u-boot/drivers/i2c/stm32f7_i2c.c
Alain Volmat c324465576 i2c: stm32f7_i2c: allows for any bus frequency
Do not limit to 3 (100KHz, 400KHz, 1MHz) bus frequencies, but
instead allow for any frequency. Depending on the requested
frequency (via the clock-frequency DT entry), use the spec
data from either Standard, Fast or Fast Plus mode.

In order to do so, the driver do not use anymore spec identifier
by directly handle the requested frequency and from it retrieve
the corresponding spec data to be used for the computation
of the timing register.

Signed-off-by: Alain Volmat <alain.volmat@st.com>
Reviewed-by: Patrick DELAUNAY <patrick.delaunay@st.com>
Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Acked-by: Patrice Chotard <patrice.chotard@st.com>
2020-03-24 14:23:32 +01:00

884 lines
22 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2017 STMicroelectronics
*/
#include <common.h>
#include <clk.h>
#include <dm.h>
#include <i2c.h>
#include <reset.h>
#include <dm/device.h>
#include <linux/err.h>
#include <linux/io.h>
/* STM32 I2C registers */
struct stm32_i2c_regs {
u32 cr1; /* I2C control register 1 */
u32 cr2; /* I2C control register 2 */
u32 oar1; /* I2C own address 1 register */
u32 oar2; /* I2C own address 2 register */
u32 timingr; /* I2C timing register */
u32 timeoutr; /* I2C timeout register */
u32 isr; /* I2C interrupt and status register */
u32 icr; /* I2C interrupt clear register */
u32 pecr; /* I2C packet error checking register */
u32 rxdr; /* I2C receive data register */
u32 txdr; /* I2C transmit data register */
};
#define STM32_I2C_CR1 0x00
#define STM32_I2C_CR2 0x04
#define STM32_I2C_TIMINGR 0x10
#define STM32_I2C_ISR 0x18
#define STM32_I2C_ICR 0x1C
#define STM32_I2C_RXDR 0x24
#define STM32_I2C_TXDR 0x28
/* STM32 I2C control 1 */
#define STM32_I2C_CR1_ANFOFF BIT(12)
#define STM32_I2C_CR1_ERRIE BIT(7)
#define STM32_I2C_CR1_TCIE BIT(6)
#define STM32_I2C_CR1_STOPIE BIT(5)
#define STM32_I2C_CR1_NACKIE BIT(4)
#define STM32_I2C_CR1_ADDRIE BIT(3)
#define STM32_I2C_CR1_RXIE BIT(2)
#define STM32_I2C_CR1_TXIE BIT(1)
#define STM32_I2C_CR1_PE BIT(0)
/* STM32 I2C control 2 */
#define STM32_I2C_CR2_AUTOEND BIT(25)
#define STM32_I2C_CR2_RELOAD BIT(24)
#define STM32_I2C_CR2_NBYTES_MASK GENMASK(23, 16)
#define STM32_I2C_CR2_NBYTES(n) ((n & 0xff) << 16)
#define STM32_I2C_CR2_NACK BIT(15)
#define STM32_I2C_CR2_STOP BIT(14)
#define STM32_I2C_CR2_START BIT(13)
#define STM32_I2C_CR2_HEAD10R BIT(12)
#define STM32_I2C_CR2_ADD10 BIT(11)
#define STM32_I2C_CR2_RD_WRN BIT(10)
#define STM32_I2C_CR2_SADD10_MASK GENMASK(9, 0)
#define STM32_I2C_CR2_SADD10(n) (n & STM32_I2C_CR2_SADD10_MASK)
