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i2c: i2c-stm32f7: add driver

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This patch adds initial support for the STM32F7 I2C controller.

Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Pierre-Yves MORDRET 2017-09-14 16:28:37 +02:00 committed by Wolfram Sang
parent df8c847b53
commit aeb068c572
3 changed files with 983 additions and 0 deletions
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10
drivers/i2c/busses/Kconfig
View file

@ -945,6 +945,16 @@ config I2C_STM32F4
This driver can also be built as module. If so, the module
will be called i2c-stm32f4.
config I2C_STM32F7
tristate "STMicroelectronics STM32F7 I2C support"
depends on ARCH_STM32 || COMPILE_TEST
help
Enable this option to add support for STM32 I2C controller embedded
in STM32F7 SoCs.
This driver can also be built as module. If so, the module
will be called i2c-stm32f7.
config I2C_STU300
tristate "ST Microelectronics DDC I2C interface"
depends on MACH_U300

1
drivers/i2c/busses/Makefile
View file

@ -94,6 +94,7 @@ obj-$(CONFIG_I2C_SIRF) += i2c-sirf.o
obj-$(CONFIG_I2C_SPRD) += i2c-sprd.o
obj-$(CONFIG_I2C_ST) += i2c-st.o
obj-$(CONFIG_I2C_STM32F4) += i2c-stm32f4.o
obj-$(CONFIG_I2C_STM32F7) += i2c-stm32f7.o
obj-$(CONFIG_I2C_STU300) += i2c-stu300.o
obj-$(CONFIG_I2C_SUN6I_P2WI) += i2c-sun6i-p2wi.o
obj-$(CONFIG_I2C_TEGRA) += i2c-tegra.o

972
drivers/i2c/busses/i2c-stm32f7.c Normal file
View file

@ -0,0 +1,972 @@
/*
* Driver for STMicroelectronics STM32F7 I2C controller
*
* This I2C controller is described in the STM32F75xxx and STM32F74xxx Soc
* reference manual.
* Please see below a link to the documentation:
* http://www.st.com/resource/en/reference_manual/dm00124865.pdf
*
* Copyright (C) M'boumba Cedric Madianga 2017
* Author: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
*
* This driver is based on i2c-stm32f4.c
*
* License terms: GNU General Public License (GPL), version 2
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/reset.h>
#include <linux/slab.h>
#include "i2c-stm32.h"
/* STM32F7 I2C registers */
#define STM32F7_I2C_CR1 0x00
#define STM32F7_I2C_CR2 0x04
#define STM32F7_I2C_TIMINGR 0x10
#define STM32F7_I2C_ISR 0x18
#define STM32F7_I2C_ICR 0x1C
#define STM32F7_I2C_RXDR 0x24
#define STM32F7_I2C_TXDR 0x28
/* STM32F7 I2C control 1 */
#define STM32F7_I2C_CR1_ANFOFF BIT(12)
#define STM32F7_I2C_CR1_ERRIE BIT(7)
#define STM32F7_I2C_CR1_TCIE BIT(6)
#define STM32F7_I2C_CR1_STOPIE BIT(5)
#define STM32F7_I2C_CR1_NACKIE BIT(4)
#define STM32F7_I2C_CR1_ADDRIE BIT(3)
#define STM32F7_I2C_CR1_RXIE BIT(2)
#define STM32F7_I2C_CR1_TXIE BIT(1)
#define STM32F7_I2C_CR1_PE BIT(0)
#define STM32F7_I2C_ALL_IRQ_MASK (STM32F7_I2C_CR1_ERRIE \
| STM32F7_I2C_CR1_TCIE \
| STM32F7_I2C_CR1_STOPIE \
| STM32F7_I2C_CR1_NACKIE \
| STM32F7_I2C_CR1_RXIE \
| STM32F7_I2C_CR1_TXIE)
/* STM32F7 I2C control 2 */
#define STM32F7_I2C_CR2_RELOAD BIT(24)
#define STM32F7_I2C_CR2_NBYTES_MASK GENMASK(23, 16)
#define STM32F7_I2C_CR2_NBYTES(n) (((n) & 0xff) << 16)
#define STM32F7_I2C_CR2_NACK BIT(15)
#define STM32F7_I2C_CR2_STOP BIT(14)
#define STM32F7_I2C_CR2_START BIT(13)
#define STM32F7_I2C_CR2_RD_WRN BIT(10)
#define STM32F7_I2C_CR2_SADD7_MASK GENMASK(7, 1)
#define STM32F7_I2C_CR2_SADD7(n) (((n) & 0x7f) << 1)
/* STM32F7 I2C Interrupt Status */
#define STM32F7_I2C_ISR_BUSY BIT(15)
