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u-boot/drivers/i2c/i2c-cdns.c
Siva Durga Prasad Paladugu 9d59d6fff6 i2c: i2c_cdns: Fix below warnings with checker tool 
This patch fixes below warnings found with checker tool.
The variable len in i2c_msg struct is of unsigned type
and it is received as recv_count which is unsigned type
but it is checked with < 0 which is always false, hence
removed it.
The local variable curr_recv_count is declared as signed
type and compared aginst unsigned recv_count which is
incorrect. This is fixed by declaring it as unsigned type.

drivers/i2c/i2c-cdns.c: In function ‘cdns_i2c_read_data’:
drivers/i2c/i2c-cdns.c:317:18: warning: comparison of
unsigned expression < 0 is always false [-Wtype-limits]
  if ((recv_count < 0))
                  ^
drivers/i2c/i2c-cdns.c:340:24: warning: comparison of
integer expressions of different signedness:
‘u32’ {aka ‘unsigned int’} and ‘int’ [-Wsign-compare]
  updatetx = recv_count > curr_recv_count;
                        ^
drivers/i2c/i2c-cdns.c:361:39: warning: comparison of
integer expressions of different signedness:
‘u32’ {aka ‘unsigned int’} and ‘int’ [-Wsign-compare]
    while (readl(&regs->transfer_size) !=

Signed-off-by: Siva Durga Prasad Paladugu <siva.durga.paladugu@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
2019-03-21 08:21:43 +01:00