#define STM32_I2C_CR2_SADD7_MASK GENMASK(7, 1)
#define STM32_I2C_CR2_SADD7(n) ((n & 0x7f) << 1)
#define STM32_I2C_CR2_RESET_MASK (STM32_I2C_CR2_HEAD10R \
| STM32_I2C_CR2_NBYTES_MASK \
| STM32_I2C_CR2_SADD7_MASK \
| STM32_I2C_CR2_RELOAD \
| STM32_I2C_CR2_RD_WRN)
/* STM32 I2C Interrupt Status */
#define STM32_I2C_ISR_BUSY BIT(15)
#define STM32_I2C_ISR_ARLO BIT(9)
#define STM32_I2C_ISR_BERR BIT(8)
#define STM32_I2C_ISR_TCR BIT(7)
#define STM32_I2C_ISR_TC BIT(6)
#define STM32_I2C_ISR_STOPF BIT(5)
#define STM32_I2C_ISR_NACKF BIT(4)
#define STM32_I2C_ISR_ADDR BIT(3)
#define STM32_I2C_ISR_RXNE BIT(2)
#define STM32_I2C_ISR_TXIS BIT(1)
#define STM32_I2C_ISR_TXE BIT(0)
#define STM32_I2C_ISR_ERRORS (STM32_I2C_ISR_BERR \
| STM32_I2C_ISR_ARLO)
/* STM32 I2C Interrupt Clear */
#define STM32_I2C_ICR_ARLOCF BIT(9)
#define STM32_I2C_ICR_BERRCF BIT(8)
#define STM32_I2C_ICR_STOPCF BIT(5)
#define STM32_I2C_ICR_NACKCF BIT(4)
/* STM32 I2C Timing */
#define STM32_I2C_TIMINGR_PRESC(n) ((n & 0xf) << 28)
#define STM32_I2C_TIMINGR_SCLDEL(n) ((n & 0xf) << 20)
#define STM32_I2C_TIMINGR_SDADEL(n) ((n & 0xf) << 16)
#define STM32_I2C_TIMINGR_SCLH(n) ((n & 0xff) << 8)
#define STM32_I2C_TIMINGR_SCLL(n) (n & 0xff)
#define STM32_I2C_MAX_LEN 0xff
#define STM32_I2C_DNF_DEFAULT 0
#define STM32_I2C_DNF_MAX 16
#define STM32_I2C_ANALOG_FILTER_ENABLE 1
#define STM32_I2C_ANALOG_FILTER_DELAY_MIN 50 /* ns */
#define STM32_I2C_ANALOG_FILTER_DELAY_MAX 260 /* ns */
#define STM32_I2C_RISE_TIME_DEFAULT 25 /* ns */
#define STM32_I2C_FALL_TIME_DEFAULT 10 /* ns */
#define STM32_PRESC_MAX BIT(4)
#define STM32_SCLDEL_MAX BIT(4)
#define STM32_SDADEL_MAX BIT(4)
#define STM32_SCLH_MAX BIT(8)
#define STM32_SCLL_MAX BIT(8)
#define STM32_NSEC_PER_SEC 1000000000L
/**
* struct stm32_i2c_spec - private i2c specification timing
* @rate: I2C bus speed (Hz)
* @rate_min: 80% of I2C bus speed (Hz)
* @rate_max: 120% of I2C bus speed (Hz)
* @fall_max: Max fall time of both SDA and SCL signals (ns)
* @rise_max: Max rise time of both SDA and SCL signals (ns)
* @hddat_min: Min data hold time (ns)
* @vddat_max: Max data valid time (ns)
* @sudat_min: Min data setup time (ns)
* @l_min: Min low period of the SCL clock (ns)
* @h_min: Min high period of the SCL clock (ns)
*/
struct stm32_i2c_spec {
u32 rate;
u32 rate_min;
u32 rate_max;
u32 fall_max;
u32 rise_max;
u32 hddat_min;
u32 vddat_max;
u32 sudat_min;
u32 l_min;
u32 h_min;
};
/**
* struct stm32_i2c_setup - private I2C timing setup parameters
* @speed_freq: I2C speed frequency (Hz)
* @clock_src: I2C clock source frequency (Hz)
* @rise_time: Rise time (ns)
* @fall_time: Fall time (ns)
