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linux-sg2042/drivers/i2c/busses/i2c-axxia.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* This driver implements I2C master functionality using the LSI API2C
* controller.
*
* NOTE: The controller has a limitation in that it can only do transfers of
* maximum 255 bytes at a time. If a larger transfer is attempted, error code
* (-EINVAL) is returned.
*/
#include <linux/clk.h>
#include <linux/clkdev.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#define SCL_WAIT_TIMEOUT_NS 25000000
#define I2C_XFER_TIMEOUT (msecs_to_jiffies(250))
#define I2C_STOP_TIMEOUT (msecs_to_jiffies(100))
#define FIFO_SIZE 8
#define SEQ_LEN 2
#define GLOBAL_CONTROL 0x00
#define GLOBAL_MST_EN BIT(0)
#define GLOBAL_SLV_EN BIT(1)
#define GLOBAL_IBML_EN BIT(2)
#define INTERRUPT_STATUS 0x04
#define INTERRUPT_ENABLE 0x08
#define INT_SLV BIT(1)
#define INT_MST BIT(0)
#define WAIT_TIMER_CONTROL 0x0c
#define WT_EN BIT(15)
#define WT_VALUE(_x) ((_x) & 0x7fff)
#define IBML_TIMEOUT 0x10
#define IBML_LOW_MEXT 0x14
#define IBML_LOW_SEXT 0x18
#define TIMER_CLOCK_DIV 0x1c
#define I2C_BUS_MONITOR 0x20
#define BM_SDAC BIT(3)
#define BM_SCLC BIT(2)
#define BM_SDAS BIT(1)
#define BM_SCLS BIT(0)
#define SOFT_RESET 0x24
#define MST_COMMAND 0x28
#define CMD_BUSY (1<<3)
#define CMD_MANUAL (0x00 | CMD_BUSY)
#define CMD_AUTO (0x01 | CMD_BUSY)
#define CMD_SEQUENCE (0x02 | CMD_BUSY)
#define MST_RX_XFER 0x2c
#define MST_TX_XFER 0x30
#define MST_ADDR_1 0x34
#define MST_ADDR_2 0x38
#define MST_DATA 0x3c
#define MST_TX_FIFO 0x40
#define MST_RX_FIFO 0x44
#define MST_INT_ENABLE 0x48
#define MST_INT_STATUS 0x4c
#define MST_STATUS_RFL (1 << 13) /* RX FIFO serivce */
#define MST_STATUS_TFL (1 << 12) /* TX FIFO service */
#define MST_STATUS_SNS (1 << 11) /* Manual mode done */
#define MST_STATUS_SS (1 << 10) /* Automatic mode done */
#define MST_STATUS_SCC (1 << 9) /* Stop complete */
#define MST_STATUS_IP (1 << 8) /* Invalid parameter */
#define MST_STATUS_TSS (1 << 7) /* Timeout */
#define MST_STATUS_AL (1 << 6) /* Arbitration lost */
#define MST_STATUS_ND (1 << 5) /* NAK on data phase */
#define MST_STATUS_NA (1 << 4) /* NAK on address phase */
#define MST_STATUS_NAK (MST_STATUS_NA | \
MST_STATUS_ND)
#define MST_STATUS_ERR (MST_STATUS_NAK | \
MST_STATUS_AL | \
MST_STATUS_IP)
#define MST_TX_BYTES_XFRD 0x50
#define MST_RX_BYTES_XFRD 0x54
#define SLV_ADDR_DEC_CTL 0x58
#define SLV_ADDR_DEC_GCE BIT(0) /* ACK to General Call Address from own master (loopback) */
#define SLV_ADDR_DEC_OGCE BIT(1) /* ACK to General Call Address from external masters */
#define SLV_ADDR_DEC_SA1E BIT(2) /* ACK to addr_1 enabled */
#define SLV_ADDR_DEC_SA1M BIT(3) /* 10-bit addressing for addr_1 enabled */
#define SLV_ADDR_DEC_SA2E BIT(4) /* ACK to addr_2 enabled */
#define SLV_ADDR_DEC_SA2M BIT(5) /* 10-bit addressing for addr_2 enabled */
