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u-boot/drivers/i2c/i2c-cdns.c
Michal Simek ad72e7622b i2c: cdns: Support different bus speeds 
400kHz is maximum freq which can be used on Xilinx ZynqMP.
Support it with standard divider calculator.
Input freq is hardcoded to 100MHz input freq till we have clock driver
which can provide this information for exact configuration.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
2016-05-17 08:28:49 +02:00

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/*
* Copyright (C) 2015 Moritz Fischer <moritz.fischer@ettus.com>
* IP from Cadence (ID T-CS-PE-0007-100, Version R1p10f2)
*
* This file is based on: drivers/i2c/zynq_i2c.c,
* with added driver-model support and code cleanup.
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <linux/types.h>
#include <linux/io.h>
#include <asm/errno.h>
#include <dm/device.h>
#include <dm/root.h>
#include <i2c.h>
#include <fdtdec.h>
#include <mapmem.h>
DECLARE_GLOBAL_DATA_PTR;
/* i2c register set */
struct cdns_i2c_regs {
u32 control;
u32 status;
u32 address;
u32 data;
u32 interrupt_status;
u32 transfer_size;
u32 slave_mon_pause;
u32 time_out;
u32 interrupt_mask;
u32 interrupt_enable;
u32 interrupt_disable;
};
/* Control register fields */
#define CDNS_I2C_CONTROL_RW 0x00000001
#define CDNS_I2C_CONTROL_MS 0x00000002
#define CDNS_I2C_CONTROL_NEA 0x00000004
#define CDNS_I2C_CONTROL_ACKEN 0x00000008
#define CDNS_I2C_CONTROL_HOLD 0x00000010
#define CDNS_I2C_CONTROL_SLVMON 0x00000020
#define CDNS_I2C_CONTROL_CLR_FIFO 0x00000040
#define CDNS_I2C_CONTROL_DIV_B_SHIFT 8
#define CDNS_I2C_CONTROL_DIV_B_MASK 0x00003F00
#define CDNS_I2C_CONTROL_DIV_A_SHIFT 14
#define CDNS_I2C_CONTROL_DIV_A_MASK 0x0000C000
/* Status register values */
#define CDNS_I2C_STATUS_RXDV 0x00000020
#define CDNS_I2C_STATUS_TXDV 0x00000040
#define CDNS_I2C_STATUS_RXOVF 0x00000080
#define CDNS_I2C_STATUS_BA 0x00000100
/* Interrupt register fields */
#define CDNS_I2C_INTERRUPT_COMP 0x00000001
#define CDNS_I2C_INTERRUPT_DATA 0x00000002
#define CDNS_I2C_INTERRUPT_NACK 0x00000004
#define CDNS_I2C_INTERRUPT_TO 0x00000008
#define CDNS_I2C_INTERRUPT_SLVRDY 0x00000010
#define CDNS_I2C_INTERRUPT_RXOVF 0x00000020
#define CDNS_I2C_INTERRUPT_TXOVF 0x00000040
#define CDNS_I2C_INTERRUPT_RXUNF 0x00000080
#define CDNS_I2C_INTERRUPT_ARBLOST 0x00000200
#define CDNS_I2C_FIFO_DEPTH 16
#define CDNS_I2C_TRANSFER_SIZE_MAX 255 /* Controller transfer limit */
#ifdef DEBUG
static void cdns_i2c_debug_status(struct cdns_i2c_regs *cdns_i2c)
{
int int_status;
int status;
int_status = readl(&cdns_i2c->interrupt_status);
status = readl(&cdns_i2c->status);
if (int_status || status) {
debug("Status: ");
if (int_status & CDNS_I2C_INTERRUPT_COMP)
debug("COMP ");
if (int_status & CDNS_I2C_INTERRUPT_DATA)
debug("DATA ");
if (int_status & CDNS_I2C_INTERRUPT_NACK)
debug("NACK ");
if (int_status & CDNS_I2C_INTERRUPT_TO)
debug("TO ");
if (int_status & CDNS_I2C_INTERRUPT_SLVRDY)
debug("SLVRDY ");
if (int_status & CDNS_I2C_INTERRUPT_RXOVF)
debug("RXOVF ");
if (int_status & CDNS_I2C_INTERRUPT_TXOVF)
debug("TXOVF ");
if (int_status & CDNS_I2C_INTERRUPT_RXUNF)
debug("RXUNF ");
if (int_status & CDNS_I2C_INTERRUPT_ARBLOST)
debug("ARBLOST ");
if (status & CDNS_I2C_STATUS_RXDV)
debug("RXDV ");
if (status & CDNS_I2C_STATUS_TXDV)
debug("TXDV ");
if (status & CDNS_I2C_STATUS_RXOVF)
debug("RXOVF ");