* @dnf: Digital filter coefficient (0-16)
* @analog_filter: Analog filter delay (On/Off)
*/
struct stm32_i2c_setup {
u32 speed_freq;
u32 clock_src;
u32 rise_time;
u32 fall_time;
u8 dnf;
bool analog_filter;
};
/**
* struct stm32_i2c_timings - private I2C output parameters
* @prec: Prescaler value
* @scldel: Data setup time
* @sdadel: Data hold time
* @sclh: SCL high period (master mode)
* @sclh: SCL low period (master mode)
*/
struct stm32_i2c_timings {
struct list_head node;
u8 presc;
u8 scldel;
u8 sdadel;
u8 sclh;
u8 scll;
};
struct stm32_i2c_priv {
struct stm32_i2c_regs *regs;
struct clk clk;
struct stm32_i2c_setup *setup;
u32 speed;
};
static const struct stm32_i2c_spec i2c_specs[] = {
/* Standard speed - 100 KHz */
[IC_SPEED_MODE_STANDARD] = {
.rate = I2C_SPEED_STANDARD_RATE,
.rate_min = 8000,
.rate_max = 120000,
.fall_max = 300,
.rise_max = 1000,
.hddat_min = 0,
.vddat_max = 3450,
.sudat_min = 250,
.l_min = 4700,
.h_min = 4000,
},
/* Fast speed - 400 KHz */
[IC_SPEED_MODE_FAST] = {
.rate = I2C_SPEED_FAST_RATE,
.rate_min = 320000,
.rate_max = 480000,
.fall_max = 300,
.rise_max = 300,
.hddat_min = 0,
.vddat_max = 900,
.sudat_min = 100,
.l_min = 1300,
.h_min = 600,
},
/* Fast Plus Speed - 1 MHz */
[IC_SPEED_MODE_FAST_PLUS] = {
.rate = I2C_SPEED_FAST_PLUS_RATE,
.rate_min = 800000,
.rate_max = 1200000,
.fall_max = 100,
.rise_max = 120,
.hddat_min = 0,
.vddat_max = 450,
.sudat_min = 50,
.l_min = 500,
.h_min = 260,
},
};
static const struct stm32_i2c_setup stm32f7_setup = {
.rise_time = STM32_I2C_RISE_TIME_DEFAULT,
.fall_time = STM32_I2C_FALL_TIME_DEFAULT,
.dnf = STM32_I2C_DNF_DEFAULT,
.analog_filter = STM32_I2C_ANALOG_FILTER_ENABLE,
};
static int stm32_i2c_check_device_busy(struct stm32_i2c_priv *i2c_priv)
{
struct stm32_i2c_regs *regs = i2c_priv->regs;
u32 status = readl(&regs->isr);
if (status & STM32_I2C_ISR_BUSY)
return -EBUSY;
return 0;
}
static void stm32_i2c_message_start(struct stm32_i2c_priv *i2c_priv,
struct i2c_msg *msg, bool stop)
{
struct stm32_i2c_regs *regs = i2c_priv->regs;
u32 cr2 = readl(&regs->cr2);
/* Set transfer direction */
cr2 &= ~STM32_I2C_CR2_RD_WRN;
if (msg->flags & I2C_M_RD)
cr2 |= STM32_I2C_CR2_RD_WRN;
/* Set slave address */
cr2 &= ~(STM32_I2C_CR2_HEAD10R | STM32_I2C_CR2_ADD10);
if (msg->flags & I2C_M_TEN) {
cr2 &= ~STM32_I2C_CR2_SADD10_MASK;
cr2 |= STM32_I2C_CR2_SADD10(msg->addr);
cr2 |= STM32_I2C_CR2_ADD10;
} else {
cr2 &= ~STM32_I2C_CR2_SADD7_MASK;
cr2 |= STM32_I2C_CR2_SADD7(msg->addr);
}
/* Set nb bytes to transfer and reload or autoend bits */
cr2 &= ~(STM32_I2C_CR2_NBYTES_MASK | STM32_I2C_CR2_RELOAD |
STM32_I2C_CR2_AUTOEND);