#define STM32F7_I2C_ISR_ARLO BIT(9)
#define STM32F7_I2C_ISR_BERR BIT(8)
#define STM32F7_I2C_ISR_TCR BIT(7)
#define STM32F7_I2C_ISR_TC BIT(6)
#define STM32F7_I2C_ISR_STOPF BIT(5)
#define STM32F7_I2C_ISR_NACKF BIT(4)
#define STM32F7_I2C_ISR_RXNE BIT(2)
#define STM32F7_I2C_ISR_TXIS BIT(1)
/* STM32F7 I2C Interrupt Clear */
#define STM32F7_I2C_ICR_ARLOCF BIT(9)
#define STM32F7_I2C_ICR_BERRCF BIT(8)
#define STM32F7_I2C_ICR_STOPCF BIT(5)
#define STM32F7_I2C_ICR_NACKCF BIT(4)
/* STM32F7 I2C Timing */
#define STM32F7_I2C_TIMINGR_PRESC(n) (((n) & 0xf) << 28)
#define STM32F7_I2C_TIMINGR_SCLDEL(n) (((n) & 0xf) << 20)
#define STM32F7_I2C_TIMINGR_SDADEL(n) (((n) & 0xf) << 16)
#define STM32F7_I2C_TIMINGR_SCLH(n) (((n) & 0xff) << 8)
#define STM32F7_I2C_TIMINGR_SCLL(n) ((n) & 0xff)
#define STM32F7_I2C_MAX_LEN 0xff
#define STM32F7_I2C_DNF_DEFAULT 0
#define STM32F7_I2C_DNF_MAX 16
#define STM32F7_I2C_ANALOG_FILTER_ENABLE 1
#define STM32F7_I2C_ANALOG_FILTER_DELAY_MIN 50 /* ns */
#define STM32F7_I2C_ANALOG_FILTER_DELAY_MAX 260 /* ns */
#define STM32F7_I2C_RISE_TIME_DEFAULT 25 /* ns */
#define STM32F7_I2C_FALL_TIME_DEFAULT 10 /* ns */
#define STM32F7_PRESC_MAX BIT(4)
#define STM32F7_SCLDEL_MAX BIT(4)
#define STM32F7_SDADEL_MAX BIT(4)
#define STM32F7_SCLH_MAX BIT(8)
#define STM32F7_SCLL_MAX BIT(8)
/**
* struct stm32f7_i2c_spec - private i2c specification timing
* @rate: I2C bus speed (Hz)
* @rate_min: 80% of I2C bus speed (Hz)
* @rate_max: 100% 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 stm32f7_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 stm32f7_i2c_setup - private I2C timing setup parameters
* @speed: I2C speed mode (standard, Fast Plus)
* @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 stm32f7_i2c_setup {
enum stm32_i2c_speed speed;
u32 speed_freq;
u32 clock_src;
u32 rise_time;
u32 fall_time;
u8 dnf;
bool analog_filter;
};
/**
* struct stm32f7_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 stm32f7_i2c_timings {
struct list_head node;
u8 presc;
u8 scldel;
u8 sdadel;
u8 sclh;
u8 scll;
};
/**
* struct stm32f7_i2c_msg - client specific data
* @addr: 8-bit slave addr, including r/w bit
* @count: number of bytes to be transferred
* @buf: data buffer
* @result: result of the transfer
* @stop: last I2C msg to be sent, i.e. STOP to be generated
*/
struct stm32f7_i2c_msg {
u8 addr;
u32 count;
u8 *buf;
int result;
bool stop;
};
/**
* struct stm32f7_i2c_dev - private data of the controller
* @adap: I2C adapter for this controller
* @dev: device for this controller
* @base: virtual memory area
* @complete: completion of I2C message
* @clk: hw i2c clock
* @speed: I2C clock frequency of the controller. Standard, Fast or Fast+
* @msg: Pointer to data to be written
* @msg_num: number of I2C messages to be executed
* @msg_id: message identifiant
* @f7_msg: customized i2c msg for driver usage
* @setup: I2C timing input setup
* @timing: I2C computed timings
*/
struct stm32f7_i2c_dev {
struct i2c_adapter adap;
struct device *dev;
void __iomem *base;
struct completion complete;
struct clk *clk;
int speed;
struct i2c_msg *msg;
unsigned int msg_num;
unsigned int msg_id;
struct stm32f7_i2c_msg f7_msg;
struct stm32f7_i2c_setup *setup;
struct stm32f7_i2c_timings timing;
};
/**
* All these values are coming from I2C Specification, Version 6.0, 4th of
* April 2014.
