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kernel-fxtec-pro1x/drivers/i2c/busses/i2c-tegra.c
Wolfram Sang 687b81d083 i2c: move OF helpers into the core 
I2C of helpers used to live in of_i2c.c but experience (from SPI) shows
that it is much cleaner to have this in the core. This also removes a
circular dependency between the helpers and the core, and so we can
finally register child nodes in the core instead of doing this manually
in each driver. So, fix the drivers and documentation, too.

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2013-08-23 10:22:20 +02:00

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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/clk/tegra.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;
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);
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);
/* 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_prepare_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_prepare_enable(i2c_dev->div_clk);
if (ret < 0) {
dev_err(i2c_dev->dev,
"Enabling div clk failed, err %d\n", ret);
clk_disable_unprepare(i2c_dev->fast_clk);
}
return ret;
}
static inline void tegra_i2c_clock_disable(struct tegra_i2c_dev *i2c_dev)
{
clk_disable_unprepare(i2c_dev->div_clk);
if (!i2c_dev->hw->has_single_clk_source)
clk_disable_unprepare(i2c_dev->fast_clk);
}
static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
{
u32 val;
int err = 0;
int clk_multiplier = I2C_CLK_MULTIPLIER_STD_FAST_MODE;
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;
}
tegra_periph_reset_assert(i2c_dev->div_clk);
udelay(2);
tegra_periph_reset_deassert(i2c_dev->div_clk);
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);
clk_multiplier *= (i2c_dev->hw->clk_divisor_std_fast_mode + 1);
clk_set_rate(i2c_dev->div_clk, i2c_dev->bus_clk_rate * clk_multiplier);
/* 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;
int ret;
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);
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 = 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));
ret = wait_for_completion_timeout(&i2c_dev->msg_complete, TEGRA_I2C_TIMEOUT);
tegra_i2c_mask_irq(i2c_dev, int_mask);
if (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;
/*
* 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;
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) {
dev_err(&pdev->dev, "Could not allocate struct tegra_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;
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);
ret = tegra_i2c_init(i2c_dev);
if (ret) {
dev_err(&pdev->dev, "Failed to initialize i2c controller");
return ret;
}
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);
return ret;
}
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;
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");
return ret;
}
return 0;
}
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);
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",
.owner = THIS_MODULE,
.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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