#define SLV_ADDR_1 0x5c
#define SLV_ADDR_2 0x60
#define SLV_RX_CTL 0x64
#define SLV_RX_ACSA1 BIT(0) /* Generate ACK for writes to addr_1 */
#define SLV_RX_ACSA2 BIT(1) /* Generate ACK for writes to addr_2 */
#define SLV_RX_ACGCA BIT(2) /* ACK data phase transfers to General Call Address */
#define SLV_DATA 0x68
#define SLV_RX_FIFO 0x6c
#define SLV_FIFO_DV1 BIT(0) /* Data Valid for addr_1 */
#define SLV_FIFO_DV2 BIT(1) /* Data Valid for addr_2 */
#define SLV_FIFO_AS BIT(2) /* (N)ACK Sent */
#define SLV_FIFO_TNAK BIT(3) /* Timeout NACK */
#define SLV_FIFO_STRC BIT(4) /* First byte after start condition received */
#define SLV_FIFO_RSC BIT(5) /* Repeated Start Condition */
#define SLV_FIFO_STPC BIT(6) /* Stop Condition */
#define SLV_FIFO_DV (SLV_FIFO_DV1 | SLV_FIFO_DV2)
#define SLV_INT_ENABLE 0x70
#define SLV_INT_STATUS 0x74
#define SLV_STATUS_RFH BIT(0) /* FIFO service */
#define SLV_STATUS_WTC BIT(1) /* Write transfer complete */
#define SLV_STATUS_SRS1 BIT(2) /* Slave read from addr 1 */
#define SLV_STATUS_SRRS1 BIT(3) /* Repeated start from addr 1 */
#define SLV_STATUS_SRND1 BIT(4) /* Read request not following start condition */
#define SLV_STATUS_SRC1 BIT(5) /* Read canceled */
#define SLV_STATUS_SRAT1 BIT(6) /* Slave Read timed out */
#define SLV_STATUS_SRDRE1 BIT(7) /* Data written after timed out */
#define SLV_READ_DUMMY 0x78
#define SCL_HIGH_PERIOD 0x80
#define SCL_LOW_PERIOD 0x84
#define SPIKE_FLTR_LEN 0x88
#define SDA_SETUP_TIME 0x8c
#define SDA_HOLD_TIME 0x90
/**
* axxia_i2c_dev - I2C device context
* @base: pointer to register struct
* @msg: pointer to current message
* @msg_r: pointer to current read message (sequence transfer)
* @msg_xfrd: number of bytes transferred in tx_fifo
* @msg_xfrd_r: number of bytes transferred in rx_fifo
* @msg_err: error code for completed message
* @msg_complete: xfer completion object
* @dev: device reference
* @adapter: core i2c abstraction
* @i2c_clk: clock reference for i2c input clock
* @bus_clk_rate: current i2c bus clock rate
* @last: a flag indicating is this is last message in transfer
*/
struct axxia_i2c_dev {
void __iomem *base;
struct i2c_msg *msg;
struct i2c_msg *msg_r;
size_t msg_xfrd;
size_t msg_xfrd_r;
int msg_err;
struct completion msg_complete;
struct device *dev;
struct i2c_adapter adapter;
struct clk *i2c_clk;
u32 bus_clk_rate;
bool last;
struct i2c_client *slave;
int irq;
};
static void i2c_int_disable(struct axxia_i2c_dev *idev, u32 mask)
{
u32 int_en;
int_en = readl(idev->base + MST_INT_ENABLE);
writel(int_en & ~mask, idev->base + MST_INT_ENABLE);
}
static void i2c_int_enable(struct axxia_i2c_dev *idev, u32 mask)
{
u32 int_en;
int_en = readl(idev->base + MST_INT_ENABLE);
writel(int_en | mask, idev->base + MST_INT_ENABLE);
}
/**
* ns_to_clk - Convert time (ns) to clock cycles for the given clock frequency.
