u-boot/drivers/i2c/i2c-microchip.c
Padmarao Begari 0dc0d1e094 i2c: Add Microchip PolarFire SoC I2C driver
Add I2C driver code for the Microchip PolarFire SoC.
This driver supports I2C data transfer and probe for I2C
slave addresses.

Signed-off-by: Padmarao Begari <padmarao.begari@microchip.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
2021-12-02 16:43:51 +08:00

482 lines
10 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Microchip I2C controller driver
*
* Copyright (C) 2021 Microchip Technology Inc.
* Padmarao Begari <padmarao.begari@microchip.com>
*/
#include <common.h>
#include <clk.h>
#include <dm.h>
#include <i2c.h>
#include <asm/io.h>
#include <dm/device_compat.h>
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/err.h>
#define MICROCHIP_I2C_TIMEOUT (1000 * 60)
#define MPFS_I2C_CTRL (0x00)
#define CTRL_CR0 (0x00)
#define CTRL_CR1 (0x01)
#define CTRL_AA BIT(2)
#define CTRL_SI BIT(3)
#define CTRL_STO BIT(4)
#define CTRL_STA BIT(5)
#define CTRL_ENS1 BIT(6)
#define CTRL_CR2 (0x07)
#define MPFS_I2C_STATUS (0x04)
#define STATUS_BUS_ERROR (0x00)
#define STATUS_M_START_SENT (0x08)
#define STATUS_M_REPEATED_START_SENT (0x10)
#define STATUS_M_SLAW_ACK (0x18)
#define STATUS_M_SLAW_NACK (0x20)
#define STATUS_M_TX_DATA_ACK (0x28)
#define STATUS_M_TX_DATA_NACK (0x30)
#define STATUS_M_ARB_LOST (0x38)
#define STATUS_M_SLAR_ACK (0x40)
#define STATUS_M_SLAR_NACK (0x48)
#define STATUS_M_RX_DATA_ACKED (0x50)
#define STATUS_M_RX_DATA_NACKED (0x58)
#define STATUS_S_SLAW_ACKED (0x60)
#define STATUS_S_ARB_LOST_SLAW_ACKED (0x68)
#define STATUS_S_GENERAL_CALL_ACKED (0x70)
#define STATUS_S_ARB_LOST_GENERAL_CALL_ACKED (0x78)
#define STATUS_S_RX_DATA_ACKED (0x80)
#define STATUS_S_RX_DATA_NACKED (0x88)
#define STATUS_S_GENERAL_CALL_RX_DATA_ACKED (0x90)
#define STATUS_S_GENERAL_CALL_RX_DATA_NACKED (0x98)
#define STATUS_S_RX_STOP (0xA0)
#define STATUS_S_SLAR_ACKED (0xA8)
#define STATUS_S_ARB_LOST_SLAR_ACKED (0xB0)
#define STATUS_S_TX_DATA_ACK (0xb8)
#define STATUS_S_TX_DATA_NACK (0xC0)
#define STATUS_LAST_DATA_ACK (0xC8)
#define STATUS_M_SMB_MASTER_RESET (0xD0)
#define STATUS_S_SCL_LOW_TIMEOUT (0xD8)
#define STATUS_NO_STATE_INFO (0xF8)
#define MPFS_I2C_DATA (0x08)
#define MPFS_I2C_SLAVE0_ADDR (0x0c)
#define MPFS_I2C_SMBUS (0x10)
#define MPFS_I2C_FREQ (0x14)
#define MPFS_I2C_GLITCHREG (0x18)
#define MPFS_I2C_SLAVE1_ADDR (0x1c)
#define PCLK_DIV_256 ((0 << CTRL_CR0) | (0 << CTRL_CR1) | (0 << CTRL_CR2))
#define PCLK_DIV_224 ((1 << CTRL_CR0) | (0 << CTRL_CR1) | (0 << CTRL_CR2))
#define PCLK_DIV_192 ((0 << CTRL_CR0) | (1 << CTRL_CR1) | (0 << CTRL_CR2))
#define PCLK_DIV_160 ((1 << CTRL_CR0) | (1 << CTRL_CR1) | (0 << CTRL_CR2))
#define PCLK_DIV_960 ((0 << CTRL_CR0) | (0 << CTRL_CR1) | (1 << CTRL_CR2))
#define PCLK_DIV_120 ((1 << CTRL_CR0) | (0 << CTRL_CR1) | (1 << CTRL_CR2))
#define PCLK_DIV_60 ((0 << CTRL_CR0) | (1 << CTRL_CR1) | (1 << CTRL_CR2))
#define BCLK_DIV_8 ((1 << CTRL_CR0) | (1 << CTRL_CR1) | (1 << CTRL_CR2))
#define CLK_MASK ((1 << CTRL_CR0) | (1 << CTRL_CR1) | (1 << CTRL_CR2))
/*
* mpfs_i2c_bus - I2C bus context
* @base: pointer to register struct
* @msg_len: number of bytes transferred in msg
* @msg_err: error code for completed message
* @i2c_clk: clock reference for i2c input clock
* @clk_rate: current i2c bus clock rate
* @buf: ptr to msg buffer for easier use.
