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// SPDX-License-Identifier: GPL-2.0-or-later
#include <linux/of_irq.h>
#include "i2c-viai2c-common.h"
int viai2c_wait_bus_not_busy(struct viai2c *i2c)
{
unsigned long timeout;
timeout = jiffies + VIAI2C_TIMEOUT;
while (!(readw(i2c->base + VIAI2C_REG_CSR) & VIAI2C_CSR_READY_MASK)) {
if (time_after(jiffies, timeout)) {
dev_warn(i2c->dev, "timeout waiting for bus ready\n");
return -EBUSY;
}
msleep(20);
}
return 0;
}
static int viai2c_write(struct viai2c *i2c, struct i2c_msg *pmsg, int last)
{
u16 val, tcr_val = i2c->tcr;
i2c->last = last;
if (pmsg->len == 0) {
/*
* We still need to run through the while (..) once, so
* start at -1 and break out early from the loop
*/
i2c->xfered_len = -1;
writew(0, i2c->base + VIAI2C_REG_CDR);
} else {
writew(pmsg->buf[0] & 0xFF, i2c->base + VIAI2C_REG_CDR);
}
if (i2c->platform == VIAI2C_PLAT_WMT && !(pmsg->flags & I2C_M_NOSTART)) {
val = readw(i2c->base + VIAI2C_REG_CR);
val &= ~VIAI2C_CR_TX_END;
val |= VIAI2C_CR_CPU_RDY;
writew(val, i2c->base + VIAI2C_REG_CR);
}
reinit_completion(&i2c->complete);
tcr_val |= pmsg->addr & VIAI2C_TCR_ADDR_MASK;
writew(tcr_val, i2c->base + VIAI2C_REG_TCR);
if (i2c->platform == VIAI2C_PLAT_WMT && pmsg->flags & I2C_M_NOSTART) {
val = readw(i2c->base + VIAI2C_REG_CR);
val |= VIAI2C_CR_CPU_RDY;
writew(val, i2c->base + VIAI2C_REG_CR);
}
if (!wait_for_completion_timeout(&i2c->complete, VIAI2C_TIMEOUT))
return -ETIMEDOUT;
return i2c->ret;
}
static int viai2c_read(struct viai2c *i2c, struct i2c_msg *pmsg, bool first)
{
u16 val, tcr_val = i2c->tcr;
val = readw(i2c->base + VIAI2C_REG_CR);
val &= ~(VIAI2C_CR_TX_END | VIAI2C_CR_RX_END);
if (i2c->platform == VIAI2C_PLAT_WMT && !(pmsg->flags & I2C_M_NOSTART))
val |= VIAI2C_CR_CPU_RDY;
if (pmsg->len == 1)
val |= VIAI2C_CR_RX_END;
writew(val, i2c->base + VIAI2C_REG_CR);
reinit_completion(&i2c->complete);
tcr_val |= VIAI2C_TCR_READ | (pmsg->addr & VIAI2C_TCR_ADDR_MASK);
writew(tcr_val, i2c->base + VIAI2C_REG_TCR);
if ((i2c->platform == VIAI2C_PLAT_WMT && (pmsg->flags & I2C_M_NOSTART)) ||
(i2c->platform == VIAI2C_PLAT_ZHAOXIN && !first)) {
val = readw(i2c->base + VIAI2C_REG_CR);
val |= VIAI2C_CR_CPU_RDY;
writew(val, i2c->base + VIAI2C_REG_CR);
}
if (!wait_for_completion_timeout(&i2c->complete, VIAI2C_TIMEOUT))
return -ETIMEDOUT;
return i2c->ret;
}
int viai2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
struct i2c_msg *pmsg;
int i;
int ret = 0;
struct viai2c *i2c = i2c_get_adapdata(adap);
i2c->mode = VIAI2C_BYTE_MODE;
for (i = 0; ret >= 0 && i < num; i++) {
pmsg = &msgs[i];
if (i2c->platform == VIAI2C_PLAT_WMT && !(pmsg->flags & I2C_M_NOSTART)) {
ret = viai2c_wait_bus_not_busy(i2c);
if (ret < 0)
return ret;
}
i2c->msg = pmsg;
i2c->xfered_len = 0;
if (pmsg->flags & I2C_M_RD)
ret = viai2c_read(i2c, pmsg, i == 0);
else
ret = viai2c_write(i2c, pmsg, (i + 1) == num);
}
return (ret < 0) ? ret : i;
}
/*
* Main process of the byte mode xfer
*
* Return value indicates whether the transfer is complete
* 1: all the data has been successfully transferred