if (msg->len > STM32_I2C_MAX_LEN) {
cr2 |= STM32_I2C_CR2_NBYTES(STM32_I2C_MAX_LEN);
cr2 |= STM32_I2C_CR2_RELOAD;
} else {
cr2 |= STM32_I2C_CR2_NBYTES(msg->len);
}
/* Write configurations register */
writel(cr2, &regs->cr2);
/* START/ReSTART generation */
setbits_le32(&regs->cr2, STM32_I2C_CR2_START);
}
/*
* RELOAD mode must be selected if total number of data bytes to be
* sent is greater than MAX_LEN
*/
static void stm32_i2c_handle_reload(struct stm32_i2c_priv *i2c_priv,
struct i2c_msg *msg, bool stop)
{
struct stm32_i2c_regs *regs = i2c_priv->regs;
u32 cr2 = readl(&regs->cr2);
cr2 &= ~STM32_I2C_CR2_NBYTES_MASK;
if (msg->len > STM32_I2C_MAX_LEN) {
cr2 |= STM32_I2C_CR2_NBYTES(STM32_I2C_MAX_LEN);
} else {
cr2 &= ~STM32_I2C_CR2_RELOAD;
cr2 |= STM32_I2C_CR2_NBYTES(msg->len);
}
writel(cr2, &regs->cr2);
}
static int stm32_i2c_wait_flags(struct stm32_i2c_priv *i2c_priv,
u32 flags, u32 *status)
{
struct stm32_i2c_regs *regs = i2c_priv->regs;
u32 time_start = get_timer(0);
*status = readl(&regs->isr);
while (!(*status & flags)) {
if (get_timer(time_start) > CONFIG_SYS_HZ) {
debug("%s: i2c timeout\n", __func__);
return -ETIMEDOUT;
}
*status = readl(&regs->isr);
}
return 0;
}
static int stm32_i2c_check_end_of_message(struct stm32_i2c_priv *i2c_priv)
{
struct stm32_i2c_regs *regs = i2c_priv->regs;
u32 mask = STM32_I2C_ISR_ERRORS | STM32_I2C_ISR_NACKF |
STM32_I2C_ISR_STOPF;
u32 status;
int ret;
ret = stm32_i2c_wait_flags(i2c_priv, mask, &status);
if (ret)
return ret;
if (status & STM32_I2C_ISR_BERR) {
debug("%s: Bus error\n", __func__);
/* Clear BERR flag */
setbits_le32(&regs->icr, STM32_I2C_ICR_BERRCF);
return -EIO;
}
if (status & STM32_I2C_ISR_ARLO) {
debug("%s: Arbitration lost\n", __func__);
/* Clear ARLO flag */
setbits_le32(&regs->icr, STM32_I2C_ICR_ARLOCF);
return -EAGAIN;
}
if (status & STM32_I2C_ISR_NACKF) {
debug("%s: Receive NACK\n", __func__);
/* Clear NACK flag */
setbits_le32(&regs->icr, STM32_I2C_ICR_NACKCF);
/* Wait until STOPF flag is set */
mask = STM32_I2C_ISR_STOPF;
ret = stm32_i2c_wait_flags(i2c_priv, mask, &status);
if (ret)
return ret;
ret = -EIO;
}
if (status & STM32_I2C_ISR_STOPF) {
/* Clear STOP flag */
setbits_le32(&regs->icr, STM32_I2C_ICR_STOPCF);
/* Clear control register 2 */
setbits_le32(&regs->cr2, STM32_I2C_CR2_RESET_MASK);
}
return ret;
}
static int stm32_i2c_message_xfer(struct stm32_i2c_priv *i2c_priv,
struct i2c_msg *msg, bool stop)
{
struct stm32_i2c_regs *regs = i2c_priv->regs;
u32 status;
u32 mask = msg->flags & I2C_M_RD ? STM32_I2C_ISR_RXNE :
STM32_I2C_ISR_TXIS | STM32_I2C_ISR_NACKF;
int bytes_to_rw = msg->len > STM32_I2C_MAX_LEN ?