*/
static u32 ns_to_clk(u64 ns, u32 clk_mhz)
{
return div_u64(ns * clk_mhz, 1000);
}
static int axxia_i2c_init(struct axxia_i2c_dev *idev)
{
u32 divisor = clk_get_rate(idev->i2c_clk) / idev->bus_clk_rate;
u32 clk_mhz = clk_get_rate(idev->i2c_clk) / 1000000;
u32 t_setup;
u32 t_high, t_low;
u32 tmo_clk;
u32 prescale;
unsigned long timeout;
dev_dbg(idev->dev, "rate=%uHz per_clk=%uMHz -> ratio=1:%u\n",
idev->bus_clk_rate, clk_mhz, divisor);
/* Reset controller */
writel(0x01, idev->base + SOFT_RESET);
timeout = jiffies + msecs_to_jiffies(100);
while (readl(idev->base + SOFT_RESET) & 1) {
if (time_after(jiffies, timeout)) {
dev_warn(idev->dev, "Soft reset failed\n");
break;
}
}
/* Enable Master Mode */
writel(0x1, idev->base + GLOBAL_CONTROL);
if (idev->bus_clk_rate <= 100000) {
/* Standard mode SCL 50/50, tSU:DAT = 250 ns */
t_high = divisor * 1 / 2;
t_low = divisor * 1 / 2;
t_setup = ns_to_clk(250, clk_mhz);
} else {
/* Fast mode SCL 33/66, tSU:DAT = 100 ns */
t_high = divisor * 1 / 3;
t_low = divisor * 2 / 3;
t_setup = ns_to_clk(100, clk_mhz);
}
/* SCL High Time */
writel(t_high, idev->base + SCL_HIGH_PERIOD);
/* SCL Low Time */
writel(t_low, idev->base + SCL_LOW_PERIOD);
/* SDA Setup Time */
writel(t_setup, idev->base + SDA_SETUP_TIME);
/* SDA Hold Time, 300ns */
writel(ns_to_clk(300, clk_mhz), idev->base + SDA_HOLD_TIME);
/* Filter <50ns spikes */
writel(ns_to_clk(50, clk_mhz), idev->base + SPIKE_FLTR_LEN);
/* Configure Time-Out Registers */
tmo_clk = ns_to_clk(SCL_WAIT_TIMEOUT_NS, clk_mhz);
/* Find prescaler value that makes tmo_clk fit in 15-bits counter. */
for (prescale = 0; prescale < 15; ++prescale) {
if (tmo_clk <= 0x7fff)
break;
tmo_clk >>= 1;
}
if (tmo_clk > 0x7fff)
tmo_clk = 0x7fff;
/* Prescale divider (log2) */
writel(prescale, idev->base + TIMER_CLOCK_DIV);
/* Timeout in divided clocks */
writel(WT_EN | WT_VALUE(tmo_clk), idev->base + WAIT_TIMER_CONTROL);
/* Mask all master interrupt bits */
i2c_int_disable(idev, ~0);
/* Interrupt enable */
writel(0x01, idev->base + INTERRUPT_ENABLE);
return 0;
}
static int i2c_m_rd(const struct i2c_msg *msg)
{
return (msg->flags & I2C_M_RD) != 0;
}
static int i2c_m_ten(const struct i2c_msg *msg)
{
return (msg->flags & I2C_M_TEN) != 0;
}
static int i2c_m_recv_len(const struct i2c_msg *msg)
{
return (msg->flags & I2C_M_RECV_LEN) != 0;
}
/**
* axxia_i2c_empty_rx_fifo - Fetch data from RX FIFO and update SMBus block
* transfer length if this is the first byte of such a transfer.
