages. + * @adap: i2c_adapter struct pointer + * + * By reading register IC_TX_ABRT_SOURCE, various transfer errors can be + * distingushed. At present, no circumstances have been found out that + * multiple errors would be occured simutaneously, so we simply use the + * register value directly. + * + * At last the error bits are cleared. (Note clear ABRT_SBYTE_NORSTRT bit need + * a few extra steps) + */ +static void mrst_i2c_abort(struct i2c_adapter *adap) +{ + struct mrst_i2c_private *i2c = (struct mrst_i2c_private *) + i2c_get_adapdata(adap); + + /* Read about source register */ + int abort = mrst_i2c_read(i2c->base + IC_TX_ABRT_SOURCE); + + dev_dbg(&adap->dev, "Abort: "); + + /* Single transfer error check: + * According to databook, TX/RX FIFOs would be flushed when + * the abort interrupt occured. + */ + switch (abort) { + case (ABRT_MASTER_DIS): + dev_err(&adap->dev, + "initiate Master operation with Master mode" + "disabled.\n"); + + break; + case (ABRT_10B_RD_NORSTRT): + dev_err(&adap->dev, + "RESTART disabled and master sends READ cmd in 10-BIT" + "addressing.\n"); + break; + case (ABRT_SBYTE_NORSTRT): + dev_err(&adap->dev, + "RESTART disabled and user is trying to send START" + "byte.\n"); + /* Page 141 data book */ + mrst_i2c_write(i2c->base + IC_TX_ABRT_SOURCE, + !(ABRT_SBYTE_NORSTRT)); + mrst_i2c_write(i2c->base + IC_CON, RESTART); + mrst_i2c_write(i2c->base + IC_TAR, !(IC_TAR_SPECIAL)); + break; + case (ABRT_SBYTE_ACKDET): + dev_err(&adap->dev, + "START byte was acknowledged.\n"); + break; + case (ABRT_TXDATA_NOACK): + dev_err(&adap->dev, + "No acknowledge received from slave.\n"); + break; + case (ABRT_10ADDR2_NOACK): + dev_err(&adap->dev, + "The 2nd address byte of 10-bit address not" + "acknowledged.\n"); + break; + case (ABRT_10ADDR1_NOACK): + dev_dbg(&adap->dev, + "The 1st address byte of 10-bit address not" + "acknowledged.\n"); + break; + case (ABRT_7B_ADDR_NOACK): + dev_err(&adap->dev, + "7-bit address not acknowledged.\n"); + break; + default: + ;; + } + + /* Clear TX_ABRT bit */ + mrst_i2c_read(i2c->base + IC_CLR_TX_ABRT); +} + +/** + * xfer_read - Internal function to implement master read transfer. + * @adap: i2c_adapter struct pointer + * @buf: buffer in i2c_msg + * @length: number of bytes to be read + * + * Return Values: + * 0 if the read transfer succeeds + * -ETIMEDOUT if cannot read the "raw" interrupt register + * -EINVAL if transfer abort occured + * + * For every byte, a "READ" command will be loaded into IC_DATA_CMD prior to + * data transfer. The actual "read" operation will be performed if the RX_FULL + * interrupt is occured. + * + * Note there may be two interrupt signals captured, one should read + * IC_RAW_INTR_STAT to seperate between errors and actual data. + */ +static int xfer_read(struct i2c_adapter *adap, unsigned char *buf, int length) +{ + struct mrst_i2c_private *i2c = (struct mrst_i2c_private *) + i2c_get_adapdata(adap); + uint32_t reg_val; + int i = length; + unsigned count = 0; + uint32_t bit_get = 1 << 3; /* receive fifo not empty */ + + while (i--) + mrst_i2c_write(i2c->base + IC_DATA_CMD, (uint16_t)0x100); + + i = length; + while (i--) { + count = 0; + reg_val = mrst_i2c_read(i2c->base + IC_STATUS); + while ((reg_val & bit_get) == 0) { + reg_val = mrst_i2c_read(i2c->base + IC_RAW_INTR_STAT); + if ((reg_val & 0x40) == 0x40) + goto read_abrt; + reg_val = mrst_i2c_read(i2c->base + IC_STATUS); + if (count++ > MAX_T_POLL_COUNT) + goto read_loop; + } + + reg_val = mrst_i2c_read(i2c->base + IC_DATA_CMD); + *buf++ = reg_val; + } + + return 0; + +read_loop: + dev_err(&adap->dev, "Time out in read\n"); + return -ETIMEDOUT; +read_abrt: + dev_err(&adap->dev, "Abort from read\n"); + mrst_i2c_abort(adap); + return -EINVAL; +} + +/** + * xfer_write - Internal function to implement master write transfer. + * @adap: i2c_adapter struct pointer + * @buf: buffer in i2c_msg + * @length: number of bytes to be read + * + * Return Values: + * 0 if the read transfer succeeds + * -ETIMEDOUT if cannot read the "raw" interrupt register + * -EINVAL if transfer abort occured + * + * For every byte, a "WRITE" command will be loaded into IC_DATA_CMD prior to + * data transfer. The actual "write" operation will be performed if the + * RX_FULL interrupt siganal is occured. + * + * Note there may be two interrupt signals captured, one should read + * IC_RAW_INTR_STAT to seperate between errors and actual data. + */ +static int xfer_write(struct i2c_adapter *adap, + unsigned char *buf, int length) +{ + struct mrst_i2c_private *i2c = (struct mrst_i2c_private *) + i2c_get_adapdata(adap); + + int i; + uint32_t reg_val; + unsigned count = 0; + uint32_t bit_get = 1 << 2; /* transmit fifo completely empty */ + + for (i = 0; i < length; i++) + mrst_i2c_write(i2c->base + IC_DATA_CMD, + (uint16_t)(*(buf + i))); + + reg_val = mrst_i2c_read(i2c->base + IC_STATUS); + while ((reg_val & bit_get) == 0) { + if (count++ > MAX_T_POLL_COUNT) + goto write_loop; + reg_val = mrst_i2c_read(i2c->base + IC_STATUS); + } + + udelay(100); + reg_val = mrst_i2c_read(i2c->base + IC_RAW_INTR_STAT); + if ((reg_val & 0x40) == 0x40) + goto write_abrt; + + return 0; + +write_loop: + dev_err(&adap->dev, "Time out in write\n"); + return -ETIMEDOUT; +write_abrt: + dev_err(&adap->dev, "Abort from write\n"); + mrst_i2c_abort(adap); + return -EINVAL; +} + +static int mrst_i2c_setup(struct i2c_adapter *adap, struct i2c_msg *pmsg) +{ + struct mrst_i2c_private *i2c = + (struct mrst_i2c_private *)i2c_get_adapdata(adap); + int err; + uint32_t reg_val; + uint32_t bit_mask; + + /* Disable device first */ + err = mrst_i2c_disable(adap); + if (err) { + dev_err(&adap->dev, + "Cannot disable i2c controller, timeout!\n"); + return -ETIMEDOUT; + } + + + reg_val = mrst_i2c_read(i2c->base + IC_ENABLE); + if (reg_val & 0x1) { + dev_dbg(&adap->dev, "i2c busy, can't setup\n"); + return -EINVAL; + } + + /* set the speed mode to standard */ + reg_val = mrst_i2c_read(i2c->base + IC_CON); + if ((reg_val & (1<<1 | 1<<2)) != 1<<1) { + dev_dbg(&adap->dev, "set standard mode\n"); + mrst_i2c_write(i2c->base + IC_CON, (reg_val & (~0x6)) | 1<<1); + } + + reg_val = mrst_i2c_read(i2c->base + IC_CON); + /* use 7-bit addressing */ + if ((reg_val & (1<<4)) != 0x0) { + dev_dbg(&adap->dev, "set i2c 7 bit address mode\n"); + mrst_i2c_write(i2c->base + IC_CON, reg_val & (~(1<<4))); + } + + /*enable restart conditions */ + reg_val = mrst_i2c_read(i2c->base + IC_CON); + if ((reg_val & (1<<5)) != 1<<5) { + dev_dbg(&adap->dev, "enable restart conditions\n"); + mrst_i2c_write(i2c->base + IC_CON, (reg_val & (~(1 << 5))) + | 1 << 5); + } + + /* enable master FSM */ + reg_val = mrst_i2c_read(i2c->base + IC_CON); + dev_dbg(&adap->dev, "ic_con reg_val is 0x%x\n", reg_val); + if ((reg_val & (1<<6)) != 1<<6) { + dev_dbg(&adap->dev, "enable master FSM\n"); + mrst_i2c_write(i2c->base + IC_CON, (reg_val & (~(1 << 6))) + | 1<<6); + dev_dbg(&adap->dev, "ic_con reg_val is 0x%x\n", reg_val); + } + + /* use target address when initiating transfer */ + reg_val = mrst_i2c_read(i2c->base + IC_TAR); + bit_mask = 1 << 11 | 1 << 10; + + if ((reg_val & bit_mask) != 0x0) { + dev_dbg(&adap->dev, "WR: use target address when intiating" + "transfer, i2c_tx_target\n"); + mrst_i2c_write(i2c->base + IC_TAR, reg_val & ~bit_mask); + } + + /* set target address to the I2C slave address */ + dev_dbg(&adap->dev, "set target address to the I2C slave address," + "addr is %x\n", pmsg->addr); + mrst_i2c_write(i2c->base + IC_TAR, pmsg->addr + | (pmsg->flags & I2C_M_TEN ? IC_TAR_10BIT_ADDR : 0)); + + /* Enable I2C controller */ + mrst_i2c_write(i2c->base + IC_ENABLE, ENABLE); + + reg_val = mrst_i2c_read(i2c->base + IC_CON); + + return 0; +} + +/** + * mrst_i2c_xfer - Main master transfer routine. + * @adap: i2c_adapter struct pointer + * @pmsg: i2c_msg struct pointer + * @num: number of i2c_msg + * + * Return Values: + * + number of messages transfered + * -ETIMEDOUT If cannot disable I2C controller or read IC_STATUS + * -EINVAL If the address in i2c_msg is invalid + * + * This function will be registered in i2c-core and exposed to external + * I2C clients. + * 1. Disable I2C controller + * 2. Unmask three interrupts: RX_FULL, TX_EMPTY, TX_ABRT + * 3. Check if address in i2c_msg is valid + * 4. Enable I2C controller + * 5. Perform real transfer (call xfer_read or xfer_write) + * 6. Wait until the current transfer is finished(check bus state) + * 7. Mask and clear all interrupts + */ +static int mrst_i2c_xfer(struct i2c_adapter *adap, + struct i2c_msg *pmsg, + int num) +{ + struct mrst_i2c_private *i2c = + (struct mrst_i2c_private *)i2c_get_adapdata(adap); + int i, err; + + dev_dbg(&adap->dev, "mrst_i2c_xfer, process %d msg(s)\n", num); + dev_dbg(&adap->dev, KERN_INFO "slave address is %x\n", pmsg->addr); + + /* if number of messages equal 0*/ + if (num == 0) + return 0; + + /* Checked the sanity of passed messages. */ + if (unlikely(mrst_i2c_invalid_address(&pmsg[0]))) { + dev_err(&adap->dev, "Invalid address 0x%03x (%d-bit)\n", + pmsg[0].addr, pmsg[0].flags & I2C_M_TEN ? 10 : 7); + return -EINVAL; + } + for (i = 0; i < num; i++) { + /* Message address equal? */ + if (unlikely(mrst_i2c_address_neq(&pmsg[0], &pmsg[i]))) { + dev_err(&adap->dev, "Invalid address in msg[%d]\n", i); + return -EINVAL; + } + } + + if (mrst_i2c_setup(adap, pmsg)) + return -EINVAL; + + for (i = 0; i < num; i++) { + dev_dbg(&adap->dev, " #%d: %sing %d byte%s %s 0x%02x\n", i, + pmsg->flags & I2C_M_RD ? "read" : "writ", + pmsg->len, pmsg->len > 1 ? "s" : "", + pmsg->flags & I2C_M_RD ? "from" : "to", pmsg->addr); + + + /* Read or Write */ + if (pmsg->len && pmsg->buf) { + if (pmsg->flags & I2C_M_RD) { + dev_dbg(&adap->dev, "I2C_M_RD\n"); + err = xfer_read(adap, pmsg->buf, pmsg->len); + } else { + dev_dbg(&adap->dev, "I2C_M_WR\n"); + err = xfer_write(adap, pmsg->buf, pmsg->len); + } + if (err < 0) + goto err_1; + } + dev_dbg(&adap->dev, "msg[%d] transfer complete\n", i); + pmsg++; /* next message */ + } + goto exit; + +err_1: + i = err; +exit: + /* Mask interrupts */ + mrst_i2c_write(i2c->base + IC_INTR_MASK, 0x0000); + /* Clear all interrupts */ + mrst_i2c_read(i2c->base + IC_CLR_INTR); + + return i; +} + +static int mrst_gpio_init(int sda, int scl) +{ + if (gpio_request(sda, "I2C_SDA")) + goto err_sda; + + if (gpio_request(scl, "I2C_SCL")) + goto err_scl; + + /* TODO: Wait for Moorestown GPIO driver into upstream to uncomment */ + /*gpio_alt_func(sda, 1);*/ + /*gpio_alt_func(scl, 1);*/ + + return 0; +err_scl: + gpio_free(sda); +err_sda: + return -1; +} + +static struct pci_device_id mrst_i2c_ids[] = { + {PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x0802)}, + {PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x0803)}, + {PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x0804)}, + {0,} +}; +MODULE_DEVICE_TABLE(pci, mrst_i2c_ids); + +static struct i2c_algorithm mrst_i2c_algorithm = { + .master_xfer = mrst_i2c_xfer, + .functionality = mrst_i2c_func, +}; + +static struct pci_driver mrst_i2c_driver = { + .name = "mrst_i2c", + .id_table = mrst_i2c_ids, + .probe = mrst_i2c_probe, + .remove = __devexit_p(mrst_i2c_remove), + .suspend = NULL, + .resume = NULL, +}; + +/** + * mrst_i2c_probe - I2C controller initialization routine + * @dev: pci device + * @id: device id + * + * Return Values: + * 0 success + * -ENODEV If cannot allocate pci resource + * -ENOMEM If the register base remapping failed, or + * if kzalloc failed + * + * Initialization steps: + * 1. Request for PCI resource + * 2. Remap the start address of PCI resource to register base + * 3. Request for device memory region + * 4. Fill in the struct members of mrst_i2c_private + * 5. Call mrst_i2c_hwinit() for hardware initialization + * 6. Read I2C device info table from memory and register into core + * 7. Register I2C adapter in i2c-core + */ +static int __devinit mrst_i2c_probe(struct pci_dev *dev, + const struct pci_device_id *id) +{ + struct mrst_i2c_private *mrst; + struct i2c_adapter *adap; + unsigned int start, len; + int err, busnum = 0; + void __iomem *base = NULL; + int gpio_sda = 0, gpio_scl = 0; + + err = pci_enable_device(dev); + if (err) { + dev_err(&dev->dev, "Failed to enable I2C PCI device (%d)\n", + err); + goto exit; + } + + /* Determine the address of the I2C area */ + start = pci_resource_start(dev, DEF_BAR); + len = pci_resource_len(dev, DEF_BAR); + if (!start || len <= 0) { + dev_err(&dev->dev, "Base address initialization failed\n"); + err = -ENODEV; + goto exit; + } + dev_dbg(&dev->dev, "mrst i2c resource start %x, len=%d\n", + start, len); + err = pci_request_region(dev, DEF_BAR, mrst_i2c_driver.name); + if (err) { + dev_err(&dev->dev, "Failed to request I2C region " + "0x%1x-0x%Lx\n", start, + (unsigned long long)pci_resource_end(dev, DEF_BAR)); + goto exit; + } + + base = ioremap_nocache(start, len); + if (!base) { + dev_err(&dev->dev, "I/O memory remapping failed\n"); + err = -ENOMEM; + goto fail0; + } + + /* Allocate the per-device data structure, mrst_i2c_private */ + mrst = kzalloc(sizeof(struct mrst_i2c_private), GFP_KERNEL); + if (mrst == NULL) { + dev_err(&dev->dev, "Can't allocate interface!\n"); + err = -ENOMEM; + goto fail1; + } + + adap = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL); + if (adap == NULL) { + dev_err(&dev->dev, "Can't allocate interface!