*
* Table10. Characteristics of the SDA and SCL bus lines for Standard, Fast,
* and Fast-mode Plus I2C-bus devices
*/
static struct stm32f7_i2c_spec i2c_specs[] = {
[STM32_I2C_SPEED_STANDARD] = {
.rate = 100000,
.rate_min = 80000,
.rate_max = 100000,
.fall_max = 300,
.rise_max = 1000,
.hddat_min = 0,
.vddat_max = 3450,
.sudat_min = 250,
.l_min = 4700,
.h_min = 4000,
},
[STM32_I2C_SPEED_FAST] = {
.rate = 400000,
.rate_min = 320000,
.rate_max = 400000,
.fall_max = 300,
.rise_max = 300,
.hddat_min = 0,
.vddat_max = 900,
.sudat_min = 100,
.l_min = 1300,
.h_min = 600,
},
[STM32_I2C_SPEED_FAST_PLUS] = {
.rate = 1000000,
.rate_min = 800000,
.rate_max = 1000000,
.fall_max = 100,
.rise_max = 120,
.hddat_min = 0,
.vddat_max = 450,
.sudat_min = 50,
.l_min = 500,
.h_min = 260,
},
};
struct stm32f7_i2c_setup stm32f7_setup = {
.rise_time = STM32F7_I2C_RISE_TIME_DEFAULT,
.fall_time = STM32F7_I2C_FALL_TIME_DEFAULT,
.dnf = STM32F7_I2C_DNF_DEFAULT,
.analog_filter = STM32F7_I2C_ANALOG_FILTER_ENABLE,
};
static inline void stm32f7_i2c_set_bits(void __iomem *reg, u32 mask)
{
writel_relaxed(readl_relaxed(reg) | mask, reg);
}
static inline void stm32f7_i2c_clr_bits(void __iomem *reg, u32 mask)
{
writel_relaxed(readl_relaxed(reg) & ~mask, reg);
}
static int stm32f7_i2c_compute_timing(struct stm32f7_i2c_dev *i2c_dev,
struct stm32f7_i2c_setup *setup,
struct stm32f7_i2c_timings *output)
{
u32 p_prev = STM32F7_PRESC_MAX;
u32 i2cclk = DIV_ROUND_CLOSEST(NSEC_PER_SEC,
setup->clock_src);
u32 i2cbus = DIV_ROUND_CLOSEST(NSEC_PER_SEC,
setup->speed_freq);
u32 clk_error_prev = i2cbus;
u32 tsync;
u32 af_delay_min, af_delay_max;
u32 dnf_delay;
u32 clk_min, clk_max;
int sdadel_min, sdadel_max;
int scldel_min;
struct stm32f7_i2c_timings *v, *_v, *s;
struct list_head solutions;
u16 p, l, a, h;
int ret = 0;
if (setup->speed >= STM32_I2C_SPEED_END) {
dev_err(i2c_dev->dev, "speed out of bound {%d/%d}\n",
setup->speed, STM32_I2C_SPEED_END - 1);
return -EINVAL;
}
if ((setup->rise_time > i2c_specs[setup->speed].rise_max) ||
(setup->fall_time > i2c_specs[setup->speed].fall_max)) {
dev_err(i2c_dev->dev,
"timings out of bound Rise{%d>%d}/Fall{%d>%d}\n",
setup->rise_time, i2c_specs[setup->speed].rise_max,
setup->fall_time, i2c_specs[setup->speed].fall_max);
return -EINVAL;
}
if (setup->dnf > STM32F7_I2C_DNF_MAX) {
dev_err(i2c_dev->dev,
"DNF out of bound %d/%d\n",
setup->dnf, STM32F7_I2C_DNF_MAX);
return -EINVAL;
}
if (setup->speed_freq > i2c_specs[setup->speed].rate) {
dev_err(i2c_dev->dev, "ERROR: Freq {%d/%d}\n",
setup->speed_freq, i2c_specs[setup->speed].rate);
return -EINVAL;
}
/* Analog and Digital Filters */
af_delay_min =
(setup->analog_filter ?