*/
static int axxia_i2c_empty_rx_fifo(struct axxia_i2c_dev *idev)
{
struct i2c_msg *msg = idev->msg_r;
size_t rx_fifo_avail = readl(idev->base + MST_RX_FIFO);
int bytes_to_transfer = min(rx_fifo_avail, msg->len - idev->msg_xfrd_r);
while (bytes_to_transfer-- > 0) {
int c = readl(idev->base + MST_DATA);
if (idev->msg_xfrd_r == 0 && i2c_m_recv_len(msg)) {
/*
* Check length byte for SMBus block read
*/
if (c <= 0 || c > I2C_SMBUS_BLOCK_MAX) {
idev->msg_err = -EPROTO;
i2c_int_disable(idev, ~MST_STATUS_TSS);
complete(&idev->msg_complete);
break;
}
msg->len = 1 + c;
writel(msg->len, idev->base + MST_RX_XFER);
}
msg->buf[idev->msg_xfrd_r++] = c;
}
return 0;
}
/**
* axxia_i2c_fill_tx_fifo - Fill TX FIFO from current message buffer.
* @return: Number of bytes left to transfer.
*/
static int axxia_i2c_fill_tx_fifo(struct axxia_i2c_dev *idev)
{
struct i2c_msg *msg = idev->msg;
size_t tx_fifo_avail = FIFO_SIZE - readl(idev->base + MST_TX_FIFO);
int bytes_to_transfer = min(tx_fifo_avail, msg->len - idev->msg_xfrd);
int ret = msg->len - idev->msg_xfrd - bytes_to_transfer;
while (bytes_to_transfer-- > 0)
writel(msg->buf[idev->msg_xfrd++], idev->base + MST_DATA);
return ret;
}
static void axxia_i2c_slv_fifo_event(struct axxia_i2c_dev *idev)
{
u32 fifo_status = readl(idev->base + SLV_RX_FIFO);
u8 val;
dev_dbg(idev->dev, "slave irq fifo_status=0x%x\n", fifo_status);
if (fifo_status & SLV_FIFO_DV1) {
if (fifo_status & SLV_FIFO_STRC)
i2c_slave_event(idev->slave,
I2C_SLAVE_WRITE_REQUESTED, &val);
val = readl(idev->base + SLV_DATA);
i2c_slave_event(idev->slave, I2C_SLAVE_WRITE_RECEIVED, &val);
}
if (fifo_status & SLV_FIFO_STPC) {
readl(idev->base + SLV_DATA); /* dummy read */
i2c_slave_event(idev->slave, I2C_SLAVE_STOP, &val);
}
if (fifo_status & SLV_FIFO_RSC)
readl(idev->base + SLV_DATA); /* dummy read */
}
static irqreturn_t axxia_i2c_slv_isr(struct axxia_i2c_dev *idev)
{
u32 status = readl(idev->base + SLV_INT_STATUS);
u8 val;
dev_dbg(idev->dev, "slave irq status=0x%x\n", status);
if (status & SLV_STATUS_RFH)
axxia_i2c_slv_fifo_event(idev);
if (status & SLV_STATUS_SRS1) {
i2c_slave_event(idev->slave, I2C_SLAVE_READ_REQUESTED, &val);
writel(val, idev->base + SLV_DATA);
}
if (status & SLV_STATUS_SRND1) {
i2c_slave_event(idev->slave, I2C_SLAVE_READ_PROCESSED, &val);
writel(val, idev->base + SLV_DATA);
}
if (status & SLV_STATUS_SRC1)
i2c_slave_event(idev->slave, I2C_SLAVE_STOP, &val);
writel(INT_SLV, idev->base + INTERRUPT_STATUS);
return IRQ_HANDLED;
}
static irqreturn_t axxia_i2c_isr(int irq, void *_dev)
{
struct axxia_i2c_dev *idev = _dev;
irqreturn_t ret = IRQ_NONE;
u32 status;
status = readl(idev->base + INTERRUPT_STATUS);
if (status & INT_SLV)
ret = axxia_i2c_slv_isr(idev);
if (!(status & INT_MST))
return ret;
/* Read interrupt status bits */
status = readl(idev->base + MST_INT_STATUS);