STM32_I2C_MAX_LEN : msg->len;
int ret = 0;
/* Add errors */
mask |= STM32_I2C_ISR_ERRORS;
stm32_i2c_message_start(i2c_priv, msg, stop);
while (msg->len) {
/*
* Wait until TXIS/NACKF/BERR/ARLO flags or
* RXNE/BERR/ARLO flags are set
*/
ret = stm32_i2c_wait_flags(i2c_priv, mask, &status);
if (ret)
break;
if (status & (STM32_I2C_ISR_NACKF | STM32_I2C_ISR_ERRORS))
break;
if (status & STM32_I2C_ISR_RXNE) {
*msg->buf++ = readb(&regs->rxdr);
msg->len--;
bytes_to_rw--;
}
if (status & STM32_I2C_ISR_TXIS) {
writeb(*msg->buf++, &regs->txdr);
msg->len--;
bytes_to_rw--;
}
if (!bytes_to_rw && msg->len) {
/* Wait until TCR flag is set */
mask = STM32_I2C_ISR_TCR;
ret = stm32_i2c_wait_flags(i2c_priv, mask, &status);
if (ret)
break;
bytes_to_rw = msg->len > STM32_I2C_MAX_LEN ?
STM32_I2C_MAX_LEN : msg->len;
mask = msg->flags & I2C_M_RD ? STM32_I2C_ISR_RXNE :
STM32_I2C_ISR_TXIS | STM32_I2C_ISR_NACKF;
stm32_i2c_handle_reload(i2c_priv, msg, stop);
} else if (!bytes_to_rw) {
/* Wait until TC flag is set */
mask = STM32_I2C_ISR_TC;
ret = stm32_i2c_wait_flags(i2c_priv, mask, &status);
if (ret)
break;
if (!stop)
/* Message sent, new message has to be sent */
return 0;
}
}
/* End of transfer, send stop condition */
mask = STM32_I2C_CR2_STOP;
setbits_le32(&regs->cr2, mask);
return stm32_i2c_check_end_of_message(i2c_priv);
}
static int stm32_i2c_xfer(struct udevice *bus, struct i2c_msg *msg,
int nmsgs)
{
struct stm32_i2c_priv *i2c_priv = dev_get_priv(bus);
int ret;
ret = stm32_i2c_check_device_busy(i2c_priv);
if (ret)
return ret;
for (; nmsgs > 0; nmsgs--, msg++) {
ret = stm32_i2c_message_xfer(i2c_priv, msg, nmsgs == 1);
if (ret)
return ret;
}
return 0;
}
static int stm32_i2c_compute_solutions(struct stm32_i2c_setup *setup,
const struct stm32_i2c_spec *specs,
struct list_head *solutions)
{
struct stm32_i2c_timings *v;
u32 p_prev = STM32_PRESC_MAX;
u32 i2cclk = DIV_ROUND_CLOSEST(STM32_NSEC_PER_SEC,
setup->clock_src);
u32 af_delay_min, af_delay_max;
u16 p, l, a;
int sdadel_min, sdadel_max, scldel_min;
int ret = 0;
af_delay_min = setup->analog_filter ?
STM32_I2C_ANALOG_FILTER_DELAY_MIN : 0;
af_delay_max = setup->analog_filter ?