\n"); + err = -ENOMEM; + goto fail2; + } + + /* Initialize struct members */ + snprintf(adap->name, sizeof(adap->name), "mrst_i2c"); + adap->owner = THIS_MODULE; + adap->algo = &mrst_i2c_algorithm; + adap->class = I2C_CLASS_HWMON; + adap->dev.parent = &dev->dev; + mrst->adap = adap; + mrst->base = base; + mrst->speed = speed_mode; + + pci_set_drvdata(dev, mrst); + i2c_set_adapdata(adap, mrst); + + /* Initialize i2c controller */ + err = mrst_i2c_hwinit(dev); + if (err < 0) { + dev_err(&dev->dev, "I2C interface initialization failed\n"); + goto fail3; + } + + switch (id->device) { + case 0x0802: + dev_dbg(&adap->dev, KERN_INFO "I2C0\n"); + gpio_sda = GPIO_I2C_0_SDA; + gpio_scl = GPIO_I2C_0_SCL; + adap->nr = busnum = 0; + break; + case 0x0803: + dev_dbg(&adap->dev, KERN_INFO "I2C1\n"); + gpio_sda = GPIO_I2C_1_SDA; + gpio_scl = GPIO_I2C_1_SCL; + adap->nr = busnum = 1; + break; + case 0x0804: + dev_dbg(&adap->dev, KERN_INFO "I2C2\n"); + gpio_sda = GPIO_I2C_2_SDA; + gpio_scl = GPIO_I2C_2_SCL; + adap->nr = busnum = 2; + break; + default: + ; + } + + /* Config GPIO pin for I2C */ + err = mrst_gpio_init(gpio_sda, gpio_scl); + if (err) { + dev_err(&dev->dev, "GPIO %s registration failed\n", + adap->name); + goto fail3; + } + + /* Register i2c board info */ + mrst_i2c_register_board_info(dev, busnum); + + /* Adapter registration */ + err = i2c_add_numbered_adapter(adap); + if (err) { + dev_err(&dev->dev, "Adapter %s registration failed\n", + adap->name); + goto fail3; + } + + dev_dbg(&dev->dev, "MRST I2C bus %d driver bind success.\n", busnum); + return 0; + +fail3: + i2c_set_adapdata(adap, NULL); + pci_set_drvdata(dev, NULL); + kfree(adap); +fail2: + kfree(mrst); +fail1: + iounmap(base); +fail0: + pci_release_region(dev, DEF_BAR); +exit: + return err; +} + +static void __devexit mrst_i2c_remove(struct pci_dev *dev) +{ + struct mrst_i2c_private *mrst = (struct mrst_i2c_private *) + pci_get_drvdata(dev); + if (i2c_del_adapter(mrst->adap)) + dev_err(&dev->dev, "Failed to delete i2c adapter"); + + kfree(mrst->mrst_i2c_info); + kfree(mrst->data); + + switch (dev->device) { + case 0x0802: + gpio_free(GPIO_I2C_0_SDA); + gpio_free(GPIO_I2C_0_SCL); + break; + case 0x0803: + gpio_free(GPIO_I2C_1_SDA); + gpio_free(GPIO_I2C_1_SCL); + break; + case 0x0804: + gpio_free(GPIO_I2C_2_SDA); + gpio_free(GPIO_I2C_2_SCL); + break; + default: + break; + } + + pci_set_drvdata(dev, NULL); + iounmap(mrst->base); + kfree(mrst); + pci_release_region(dev, DEF_BAR); +} + +static int __init mrst_i2c_init(void) +{ + printk(KERN_NOTICE "Moorestown I2C driver %s\n", VERSION); + return pci_register_driver(&mrst_i2c_driver); +} + +static void __exit mrst_i2c_exit(void) +{ + pci_unregister_driver(&mrst_i2c_driver); +} + +module_init(mrst_i2c_init); +module_exit(mrst_i2c_exit); + +MODULE_AUTHOR("Ba Zheng <zheng.ba@xxxxxxxxx>"); +MODULE_DESCRIPTION("I2C driver for Moorestown Platform"); +MODULE_LICENSE("GPL"); +MODULE_VERSION(VERSION); diff --git a/drivers/i2c/busses/i2c-mrst.h b/drivers/i2c/busses/i2c-mrst.h new file mode 100755 index 0000000..3a51bd2 --- /dev/null +++ b/drivers/i2c/busses/i2c-mrst.h @@ -0,0 +1,279 @@ +#ifndef __I2C_MRST_H +#define __I2C_MRST_H + +#include <linux/i2c.h> + +/* Update for 2.6.27 kernel by Wen */ + +/* PCI config table macros */ +/* Offests */ +#define I2C_INFO_TABLE_LENGTH 4 +#define I2C_INFO_DEV_BLOCK 10 +#define I2C_DEV_ADDR 2 +#define I2C_DEV_IRQ 4 +#define I2C_DEV_NAME 6 +#define I2C_DEV_INFO 22 +/* Length */ +#define HEAD_LENGTH 10 +#define BLOCK_LENGTH 32 +#define ADDR_LENGTH 2 +#define IRQ_LENGTH 2 +#define NAME_LENGTH 16 +#define