* @addr: i2c address.
* @isr_status: cached copy of local ISR status.
*/
struct mpfs_i2c_bus {
void __iomem *base;
size_t msg_len;
int msg_err;
struct clk i2c_clk;
u32 clk_rate;
u8 *buf;
u8 addr;
u32 isr_status;
};
static inline u8 i2c_8bit_addr_from_msg(const struct i2c_msg *msg)
{
return (msg->addr << 1) | (msg->flags & I2C_M_RD ? 1 : 0);
}
static void mpfs_i2c_int_clear(struct mpfs_i2c_bus *bus)
{
u8 ctrl = readl(bus->base + MPFS_I2C_CTRL);
ctrl &= ~CTRL_SI;
writel(ctrl, bus->base + MPFS_I2C_CTRL);
}
static void mpfs_i2c_core_disable(struct mpfs_i2c_bus *bus)
{
u8 ctrl = readl(bus->base + MPFS_I2C_CTRL);
ctrl &= ~CTRL_ENS1;
writel(ctrl, bus->base + MPFS_I2C_CTRL);
}
static void mpfs_i2c_core_enable(struct mpfs_i2c_bus *bus)
{
u8 ctrl = readl(bus->base + MPFS_I2C_CTRL);
ctrl |= CTRL_ENS1;
writel(ctrl, bus->base + MPFS_I2C_CTRL);
}
static void mpfs_i2c_reset(struct mpfs_i2c_bus *bus)
{
mpfs_i2c_core_disable(bus);
mpfs_i2c_core_enable(bus);
}
static inline void mpfs_i2c_stop(struct mpfs_i2c_bus *bus)
{
u8 ctrl = readl(bus->base + MPFS_I2C_CTRL);
ctrl |= CTRL_STO;
writel(ctrl, bus->base + MPFS_I2C_CTRL);
}
static inline int mpfs_generate_divisor(u32 rate, u8 *code)
{
int ret = 0;
if (rate >= 960)
*code = PCLK_DIV_960;
else if (rate >= 256)
*code = PCLK_DIV_256;
else if (rate >= 224)
*code = PCLK_DIV_224;
else if (rate >= 192)
*code = PCLK_DIV_192;
else if (rate >= 160)
*code = PCLK_DIV_160;
else if (rate >= 120)
*code = PCLK_DIV_120;
else if (rate >= 60)
*code = PCLK_DIV_60;
else if (rate >= 8)
*code = BCLK_DIV_8;
else
ret = -EINVAL;
return ret;
}
static int mpfs_i2c_init(struct mpfs_i2c_bus *bus, struct udevice *dev)
{
u32 clk_rate, divisor;
u8 clkval, ctrl;
int ret;
ret = clk_get_by_index(dev, 0, &bus->i2c_clk);
if (ret)
return -EINVAL;
ret = clk_enable(&bus->i2c_clk);
if (ret)
return ret;
clk_rate = clk_get_rate(&bus->i2c_clk);
if (!clk_rate)
return -EINVAL;
clk_free(&bus->i2c_clk);
divisor = clk_rate / bus->clk_rate;
ctrl = readl(bus->base + MPFS_I2C_CTRL);
ctrl &= ~CLK_MASK;
ret = mpfs_generate_divisor(divisor, &clkval);
if (ret)
return -EINVAL;
ctrl |= clkval;
writel(ctrl, bus->base + MPFS_I2C_CTRL);
ctrl = readl(bus->base + MPFS_I2C_CTRL);
/* Reset I2C core */
mpfs_i2c_reset(bus);
return 0;
}
static void mpfs_i2c_transfer(struct mpfs_i2c_bus *bus, u32 data)
{
if (bus->msg_len > 0)
writel(data, bus->base + MPFS_I2C_DATA);
}
static void mpfs_i2c_empty_rx(struct mpfs_i2c_bus *bus)