STM32F7_I2C_ANALOG_FILTER_DELAY_MIN : 0);
af_delay_max =
(setup->analog_filter ?
STM32F7_I2C_ANALOG_FILTER_DELAY_MAX : 0);
dnf_delay = setup->dnf * i2cclk;
sdadel_min = setup->fall_time - i2c_specs[setup->speed].hddat_min -
af_delay_min - (setup->dnf + 3) * i2cclk;
sdadel_max = i2c_specs[setup->speed].vddat_max - setup->rise_time -
af_delay_max - (setup->dnf + 4) * i2cclk;
scldel_min = setup->rise_time + i2c_specs[setup->speed].sudat_min;
if (sdadel_min < 0)
sdadel_min = 0;
if (sdadel_max < 0)
sdadel_max = 0;
dev_dbg(i2c_dev->dev, "SDADEL(min/max): %i/%i, SCLDEL(Min): %i\n",
sdadel_min, sdadel_max, scldel_min);
INIT_LIST_HEAD(&solutions);
/* Compute possible values for PRESC, SCLDEL and SDADEL */
for (p = 0; p < STM32F7_PRESC_MAX; p++) {
for (l = 0; l < STM32F7_SCLDEL_MAX; l++) {
u32 scldel = (l + 1) * (p + 1) * i2cclk;
if (scldel < scldel_min)
continue;
for (a = 0; a < STM32F7_SDADEL_MAX; a++) {
u32 sdadel = (a * (p + 1) + 1) * i2cclk;
if (((sdadel >= sdadel_min) &&
(sdadel <= sdadel_max)) &&
(p != p_prev)) {
v = kmalloc(sizeof(*v), GFP_KERNEL);
if (!v) {
ret = -ENOMEM;
goto exit;
}
v->presc = p;
v->scldel = l;
v->sdadel = a;
p_prev = p;
list_add_tail(&v->node,
&solutions);
}
}
}
}
if (list_empty(&solutions)) {
dev_err(i2c_dev->dev, "no Prescaler solution\n");
ret = -EPERM;
goto exit;
}
tsync = af_delay_min + dnf_delay + (2 * i2cclk);
s = NULL;
clk_max = NSEC_PER_SEC / i2c_specs[setup->speed].rate_min;
clk_min = NSEC_PER_SEC / i2c_specs[setup->speed].rate_max;
/*
* Among Prescaler possibilities discovered above figures out SCL Low
* and High Period. Provided:
* - SCL Low Period has to be higher than SCL Clock Low Period
* 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 SCL Clock High Period
* 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 < STM32F7_SCLL_MAX; l++) {
u32 tscl_l = (l + 1) * prescaler + tsync;
if ((tscl_l < i2c_specs[setup->speed].l_min) ||
(i2cclk >=
((tscl_l - af_delay_min - dnf_delay) / 4))) {
continue;
}
for (h = 0; h < STM32F7_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 >= i2c_specs[setup->speed].h_min) &&
(i2cclk < tscl_h)) {
int clk_error = tscl - i2cbus;
if (clk_error < 0)
clk_error = -clk_error;
if (clk_error < clk_error_prev) {
clk_error_prev = clk_error;
v->scll = l;
v->sclh = h;
s = v;
}
}
}
}
}
if (!s) {
dev_err(i2c_dev->dev, "no solution at all\n");
ret = -EPERM;
goto exit;
}
output->presc = s->presc;
output->scldel = s->scldel;
output->sdadel = s->sdadel;
output->scll = s->scll;
output->sclh = s->sclh;
dev_dbg(i2c_dev->dev,
"Presc: %i, scldel: %i, sdadel: %i, scll: %i, sclh: %i\n",
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);
kfree(v);
}
return ret;
}
static int stm32f7_i2c_setup_timing(struct stm32f7_i2c_dev *i2c_dev,
struct stm32f7_i2c_setup *setup)
{
int ret = 0;