STM32_I2C_ANALOG_FILTER_DELAY_MAX : 0;
sdadel_min = specs->hddat_min + setup->fall_time -
af_delay_min - (setup->dnf + 3) * i2cclk;
sdadel_max = specs->vddat_max - setup->rise_time -
af_delay_max - (setup->dnf + 4) * i2cclk;
scldel_min = setup->rise_time + specs->sudat_min;
if (sdadel_min < 0)
sdadel_min = 0;
if (sdadel_max < 0)
sdadel_max = 0;
debug("%s: SDADEL(min/max): %i/%i, SCLDEL(Min): %i\n", __func__,
sdadel_min, sdadel_max, scldel_min);
/* Compute possible values for PRESC, SCLDEL and SDADEL */
for (p = 0; p < STM32_PRESC_MAX; p++) {
for (l = 0; l < STM32_SCLDEL_MAX; l++) {
int scldel = (l + 1) * (p + 1) * i2cclk;
if (scldel < scldel_min)
continue;
for (a = 0; a < STM32_SDADEL_MAX; a++) {
int sdadel = (a * (p + 1) + 1) * i2cclk;
if (((sdadel >= sdadel_min) &&
(sdadel <= sdadel_max)) &&
(p != p_prev)) {
v = calloc(1, sizeof(*v));
if (!v)
return -ENOMEM;
v->presc = p;
v->scldel = l;
v->sdadel = a;
p_prev = p;
list_add_tail(&v->node, solutions);
break;
}
}
if (p_prev == p)
break;
}
}
if (list_empty(solutions)) {
pr_err("%s: no Prescaler solution\n", __func__);
ret = -EPERM;
}
return ret;
}
static int stm32_i2c_choose_solution(struct stm32_i2c_setup *setup,
const struct stm32_i2c_spec *specs,
struct list_head *solutions,
struct stm32_i2c_timings *s)
{
struct stm32_i2c_timings *v;
u32 i2cbus = DIV_ROUND_CLOSEST(STM32_NSEC_PER_SEC,
setup->speed_freq);
u32 clk_error_prev = i2cbus;
u32 i2cclk = DIV_ROUND_CLOSEST(STM32_NSEC_PER_SEC,
setup->clock_src);
u32 clk_min, clk_max;
u32 af_delay_min;
u32 dnf_delay;
u32 tsync;
u16 l, h;
bool sol_found = false;
int ret = 0;
af_delay_min = setup->analog_filter ?
STM32_I2C_ANALOG_FILTER_DELAY_MIN : 0;
dnf_delay = setup->dnf * i2cclk;
tsync = af_delay_min + dnf_delay + (2 * i2cclk);
clk_max = STM32_NSEC_PER_SEC / specs->rate_min;
clk_min = STM32_NSEC_PER_SEC / specs->rate_max;
/*
* Among Prescaler possibilities discovered above figures out SCL Low
* and High Period. Provided:
* - SCL Low Period has to be higher than Low Period of the SCL Clock
* defined by I2C Specification. I2C Clock has to be lower than
* (SCL Low Period - Analog/Digital filters) / 4.
* - SCL High Period has to be lower than High Period of the SCL Clock
* defined by I2C Specification
* - I2C Clock has to be lower than SCL High Period
*/
list_for_each_entry(v, solutions, node) {
u32 prescaler = (v->presc + 1) * i2cclk;
for (l = 0; l < STM32_SCLL_MAX; l++) {
u32 tscl_l = (l + 1) * prescaler + tsync;
if (tscl_l < specs->l_min ||
(i2cclk >=
((tscl_l - af_delay_min - dnf_delay) / 4))) {
continue;
}
for (h = 0; h < STM32_SCLH_MAX; h++) {
u32 tscl_h = (h + 1) * prescaler + tsync;
u32 tscl = tscl_l + tscl_h +
setup->rise_time + setup->fall_time;
if ((tscl >= clk_min) && (tscl <= clk_max) &&
(tscl_h >= specs->h_min) &&
(i2cclk < tscl_h)) {
u32 clk_error;
if (tscl > i2cbus)
clk_error = tscl - i2cbus;
else
clk_error = i2cbus - tscl;