if (!idev->msg) {
dev_warn(idev->dev, "unexpected interrupt\n");
goto out;
}
/* RX FIFO needs service? */
if (i2c_m_rd(idev->msg_r) && (status & MST_STATUS_RFL))
axxia_i2c_empty_rx_fifo(idev);
/* TX FIFO needs service? */
if (!i2c_m_rd(idev->msg) && (status & MST_STATUS_TFL)) {
if (axxia_i2c_fill_tx_fifo(idev) == 0)
i2c_int_disable(idev, MST_STATUS_TFL);
}
if (unlikely(status & MST_STATUS_ERR)) {
/* Transfer error */
i2c_int_disable(idev, ~0);
if (status & MST_STATUS_AL)
idev->msg_err = -EAGAIN;
else if (status & MST_STATUS_NAK)
idev->msg_err = -ENXIO;
else
idev->msg_err = -EIO;
dev_dbg(idev->dev, "error %#x, addr=%#x rx=%u/%u tx=%u/%u\n",
status,
idev->msg->addr,
readl(idev->base + MST_RX_BYTES_XFRD),
readl(idev->base + MST_RX_XFER),
readl(idev->base + MST_TX_BYTES_XFRD),
readl(idev->base + MST_TX_XFER));
complete(&idev->msg_complete);
} else if (status & MST_STATUS_SCC) {
/* Stop completed */
i2c_int_disable(idev, ~MST_STATUS_TSS);
complete(&idev->msg_complete);
} else if (status & (MST_STATUS_SNS | MST_STATUS_SS)) {
/* Transfer done */
int mask = idev->last ? ~0 : ~MST_STATUS_TSS;
i2c_int_disable(idev, mask);
if (i2c_m_rd(idev->msg_r) && idev->msg_xfrd_r < idev->msg_r->len)
axxia_i2c_empty_rx_fifo(idev);
complete(&idev->msg_complete);
} else if (status & MST_STATUS_TSS) {
/* Transfer timeout */
idev->msg_err = -ETIMEDOUT;
i2c_int_disable(idev, ~MST_STATUS_TSS);
complete(&idev->msg_complete);
}
out:
/* Clear interrupt */
writel(INT_MST, idev->base + INTERRUPT_STATUS);
return IRQ_HANDLED;
}
static void axxia_i2c_set_addr(struct axxia_i2c_dev *idev, struct i2c_msg *msg)
{
u32 addr_1, addr_2;
if (i2c_m_ten(msg)) {
/* 10-bit address
* addr_1: 5'b11110 | addr[9:8] | (R/nW)
* addr_2: addr[7:0]
*/
addr_1 = 0xF0 | ((msg->addr >> 7) & 0x06);
if (i2c_m_rd(msg))
addr_1 |= 1; /* Set the R/nW bit of the address */
addr_2 = msg->addr & 0xFF;
} else {
/* 7-bit address
* addr_1: addr[6:0] | (R/nW)
* addr_2: dont care
*/
addr_1 = i2c_8bit_addr_from_msg(msg);
addr_2 = 0;
}
writel(addr_1, idev->base + MST_ADDR_1);
writel(addr_2, idev->base + MST_ADDR_2);
}
/* The NAK interrupt will be sent _before_ issuing STOP command
* so the controller might still be busy processing it. No
* interrupt will be sent at the end so we have to poll for it
*/
static int axxia_i2c_handle_seq_nak(struct axxia_i2c_dev *idev)
{
unsigned long timeout = jiffies + I2C_XFER_TIMEOUT;
do {
if ((readl(idev->base + MST_COMMAND) & CMD_BUSY) == 0)
return 0;
usleep_range(1, 100);
} while (time_before(jiffies, timeout));
return -ETIMEDOUT;
}
static int axxia_i2c_xfer_seq(struct axxia_i2c_dev *idev, struct i2c_msg msgs[])
{
u32 int_mask = MST_STATUS_ERR | MST_STATUS_SS | MST_STATUS_RFL;
u32 rlen = i2c_m_recv_len(&msgs[1]) ? I2C_SMBUS_BLOCK_MAX : msgs[1].len;
unsigned long time_left;
