/* * drivers/i2c/busses/i2c-tegra.c * * Copyright (C) 2010 Google, Inc. * Author: Colin Cross * * This software is licensed under the terms of the GNU General Public * License version 2, as published by the Free Software Foundation, and * may be copied, distributed, and modified under those terms. * * This program is distributed in the hope that 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. * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #define TEGRA_I2C_TIMEOUT (msecs_to_jiffies(1000)) #define BYTES_PER_FIFO_WORD 4 #define I2C_CNFG 0x000 #define I2C_CNFG_PACKET_MODE_EN (1<<10) #define I2C_CNFG_NEW_MASTER_FSM (1<<11) #define I2C_SL_CNFG 0x020 #define I2C_SL_CNFG_NEWSL (1<<2) #define I2C_SL_ADDR1 0x02c #define I2C_TX_FIFO 0x050 #define I2C_RX_FIFO 0x054 #define I2C_PACKET_TRANSFER_STATUS 0x058 #define I2C_FIFO_CONTROL 0x05c #define I2C_FIFO_CONTROL_TX_FLUSH (1<<1) #define I2C_FIFO_CONTROL_RX_FLUSH (1<<0) #define I2C_FIFO_CONTROL_TX_TRIG_SHIFT 5 #define I2C_FIFO_CONTROL_RX_TRIG_SHIFT 2 #define I2C_FIFO_STATUS 0x060 #define I2C_FIFO_STATUS_TX_MASK 0xF0 #define I2C_FIFO_STATUS_TX_SHIFT 4 #define I2C_FIFO_STATUS_RX_MASK 0x0F #define I2C_FIFO_STATUS_RX_SHIFT 0 #define I2C_INT_MASK 0x064 #define I2C_INT_STATUS 0x068 #define I2C_INT_PACKET_XFER_COMPLETE (1<<7) #define I2C_INT_ALL_PACKETS_XFER_COMPLETE (1<<6) #define I2C_INT_TX_FIFO_OVERFLOW (1<<5) #define I2C_INT_RX_FIFO_UNDERFLOW (1<<4) #define I2C_INT_NO_ACK (1<<3) #define I2C_INT_ARBITRATION_LOST (1<<2) #define I2C_INT_TX_FIFO_DATA_REQ (1<<1) #define I2C_INT_RX_FIFO_DATA_REQ (1<<0) #define I2C_CLK_DIVISOR 0x06c #define DVC_CTRL_REG1 0x000 #define DVC_CTRL_REG1_INTR_EN (1<<10) #define DVC_CTRL_REG2 0x004 #define DVC_CTRL_REG3 0x008 #define DVC_CTRL_REG3_SW_PROG (1<<26) #define DVC_CTRL_REG3_I2C_DONE_INTR_EN (1<<30) #define DVC_STATUS 0x00c #define DVC_STATUS_I2C_DONE_INTR (1<<30) #define I2C_ERR_NONE 0x00 #define I2C_ERR_NO_ACK 0x01 #define I2C_ERR_ARBITRATION_LOST 0x02 #define PACKET_HEADER0_HEADER_SIZE_SHIFT 28 #define PACKET_HEADER0_PACKET_ID_SHIFT 16 #define PACKET_HEADER0_CONT_ID_SHIFT 12 #define PACKET_HEADER0_PROTOCOL_I2C (1<<4) #define I2C_HEADER_HIGHSPEED_MODE (1<<22) #define I2C_HEADER_CONT_ON_NAK (1<<21) #define I2C_HEADER_SEND_START_BYTE (1<<20) #define I2C_HEADER_READ (1<<19) #define I2C_HEADER_10BIT_ADDR (1<<18) #define I2C_HEADER_IE_ENABLE (1<<17) #define I2C_HEADER_REPEAT_START (1<<16) #define I2C_HEADER_MASTER_ADDR_SHIFT 12 #define I2C_HEADER_SLAVE_ADDR_SHIFT 1 /** * struct tegra_i2c_dev - per device i2c context * @dev: device reference for power management * @adapter: core i2c layer adapter information * @clk: clock reference for i2c controller * @i2c_clk: clock reference for i2c bus * @iomem: memory resource for registers * @base: ioremapped registers cookie * @cont_id: i2c controller id, used for for packet header * @irq: irq number of transfer complete interrupt * @is_dvc: identifies the DVC i2c controller, has a different register layout * @msg_complete: transfer