setup->speed = i2c_dev->speed;
setup->speed_freq = i2c_specs[setup->speed].rate;
setup->clock_src = clk_get_rate(i2c_dev->clk);
if (!setup->clock_src) {
dev_err(i2c_dev->dev, "clock rate is 0\n");
return -EINVAL;
}
do {
ret = stm32f7_i2c_compute_timing(i2c_dev, setup,
&i2c_dev->timing);
if (ret) {
dev_err(i2c_dev->dev,
"failed to compute I2C timings.\n");
if (i2c_dev->speed > STM32_I2C_SPEED_STANDARD) {
i2c_dev->speed--;
setup->speed = i2c_dev->speed;
setup->speed_freq =
i2c_specs[setup->speed].rate;
dev_warn(i2c_dev->dev,
"downgrade I2C Speed Freq to (%i)\n",
i2c_specs[setup->speed].rate);
} else {
break;
}
}
} while (ret);
if (ret) {
dev_err(i2c_dev->dev, "Impossible to compute I2C timings.\n");
return ret;
}
dev_dbg(i2c_dev->dev, "I2C Speed(%i), Freq(%i), Clk Source(%i)\n",
setup->speed, setup->speed_freq, setup->clock_src);
dev_dbg(i2c_dev->dev, "I2C Rise(%i) and Fall(%i) Time\n",
setup->rise_time, setup->fall_time);
dev_dbg(i2c_dev->dev, "I2C Analog Filter(%s), DNF(%i)\n",
(setup->analog_filter ? "On" : "Off"), setup->dnf);
return 0;
}
static void stm32f7_i2c_hw_config(struct stm32f7_i2c_dev *i2c_dev)
{
struct stm32f7_i2c_timings *t = &i2c_dev->timing;
u32 timing = 0;
/* Timing settings */
timing |= STM32F7_I2C_TIMINGR_PRESC(t->presc);
timing |= STM32F7_I2C_TIMINGR_SCLDEL(t->scldel);
timing |= STM32F7_I2C_TIMINGR_SDADEL(t->sdadel);
timing |= STM32F7_I2C_TIMINGR_SCLH(t->sclh);
timing |= STM32F7_I2C_TIMINGR_SCLL(t->scll);
writel_relaxed(timing, i2c_dev->base + STM32F7_I2C_TIMINGR);
/* Enable I2C */
if (i2c_dev->setup->analog_filter)
stm32f7_i2c_clr_bits(i2c_dev->base + STM32F7_I2C_CR1,
STM32F7_I2C_CR1_ANFOFF);
else
stm32f7_i2c_set_bits(i2c_dev->base + STM32F7_I2C_CR1,
STM32F7_I2C_CR1_ANFOFF);
stm32f7_i2c_set_bits(i2c_dev->base + STM32F7_I2C_CR1,
STM32F7_I2C_CR1_PE);
}
static void stm32f7_i2c_write_tx_data(struct stm32f7_i2c_dev *i2c_dev)
{
struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
void __iomem *base = i2c_dev->base;
if (f7_msg->count) {
writeb_relaxed(*f7_msg->buf++, base + STM32F7_I2C_TXDR);
f7_msg->count--;
}
}
static void stm32f7_i2c_read_rx_data(struct stm32f7_i2c_dev *i2c_dev)
{
struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
void __iomem *base = i2c_dev->base;
if (f7_msg->count) {
*f7_msg->buf++ = readb_relaxed(base + STM32F7_I2C_RXDR);
f7_msg->count--;
}
}
static void stm32f7_i2c_reload(struct stm32f7_i2c_dev *i2c_dev)
{
struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
u32 cr2;
cr2 = readl_relaxed(i2c_dev->base + STM32F7_I2C_CR2);
cr2 &= ~STM32F7_I2C_CR2_NBYTES_MASK;
if (f7_msg->count > STM32F7_I2C_MAX_LEN) {
cr2 |= STM32F7_I2C_CR2_NBYTES(STM32F7_I2C_MAX_LEN);
} else {
cr2 &= ~STM32F7_I2C_CR2_RELOAD;
cr2 |= STM32F7_I2C_CR2_NBYTES(f7_msg->count);
}
writel_relaxed(cr2, i2c_dev->base + STM32F7_I2C_CR2);
