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linux/drivers/i2c/busses/i2c-tegra.c

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/*
* 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_SMBUS_QUICK) |
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,
};
/* payload size is only 12 bit */
static struct i2c_adapter_quirks tegra_i2c_quirks = {
.max_read_len = 4096,
.max_write_len = 4096,
};
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->adapter.quirks = &tegra_i2c_quirks;
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");
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