INFO_LENGTH 10 + +struct mrst_i2c_private { + struct i2c_adapter *adap; + /* Register base address */ + void __iomem *base; + /* Speed mode */ + int speed; + struct i2c_board_info *mrst_i2c_info; + char (*data)[INFO_LENGTH]; +}; + +/* Speed mode macros */ +#define STANDARD 100 +#define FAST 25 +#define HIGH 3 + +/* Control register */ +#define IC_CON 0x00 +#define SLV_DIS (1 << 6) /* Disable slave mode */ +#define RESTART (1 << 5) /* Send a Restart condition */ +#define ADDR_10BIT (1 << 4) /* 10-bit addressing */ +#define STANDARD_MODE (1 << 1) /* standard mode */ +#define FAST_MODE (2 << 1) /* fast mode */ +#define HIGH_MODE (3 << 1) /* high speed mode */ +#define MASTER_EN (1 << 0) /* Master mode */ + +/* Target address register */ +#define IC_TAR 0x04 +#define IC_TAR_10BIT_ADDR (1 << 12) /* 10-bit addressing */ +#define IC_TAR_SPECIAL (1 << 11) /* Perform special I2C cmd */ +#define IC_TAR_GC_OR_START (1 << 10) /* 0: Gerneral Call Address */ + /* 1: START BYTE */ + +/* Slave Address Register */ +#define IC_SAR 0x08 /* Not used in Master mode */ + +/* High Speed Master Mode Code Address Register */ +#define IC_HS_MADDR 0x0c + +/* Rx/Tx Data Buffer and Command Register */ +#define IC_DATA_CMD 0x10 +#define IC_RD (1 << 8) /* 1: Read 0: Write */ + +/* Standard Speed Clock SCL High Count Register */ +#define IC_SS_SCL_HCNT 0x14 + +/* Standard Speed Clock SCL Low Count Register */ +#define IC_SS_SCL_LCNT 0x18 + +/* Fast Speed Clock SCL High Count Register */ +#define IC_FS_SCL_HCNT 0x1c + +/* Fast Spedd Clock SCL Low Count Register */ +#define IC_FS_SCL_LCNT 0x20 + +/* High Speed Clock SCL High Count Register */ +#define IC_HS_SCL_HCNT 0x24 + +/* High Speed Clock SCL Low Count Register */ +#define IC_HS_SCL_LCNT 0x28 + +/* Interrupt Status Register */ +#define IC_INTR_STAT 0x2c /* Read only */ +#define R_GEN_CALL (1 << 11) +#define R_START_DET (1 << 10) +#define R_STOP_DET (1 << 9) +#define R_ACTIVITY (1 << 8) +#define R_RX_DONE (1 << 7) +#define R_TX_ABRT (1 << 6) +#define R_RD_REQ (1 << 5) +#define R_TX_EMPTY (1 << 4) +#define R_TX_OVER (1 << 3) +#define R_RX_FULL (1 << 2) +#define R_RX_OVER (1 << 1) +#define R_RX_UNDER (1 << 0) + +/* Interrupt Mask Register */ +#define IC_INTR_MASK 0x30 /* Read and Write */ +#define M_GEN_CALL (1 << 11) +#define M_START_DET (1 << 10) +#define M_STOP_DET (1 << 9) +#define M_ACTIVITY (1 << 8) +#define M_RX_DONE (1 << 7) +#define M_TX_ABRT (1 << 6) +#define M_RD_REQ (1 << 5) +#define M_TX_EMPTY (1 << 4) +#define M_TX_OVER (1 << 3) +#define M_RX_FULL (1 << 2) +#define M_RX_OVER (1 << 1) +#define M_RX_UNDER (1 << 0) + +/* Raw Interrupt Status Register */ +#define IC_RAW_INTR_STAT 0x34 /* Read Only */ +#define GEN_CALL (1 << 11) /* General call */ +#define START_DET (1 << 10) /* (RE)START occured */ +#define STOP_DET (1 << 9) /* STOP occured */ +#define ACTIVITY (1 << 8) /* Bus busy */ +#define RX_DONE (1 << 7) /* Not used in Master mode */ +#define TX_ABRT (1 << 6) /* Transmit Abort */ +#define RD_REQ (1 << 5) /* Not used in Master mode */ +#define TX_EMPTY (1 << 4) /* TX FIFO <= threshold */ +#define TX_OVER (1 << 3) /* TX FIFO overflow */ +#define RX_FULL (1 << 2) /* RX FIFO >= threshold */ +#define RX_OVER (1 << 1) /* RX FIFO overflow */ +#define RX_UNDER (1 << 0) /* RX FIFO empty */ + +/* Receive FIFO Threshold Register */ +#define IC_RX_TL 0x38 + +/* Transmit FIFO Treshold Register */ +#define IC_TX_TL 0x3c + +/* Clear Combined and Individual Interrupt Register */ +#define IC_CLR_INTR 0x40 +#define CLR_INTR (1 << 0) + +/* Clear RX_UNDER Interrupt Register */ +#define IC_CLR_RX_UNDER 0x44 +#define CLR_RX_UNDER (1 << 0) + +/* Clear RX_OVER Interrupt Register */ +#define IC_CLR_RX_OVER 0x48 +#define CLR_RX_OVER (1 << 0) + +/* Clear TX_OVER Interrupt Register */ +#define IC_CLR_TX_OVER 0x4c +#define CLR_TX_OVER (1 << 0) + +#define IC_CLR_RD_REQ 0x50 + +/* Clear TX_ABRT Interrupt Register */ +#define IC_CLR_TX_ABRT 0x54 +#define CLR_TX_ABRT (1 << 0) + +#define IC_CLR_RX_DONE 0x58 + + +/* Clear ACTIVITY Interrupt Register */ +#define IC_CLR_ACTIVITY 0x5c +#define CLR_ACTIVITY (1 << 0) + +/* Clear STOP_DET Interrupt Register */ +#define IC_CLR_STOP_DET 0x60 +#define CLR_STOP_DET (1 << 0) + +/* Clear START_DET Interrupt Register */ +#define IC_CLR_START_DET 0x64 +#define CLR_START_DET (1 << 0) + +/* Clear GEN_CALL Interrupt Register */ +#define IC_CLR_GEN_CALL 0x68 +#define CLR_GEN_CALL (1 << 0) + +/* Enable Register */ +#define IC_ENABLE 0x6c +#define ENABLE (1 << 0) + +/* Status Register */ +#define IC_STATUS 0x70 /* Read Only */ +#define STAT_SLV_ACTIVITY (1 << 6) /* Slave not in idle */ +#define STAT_MST_ACTIVITY (1 << 5) /* Master not in idle */ +#define STAT_RFF (1 << 4) /* RX FIFO Full */ +#define STAT_RFNE (1 << 3) /* RX FIFO Not Empty */ +#define STAT_TFE (1 << 2) /* TX FIFO Empty */ +#define STAT_TFNF (1 << 1) /* TX FIFO Not Full */ +#define STAT_ACTIVITY (1 << 0) /* Activity Status */ + +/* Transmit FIFO Level Register */ +#define IC_TXFLR 0x74 /* Read Only */ +#define TXFLR (1 << 0) /* TX FIFO level */ + +/* Receive FIFO Level Register */ +#define IC_RXFLR 0x78 /* Read Only */ +#define RXFLR (1 << 0) /* RX FIFO level */ + +/* Transmit Abort Source Register */ +#define IC_TX_ABRT_SOURCE 0x80 +#define ABRT_SLVRD_INTX (1 << 15) +#define ABRT_SLV_ARBLOST (1 << 14) +#define ABRT_SLVFLUSH_TXFIFO (1 << 13) +#define ARB_LOST (1 << 12) +#define ABRT_MASTER_DIS (1 << 11) +#define ABRT_10B_RD_NORSTRT (1 << 10) +#define ABRT_SBYTE_NORSTRT (1 << 9) +#define ABRT_HS_NORSTRT (1 << 8) +#define ABRT_SBYTE_ACKDET (1 << 7) +#define ABRT_HS_ACKDET (1 << 6) +#define ABRT_GCALL_READ (1 << 5) +#define ABRT_GCALL_NOACK (1 << 4) +#define ABRT_TXDATA_NOACK (1 << 3) +#define ABRT_10ADDR2_NOACK (1 << 2) +#define ABRT_10ADDR1_NOACK (1 << 1) +#define ABRT_7B_ADDR_NOACK (1 << 0) + +/* Enable Status Register */ +#define IC_ENABLE_STATUS 0x9c +#define IC_EN (1 << 0) /* I2C in an enabled state */ + +/* Component Parameter Register 1*/ +#define IC_COMP_PARAM_1 0xf4 +#define APB_DATA_WIDTH (0x3 << 0) + +/* GPIO_PINS */ +#define GPIO_I2C_0_SDA 56 +#define GPIO_I2C_0_SCL 57 + +#define GPIO_I2C_1_SDA 54 +#define GPIO_I2C_1_SCL 55 + +#define GPIO_I2C_2_SDA 52 +#define GPIO_I2C_2_SCL 53 + +/* added by xiaolin --begin */ +#define SS_MIN_SCL_HIGH 4000 +#define SS_MIN_SCL_LOW 4700 +#define FS_MIN_SCL_HIGH 600 +#define FS_MIN_SCL_LOW 1300 +#define HS_MIN_SCL_HIGH_100PF 60 +#define HS_MIN_SCL_LOW_100PF 120 + +enum mrst_i2c_irq { + i2c_irq_none = 0x000, + i2c_irq_rx_under = 0x001, + i2c_irq_rx_over = 0x002, + i2c_irq_rx_full = 0x004, + i2c_irq_tx_over = 0x008, + i2c_irq_tx_empty = 0x010, + i2c_irq_rd_req = 0x020, + i2c_irq_tx_abrt = 0x040, + i2c_irq_rx_done = 0x080, + i2c_irq_activity = 0x100, + i2c_irq_stop_det = 0x200, + i2c_irq_start_det = 0x400, + i2c_irq_gen_call = 0x800, + i2c_irq_all = 0xfff +}; + +/* Function declarations */ +static int mrst_i2c_disable(struct i2c_adapter *); +static int __devinit mrst_i2c_hwinit(struct pci_dev *); +static u32 mrst_i2c_func(struct i2c_adapter *); +static inline int mrst_i2c_invalid_address(const struct i2c_msg *); +static inline int mrst_i2c_address_neq(const struct i2c_msg *, + const struct i2c_msg *); +static int mrst_i2c_xfer(struct i2c_adapter *, + struct i2c_msg *, + int); +static int __devinit mrst_i2c_probe(struct pci_dev *, + const struct pci_device_id *); +static void __devexit mrst_i2c_remove(struct pci_dev *); +static int __init mrst_i2c_init(void); +static void __exit mrst_i2c_exit(void); +static int xfer_read(struct i2c_adapter *, + unsigned char *, int); +static int xfer_write(struct i2c_adapter *, + unsigned char *, int); +#endif /* __I2C_MRST_H */ diff --git a/drivers/i2c/i2c-boardinfo.c b/drivers/i2c/i2c-boardinfo.c index ffb35f0..72bde31 100644 --- a/drivers/i2c/i2c-boardinfo.c +++ b/drivers/i2c/i2c-boardinfo.c @@ -57,11 +57,13 @@ EXPORT_SYMBOL_GPL(__i2c_first_dynamic_bus_num); * The board info passed can safely be __initdata, but be careful of embedded * pointers (for platform_data, functions, etc) since that won't be copied. */ -int __init +int i2c_register_board_info(int busnum, struct i2c_board_info const *info, unsigned len) { int status; + int flag = 0; + struct i2c_devinfo *devinfo; mutex_lock(&__i2c_board_lock); @@ -69,22 +71,34 @@ i2c_register_board_info(int busnum, if (busnum >= __i2c_first_dynamic_bus_num) __i2c_first_dynamic_bus_num = busnum + 1; + /* Detect if the device is already in i2c_board_list */ for (status = 0; len; len--, info++) { - struct i2c_devinfo *devinfo; - - devinfo = kzalloc(sizeof(*devinfo), GFP_KERNEL); - if (!devinfo) { - pr_debug("i2c-core: can't register boardinfo!\n"); - status = -ENOMEM; - break; + list_for_each_entry(devinfo, &__i2c_board_list, list) { + if (devinfo->busnum == busnum + && devinfo->board_info.addr == info->addr) { + flag = 1; + break; + } } + if (flag != 1) { + struct i2c_devinfo *dev; + dev = kzalloc(sizeof(*dev), GFP_KERNEL); + if (!dev) { + pr_debug("i2c-core: can't register" + "boardinfo!\n"); + status = -ENOMEM; + break; + } - devinfo->busnum = busnum; - devinfo->board_info = *info; - list_add_tail(&devinfo->list, &__i2c_board_list); + dev->busnum = busnum; + dev->board_info = *info; + list_add_tail(&dev->list, &__i2c_board_list); + } + flag = 0; } mutex_unlock(&__i2c_board_lock); return status; } +EXPORT_SYMBOL_GPL(i2c_register_board_info); -- 1.5.5.1 -----Original Message----- From: Wang, Wen W Sent: 2009年4月23日 17:01 To: 'Jean Delvare' Cc: linux-i2c@xxxxxxxxxxxxxxx Subject: [PATCH 0/1] I2C: I2C controller driver for Intel Moorestown platform Hi Jean, This is a description for the patch: 1. Patch for I2C controller driver for Intel low power platform "Moorestown". 2. The driver depends on a GPIO driver for Intel Moorestown platform. 3. The patch will: a. Add i2c_mrst.c and i2c_mrst.h to kernel directory "drivers/i2c/busses" b. Add items into kernel files "drivers/i2c/busses/Kconfig" and "drivers/i2c/Makefile". c. Modify i2c-boardinfo.c to export i2c_register_board_info() function and add code to detect if a device is already in i2c_board_list. Thanks Wen ?韬{.n?????%??檩??w?{.n???{炳-?)?骅w*jg????????G??⒏⒎?:+v????????????"??????