axxia_i2c_set_addr(idev, &msgs[0]);
writel(msgs[0].len, idev->base + MST_TX_XFER);
writel(rlen, idev->base + MST_RX_XFER);
idev->msg = &msgs[0];
idev->msg_r = &msgs[1];
idev->msg_xfrd = 0;
idev->msg_xfrd_r = 0;
idev->last = true;
axxia_i2c_fill_tx_fifo(idev);
writel(CMD_SEQUENCE, idev->base + MST_COMMAND);
reinit_completion(&idev->msg_complete);
i2c_int_enable(idev, int_mask);
time_left = wait_for_completion_timeout(&idev->msg_complete,
I2C_XFER_TIMEOUT);
if (idev->msg_err == -ENXIO) {
if (axxia_i2c_handle_seq_nak(idev))
axxia_i2c_init(idev);
} else if (readl(idev->base + MST_COMMAND) & CMD_BUSY) {
dev_warn(idev->dev, "busy after xfer\n");
}
if (time_left == 0) {
idev->msg_err = -ETIMEDOUT;
i2c_recover_bus(&idev->adapter);
axxia_i2c_init(idev);
}
if (unlikely(idev->msg_err) && idev->msg_err != -ENXIO)
axxia_i2c_init(idev);
return idev->msg_err;
}
static int axxia_i2c_xfer_msg(struct axxia_i2c_dev *idev, struct i2c_msg *msg,
bool last)
{
u32 int_mask = MST_STATUS_ERR;
u32 rx_xfer, tx_xfer;
unsigned long time_left;
unsigned int wt_value;
idev->msg = msg;
idev->msg_r = msg;
idev->msg_xfrd = 0;
idev->msg_xfrd_r = 0;
idev->last = last;
reinit_completion(&idev->msg_complete);
axxia_i2c_set_addr(idev, msg);
if (i2c_m_rd(msg)) {
/* I2C read transfer */
rx_xfer = i2c_m_recv_len(msg) ? I2C_SMBUS_BLOCK_MAX : msg->len;
tx_xfer = 0;
} else {
/* I2C write transfer */
rx_xfer = 0;
tx_xfer = msg->len;
}
writel(rx_xfer, idev->base + MST_RX_XFER);
writel(tx_xfer, idev->base + MST_TX_XFER);
if (i2c_m_rd(msg))
int_mask |= MST_STATUS_RFL;
else if (axxia_i2c_fill_tx_fifo(idev) != 0)
int_mask |= MST_STATUS_TFL;
wt_value = WT_VALUE(readl(idev->base + WAIT_TIMER_CONTROL));
/* Disable wait timer temporarly */
writel(wt_value, idev->base + WAIT_TIMER_CONTROL);
/* Check if timeout error happened */
if (idev->msg_err)
goto out;
if (!last) {
writel(CMD_MANUAL, idev->base + MST_COMMAND);
int_mask |= MST_STATUS_SNS;
} else {
writel(CMD_AUTO, idev->base + MST_COMMAND);
int_mask |= MST_STATUS_SS;
}
writel(WT_EN | wt_value, idev->base + WAIT_TIMER_CONTROL);
i2c_int_enable(idev, int_mask);
time_left = wait_for_completion_timeout(&idev->msg_complete,
I2C_XFER_TIMEOUT);
i2c_int_disable(idev, int_mask);
if (readl(idev->base + MST_COMMAND) & CMD_BUSY)
dev_warn(idev->dev, "busy after xfer\n");
if (time_left == 0) {
idev->msg_err = -ETIMEDOUT;
i2c_recover_bus(&idev->adapter);
axxia_i2c_init(idev);
}
out:
if (unlikely(idev->msg_err) && idev->msg_err != -ENXIO &&
idev->msg_err != -ETIMEDOUT)
axxia_i2c_init(idev);
return idev->msg_err;
}
/* This function checks if the msgs[] array contains messages compatible with
* Sequence mode of operation. This mode assumes there will be exactly one
* write of non-zero length followed by exactly one read of non-zero length,
* both targeted at the same client device.