}
static int stm32f7_i2c_wait_free_bus(struct stm32f7_i2c_dev *i2c_dev)
{
u32 status;
int ret;
ret = readl_relaxed_poll_timeout(i2c_dev->base + STM32F7_I2C_ISR,
status,
!(status & STM32F7_I2C_ISR_BUSY),
10, 1000);
if (ret) {
dev_dbg(i2c_dev->dev, "bus busy\n");
ret = -EBUSY;
}
return ret;
}
static void stm32f7_i2c_xfer_msg(struct stm32f7_i2c_dev *i2c_dev,
struct i2c_msg *msg)
{
struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
void __iomem *base = i2c_dev->base;
u32 cr1, cr2;
f7_msg->addr = msg->addr;
f7_msg->buf = msg->buf;
f7_msg->count = msg->len;
f7_msg->result = 0;
f7_msg->stop = (i2c_dev->msg_id >= i2c_dev->msg_num - 1);
reinit_completion(&i2c_dev->complete);
cr1 = readl_relaxed(base + STM32F7_I2C_CR1);
cr2 = readl_relaxed(base + STM32F7_I2C_CR2);
/* Set transfer direction */
cr2 &= ~STM32F7_I2C_CR2_RD_WRN;
if (msg->flags & I2C_M_RD)
cr2 |= STM32F7_I2C_CR2_RD_WRN;
/* Set slave address */
cr2 &= ~STM32F7_I2C_CR2_SADD7_MASK;
cr2 |= STM32F7_I2C_CR2_SADD7(f7_msg->addr);
/* Set nb bytes to transfer and reload if needed */
cr2 &= ~(STM32F7_I2C_CR2_NBYTES_MASK | STM32F7_I2C_CR2_RELOAD);
if (f7_msg->count > STM32F7_I2C_MAX_LEN) {
cr2 |= STM32F7_I2C_CR2_NBYTES(STM32F7_I2C_MAX_LEN);
cr2 |= STM32F7_I2C_CR2_RELOAD;
} else {
cr2 |= STM32F7_I2C_CR2_NBYTES(f7_msg->count);
}
/* Enable NACK, STOP, error and transfer complete interrupts */
cr1 |= STM32F7_I2C_CR1_ERRIE | STM32F7_I2C_CR1_TCIE |
STM32F7_I2C_CR1_STOPIE | STM32F7_I2C_CR1_NACKIE;
/* Clear TX/RX interrupt */
cr1 &= ~(STM32F7_I2C_CR1_RXIE | STM32F7_I2C_CR1_TXIE);
/* Enable RX/TX interrupt according to msg direction */
if (msg->flags & I2C_M_RD)
cr1 |= STM32F7_I2C_CR1_RXIE;
else
cr1 |= STM32F7_I2C_CR1_TXIE;
/* Configure Start/Repeated Start */
cr2 |= STM32F7_I2C_CR2_START;
/* Write configurations registers */
writel_relaxed(cr1, base + STM32F7_I2C_CR1);
writel_relaxed(cr2, base + STM32F7_I2C_CR2);
}
static void stm32f7_i2c_disable_irq(struct stm32f7_i2c_dev *i2c_dev, u32 mask)
{
stm32f7_i2c_clr_bits(i2c_dev->base + STM32F7_I2C_CR1, mask);
}
static irqreturn_t stm32f7_i2c_isr_event(int irq, void *data)
{
struct stm32f7_i2c_dev *i2c_dev = data;
struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
void __iomem *base = i2c_dev->base;
u32 status, mask;
status = readl_relaxed(i2c_dev->base + STM32F7_I2C_ISR);
/* Tx empty */
if (status & STM32F7_I2C_ISR_TXIS)
stm32f7_i2c_write_tx_data(i2c_dev);
/* RX not empty */
if (status & STM32F7_I2C_ISR_RXNE)
stm32f7_i2c_read_rx_data(i2c_dev);
/* NACK received */
if (status & STM32F7_I2C_ISR_NACKF) {
dev_dbg(i2c_dev->dev, "<%s>: Receive NACK\n", __func__);
writel_relaxed(STM32F7_I2C_ICR_NACKCF, base + STM32F7_I2C_ICR);
f7_msg->result = -ENXIO;
}
/* STOP detection flag */
if (status & STM32F7_I2C_ISR_STOPF) {