if (status & CDNS_I2C_STATUS_BA)
debug("BA ");
debug("TS%d ", readl(&cdns_i2c->transfer_size));
debug("\n");
}
}
#endif
struct i2c_cdns_bus {
int id;
unsigned int input_freq;
struct cdns_i2c_regs __iomem *regs; /* register base */
};
/* Wait for an interrupt */
static u32 cdns_i2c_wait(struct cdns_i2c_regs *cdns_i2c, u32 mask)
{
int timeout, int_status;
for (timeout = 0; timeout < 100; timeout++) {
udelay(100);
int_status = readl(&cdns_i2c->interrupt_status);
if (int_status & mask)
break;
}
/* Clear interrupt status flags */
writel(int_status & mask, &cdns_i2c->interrupt_status);
return int_status & mask;
}
#define CDNS_I2C_DIVA_MAX 4
#define CDNS_I2C_DIVB_MAX 64
static int cdns_i2c_calc_divs(unsigned long *f, unsigned long input_clk,
unsigned int *a, unsigned int *b)
{
unsigned long fscl = *f, best_fscl = *f, actual_fscl, temp;
unsigned int div_a, div_b, calc_div_a = 0, calc_div_b = 0;
unsigned int last_error, current_error;
/* calculate (divisor_a+1) x (divisor_b+1) */
temp = input_clk / (22 * fscl);
/*
* If the calculated value is negative or 0CDNS_I2C_DIVA_MAX,
* the fscl input is out of range. Return error.
*/
if (!temp || (temp > (CDNS_I2C_DIVA_MAX * CDNS_I2C_DIVB_MAX)))
return -EINVAL;
last_error = -1;
for (div_a = 0; div_a < CDNS_I2C_DIVA_MAX; div_a++) {
div_b = DIV_ROUND_UP(input_clk, 22 * fscl * (div_a + 1));
if ((div_b < 1) || (div_b > CDNS_I2C_DIVB_MAX))
continue;
div_b--;
actual_fscl = input_clk / (22 * (div_a + 1) * (div_b + 1));
if (actual_fscl > fscl)
continue;
current_error = ((actual_fscl > fscl) ? (actual_fscl - fscl) :
(fscl - actual_fscl));
if (last_error > current_error) {
calc_div_a = div_a;
calc_div_b = div_b;
best_fscl = actual_fscl;
last_error = current_error;
}
}
*a = calc_div_a;
*b = calc_div_b;
*f = best_fscl;
return 0;
}
static int cdns_i2c_set_bus_speed(struct udevice *dev, unsigned int speed)
{
struct i2c_cdns_bus *bus = dev_get_priv(dev);
u32 div_a = 0, div_b = 0;
unsigned long speed_p = speed;
int ret = 0;
if (speed > 400000) {
debug("%s, failed to set clock speed to %u\n", __func__,
speed);
return -EINVAL;
}
ret = cdns_i2c_calc_divs(&speed_p, bus->input_freq, &div_a, &div_b);
if (ret)
return ret;
debug("%s: div_a: %d, div_b: %d, input freq: %d, speed: %d/%ld\n",
__func__, div_a, div_b, bus->input_freq, speed, speed_p);
writel((div_b << CDNS_I2C_CONTROL_DIV_B_SHIFT) |
(div_a << CDNS_I2C_CONTROL_DIV_A_SHIFT), &bus->regs->control);
/* Enable master mode, ack, and 7-bit addressing */
setbits_le32(&bus->regs->control, CDNS_I2C_CONTROL_MS |
CDNS_I2C_CONTROL_ACKEN | CDNS_I2C_CONTROL_NEA);
return 0;
}
/* Probe to see if a chip is present. */
static int cdns_i2c_probe_chip(struct udevice *bus, uint chip_addr,
uint chip_flags)
{
struct i2c_cdns_bus *i2c_bus = dev_get_priv(bus);
struct cdns_i2c_regs *regs = i2c_bus->regs;
/* Attempt to read a byte */
setbits_le32(&regs->control, CDNS_I2C_CONTROL_CLR_FIFO |
CDNS_I2C_CONTROL_RW);
clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
writel(0xFF, &regs->interrupt_status);
writel(chip_addr, &regs->address);
writel(1, &regs->transfer_size);
return (cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP |
CDNS_I2C_INTERRUPT_NACK) &
CDNS_I2C_INTERRUPT_COMP) ? 0 : -ETIMEDOUT;
}
static int cdns_i2c_write_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
u32 len, bool next_is_read)
{
u8 *cur_data = data;
struct cdns_i2c_regs *regs = i2c_bus->regs;