*/
static bool axxia_i2c_sequence_ok(struct i2c_msg msgs[], int num)
{
return num == SEQ_LEN && !i2c_m_rd(&msgs[0]) && i2c_m_rd(&msgs[1]) &&
msgs[0].len > 0 && msgs[0].len <= FIFO_SIZE &&
msgs[1].len > 0 && msgs[0].addr == msgs[1].addr;
}
static int
axxia_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
int i;
int ret = 0;
idev->msg_err = 0;
if (axxia_i2c_sequence_ok(msgs, num)) {
ret = axxia_i2c_xfer_seq(idev, msgs);
return ret ? : SEQ_LEN;
}
i2c_int_enable(idev, MST_STATUS_TSS);
for (i = 0; ret == 0 && i < num; ++i)
ret = axxia_i2c_xfer_msg(idev, &msgs[i], i == (num - 1));
return ret ? : i;
}
static int axxia_i2c_get_scl(struct i2c_adapter *adap)
{
struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
return !!(readl(idev->base + I2C_BUS_MONITOR) & BM_SCLS);
}
static void axxia_i2c_set_scl(struct i2c_adapter *adap, int val)
{
struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
u32 tmp;
/* Preserve SDA Control */
tmp = readl(idev->base + I2C_BUS_MONITOR) & BM_SDAC;
if (!val)
tmp |= BM_SCLC;
writel(tmp, idev->base + I2C_BUS_MONITOR);
}
static int axxia_i2c_get_sda(struct i2c_adapter *adap)
{
struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
return !!(readl(idev->base + I2C_BUS_MONITOR) & BM_SDAS);
}
static struct i2c_bus_recovery_info axxia_i2c_recovery_info = {
.recover_bus = i2c_generic_scl_recovery,
.get_scl = axxia_i2c_get_scl,
.set_scl = axxia_i2c_set_scl,
.get_sda = axxia_i2c_get_sda,
};
static u32 axxia_i2c_func(struct i2c_adapter *adap)
{
u32 caps = (I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR |
I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA);
return caps;
}
static int axxia_i2c_reg_slave(struct i2c_client *slave)
{
struct axxia_i2c_dev *idev = i2c_get_adapdata(slave->adapter);
u32 slv_int_mask = SLV_STATUS_RFH;
u32 dec_ctl;
if (idev->slave)
return -EBUSY;
idev->slave = slave;
/* Enable slave mode as well */
writel(GLOBAL_MST_EN | GLOBAL_SLV_EN, idev->base + GLOBAL_CONTROL);
writel(INT_MST | INT_SLV, idev->base + INTERRUPT_ENABLE);
/* Set slave address */
dec_ctl = SLV_ADDR_DEC_SA1E;
if (slave->flags & I2C_CLIENT_TEN)
dec_ctl |= SLV_ADDR_DEC_SA1M;
writel(SLV_RX_ACSA1, idev->base + SLV_RX_CTL);
writel(dec_ctl, idev->base + SLV_ADDR_DEC_CTL);
writel(slave->addr, idev->base + SLV_ADDR_1);
/* Enable interrupts */
slv_int_mask |= SLV_STATUS_SRS1 | SLV_STATUS_SRRS1 | SLV_STATUS_SRND1;
slv_int_mask |= SLV_STATUS_SRC1;
writel(slv_int_mask, idev->base + SLV_INT_ENABLE);
return 0;
}
static int axxia_i2c_unreg_slave(struct i2c_client *slave)
{
struct axxia_i2c_dev *idev = i2c_get_adapdata(slave->adapter);
/* Disable slave mode */
writel(GLOBAL_MST_EN, idev->base + GLOBAL_CONTROL);
writel(INT_MST, idev->base + INTERRUPT_ENABLE);
synchronize_irq(idev->irq);
idev->slave = NULL;
return 0;
}
static const struct i2c_algorithm axxia_i2c_algo = {