/* Disable interrupts */
stm32f7_i2c_disable_irq(i2c_dev, STM32F7_I2C_ALL_IRQ_MASK);
/* Clear STOP flag */
writel_relaxed(STM32F7_I2C_ICR_STOPCF, base + STM32F7_I2C_ICR);
complete(&i2c_dev->complete);
}
/* Transfer complete */
if (status & STM32F7_I2C_ISR_TC) {
if (f7_msg->stop) {
mask = STM32F7_I2C_CR2_STOP;
stm32f7_i2c_set_bits(base + STM32F7_I2C_CR2, mask);
} else {
i2c_dev->msg_id++;
i2c_dev->msg++;
stm32f7_i2c_xfer_msg(i2c_dev, i2c_dev->msg);
}
}
/*
* Transfer Complete Reload: 255 data bytes have been transferred
* We have to prepare the I2C controller to transfer the remaining
* data.
*/
if (status & STM32F7_I2C_ISR_TCR)
stm32f7_i2c_reload(i2c_dev);
return IRQ_HANDLED;
}
static irqreturn_t stm32f7_i2c_isr_error(int irq, void *data)
{
struct stm32f7_i2c_dev *i2c_dev = data;
struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
void __iomem *base = i2c_dev->base;
struct device *dev = i2c_dev->dev;
u32 status;
status = readl_relaxed(i2c_dev->base + STM32F7_I2C_ISR);
/* Bus error */
if (status & STM32F7_I2C_ISR_BERR) {
dev_err(dev, "<%s>: Bus error\n", __func__);
writel_relaxed(STM32F7_I2C_ICR_BERRCF, base + STM32F7_I2C_ICR);
f7_msg->result = -EIO;
}
/* Arbitration loss */
if (status & STM32F7_I2C_ISR_ARLO) {
dev_dbg(dev, "<%s>: Arbitration loss\n", __func__);
writel_relaxed(STM32F7_I2C_ICR_ARLOCF, base + STM32F7_I2C_ICR);
f7_msg->result = -EAGAIN;
}
stm32f7_i2c_disable_irq(i2c_dev, STM32F7_I2C_ALL_IRQ_MASK);
complete(&i2c_dev->complete);
return IRQ_HANDLED;
}
static int stm32f7_i2c_xfer(struct i2c_adapter *i2c_adap,
struct i2c_msg msgs[], int num)
{
struct stm32f7_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap);
struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
unsigned long time_left;
int ret;
i2c_dev->msg = msgs;
i2c_dev->msg_num = num;
i2c_dev->msg_id = 0;
ret = clk_enable(i2c_dev->clk);
if (ret) {
dev_err(i2c_dev->dev, "Failed to enable clock\n");
return ret;
}
ret = stm32f7_i2c_wait_free_bus(i2c_dev);
if (ret)
goto clk_free;
stm32f7_i2c_xfer_msg(i2c_dev, msgs);
time_left = wait_for_completion_timeout(&i2c_dev->complete,
i2c_dev->adap.timeout);
ret = f7_msg->result;
if (!time_left) {
dev_dbg(i2c_dev->dev, "Access to slave 0x%x timed out\n",
i2c_dev->msg->addr);
ret = -ETIMEDOUT;
}
clk_free:
clk_disable(i2c_dev->clk);
return (ret < 0) ? ret : num;
}
static u32 stm32f7_i2c_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static struct i2c_algorithm stm32f7_i2c_algo = {
.master_xfer = stm32f7_i2c_xfer,
.functionality = stm32f7_i2c_func,
};
static int stm32f7_i2c_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
struct stm32f7_i2c_dev *i2c_dev;
const struct stm32f7_i2c_setup *setup;
struct resource *res;
u32 irq_error, irq_event, clk_rate, rise_time, fall_time;
struct i2c_adapter *adap;
struct reset_control *rst;