completion notifier * @msg_err: error code for completed message * @msg_buf: pointer to current message data * @msg_buf_remaining: size of unsent data in the message buffer * @msg_read: identifies read transfers * @bus_clk_rate: current i2c bus clock rate * @is_suspended: prevents i2c controller accesses after suspend is called */ struct tegra_i2c_dev { struct device *dev; struct i2c_adapter adapter; struct clk *clk; struct clk *i2c_clk; struct resource *iomem; void __iomem *base; int cont_id; int irq; int is_dvc; struct completion msg_complete; int msg_err; u8 *msg_buf; size_t msg_buf_remaining; int msg_read; unsigned long bus_clk_rate; bool is_suspended; }; static void dvc_writel(struct tegra_i2c_dev *i2c_dev, u32 val, unsigned long reg) { writel(val, i2c_dev->base + reg); } static u32 dvc_readl(struct tegra_i2c_dev *i2c_dev, unsigned long reg) { return readl(i2c_dev->base + reg); } /* * i2c_writel and i2c_readl will offset the register if necessary to talk * to the I2C block inside the DVC block */ static unsigned long tegra_i2c_reg_addr(struct tegra_i2c_dev *i2c_dev, unsigned long reg) { if (i2c_dev->is_dvc) reg += (reg >= I2C_TX_FIFO) ? 0x10 : 0x40; return reg; } static void i2c_writel(struct tegra_i2c_dev *i2c_dev, u32 val, unsigned long reg) { writel(val, i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg)); } static u32 i2c_readl(struct tegra_i2c_dev *i2c_dev, unsigned long reg) { return readl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg)); } static void i2c_writesl(struct tegra_i2c_dev *i2c_dev, void *data, unsigned long reg, int len) { writesl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg), data, len); } static void i2c_readsl(struct tegra_i2c_dev *i2c_dev, void *data, unsigned long reg, int len) { readsl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg), data, len); } static void tegra_i2c_mask_irq(struct tegra_i2c_dev *i2c_dev, u32 mask) { u32 int_mask = i2c_readl(i2c_dev, I2C_INT_MASK); int_mask &= ~mask; i2c_writel(i2c_dev, int_mask, I2C_INT_MASK); } static void tegra_i2c_unmask_irq(struct tegra_i2c_dev *i2c_dev, u32 mask) { u32 int_mask = i2c_readl(i2c_dev, I2C_INT_MASK); int_mask |= mask; i2c_writel(i2c_dev, int_mask, I2C_INT_MASK); } static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev) { unsigned long timeout = jiffies + HZ; u32 val = i2c_readl(i2c_dev, I2C_FIFO_CONTROL); val |= I2C_FIFO_CONTROL_TX_FLUSH | I2C_FIFO_CONTROL_RX_FLUSH; i2c_writel(i2c_dev, val, I2C_FIFO_CONTROL); while (i2c_readl(i2c_dev, I2C_FIFO_CONTROL) & (I2C_FIFO_CONTROL_TX_FLUSH | I2C_FIFO_CONTROL_RX_FLUSH)) { if (time_after(jiffies, timeout)) { dev_warn(i2c_dev->dev, "timeout waiting for fifo flush\n"); return -ETIMEDOUT; } msleep(1); } return 0; } static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev) { u32 val; int rx_fifo_avail; u8 *buf = i2c_dev->msg_buf; size_t buf_remaining = i2c_dev->msg_buf_remaining; int words_to_transfer; val = i2c_readl(i2c_dev, I2C_FIFO_STATUS); rx_fifo_avail = (val & I2C_FIFO_STATUS_RX_MASK) >> I2C_FIFO_STATUS_RX_SHIFT; /* Rounds down to not include partial word at the end of buf */ words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD; if (words_to_transfer > rx_fifo_avail) words_to_transfer = rx_fifo_avail; i2c_readsl(i2c_dev, buf, I2C_RX_FIFO, words_to_transfer); buf += words_to_transfer * BYTES_PER_FIFO_WORD; buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD; rx_fifo_avail -= words_to_transfer; /* * If there is a partial word at the end of buf, handle it manually to * prevent overwriting past the end of buf */ if (rx_fifo_avail > 0 && buf_remaining > 0) { BUG_ON(buf_remaining > 3); val = i2c_readl(i2c_dev, I2C_RX_FIFO); memcpy(buf, &val, buf_remaining); buf_remaining = 0; rx_fifo_avail--; } BUG_ON(rx_fifo_avail > 0 && buf_remaining > 0); i2c_dev->msg_buf_remaining = buf_remaining; i2c_dev->msg_buf = buf; return 0; } static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev) { u32 val; int tx_fifo_avail; u8 *buf = i2c_dev->msg_buf; size_t buf_remaining = i2c_dev->msg_buf_remaining; int words_to_transfer; val = i2c_readl(i2c_dev, I2C_FIFO_STATUS); tx_fifo_avail = (val & I2C_FIFO_STATUS_TX_MASK) >> I2C_FIFO_STATUS_TX_SHIFT; /* Rounds down to not include partial word at the end of buf */ words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD; if (words_to_transfer > tx_fifo_avail) words_to_transfer = tx_fifo_avail; i2c_writesl(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer); buf += words_to_transfer * BYTES_PER_FIFO_WORD; buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD; tx_fifo_avail -= words_to_transfer; /* * If there is a partial word at the end of buf, handle it manually to * prevent reading past the end of buf, which could cross a page * boundary and fault. */ if (tx_fifo_avail > 0 && buf_remaining > 0) { BUG_ON(buf_remaining > 3); memcpy(&val, buf, buf_remaining); i2c_writel(i2c_dev, val, I2C_TX_FIFO); buf_remaining = 0; tx_fifo_avail--; } BUG_ON(tx_fifo_avail > 0 && buf_remaining > 0); i2c_dev->msg_buf_remaining = buf_remaining; i2c_dev->msg_buf = buf; return 0; } /* * One of the Tegra I2C blocks is inside the DVC (Digital Voltage Controller) * block. This block is identical to the rest of the I2C blocks, except that * it only supports master mode, it has registers moved around, and it needs * some extra init to get it into I2C mode. The register moves are handled * by i2c_readl and i2c_writel */ static void tegra_dvc_init(struct tegra_i2c_dev *i2c_dev) { u32 val = 0; val = dvc_readl(i2c_dev, DVC_CTRL_REG3); val |= DVC_CTRL_REG3_SW_PROG; val |= DVC_CTRL_REG3_I2C_DONE_INTR_EN; dvc_writel(i2c_dev, val, DVC_CTRL_REG3); val = dvc_readl(i2c_dev, DVC_CTRL_REG1); val |= DVC_CTRL_REG1_INTR_EN; dvc_writel(i2c_dev, val, DVC_CTRL_REG1); } static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev) { u32 val; int err = 0; clk_enable(i2c_dev->clk); tegra_periph_reset_assert(i2c_dev->clk); udelay(2); tegra_periph_reset_deassert(i2c_dev->clk); if (i2c_dev->is_dvc) tegra_dvc_init(i2c_dev); val = I2C_CNFG_NEW_MASTER_FSM | I2C_CNFG_PACKET_MODE_EN; i2c_writel(i2c_dev, val, I2C_CNFG); i2c_writel(i2c_dev, 0, I2C_INT_MASK); clk_set_rate(i2c_dev->clk, i2c_dev->bus_clk_rate * 8); if (!i2c_dev->is_dvc) { u32 sl_cfg = i2c_readl(i2c_dev, I2C_SL_CNFG); i2c_writel(i2c_dev, sl_cfg | I2C_SL_CNFG_NEWSL, I2C_SL_CNFG); } val = 7 << I2C_FIFO_CONTROL_TX_TRIG_SHIFT | 0 << I2C_FIFO_CONTROL_RX_TRIG_SHIFT; i2c_writel(i2c_dev, val, I2C_FIFO_CONTROL); if (tegra_i2c_flush_fifos(i2c_dev)) err = -ETIMEDOUT; clk_disable(i2c_dev->clk); return err; } static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) { u32 status; const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST; struct tegra_i2c_dev *i2c_dev = dev_id; status = i2c_readl(i2c_dev, I2C_INT_STATUS); if (status == 0) { dev_warn(i2c_dev->dev, "interrupt with no status\n"); return IRQ_NONE; } if (unlikely(status & status_err)) { if (status & I2C_INT_NO_ACK) i2c_dev->msg_err |= I2C_ERR_NO_ACK; if (status & I2C_INT_ARBITRATION_LOST) i2c_dev->msg_err |= I2C_ERR_ARBITRATION_LOST; complete(&i2c_dev->msg_complete); goto err; } if (i2c_dev->msg_read && (status & I2C_INT_RX_FIFO_DATA_REQ)) { if (i2c_dev->msg_buf_remaining) tegra_i2c_empty_rx_fifo(i2c_dev); else BUG(); } if (!i2c_dev->msg_read && (status & I2C_INT_TX_FIFO_DATA_REQ)) { if (i2c_dev->msg_buf_remaining) tegra_i2c_fill_tx_fifo(i2c_dev); else tegra_i2c_mask_irq(i2c_dev, I2C_INT_TX_FIFO_DATA_REQ); } if ((status & I2C_INT_PACKET_XFER_COMPLETE) && !i2c_dev->msg_buf_remaining) complete(&i2c_dev->msg_complete); i2c_writel(i2c_dev, status, I2C_INT_STATUS); if (i2c_dev->is_dvc) dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS); return IRQ_HANDLED; err: /* An error occurred, mask all interrupts */ tegra_i2c_mask_irq(i2c_dev, I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST | I2C_INT_PACKET_XFER_COMPLETE | I2C_INT_TX_FIFO_DATA_REQ | I2C_INT_RX_FIFO_DATA_REQ); i2c_writel(i2c_dev, status, I2C_INT_STATUS); return IRQ_HANDLED; } static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev, struct i2c_msg *msg, int stop) { u32 packet_header; u32 int_mask; int ret; tegra_i2c_flush_fifos(i2c_dev); i2c_writel(i2c_dev, 0xFF, I2C_INT_STATUS); if (msg->len == 0) return -EINVAL; i2c_dev->msg_buf = msg->buf; i2c_dev->msg_buf_remaining = msg->len; i2c_dev->msg_err = I2C_ERR_NONE; i2c_dev->msg_read = (msg->flags & I2C_M_RD); INIT_COMPLETION(i2c_dev->msg_complete); packet_header = (0 << PACKET_HEADER0_HEADER_SIZE_SHIFT) | PACKET_HEADER0_PROTOCOL_I2C | (i2c_dev->cont_id << PACKET_HEADER0_CONT_ID_SHIFT) | (1 << PACKET_HEADER0_PACKET_ID_SHIFT); i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO); packet_header = msg->len - 1; i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO); packet_header = msg->addr << I2C_HEADER_SLAVE_ADDR_SHIFT; packet_header |= I2C_HEADER_IE_ENABLE; if (msg->flags & I2C_M_TEN) packet_header |= I2C_HEADER_10BIT_ADDR; if (msg->flags & I2C_M_IGNORE_NAK) packet_header |= I2C_HEADER_CONT_ON_NAK; if (msg->flags & I2C_M_NOSTART) packet_header |= I2C_HEADER_REPEAT_START; if (msg->flags & I2C_M_RD) packet_header |= I2C_HEADER_READ; i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO); if (!