leandrof/u-boot
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
e530d2e15b
u-boot/drivers/i2c/i2c-uniphier-f.c
Masahiro Yamada 68578582ab i2c: uniphier-f: use readl_poll_timeout() to poll registers 
The readl_poll_timeout() is a useful helper to poll registers
and error out if the condition is not met.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-01-29 20:59:08 +09:00

342 lines
8.2 KiB
C
Raw Blame History

/*
* Copyright (C) 2014 Panasonic Corporation
* Copyright (C) 2015-2016 Socionext Inc.
* Author: Masahiro Yamada <yamada.masahiro@socionext.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <linux/types.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/sizes.h>
#include <linux/errno.h>
#include <dm/device.h>
#include <i2c.h>
#include <fdtdec.h>
struct uniphier_fi2c_regs {
u32 cr; /* control register */
#define I2C_CR_MST (1 << 3) /* master mode */
#define I2C_CR_STA (1 << 2) /* start condition */
#define I2C_CR_STO (1 << 1) /* stop condition */
#define I2C_CR_NACK (1 << 0) /* not ACK */
u32 dttx; /* send FIFO (write-only) */
#define dtrx dttx /* receive FIFO (read-only) */
#define I2C_DTTX_CMD (1 << 8) /* send command (slave addr) */
#define I2C_DTTX_RD (1 << 0) /* read */
u32 __reserved; /* no register at offset 0x08 */
u32 slad; /* slave address */
u32 cyc; /* clock cycle control */
u32 lctl; /* clock low period control */
u32 ssut; /* restart/stop setup time control */
u32 dsut; /* data setup time control */
u32 intr; /* interrupt status */
u32 ie; /* interrupt enable */
u32 ic; /* interrupt clear */
#define I2C_INT_TE (1 << 9) /* TX FIFO empty */
#define I2C_INT_RB (1 << 4) /* received specified bytes */
#define I2C_INT_NA (1 << 2) /* no answer */
#define I2C_INT_AL (1 << 1) /* arbitration lost */
u32 sr; /* status register */
#define I2C_SR_DB (1 << 12) /* device busy */
#define I2C_SR_BB (1 << 8) /* bus busy */
#define I2C_SR_RFF (1 << 3) /* Rx FIFO full */
#define I2C_SR_RNE (1 << 2) /* Rx FIFO not empty */
#define I2C_SR_TNF (1 << 1) /* Tx FIFO not full */
#define I2C_SR_TFE (1 << 0) /* Tx FIFO empty */
u32 __reserved2; /* no register at offset 0x30 */
u32 rst; /* reset control */
#define I2C_RST_TBRST (1 << 2) /* clear Tx FIFO */
#define I2C_RST_RBRST (1 << 1) /* clear Rx FIFO */
#define I2C_RST_RST (1 << 0) /* forcible bus reset */
u32 bm; /* bus monitor */
u32 noise; /* noise filter control */
u32 tbc; /* Tx byte count setting */
u32 rbc; /* Rx byte count setting */
u32 tbcm; /* Tx byte count monitor */
u32 rbcm; /* Rx byte count monitor */
u32 brst; /* bus reset */
#define I2C_BRST_FOEN (1 << 1) /* normal operation */
#define I2C_BRST_RSCLO (1 << 0) /* release SCL low fixing */
};
#define FIOCLK 50000000
struct uniphier_fi2c_dev {
struct uniphier_fi2c_regs __iomem *regs; /* register base */
unsigned long fioclk; /* internal operation clock */
unsigned long timeout; /* time out (us) */
};
static int reset_bus(struct uniphier_fi2c_regs __iomem *regs)
{
u32 val;
int ret;
/* bus forcible reset */
writel(I2C_RST_RST, &regs->rst);
ret = readl_poll_timeout(&regs->rst, val, !(val & I2C_RST_RST), 1);
if (ret < 0)
debug("error: fail to reset I2C controller\n");
return ret;
}
static int check_device_busy(struct uniphier_fi2c_regs __iomem *regs)
{
u32 val;
int ret;
ret = readl_poll_timeout(&regs->sr, val, !(val & I2C_SR_DB), 100);
if (ret < 0) {
debug("error: device busy too long. reset...\n");
ret = reset_bus(regs);
}
return ret;
}
static int uniphier_fi2c_probe(struct udevice *dev)
{
fdt_addr_t addr;
struct uniphier_fi2c_dev *priv = dev_get_priv(dev);
int ret;
addr = dev_get_addr(dev);
if (addr == FDT_ADDR_T_NONE)
return -EINVAL;
priv->regs = devm_ioremap(dev, addr, SZ_128);
if (!priv->regs)
return -ENOMEM;
priv->fioclk = FIOCLK;
/* bus forcible reset */
ret = reset_bus(priv->regs);
if (ret < 0)
return ret;
writel(I2C_BRST_FOEN | I2C_BRST_RSCLO, &priv->regs->brst);
return 0;
}
static int wait_for_irq(struct uniphier_fi2c_dev *dev, u32 flags,
bool *stop)
{
u32 irq;
int ret;
ret = readl_poll_timeout(&dev->regs->intr, irq, irq & flags,
dev->timeout);
if (ret < 0) {
debug("error: time out\n");
return ret;
}
if (irq & I2C_INT_AL) {
debug("error: arbitration lost\n");
*stop = false;
return ret;
}