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// SPDX-License-Identifier: GPL-2.0+
/*
* 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.
*/
#include <common.h>
#include <dm.h>
#include <linux/types.h>
#include <linux/io.h>
#include <linux/errno.h>
#include <dm/root.h>
#include <i2c.h>
#include <fdtdec.h>
#include <mapmem.h>
#include <wait_bit.h>
#include <clk.h>
/* 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_INTERRUPTS_MASK (CDNS_I2C_INTERRUPT_COMP | \
CDNS_I2C_INTERRUPT_DATA | \
CDNS_I2C_INTERRUPT_NACK | \
CDNS_I2C_INTERRUPT_TO | \
CDNS_I2C_INTERRUPT_SLVRDY | \
CDNS_I2C_INTERRUPT_RXOVF | \
CDNS_I2C_INTERRUPT_TXOVF | \
CDNS_I2C_INTERRUPT_RXUNF | \
CDNS_I2C_INTERRUPT_ARBLOST)
#define CDNS_I2C_FIFO_DEPTH 16
#define CDNS_I2C_TRANSFER_SIZE_MAX 255 /* Controller transfer limit */
#define CDNS_I2C_TRANSFER_SIZE (CDNS_I2C_TRANSFER_SIZE_MAX - 3)
#define CDNS_I2C_BROKEN_HOLD_BIT BIT(0)
#define CDNS_I2C_ARB_LOST_MAX_RETRIES 10
#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 */
int hold_flag;
u32 quirks;
};
struct cdns_i2c_platform_data {
u32 quirks;
};
/* 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++) {
int_status = readl(&cdns_i2c->interrupt_status);
if (int_status & mask)
break;
udelay(100);
}
/* 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;
}
static inline u32 is_arbitration_lost(struct cdns_i2c_regs *regs)
{
return (readl(&regs->interrupt_status) & CDNS_I2C_INTERRUPT_ARBLOST);
}
static int cdns_i2c_write_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
u32 len)
{
u8 *cur_data = data;
struct cdns_i2c_regs *regs = i2c_bus->regs;
u32 ret;
/* Set the controller in Master transmit mode and clear FIFO */
setbits_le32(&regs->control, CDNS_I2C_CONTROL_CLR_FIFO);
clrbits_le32(&regs->control, CDNS_I2C_CONTROL_RW);
/* Check message size against FIFO depth, and set hold bus bit
* if it is greater than FIFO depth
*/
if (len > CDNS_I2C_FIFO_DEPTH)
setbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
/* Clear the interrupts in status register */
writel(CDNS_I2C_INTERRUPTS_MASK, &regs->interrupt_status);
writel(addr, &regs->address);
while (len-- && !is_arbitration_lost(regs)) {
writel(*(cur_data++), &regs->data);
if (readl(&regs->transfer_size) == CDNS_I2C_FIFO_DEPTH) {
ret = cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP |
CDNS_I2C_INTERRUPT_ARBLOST);
if (ret & CDNS_I2C_INTERRUPT_ARBLOST)
return -EAGAIN;
if (ret & CDNS_I2C_INTERRUPT_COMP)
continue;
/* Release the bus */
clrbits_le32(&regs->control,
CDNS_I2C_CONTROL_HOLD);
return -ETIMEDOUT;
}
}
if (len && is_arbitration_lost(regs))
return -EAGAIN;
/* All done... release the bus */
if (!i2c_bus->hold_flag)
clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
/* Wait for the address and data to be sent */
ret = cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP |
CDNS_I2C_INTERRUPT_ARBLOST);
if (!(ret & (CDNS_I2C_INTERRUPT_ARBLOST |
CDNS_I2C_INTERRUPT_COMP)))
return -ETIMEDOUT;
if (ret & CDNS_I2C_INTERRUPT_ARBLOST)
return -EAGAIN;
return 0;
}
static inline bool cdns_is_hold_quirk(int hold_quirk, int curr_recv_count)
{
return hold_quirk && (curr_recv_count == CDNS_I2C_FIFO_DEPTH + 1);
}
static int cdns_i2c_read_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
u32 recv_count)
{
u8 *cur_data = data;
struct cdns_i2c_regs *regs = i2c_bus->regs;
u32 curr_recv_count;
int updatetx, hold_quirk;
u32 ret;
curr_recv_count = recv_count;
/* Check for the message size against the FIFO depth */
if (recv_count > CDNS_I2C_FIFO_DEPTH)
setbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
setbits_le32(&regs->control, CDNS_I2C_CONTROL_CLR_FIFO |
CDNS_I2C_CONTROL_RW);
if (recv_count > CDNS_I2C_TRANSFER_SIZE) {
curr_recv_count = CDNS_I2C_TRANSFER_SIZE;
writel(curr_recv_count, &regs->transfer_size);
} else {
writel(recv_count, &regs->transfer_size);
}
/* Start reading data */
writel(addr, &regs->address);
updatetx = recv_count > curr_recv_count;
hold_quirk = (i2c_bus->quirks & CDNS_I2C_BROKEN_HOLD_BIT) && updatetx;
while (recv_count && !is_arbitration_lost(regs)) {
while (readl(&regs->status) & CDNS_I2C_STATUS_RXDV) {
if (recv_count < CDNS_I2C_FIFO_DEPTH &&
!i2c_bus->hold_flag) {
clrbits_le32(&regs->control,
CDNS_I2C_CONTROL_HOLD);
}
*(cur_data)++ = readl(&regs->data);
recv_count--;
curr_recv_count--;
if (cdns_is_hold_quirk(hold_quirk, curr_recv_count))
break;
}
if (cdns_is_hold_quirk(hold_quirk, curr_recv_count)) {
/* wait while fifo is full */
while (readl(&regs->transfer_size) !=
(curr_recv_count - CDNS_I2C_FIFO_DEPTH))
;
/*
* Check number of bytes to be received against maximum
* transfer size and update register accordingly.
*/
if ((recv_count - CDNS_I2C_FIFO_DEPTH) >
CDNS_I2C_TRANSFER_SIZE) {
writel(CDNS_I2C_TRANSFER_SIZE,
&regs->transfer_size);
curr_recv_count = CDNS_I2C_TRANSFER_SIZE +
CDNS_I2C_FIFO_DEPTH;
} else {
writel(recv_count - CDNS_I2C_FIFO_DEPTH,
&regs->transfer_size);
curr_recv_count = recv_count;
}
} else if (recv_count && !hold_quirk && !curr_recv_count) {
writel(addr, &regs->address);
if (recv_count > CDNS_I2C_TRANSFER_SIZE) {
writel(CDNS_I2C_TRANSFER_SIZE,
&regs->transfer_size);
curr_recv_count = CDNS_I2C_TRANSFER_SIZE;
} else {
writel(recv_count, &regs->transfer_size);
curr_recv_count = recv_count;
}
}
}
/* Wait for the address and data to be sent */
ret = cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP |
CDNS_I2C_INTERRUPT_ARBLOST);
if (!(ret & (CDNS_I2C_INTERRUPT_ARBLOST |
CDNS_I2C_INTERRUPT_COMP)))
return -ETIMEDOUT;
if (ret & CDNS_I2C_INTERRUPT_ARBLOST)
return -EAGAIN;
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 = 0;
int count;
bool hold_quirk;
struct i2c_msg *message = msg;
int num_msgs = nmsgs;
hold_quirk = !!(i2c_bus->quirks & CDNS_I2C_BROKEN_HOLD_BIT);
if (nmsgs > 1) {
/*
* This controller does not give completion interrupt after a
* master receive message if HOLD bit is set (repeated start),
* resulting in SW timeout. Hence, if a receive message is
* followed by any other message, an error is returned
* indicating that this sequence is not supported.
*/
for (count = 0; (count < nmsgs - 1) && hold_quirk; count++) {
if (msg[count].flags & I2C_M_RD) {
printf("Can't do repeated start after a receive message\n");
return -EOPNOTSUPP;
}
}
i2c_bus->hold_flag = 1;
setbits_le32(&i2c_bus->regs->control, CDNS_I2C_CONTROL_HOLD);
} else {
i2c_bus->hold_flag = 0;
}
debug("i2c_xfer: %d messages\n", nmsgs);
for (u8 retry = 0; retry < CDNS_I2C_ARB_LOST_MAX_RETRIES &&
nmsgs > 0; nmsgs--, msg++) {
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);
}
if (ret == -EAGAIN) {
msg = message;
nmsgs = num_msgs;
retry++;
printf("%s,arbitration lost, retrying:%d\n", __func__,
retry);
continue;
}
if (ret) {
debug("i2c_write: error sending\n");
return -EREMOTEIO;
}
}
return ret;
}
static int cdns_i2c_ofdata_to_platdata(struct udevice *dev)
{
struct i2c_cdns_bus *i2c_bus = dev_get_priv(dev);
struct cdns_i2c_platform_data *pdata =
(struct cdns_i2c_platform_data *)dev_get_driver_data(dev);
struct clk clk;
int ret;
i2c_bus->regs = (struct cdns_i2c_regs *)dev_read_addr(dev);
if (!i2c_bus->regs)
return -ENOMEM;
if (pdata)
i2c_bus->quirks = pdata->quirks;
ret = clk_get_by_index(dev, 0, &clk);
if (ret)
return ret;
i2c_bus->input_freq = clk_get_rate(&clk);
return 0;
}
static const struct dm_i2c_ops cdns_i2c_ops = {
.xfer = cdns_i2c_xfer,
.set_bus_speed = cdns_i2c_set_bus_speed,
};
static const struct cdns_i2c_platform_data r1p10_i2c_def = {
.quirks = CDNS_I2C_BROKEN_HOLD_BIT,
};
static const struct udevice_id cdns_i2c_of_match[] = {
{ .compatible = "cdns,i2c-r1p10", .data = (ulong)&r1p10_i2c_def },
{ .compatible = "cdns,i2c-r1p14" },
{ /* 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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