setbits_le32(&regs->control, CDNS_I2C_CONTROL_CLR_FIFO |
CDNS_I2C_CONTROL_HOLD);
/* if next is a read, we need to clear HOLD, doesn't work */
if (next_is_read)
clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
clrbits_le32(&regs->control, CDNS_I2C_CONTROL_RW);
writel(0xFF, &regs->interrupt_status);
writel(addr, &regs->address);
while (len--) {
writel(*(cur_data++), &regs->data);
if (readl(&regs->transfer_size) == CDNS_I2C_FIFO_DEPTH) {
if (!cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP)) {
/* Release the bus */
clrbits_le32(&regs->control,
CDNS_I2C_CONTROL_HOLD);
return -ETIMEDOUT;
}
}
}
/* All done... release the bus */
clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
/* Wait for the address and data to be sent */
if (!cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP))
return -ETIMEDOUT;
return 0;
}
static int cdns_i2c_read_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
u32 len)
{
u32 status;
u32 i = 0;
u8 *cur_data = data;
/* TODO: Fix this */
struct cdns_i2c_regs *regs = i2c_bus->regs;
/* Check the hardware can handle the requested bytes */
if ((len < 0) || (len > CDNS_I2C_TRANSFER_SIZE_MAX))
return -EINVAL;
setbits_le32(&regs->control, CDNS_I2C_CONTROL_CLR_FIFO |
CDNS_I2C_CONTROL_RW);
/* Start reading data */
writel(addr, &regs->address);
writel(len, &regs->transfer_size);
/* Wait for data */
do {
status = cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP |
CDNS_I2C_INTERRUPT_DATA);
if (!status) {
/* Release the bus */
clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
return -ETIMEDOUT;
}
debug("Read %d bytes\n",
len - readl(&regs->transfer_size));
for (; i < len - readl(&regs->transfer_size); i++)
*(cur_data++) = readl(&regs->data);
} while (readl(&regs->transfer_size) != 0);
/* All done... release the bus */
clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
#ifdef DEBUG
cdns_i2c_debug_status(regs);
#endif
return 0;
}
static int cdns_i2c_xfer(struct udevice *dev, struct i2c_msg *msg,
int nmsgs)
{
struct i2c_cdns_bus *i2c_bus = dev_get_priv(dev);
int ret;
debug("i2c_xfer: %d messages\n", nmsgs);
for (; nmsgs > 0; nmsgs--, msg++) {
bool next_is_read = nmsgs > 1 && (msg[1].flags & I2C_M_RD);
debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len);
if (msg->flags & I2C_M_RD) {
ret = cdns_i2c_read_data(i2c_bus, msg->addr, msg->buf,
msg->len);
} else {
ret = cdns_i2c_write_data(i2c_bus, msg->addr, msg->buf,
msg->len, next_is_read);
}
if (ret) {
debug("i2c_write: error sending\n");
return -EREMOTEIO;
}
}
return 0;
}
static int cdns_i2c_ofdata_to_platdata(struct udevice *dev)
{
struct i2c_cdns_bus *i2c_bus = dev_get_priv(dev);
i2c_bus->regs = (struct cdns_i2c_regs *)dev_get_addr(dev);
if (!i2c_bus->regs)
return -ENOMEM;
i2c_bus->input_freq = 100000000; /* TODO hardcode input freq for now */
return 0;
}
static const struct dm_i2c_ops cdns_i2c_ops = {
.xfer = cdns_i2c_xfer,
.probe_chip = cdns_i2c_probe_chip,
.set_bus_speed = cdns_i2c_set_bus_speed,
};
static const struct udevice_id cdns_i2c_of_match[] = {
{ .compatible = "cdns,i2c-r1p10" },
{ /* end of table */ }
};
U_BOOT_DRIVER(cdns_i2c) = {
.name = "i2c-cdns",
.id = UCLASS_I2C,
.of_match = cdns_i2c_of_match,
.ofdata_to_platdata = cdns_i2c_ofdata_to_platdata,
.priv_auto_alloc_size = sizeof(struct i2c_cdns_bus),
.ops = &cdns_i2c_ops,
};
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