if (clk_error < clk_error_prev) {
clk_error_prev = clk_error;
v->scll = l;
v->sclh = h;
sol_found = true;
memcpy(s, v, sizeof(*s));
}
}
}
}
}
if (!sol_found) {
pr_err("%s: no solution at all\n", __func__);
ret = -EPERM;
}
return ret;
}
static const struct stm32_i2c_spec *get_specs(u32 rate)
{
unsigned int i;
for (i = 0; i < ARRAY_SIZE(i2c_specs); i++)
if (rate <= i2c_specs[i].rate)
return &i2c_specs[i];
/* NOT REACHED */
return ERR_PTR(-EINVAL);
}
static int stm32_i2c_compute_timing(struct stm32_i2c_priv *i2c_priv,
struct stm32_i2c_setup *setup,
struct stm32_i2c_timings *output)
{
const struct stm32_i2c_spec *specs;
struct stm32_i2c_timings *v, *_v;
struct list_head solutions;
int ret;
specs = get_specs(setup->speed_freq);
if (specs == ERR_PTR(-EINVAL)) {
pr_err("%s: speed out of bound {%d}\n", __func__,
setup->speed_freq);
return -EINVAL;
}
if (setup->rise_time > specs->rise_max ||
setup->fall_time > specs->fall_max) {
pr_err("%s :timings out of bound Rise{%d>%d}/Fall{%d>%d}\n",
__func__,
setup->rise_time, specs->rise_max,
setup->fall_time, specs->fall_max);
return -EINVAL;
}
if (setup->dnf > STM32_I2C_DNF_MAX) {
pr_err("%s: DNF out of bound %d/%d\n", __func__,
setup->dnf, STM32_I2C_DNF_MAX);
return -EINVAL;
}
INIT_LIST_HEAD(&solutions);
ret = stm32_i2c_compute_solutions(setup, specs, &solutions);
if (ret)
goto exit;
ret = stm32_i2c_choose_solution(setup, specs, &solutions, output);
if (ret)
goto exit;
debug("%s: Presc: %i, scldel: %i, sdadel: %i, scll: %i, sclh: %i\n",
__func__, output->presc,
output->scldel, output->sdadel,
output->scll, output->sclh);
exit:
/* Release list and memory */
list_for_each_entry_safe(v, _v, &solutions, node) {
list_del(&v->node);
free(v);
}
return ret;
}
static u32 get_lower_rate(u32 rate)
{
int i;
for (i = ARRAY_SIZE(i2c_specs) - 1; i >= 0; i--)
if (rate > i2c_specs[i].rate)
return i2c_specs[i].rate;
return i2c_specs[0].rate;
}
static int stm32_i2c_setup_timing(struct stm32_i2c_priv *i2c_priv,
struct stm32_i2c_timings *timing)
{
struct stm32_i2c_setup *setup = i2c_priv->setup;
int ret = 0;
setup->speed_freq = i2c_priv->speed;
setup->clock_src = clk_get_rate(&i2c_priv->clk);
if (!setup->clock_src) {
pr_err("%s: clock rate is 0\n", __func__);
return -EINVAL;
}
do {
ret = stm32_i2c_compute_timing(i2c_priv, setup, timing);
if (ret) {
debug("%s: failed to compute I2C timings.\n",
__func__);
if (setup->speed_freq > I2C_SPEED_STANDARD_RATE) {
setup->speed_freq =
get_lower_rate(setup->speed_freq);
debug("%s: downgrade I2C Speed Freq to (%i)\n",
__func__, setup->speed_freq);
} else {
break;
}
}
} while (ret);
if (ret) {
pr_err("%s: impossible to compute I2C timings.\n", __func__);
return ret;
}
debug("%s: I2C Freq(%i), Clk Source(%i)\n", __func__,
setup->speed_freq, setup->clock_src);
debug("%s: I2C Rise(%i) and Fall(%i) Time\n", __func__,
setup->rise_time, setup->fall_time);