* 0: there is still data that needs to be transferred
* -EIO: error occurred
*/
static int viai2c_irq_xfer(struct viai2c *i2c)
{
u16 val;
struct i2c_msg *msg = i2c->msg;
u8 read = msg->flags & I2C_M_RD;
void __iomem *base = i2c->base;
if (read) {
msg->buf[i2c->xfered_len] = readw(base + VIAI2C_REG_CDR) >> 8;
val = readw(base + VIAI2C_REG_CR) | VIAI2C_CR_CPU_RDY;
if (i2c->xfered_len == msg->len - 2)
val |= VIAI2C_CR_RX_END;
writew(val, base + VIAI2C_REG_CR);
} else {
val = readw(base + VIAI2C_REG_CSR);
if (val & VIAI2C_CSR_RCV_NOT_ACK)
return -EIO;
/* I2C_SMBUS_QUICK */
if (msg->len == 0) {
val = VIAI2C_CR_TX_END | VIAI2C_CR_CPU_RDY | VIAI2C_CR_ENABLE;
writew(val, base + VIAI2C_REG_CR);
return 1;
}
if ((i2c->xfered_len + 1) == msg->len) {
if (i2c->platform == VIAI2C_PLAT_WMT && !i2c->last)
writew(VIAI2C_CR_ENABLE, base + VIAI2C_REG_CR);
else if (i2c->platform == VIAI2C_PLAT_ZHAOXIN && i2c->last)
writeb(VIAI2C_CR_TX_END, base + VIAI2C_REG_CR);
} else {
writew(msg->buf[i2c->xfered_len + 1] & 0xFF, base + VIAI2C_REG_CDR);
writew(VIAI2C_CR_CPU_RDY | VIAI2C_CR_ENABLE, base + VIAI2C_REG_CR);
}
}
i2c->xfered_len++;
return i2c->xfered_len == msg->len;
}
int __weak viai2c_fifo_irq_xfer(struct viai2c *i2c, bool irq)
{
return 0;
}
static irqreturn_t viai2c_isr(int irq, void *data)
{
struct viai2c *i2c = data;
u8 status;
/* save the status and write-clear it */
status = readw(i2c->base + VIAI2C_REG_ISR);
if (!status && i2c->platform == VIAI2C_PLAT_ZHAOXIN)
return IRQ_NONE;
writew(status, i2c->base + VIAI2C_REG_ISR);
i2c->ret = 0;
if (status & VIAI2C_ISR_NACK_ADDR)
i2c->ret = -EIO;
if (i2c->platform == VIAI2C_PLAT_WMT && (status & VIAI2C_ISR_SCL_TIMEOUT))
i2c->ret = -ETIMEDOUT;
if (!i2c->ret) {
if (i2c->mode == VIAI2C_BYTE_MODE)
i2c->ret = viai2c_irq_xfer(i2c);
else
i2c->ret = viai2c_fifo_irq_xfer(i2c, true);
}
/* All the data has been successfully transferred or error occurred */
if (i2c->ret)
complete(&i2c->complete);
return IRQ_HANDLED;
}
int viai2c_init(struct platform_device *pdev, struct viai2c **pi2c, int plat)
{
int err;
int irq_flags;
struct viai2c *i2c;
struct device_node *np = pdev->dev.of_node;
i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
if (!i2c)
return -ENOMEM;
i2c->base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
if (IS_ERR(i2c->base))
return PTR_ERR(i2c->base);
if (plat == VIAI2C_PLAT_WMT) {
irq_flags = 0;
i2c->irq = irq_of_parse_and_map(np, 0);
if (!i2c->irq)
return -EINVAL;
} else if (plat == VIAI2C_PLAT_ZHAOXIN) {
irq_flags = IRQF_SHARED;
i2c->irq = platform_get_irq(pdev, 0);
if (i2c->irq < 0)
return i2c->irq;
} else {
return dev_err_probe(&pdev->dev, -EINVAL, "wrong platform type\n");
}
i2c->platform = plat;
err = devm_request_irq(&pdev->dev, i2c->irq, viai2c_isr,
irq_flags, pdev->name, i2c);
if (err)
return dev_err_probe(&pdev->dev, err,
"failed to request irq %i\n", i2c->irq);
i2c->dev = &pdev->dev;
init_completion(&i2c->complete);
platform_set_drvdata(pdev, i2c);
*pi2c = i2c;
return 0;
}
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