{
u8 ctrl;
u8 data_read;
if (bus->msg_len > 0) {
data_read = readl(bus->base + MPFS_I2C_DATA);
*bus->buf++ = data_read;
bus->msg_len--;
}
if (bus->msg_len == 0) {
ctrl = readl(bus->base + MPFS_I2C_CTRL);
ctrl &= ~CTRL_AA;
writel(ctrl, bus->base + MPFS_I2C_CTRL);
}
}
static int mpfs_i2c_fill_tx(struct mpfs_i2c_bus *bus)
{
mpfs_i2c_transfer(bus, *bus->buf++);
bus->msg_len--;
return 0;
}
static int mpfs_i2c_service_handler(struct mpfs_i2c_bus *bus)
{
bool finish = false;
u32 status;
u8 ctrl;
status = bus->isr_status;
switch (status) {
case STATUS_M_START_SENT:
case STATUS_M_REPEATED_START_SENT:
ctrl = readl(bus->base + MPFS_I2C_CTRL);
ctrl &= ~CTRL_STA;
writel(bus->addr, bus->base + MPFS_I2C_DATA);
writel(ctrl, bus->base + MPFS_I2C_CTRL);
break;
case STATUS_M_SLAW_ACK:
case STATUS_M_TX_DATA_ACK:
if (bus->msg_len > 0) {
mpfs_i2c_fill_tx(bus);
} else {
/* On the last byte to be transmitted, send STOP */
mpfs_i2c_stop(bus);
finish = true;
}
break;
case STATUS_M_SLAR_ACK:
ctrl = readl(bus->base + MPFS_I2C_CTRL);
ctrl |= CTRL_AA;
writel(ctrl, bus->base + MPFS_I2C_CTRL);
if (bus->msg_len == 0) {
/* On the last byte to be transmitted, send STOP */
mpfs_i2c_stop(bus);
finish = true;
}
break;
case STATUS_M_RX_DATA_ACKED:
mpfs_i2c_empty_rx(bus);
if (bus->msg_len == 0) {
/* On the last byte to be transmitted, send STOP */
mpfs_i2c_stop(bus);
finish = true;
}
break;
case STATUS_M_TX_DATA_NACK:
case STATUS_M_RX_DATA_NACKED:
case STATUS_M_SLAR_NACK:
case STATUS_M_SLAW_NACK:
bus->msg_err = -ENXIO;
mpfs_i2c_stop(bus);
finish = true;
break;
case STATUS_M_ARB_LOST:
/* Handle Lost Arbitration */
bus->msg_err = -EAGAIN;
finish = true;
break;
default:
break;
}
if (finish) {
ctrl = readl(bus->base + MPFS_I2C_CTRL);
ctrl &= ~CTRL_AA;
writel(ctrl, bus->base + MPFS_I2C_CTRL);
return 0;
}
return 1;
}
static int mpfs_i2c_service(struct mpfs_i2c_bus *bus)
{
int ret = 0;
int si_bit;
si_bit = readl(bus->base + MPFS_I2C_CTRL);
if (si_bit & CTRL_SI) {
bus->isr_status = readl(bus->base + MPFS_I2C_STATUS);
ret = mpfs_i2c_service_handler(bus);
}
/* Clear the si flag */
mpfs_i2c_int_clear(bus);
si_bit = readl(bus->base + MPFS_I2C_CTRL);
return ret;
}
static int mpfs_i2c_check_service_change(struct mpfs_i2c_bus *bus)
{
u8 ctrl;
u32 count = 0;
while (1) {
ctrl = readl(bus->base + MPFS_I2C_CTRL);
if (ctrl & CTRL_SI)
break;
udelay(1);
count += 1;
if (count == MICROCHIP_I2C_TIMEOUT)
return -ETIMEDOUT;
