diff options
Diffstat (limited to 'kernel/drivers/i2c/busses/i2c-tegra.c')
| -rw-r--r-- | kernel/drivers/i2c/busses/i2c-tegra.c | 920 |
1 files changed, 920 insertions, 0 deletions
diff --git a/kernel/drivers/i2c/busses/i2c-tegra.c b/kernel/drivers/i2c/busses/i2c-tegra.c new file mode 100644 index 000000000..1bcd75ea0 --- /dev/null +++ b/kernel/drivers/i2c/busses/i2c-tegra.c @@ -0,0 +1,920 @@ +/* + * drivers/i2c/busses/i2c-tegra.c + * + * Copyright (C) 2010 Google, Inc. + * Author: Colin Cross <ccross@android.com> + * + * 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 <linux/kernel.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/i2c.h> +#include <linux/io.h> +#include <linux/interrupt.h> +#include <linux/delay.h> +#include <linux/slab.h> +#include <linux/of_device.h> +#include <linux/module.h> +#include <linux/reset.h> + +#include <asm/unaligned.h> + +#define TEGRA_I2C_TIMEOUT (msecs_to_jiffies(1000)) +#define BYTES_PER_FIFO_WORD 4 + +#define I2C_CNFG 0x000 +#define I2C_CNFG_DEBOUNCE_CNT_SHIFT 12 +#define I2C_CNFG_PACKET_MODE_EN (1<<10) +#define I2C_CNFG_NEW_MASTER_FSM (1<<11) +#define I2C_STATUS 0x01C +#define I2C_SL_CNFG 0x020 +#define I2C_SL_CNFG_NACK (1<<1) +#define I2C_SL_CNFG_NEWSL (1<<2) +#define I2C_SL_ADDR1 0x02c +#define I2C_SL_ADDR2 0x030 +#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 I2C_CLK_DIVISOR_STD_FAST_MODE_SHIFT 16 +#define I2C_CLK_MULTIPLIER_STD_FAST_MODE 8 + +#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 I2C_ERR_UNKNOWN_INTERRUPT 0x04 + +#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_CONTINUE_XFER (1<<15) +#define I2C_HEADER_MASTER_ADDR_SHIFT 12 +#define I2C_HEADER_SLAVE_ADDR_SHIFT 1 +/* + * msg_end_type: The bus control which need to be send at end of transfer. + * @MSG_END_STOP: Send stop pulse at end of transfer. + * @MSG_END_REPEAT_START: Send repeat start at end of transfer. + * @MSG_END_CONTINUE: The following on message is coming and so do not send + * stop or repeat start. + */ +enum msg_end_type { + MSG_END_STOP, + MSG_END_REPEAT_START, + MSG_END_CONTINUE, +}; + +/** + * struct tegra_i2c_hw_feature : Different HW support on Tegra + * @has_continue_xfer_support: Continue transfer supports. + * @has_per_pkt_xfer_complete_irq: Has enable/disable capability for transfer + * complete interrupt per packet basis. + * @has_single_clk_source: The i2c controller has single clock source. Tegra30 + * and earlier Socs has two clock sources i.e. div-clk and + * fast-clk. + * @clk_divisor_hs_mode: Clock divisor in HS mode. + * @clk_divisor_std_fast_mode: Clock divisor in standard/fast mode. It is + * applicable if there is no fast clock source i.e. single clock + * source. + */ + +struct tegra_i2c_hw_feature { + bool has_continue_xfer_support; + bool has_per_pkt_xfer_complete_irq; + bool has_single_clk_source; + int clk_divisor_hs_mode; + int clk_divisor_std_fast_mode; +}; + +/** + * struct tegra_i2c_dev - per device i2c context + * @dev: device reference for power management + * @hw: Tegra i2c hw feature. + * @adapter: core i2c layer adapter information + * @div_clk: clock reference for div clock of i2c controller. + * @fast_clk: clock reference for fast clock of i2c controller. + * @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; + const