.master_xfer = axxia_i2c_xfer,
.functionality = axxia_i2c_func,
.reg_slave = axxia_i2c_reg_slave,
.unreg_slave = axxia_i2c_unreg_slave,
};
static const struct i2c_adapter_quirks axxia_i2c_quirks = {
.max_read_len = 255,
.max_write_len = 255,
};
static int axxia_i2c_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
struct axxia_i2c_dev *idev = NULL;
struct resource *res;
void __iomem *base;
int ret = 0;
idev = devm_kzalloc(&pdev->dev, sizeof(*idev), GFP_KERNEL);
if (!idev)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(base))
return PTR_ERR(base);
idev->irq = platform_get_irq(pdev, 0);
if (idev->irq < 0) {
dev_err(&pdev->dev, "missing interrupt resource\n");
return idev->irq;
}
idev->i2c_clk = devm_clk_get(&pdev->dev, "i2c");
if (IS_ERR(idev->i2c_clk)) {
dev_err(&pdev->dev, "missing clock\n");
return PTR_ERR(idev->i2c_clk);
}
idev->base = base;
idev->dev = &pdev->dev;
init_completion(&idev->msg_complete);
of_property_read_u32(np, "clock-frequency", &idev->bus_clk_rate);
if (idev->bus_clk_rate == 0)
idev->bus_clk_rate = 100000; /* default clock rate */
ret = clk_prepare_enable(idev->i2c_clk);
if (ret) {
dev_err(&pdev->dev, "failed to enable clock\n");
return ret;
}
ret = axxia_i2c_init(idev);
if (ret) {
dev_err(&pdev->dev, "failed to initialize\n");
goto error_disable_clk;
}
ret = devm_request_irq(&pdev->dev, idev->irq, axxia_i2c_isr, 0,
pdev->name, idev);
if (ret) {
dev_err(&pdev->dev, "failed to claim IRQ%d\n", idev->irq);
goto error_disable_clk;
}
i2c_set_adapdata(&idev->adapter, idev);
strlcpy(idev->adapter.name, pdev->name, sizeof(idev->adapter.name));
idev->adapter.owner = THIS_MODULE;
idev->adapter.algo = &axxia_i2c_algo;
idev->adapter.bus_recovery_info = &axxia_i2c_recovery_info;
idev->adapter.quirks = &axxia_i2c_quirks;
idev->adapter.dev.parent = &pdev->dev;
idev->adapter.dev.of_node = pdev->dev.of_node;
platform_set_drvdata(pdev, idev);
ret = i2c_add_adapter(&idev->adapter);
if (ret)
goto error_disable_clk;
return 0;
error_disable_clk:
clk_disable_unprepare(idev->i2c_clk);
return ret;
}
static int axxia_i2c_remove(struct platform_device *pdev)
{
struct axxia_i2c_dev *idev = platform_get_drvdata(pdev);
clk_disable_unprepare(idev->i2c_clk);
i2c_del_adapter(&idev->adapter);
return 0;
}
/* Match table for of_platform binding */
static const struct of_device_id axxia_i2c_of_match[] = {
{ .compatible = "lsi,api2c", },
{},
};
MODULE_DEVICE_TABLE(of, axxia_i2c_of_match);
static struct platform_driver axxia_i2c_driver = {
.probe = axxia_i2c_probe,
.remove = axxia_i2c_remove,
.driver = {
.name = "axxia-i2c",
.of_match_table = axxia_i2c_of_match,
},
};
module_platform_driver(axxia_i2c_driver);
MODULE_DESCRIPTION("Axxia I2C Bus driver");
MODULE_AUTHOR("Anders Berg <anders.berg@lsi.com>");
MODULE_LICENSE("GPL v2");
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