debug("%s: I2C Analog Filter(%s), DNF(%i)\n", __func__,
setup->analog_filter ? "On" : "Off", setup->dnf);
i2c_priv->speed = setup->speed_freq;
return 0;
}
static int stm32_i2c_hw_config(struct stm32_i2c_priv *i2c_priv)
{
struct stm32_i2c_regs *regs = i2c_priv->regs;
struct stm32_i2c_timings t;
int ret;
u32 timing = 0;
ret = stm32_i2c_setup_timing(i2c_priv, &t);
if (ret)
return ret;
/* Disable I2C */
clrbits_le32(&regs->cr1, STM32_I2C_CR1_PE);
/* Timing settings */
timing |= STM32_I2C_TIMINGR_PRESC(t.presc);
timing |= STM32_I2C_TIMINGR_SCLDEL(t.scldel);
timing |= STM32_I2C_TIMINGR_SDADEL(t.sdadel);
timing |= STM32_I2C_TIMINGR_SCLH(t.sclh);
timing |= STM32_I2C_TIMINGR_SCLL(t.scll);
writel(timing, &regs->timingr);
/* Enable I2C */
if (i2c_priv->setup->analog_filter)
clrbits_le32(&regs->cr1, STM32_I2C_CR1_ANFOFF);
else
setbits_le32(&regs->cr1, STM32_I2C_CR1_ANFOFF);
setbits_le32(&regs->cr1, STM32_I2C_CR1_PE);
return 0;
}
static int stm32_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
{
struct stm32_i2c_priv *i2c_priv = dev_get_priv(bus);
if (speed > I2C_SPEED_FAST_PLUS_RATE) {
debug("%s: Speed %d not supported\n", __func__, speed);
return -EINVAL;
}
i2c_priv->speed = speed;
return stm32_i2c_hw_config(i2c_priv);
}
static int stm32_i2c_probe(struct udevice *dev)
{
struct stm32_i2c_priv *i2c_priv = dev_get_priv(dev);
struct reset_ctl reset_ctl;
fdt_addr_t addr;
int ret;
addr = dev_read_addr(dev);
if (addr == FDT_ADDR_T_NONE)
return -EINVAL;
i2c_priv->regs = (struct stm32_i2c_regs *)addr;
ret = clk_get_by_index(dev, 0, &i2c_priv->clk);
if (ret)
return ret;
ret = clk_enable(&i2c_priv->clk);
if (ret)
goto clk_free;
ret = reset_get_by_index(dev, 0, &reset_ctl);
if (ret)
goto clk_disable;
reset_assert(&reset_ctl);
udelay(2);
reset_deassert(&reset_ctl);
return 0;
clk_disable:
clk_disable(&i2c_priv->clk);
clk_free:
clk_free(&i2c_priv->clk);
return ret;
}
static int stm32_ofdata_to_platdata(struct udevice *dev)
{
struct stm32_i2c_priv *i2c_priv = dev_get_priv(dev);
u32 rise_time, fall_time;
i2c_priv->setup = (struct stm32_i2c_setup *)dev_get_driver_data(dev);
if (!i2c_priv->setup)
return -EINVAL;
rise_time = dev_read_u32_default(dev, "i2c-scl-rising-time-ns", 0);
if (rise_time)
i2c_priv->setup->rise_time = rise_time;
fall_time = dev_read_u32_default(dev, "i2c-scl-falling-time-ns", 0);
if (fall_time)
i2c_priv->setup->fall_time = fall_time;
return 0;
}
static const struct dm_i2c_ops stm32_i2c_ops = {
.xfer = stm32_i2c_xfer,
.set_bus_speed = stm32_i2c_set_bus_speed,
};
static const struct udevice_id stm32_i2c_of_match[] = {
{ .compatible = "st,stm32f7-i2c", .data = (ulong)&stm32f7_setup },
{}
};
U_BOOT_DRIVER(stm32f7_i2c) = {
.name = "stm32f7-i2c",
.id = UCLASS_I2C,
.of_match = stm32_i2c_of_match,
.ofdata_to_platdata = stm32_ofdata_to_platdata,
.probe = stm32_i2c_probe,
.priv_auto_alloc_size = sizeof(struct stm32_i2c_priv),
.ops = &stm32_i2c_ops,
};