struct tegra_i2c_hw_feature *hw; + struct i2c_adapter adapter; + struct clk *div_clk; + struct clk *fast_clk; + struct reset_control *rst; + void __iomem *base; + int cont_id; + int irq; + bool irq_disabled; + int is_dvc; + struct completion msg_complete; + int msg_err; + u8 *msg_buf; + size_t msg_buf_remaining; + int msg_read; + u32 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)); + + /* Read back register to make sure that register writes completed */ + if (reg != I2C_TX_FIFO) + readl(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); + val = cpu_to_le32(val); + 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; + + /* It's very common to have < 4 bytes, so optimize that case. */ + if (words_to_transfer) { + if (words_to_transfer > tx_fifo_avail) + words_to_transfer = tx_fifo_avail; + + /* + * Update state before writing to FIFO. If this casues us + * to finish writing all bytes (AKA buf_remaining goes to 0) we + * have a potential for an interrupt (PACKET_XFER_COMPLETE is + * not maskable). We need to make sure that the isr sees + * buf_remaining as 0 and doesn't call us back re-entrantly. + */ + buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD; + tx_fifo_avail -= words_to_transfer; + i2c_dev->msg_buf_remaining = buf_remaining; + i2c_dev->msg_buf = buf + + words_to_transfer * BYTES_PER_FIFO_WORD; + barrier(); + + i2c_writesl(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer); + + buf += words_to_transfer * BYTES_PER_FIFO_WORD; + } + + /* + * 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); + val = le32_to_cpu(val); + + /* Again update before writing to FIFO to make sure isr sees. */ + i2c_dev->msg_buf_remaining = 0; + i2c_dev->msg_buf = NULL; + barrier(); + + i2c_writel(i2c_dev, val, I2C_TX_FIFO); + } + + 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 inline int tegra_i2c_clock_enable(struct tegra_i2c_dev *i2c_dev) +{ + int ret; + if (!i2c_dev->hw->has_single_clk_source) { + ret = clk_enable(i2c_dev->fast_clk); + if (ret < 0) { + dev_err(i2c_dev->dev, + "Enabling fast clk failed, err %d\n", ret); + return ret; + } + } + ret = clk_enable(i2c_dev->div_clk); + if (ret < 0) { + dev_err(i2c_dev->dev, + "Enabling div clk failed, err %d\n", ret); + clk_disable(i2c_dev->fast_clk); + } + return ret; +} + +static inline void tegra_i2c_clock_disable(struct tegra_i2c_dev *i2c_dev) +{ + clk_disable(i2c_dev->div_clk); + if (!i2c_dev->hw->has_single_clk_source) + clk_disable(i2c_dev->fast_clk); +} + +static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev) +{ + u32 val; + int err = 0; + u32 clk_divisor; + + err = tegra_i2c_clock_enable(i2c_dev); + if (err < 0) { + dev_err(i2c_dev->dev, "Clock enable failed %d\n", err); + return err; + } + + reset_control_assert(i2c_dev->rst); + udelay(2); + reset_control_deassert(i2c_dev->rst); + + if (i2c_dev->is_dvc) + tegra_dvc_init(i2c_dev); + + val = I2C_CNFG_NEW_MASTER_FSM | I2C_CNFG_PACKET_MODE_EN | + (0x2 << I2C_CNFG_DEBOUNCE_CNT_SHIFT); + i2c_writel(i2c_dev, val, I2C_CNFG); + i2c_writel(i2c_dev, 0, I2C_INT_MASK); + + /* Make sure clock divisor programmed correctly */ + clk_divisor = i2c_dev->hw->clk_divisor_hs_mode; + clk_divisor |= i2c_dev->hw->clk_divisor_std_fast_mode << + I2C_CLK_DIVISOR_STD_FAST_MODE_SHIFT; + i2c_writel(i2c_dev, clk_divisor, I2C_CLK_DIVISOR); + + if (!i2c_dev->is_dvc) { + u32 sl_cfg = i2c_readl(i2c_dev, I2C_SL_CNFG); + sl_cfg |= I2C_SL_CNFG_NACK | I2C_SL_CNFG_NEWSL; + i2c_writel(i2c_dev, sl_cfg, I2C_SL_CNFG); + i2c_writel(i2c_dev, 0xfc, I2C_SL_ADDR1); + i2c_writel(i2c_dev, 0x00, I2C_SL_ADDR2); + + } + + 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; + + tegra_i2c_clock_disable(i2c_dev); + + if (i2c_dev->irq_disabled) { + i2c_dev->irq_disabled = 0; + enable_irq(i2c_dev->irq); + } + + 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, "irq status 0 %08x %08x %08x\n", + i2c_readl(i2c_dev, I2C_PACKET_TRANSFER_STATUS), + i2c_readl(i2c_dev, I2C_STATUS), + i2c_readl(i2c_dev, I2C_CNFG)); + i2c_dev->msg_err |= I2C_ERR_UNKNOWN_INTERRUPT; + + if (!i2c_dev->irq_disabled) { + disable_irq_nosync(i2c_dev->irq); + i2c_dev->irq_disabled = 1; + } + goto err; + } + + 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; + 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); + } + + i2c_writel(i2c_dev, status, I2C_INT_STATUS); + if (i2c_dev->is_dvc) + dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS); + + if (status & I2C_INT_PACKET_XFER_COMPLETE) { + BUG_ON(i2c_dev->msg_buf_remaining); + complete(&i2c_dev->msg_complete); + } + 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); + if (i2c_dev->is_dvc) + dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS); + + complete(&i2c_dev->msg_complete); + return IRQ_HANDLED; +} + +static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev, + struct i2c_msg *msg, enum msg_end_type end_state) +{ + u32 packet_header; + u32 int_mask; + unsigned long time_left; + + tegra_i2c_flush_fifos(i2c_dev); + + 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); + reinit_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 = I2C_HEADER_IE_ENABLE; + if (end_state == MSG_END_CONTINUE) + packet_header |= I2C_HEADER_CONTINUE_XFER; + else if (end_state == MSG_END_REPEAT_START) + packet_header |= I2C_HEADER_REPEAT_START; + if (msg->flags & I2C_M_TEN) { + packet_header |= msg->addr; + packet_header |= I2C_HEADER_10BIT_ADDR; + } else { + packet_header |= msg->addr << I2C_HEADER_SLAVE_ADDR_SHIFT; + } + if (msg->flags & I2C_M_IGNORE_NAK) + packet_header |= I2C_HEADER_CONT_ON_NAK; + 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 (i2c_dev->hw->has_per_pkt_xfer_complete_irq) + int_mask |= I2C_INT_PACKET_XFER_COMPLETE; + 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)); + + time_left = wait_for_completion_timeout(&i2c_dev->msg_complete, + TEGRA_I2C_TIMEOUT); + tegra_i2c_mask_irq(i2c_dev, int_mask); + + if (time_left == 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: %lu %d %d\n", + time_left, completion_done(&i2c_dev->msg_complete), + i2c_dev->msg_err); + + if (likely(i2c_dev->msg_err == I2C_ERR_NONE)) + return 0; + + /* + * NACK interrupt is generated before the I2C controller generates the + * STOP condition on the bus. So wait for 2 clock periods before resetting + * the controller so that STOP condition has been delivered properly. + */ + if (i2c_dev->msg_err == I2C_ERR_NO_ACK) + udelay(DIV_ROUND_UP(2 * 1000000, i2c_dev->bus_clk_rate)); + + 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; + + ret = tegra_i2c_clock_enable(i2c_dev); + if (ret < 0) { + dev_err(i2c_dev->dev, "Clock enable failed %d\n", ret); + return ret; + } + + for (i = 0; i < num; i++) { + enum msg_end_type end_type = MSG_END_STOP; + if (i < (num - 1)) { + if (msgs[i + 1].flags & I2C_M_NOSTART) + end_type = MSG_END_CONTINUE; + else + end_type = MSG_END_REPEAT_START; + } + ret = tegra_i2c_xfer_msg(i2c_dev, &msgs[i], end_type); + if (ret) + break; + } + tegra_i2c_clock_disable(i2c_dev); + return ret ?: i; +} + +static u32 tegra_i2c_func(struct i2c_adapter *adap) +{ + struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap); + u32 ret = I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR | + I2C_FUNC_PROTOCOL_MANGLING; + + if (i2c_dev->hw->has_continue_xfer_support) + ret |= I2C_FUNC_NOSTART; + return ret; +} + +static const struct i2c_algorithm tegra_i2c_algo = { + .master_xfer = tegra_i2c_xfer, + .functionality = tegra_i2c_func, +}; + +static const struct tegra_i2c_hw_feature tegra20_i2c_hw = { + .has_continue_xfer_support = false, + .has_per_pkt_xfer_complete_irq = false, + .has_single_clk_source = false, + .clk_divisor_hs_mode = 3, + .clk_divisor_std_fast_mode = 0, +}; + +static const struct tegra_i2c_hw_feature tegra30_i2c_hw = { + .has_continue_xfer_support = true, + .has_per_pkt_xfer_complete_irq = false, + .has_single_clk_source = false, + .clk_divisor_hs_mode = 3, + .clk_divisor_std_fast_mode = 0, +}; + +static const struct tegra_i2c_hw_feature tegra114_i2c_hw = { + .has_continue_xfer_support = true, + .has_per_pkt_xfer_complete_irq = true, + .has_single_clk_source = true, + .clk_divisor_hs_mode = 1, + .clk_divisor_std_fast_mode = 0x19, +}; + +/* Match table for of_platform binding */ +static const struct of_device_id tegra_i2c_of_match[] = { + { .compatible = "nvidia,tegra114-i2c", .data = &tegra114_i2c_hw, }, + { .compatible = "nvidia,tegra30-i2c", .data = &tegra30_i2c_hw, }, + { .compatible = "nvidia,tegra20-i2c", .data = &tegra20_i2c_hw, }, + { .compatible = "nvidia,tegra20-i2c-dvc", .data = &tegra20_i2c_hw, }, + {}, +}; +MODULE_DEVICE_TABLE(of, tegra_i2c_of_match); + +static int tegra_i2c_probe(struct platform_device *pdev) +{ + struct tegra_i2c_dev *i2c_dev; + struct resource *res; + struct clk *div_clk; + struct clk *fast_clk; + void __iomem *base; + int irq; + int ret = 0; + int clk_multiplier = I2C_CLK_MULTIPLIER_STD_FAST_MODE; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(base)) + return PTR_ERR(base); + + res = platform_get_resource(pdev, IORESOURCE_IRQ, 0); + if (!res) { + dev_err(&pdev->dev, "no irq resource\n"); + return -EINVAL; + } + irq = res->start; + + div_clk = devm_clk_get(&pdev->dev, "div-clk"); + if (IS_ERR(div_clk)) { + dev_err(&pdev->dev, "missing controller clock"); + return PTR_ERR(div_clk); + } + + i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL); + if (!i2c_dev) + return -ENOMEM; + + i2c_dev->base = base; + i2c_dev->div_clk = div_clk; + i2c_dev->adapter.algo = &tegra_i2c_algo; + i2c_dev->irq = irq; + i2c_dev->cont_id = pdev->id; + i2c_dev->dev = &pdev->dev; + + i2c_dev->rst = devm_reset_control_get(&pdev->dev, "i2c"); + if (IS_ERR(i2c_dev->rst)) { + dev_err(&pdev->dev, "missing controller reset"); + return PTR_ERR(i2c_dev->rst); + } + + ret = of_property_read_u32(i2c_dev->dev->of_node, "clock-frequency", + &i2c_dev->bus_clk_rate); + if (ret) + i2c_dev->bus_clk_rate = 100000; /* default clock rate */ + + i2c_dev->hw = &tegra20_i2c_hw; + + if (pdev->dev.of_node) { + const struct of_device_id *match; + match = of_match_device(tegra_i2c_of_match, &pdev->dev); + i2c_dev->hw = match->data; + i2c_dev->is_dvc = of_device_is_compatible(pdev->dev.of_node, + "nvidia,tegra20-i2c-dvc"); + } else if (pdev->id == 3) { + i2c_dev->is_dvc = 1; + } + init_completion(&i2c_dev->msg_complete); + + if (!i2c_dev->hw->has_single_clk_source) { + fast_clk = devm_clk_get(&pdev->dev, "fast-clk"); + if (IS_ERR(fast_clk)) { + dev_err(&pdev->dev, "missing fast clock"); + return PTR_ERR(fast_clk); + } + i2c_dev->fast_clk = fast_clk; + } + + platform_set_drvdata(pdev, i2c_dev); + + if (!i2c_dev->hw->has_single_clk_source) { + ret = clk_prepare(i2c_dev->fast_clk); + if (ret < 0) { + dev_err(i2c_dev->dev, "Clock prepare failed %d\n", ret); + return ret; + } + } + + clk_multiplier *= (i2c_dev->hw->clk_divisor_std_fast_mode + 1); + ret = clk_set_rate(i2c_dev->div_clk, + i2c_dev->bus_clk_rate * clk_multiplier); + if (ret) { + dev_err(i2c_dev->dev, "Clock rate change failed %d\n", ret); + goto unprepare_fast_clk; + } + + ret = clk_prepare(i2c_dev->div_clk); + if (ret < 0) { + dev_err(i2c_dev->dev, "Clock prepare failed %d\n", ret); + goto unprepare_fast_clk; + } + + ret = tegra_i2c_init(i2c_dev); + if (ret) { + dev_err(&pdev->dev, "Failed to initialize i2c controller"); + goto unprepare_div_clk; + } + + ret = devm_request_irq(&pdev->dev, i2c_dev->irq, + tegra_i2c_isr, 0, dev_name(&pdev->dev), i2c_dev); + if (ret) { + dev_err(&pdev->dev, "Failed to request irq %i\n", i2c_dev->irq); + goto unprepare_div_clk; + } + + i2c_set_adapdata(&i2c_dev->adapter, i2c_dev); + i2c_dev->adapter.owner = THIS_MODULE; + i2c_dev->adapter.class = I2C_CLASS_DEPRECATED; + 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; + i2c_dev->adapter.dev.of_node = pdev->dev.of_node; + + ret = i2c_add_numbered_adapter(&i2c_dev->adapter); + if (ret) { + dev_err(&pdev->dev, "Failed to add I2C adapter\n"); + goto unprepare_div_clk; + } + + return 0; + +unprepare_div_clk: + clk_unprepare(i2c_dev->div_clk); + +unprepare_fast_clk: + if (!i2c_dev->hw->has_single_clk_source) + clk_unprepare(i2c_dev->fast_clk); + + 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); + + clk_unprepare(i2c_dev->div_clk); + if (!i2c_dev->hw->has_single_clk_source) + clk_unprepare(i2c_dev->fast_clk); + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int tegra_i2c_suspend(struct device *dev) +{ + struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev); + + 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 device *dev) +{ + struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev); + 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; +} + +static SIMPLE_DEV_PM_OPS(tegra_i2c_pm, tegra_i2c_suspend, tegra_i2c_resume); +#define TEGRA_I2C_PM (&tegra_i2c_pm) +#else +#define TEGRA_I2C_PM NULL +#endif + +static struct platform_driver tegra_i2c_driver = { + .probe = tegra_i2c_probe, + .remove = tegra_i2c_remove, + .driver = { + .name = "tegra-i2c", + .of_match_table = tegra_i2c_of_match, + .pm = TEGRA_I2C_PM, + }, +}; + +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"); |