(msg->flags & I2C_M_RD)) tegra_i2c_fill_tx_fifo(i2c_dev); int_mask = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST; if (msg->flags & I2C_M_RD) int_mask |= I2C_INT_RX_FIFO_DATA_REQ; else if (i2c_dev->msg_buf_remaining) int_mask |= I2C_INT_TX_FIFO_DATA_REQ; tegra_i2c_unmask_irq(i2c_dev, int_mask); dev_dbg(i2c_dev->dev, "unmasked irq: %02x\n", i2c_readl(i2c_dev, I2C_INT_MASK)); ret = wait_for_completion_timeout(&i2c_dev->msg_complete, TEGRA_I2C_TIMEOUT); tegra_i2c_mask_irq(i2c_dev, int_mask); if (WARN_ON(ret == 0)) { dev_err(i2c_dev->dev, "i2c transfer timed out\n"); tegra_i2c_init(i2c_dev); return -ETIMEDOUT; } dev_dbg(i2c_dev->dev, "transfer complete: %d %d %d\n", ret, completion_done(&i2c_dev->msg_complete), i2c_dev->msg_err); if (likely(i2c_dev->msg_err == I2C_ERR_NONE)) return 0; tegra_i2c_init(i2c_dev); if (i2c_dev->msg_err == I2C_ERR_NO_ACK) { if (msg->flags & I2C_M_IGNORE_NAK) return 0; return -EREMOTEIO; } return -EIO; } static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) { struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap); int i; int ret = 0; if (i2c_dev->is_suspended) return -EBUSY; clk_enable(i2c_dev->clk); for (i = 0; i < num; i++) { int stop = (i == (num - 1)) ? 1 : 0; ret = tegra_i2c_xfer_msg(i2c_dev, &msgs[i], stop); if (ret) break; } clk_disable(i2c_dev->clk); return ret ?: i; } static u32 tegra_i2c_func(struct i2c_adapter *adap) { return I2C_FUNC_I2C; } static const struct i2c_algorithm tegra_i2c_algo = { .master_xfer = tegra_i2c_xfer, .functionality = tegra_i2c_func, }; static int tegra_i2c_probe(struct platform_device *pdev) { struct tegra_i2c_dev *i2c_dev; struct tegra_i2c_platform_data *pdata = pdev->dev.platform_data; struct resource *res; struct resource *iomem; struct clk *clk; struct clk *i2c_clk; void *base; int irq; int ret = 0; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!res) { dev_err(&pdev->dev, "no mem resource\n"); return -EINVAL; } iomem = request_mem_region(res->start, resource_size(res), pdev->name); if (!iomem) { dev_err(&pdev->dev, "I2C region already claimed\n"); return -EBUSY; } base = ioremap(iomem->start, resource_size(iomem)); if (!base) { dev_err(&pdev->dev, "Cannot ioremap I2C region\n"); return -ENOMEM; } res = platform_get_resource(pdev, IORESOURCE_IRQ, 0); if (!res) { dev_err(&pdev->dev, "no irq resource\n"); ret = -EINVAL; goto err_iounmap; } irq = res->start; clk = clk_get(&pdev->dev, NULL); if (IS_ERR(clk)) { dev_err(&pdev->dev, "missing controller clock"); ret = PTR_ERR(clk); goto err_release_region; } i2c_clk = clk_get(&pdev->dev, "i2c"); if (IS_ERR(i2c_clk)) { dev_err(&pdev->dev, "missing bus clock"); ret = PTR_ERR(i2c_clk); goto err_clk_put; } i2c_dev = kzalloc(sizeof(struct tegra_i2c_dev), GFP_KERNEL); if (!i2c_dev) { ret = -ENOMEM; goto err_i2c_clk_put; } i2c_dev->base = base; i2c_dev->clk = clk; i2c_dev->i2c_clk = i2c_clk; i2c_dev->iomem = iomem; i2c_dev->adapter.algo = &tegra_i2c_algo; i2c_dev->irq = irq; i2c_dev->cont_id = pdev->id; i2c_dev->dev = &pdev->dev; i2c_dev->bus_clk_rate = pdata ? pdata->bus_clk_rate : 100000; if (pdev->id == 3) i2c_dev->is_dvc = 1; init_completion(&i2c_dev->msg_complete); platform_set_drvdata(pdev, i2c_dev); ret = tegra_i2c_init(i2c_dev); if (ret) { dev_err(&pdev->dev, "Failed to initialize i2c controller"); goto err_free; } ret = request_irq(i2c_dev->irq, tegra_i2c_isr, 0, pdev->name, i2c_dev); if (ret) { dev_err(&pdev->dev, "Failed to request irq %i\n", i2c_dev->irq); goto err_free; } clk_enable(i2c_dev->i2c_clk); i2c_set_adapdata(&i2c_dev->adapter, i2c_dev); i2c_dev->adapter.owner = THIS_MODULE; i2c_dev->adapter.class = I2C_CLASS_HWMON; strlcpy(i2c_dev->adapter.name, "Tegra I2C adapter", sizeof(i2c_dev->adapter.name)); i2c_dev->adapter.algo = &tegra_i2c_algo; i2c_dev->adapter.dev.parent = &pdev->dev; i2c_dev->adapter.nr = pdev->id; ret = i2c_add_numbered_adapter(&i2c_dev->adapter); if (ret) { dev_err(&pdev->dev, "Failed to add I2C adapter\n"); goto err_free_irq; } return 0; err_free_irq: free_irq(i2c_dev->irq, i2c_dev); err_free: kfree(i2c_dev); err_i2c_clk_put: clk_put(i2c_clk); err_clk_put: clk_put(clk); err_release_region: release_mem_region(iomem->start, resource_size(iomem)); err_iounmap: iounmap(base); return ret; } static int tegra_i2c_remove(struct platform_device *pdev) { struct tegra_i2c_dev *i2c_dev = platform_get_drvdata(pdev); i2c_del_adapter(&i2c_dev->adapter); free_irq(i2c_dev->irq, i2c_dev); clk_put(i2c_dev->i2c_clk); clk_put(i2c_dev->clk); release_mem_region(i2c_dev->iomem->start, resource_size(i2c_dev->iomem)); iounmap(i2c_dev->base); kfree(i2c_dev); return 0; } #ifdef CONFIG_PM static int tegra_i2c_suspend(struct platform_device *pdev, pm_message_t state) { struct tegra_i2c_dev *i2c_dev = platform_get_drvdata(pdev); i2c_lock_adapter(&i2c_dev->adapter); i2c_dev->is_suspended = true; i2c_unlock_adapter(&i2c_dev->adapter); return 0; } static int tegra_i2c_resume(struct platform_device *pdev) { struct tegra_i2c_dev *i2c_dev = platform_get_drvdata(pdev); int ret; i2c_lock_adapter(&i2c_dev->adapter); ret = tegra_i2c_init(i2c_dev); if (ret) { i2c_unlock_adapter(&i2c_dev->adapter); return ret; } i2c_dev->is_suspended = false; i2c_unlock_adapter(&i2c_dev->adapter); return 0; } #endif static struct platform_driver tegra_i2c_driver = { .probe = tegra_i2c_probe, .remove = tegra_i2c_remove, #ifdef CONFIG_PM .suspend = tegra_i2c_suspend, .resume = tegra_i2c_resume, #endif .driver = { .name = "tegra-i2c", .owner = THIS_MODULE, }, }; static int __init tegra_i2c_init_driver(void) { return platform_driver_register(&tegra_i2c_driver); } static void __exit tegra_i2c_exit_driver(void) { platform_driver_unregister(&tegra_i2c_driver); } subsys_initcall(tegra_i2c_init_driver); module_exit(tegra_i2c_exit_driver); MODULE_DESCRIPTION("nVidia Tegra2 I2C Bus Controller driver"); MODULE_AUTHOR("Colin Cross"); MODULE_LICENSE("GPL v2");