if (irq & I2C_INT_NA) {
debug("error: no answer\n");
return ret;
}
return 0;
}
static int issue_stop(struct uniphier_fi2c_dev *dev, int old_ret)
{
int ret;
debug("stop condition\n");
writel(I2C_CR_MST | I2C_CR_STO, &dev->regs->cr);
ret = check_device_busy(dev->regs);
if (ret < 0)
debug("error: device busy after operation\n");
return old_ret ? old_ret : ret;
}
static int uniphier_fi2c_transmit(struct uniphier_fi2c_dev *dev, uint addr,
uint len, const u8 *buf, bool *stop)
{
int ret;
const u32 irq_flags = I2C_INT_TE | I2C_INT_NA | I2C_INT_AL;
struct uniphier_fi2c_regs __iomem *regs = dev->regs;
debug("%s: addr = %x, len = %d\n", __func__, addr, len);
writel(I2C_DTTX_CMD | addr << 1, &regs->dttx);
writel(irq_flags, &regs->ie);
writel(irq_flags, &regs->ic);
debug("start condition\n");
writel(I2C_CR_MST | I2C_CR_STA, &regs->cr);
ret = wait_for_irq(dev, irq_flags, stop);
if (ret < 0)
goto error;
while (len--) {
debug("sending %x\n", *buf);
writel(*buf++, &regs->dttx);
writel(irq_flags, &regs->ic);
ret = wait_for_irq(dev, irq_flags, stop);
if (ret < 0)
goto error;
}
error:
writel(irq_flags, &regs->ic);
if (*stop)
ret = issue_stop(dev, ret);
return ret;
}
static int uniphier_fi2c_receive(struct uniphier_fi2c_dev *dev, uint addr,
uint len, u8 *buf, bool *stop)
{
int ret = 0;
const u32 irq_flags = I2C_INT_RB | I2C_INT_NA | I2C_INT_AL;
struct uniphier_fi2c_regs __iomem *regs = dev->regs;
debug("%s: addr = %x, len = %d\n", __func__, addr, len);
/*
* In case 'len == 0', only the slave address should be sent
* for probing, which is covered by the transmit function.
*/
if (len == 0)
return uniphier_fi2c_transmit(dev, addr, len, buf, stop);
writel(I2C_DTTX_CMD | I2C_DTTX_RD | addr << 1, &regs->dttx);
writel(0, &regs->rbc);
writel(irq_flags, &regs->ie);
writel(irq_flags, &regs->ic);
debug("start condition\n");
writel(I2C_CR_MST | I2C_CR_STA | (len == 1 ? I2C_CR_NACK : 0),
&regs->cr);
while (len--) {
ret = wait_for_irq(dev, irq_flags, stop);
if (ret < 0)
goto error;
*buf++ = readl(&regs->dtrx);
debug("received %x\n", *(buf - 1));
if (len == 1)
writel(I2C_CR_MST | I2C_CR_NACK, &regs->cr);
writel(irq_flags, &regs->ic);
}
error:
writel(irq_flags, &regs->ic);
if (*stop)
ret = issue_stop(dev, ret);
return ret;
}
static int uniphier_fi2c_xfer(struct udevice *bus, struct i2c_msg *msg,
int nmsgs)
{
int ret;
struct uniphier_fi2c_dev *dev = dev_get_priv(bus);
bool stop;
ret = check_device_busy(dev->regs);
if (ret < 0)
return ret;
for (; nmsgs > 0; nmsgs--, msg++) {
/* If next message is read, skip the stop condition */
stop = nmsgs > 1 && msg[1].flags & I2C_M_RD ? false : true;
if (msg->flags & I2C_M_RD)
ret = uniphier_fi2c_receive(dev, msg->addr, msg->len,
msg->buf, &stop);
else
ret = uniphier_fi2c_transmit(dev, msg->addr, msg->len,
msg->buf, &stop);
if (ret < 0)
break;
}
return ret;
}
static int uniphier_fi2c_set_bus_speed(struct udevice *bus, unsigned int speed)
{
int ret;
unsigned int clk_count;
struct uniphier_fi2c_dev *dev = dev_get_priv(bus);
struct uniphier_fi2c_regs __iomem *regs = dev->regs;
/* max supported frequency is 400 kHz */
if (speed > 400000)
return -EINVAL;
ret = check_device_busy(dev->regs);
if (ret < 0)
return ret;
/* make sure the bus is idle when changing the frequency */
writel(I2C_BRST_RSCLO, &regs->brst);
clk_count = dev->fioclk / speed;
writel(clk_count, &regs->cyc);
writel(clk_count / 2, &regs->lctl);
writel(clk_count / 2, &regs->ssut);
writel(clk_count / 16, &regs->dsut);
writel(I2C_BRST_FOEN | I2C_BRST_RSCLO, &regs->brst);
/*
* Theoretically, each byte can be transferred in
* 1000000 * 9 / speed usec.
* This time out value is long enough.
*/
dev->timeout = 100000000L / speed;
return 0;
}
static const struct dm_i2c_ops uniphier_fi2c_ops = {
.xfer = uniphier_fi2c_xfer,
.set_bus_speed = uniphier_fi2c_set_bus_speed,
};
static const struct udevice_id uniphier_fi2c_of_match[] = {
{ .compatible = "socionext,uniphier-fi2c" },
{ /* sentinel */ }
};
U_BOOT_DRIVER(uniphier_fi2c) = {
.name = "uniphier-fi2c",
.id = UCLASS_I2C,
.of_match = uniphier_fi2c_of_match,
.probe = uniphier_fi2c_probe,
.priv_auto_alloc_size = sizeof(struct uniphier_fi2c_dev),
.ops = &uniphier_fi2c_ops,
};
Reference in New Issue View Git Blame Copy Permalink