}
return 0;
}
static int mpfs_i2c_poll_device(struct mpfs_i2c_bus *bus)
{
int ret;
while (1) {
ret = mpfs_i2c_check_service_change(bus);
if (ret)
return ret;
ret = mpfs_i2c_service(bus);
if (!ret)
/* all messages have been transferred */
return ret;
}
}
static int mpfs_i2c_xfer_msg(struct mpfs_i2c_bus *bus, struct i2c_msg *msg)
{
u8 ctrl;
int ret;
if (!msg->len || !msg->buf)
return -EINVAL;
bus->addr = i2c_8bit_addr_from_msg(msg);
bus->msg_len = msg->len;
bus->buf = msg->buf;
bus->msg_err = 0;
mpfs_i2c_core_enable(bus);
ctrl = readl(bus->base + MPFS_I2C_CTRL);
ctrl |= CTRL_STA;
writel(ctrl, bus->base + MPFS_I2C_CTRL);
ret = mpfs_i2c_poll_device(bus);
if (ret)
return ret;
return bus->msg_err;
}
static int mpfs_i2c_xfer(struct udevice *dev, struct i2c_msg *msgs, int num_msgs)
{
struct mpfs_i2c_bus *bus = dev_get_priv(dev);
int idx, ret;
if (!msgs || !num_msgs)
return -EINVAL;
for (idx = 0; idx < num_msgs; idx++) {
ret = mpfs_i2c_xfer_msg(bus, msgs++);
if (ret)
return ret;
}
return ret;
}
static int mpfs_i2c_probe_chip(struct udevice *dev, uint addr, uint flags)
{
struct mpfs_i2c_bus *bus = dev_get_priv(dev);
int ret;
u8 ctrl, reg = 0;
/*
* Send the chip address and verify that the
* address was <ACK>ed.
*/
bus->addr = addr << 1 | I2C_M_RD;
bus->buf = &reg;
bus->msg_len = 0;
bus->msg_err = 0;
mpfs_i2c_core_enable(bus);
ctrl = readl(bus->base + MPFS_I2C_CTRL);
ctrl |= CTRL_STA;
writel(ctrl, bus->base + MPFS_I2C_CTRL);
ret = mpfs_i2c_poll_device(bus);
if (ret)
return ret;
return bus->msg_err;
}
static int mpfs_i2c_probe(struct udevice *dev)
{
int ret;
u32 val;
struct mpfs_i2c_bus *bus = dev_get_priv(dev);
bus->base = dev_read_addr_ptr(dev);
if (!bus->base)
return -EINVAL;
val = dev_read_u32(dev, "clock-frequency", &bus->clk_rate);
if (val) {
printf("Default to 100kHz\n");
/* default clock rate */
bus->clk_rate = 100000;
}
if (bus->clk_rate > 400000 || bus->clk_rate <= 0) {
printf("Invalid clock-frequency %d\n", bus->clk_rate);
return -EINVAL;
}
ret = mpfs_i2c_init(bus, dev);
return ret;
}
static const struct dm_i2c_ops mpfs_i2c_ops = {
.xfer = mpfs_i2c_xfer,
.probe_chip = mpfs_i2c_probe_chip,
};
static const struct udevice_id mpfs_i2c_ids[] = {
{.compatible = "microchip,mpfs-i2c"},
{}
};
U_BOOT_DRIVER(mpfs_i2c) = {
.name = "mpfs_i2c",
.id = UCLASS_I2C,
.of_match = mpfs_i2c_ids,
.ops = &mpfs_i2c_ops,
.probe = mpfs_i2c_probe,
.priv_auto = sizeof(struct mpfs_i2c_bus),
};