int ret;
i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
if (!i2c_dev)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
i2c_dev->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(i2c_dev->base))
return PTR_ERR(i2c_dev->base);
irq_event = irq_of_parse_and_map(np, 0);
if (!irq_event) {
dev_err(&pdev->dev, "IRQ event missing or invalid\n");
return -EINVAL;
}
irq_error = irq_of_parse_and_map(np, 1);
if (!irq_error) {
dev_err(&pdev->dev, "IRQ error missing or invalid\n");
return -EINVAL;
}
i2c_dev->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(i2c_dev->clk)) {
dev_err(&pdev->dev, "Error: Missing controller clock\n");
return PTR_ERR(i2c_dev->clk);
}
ret = clk_prepare_enable(i2c_dev->clk);
if (ret) {
dev_err(&pdev->dev, "Failed to prepare_enable clock\n");
return ret;
}
i2c_dev->speed = STM32_I2C_SPEED_STANDARD;
ret = device_property_read_u32(&pdev->dev, "clock-frequency",
&clk_rate);
if (!ret && clk_rate >= 1000000)
i2c_dev->speed = STM32_I2C_SPEED_FAST_PLUS;
else if (!ret && clk_rate >= 400000)
i2c_dev->speed = STM32_I2C_SPEED_FAST;
else if (!ret && clk_rate >= 100000)
i2c_dev->speed = STM32_I2C_SPEED_STANDARD;
rst = devm_reset_control_get(&pdev->dev, NULL);
if (IS_ERR(rst)) {
dev_err(&pdev->dev, "Error: Missing controller reset\n");
ret = PTR_ERR(rst);
goto clk_free;
}
reset_control_assert(rst);
udelay(2);
reset_control_deassert(rst);
i2c_dev->dev = &pdev->dev;
ret = devm_request_irq(&pdev->dev, irq_event, stm32f7_i2c_isr_event, 0,
pdev->name, i2c_dev);
if (ret) {
dev_err(&pdev->dev, "Failed to request irq event %i\n",
irq_event);
goto clk_free;
}
ret = devm_request_irq(&pdev->dev, irq_error, stm32f7_i2c_isr_error, 0,
pdev->name, i2c_dev);
if (ret) {
dev_err(&pdev->dev, "Failed to request irq error %i\n",
irq_error);
goto clk_free;
}
setup = of_device_get_match_data(&pdev->dev);
i2c_dev->setup->rise_time = setup->rise_time;
i2c_dev->setup->fall_time = setup->fall_time;
i2c_dev->setup->dnf = setup->dnf;
i2c_dev->setup->analog_filter = setup->analog_filter;
ret = device_property_read_u32(i2c_dev->dev, "i2c-scl-rising-time-ns",
&rise_time);
if (!ret)
i2c_dev->setup->rise_time = rise_time;
ret = device_property_read_u32(i2c_dev->dev, "i2c-scl-falling-time-ns",
&fall_time);
if (!ret)
i2c_dev->setup->fall_time = fall_time;
ret = stm32f7_i2c_setup_timing(i2c_dev, i2c_dev->setup);
if (ret)
goto clk_free;
stm32f7_i2c_hw_config(i2c_dev);
adap = &i2c_dev->adap;
i2c_set_adapdata(adap, i2c_dev);
snprintf(adap->name, sizeof(adap->name), "STM32F7 I2C(%pa)",
&res->start);
adap->owner = THIS_MODULE;
adap->timeout = 2 * HZ;
adap->retries = 3;
adap->algo = &stm32f7_i2c_algo;
adap->dev.parent = &pdev->dev;
adap->dev.of_node = pdev->dev.of_node;
init_completion(&i2c_dev->complete);
ret = i2c_add_adapter(adap);
if (ret)
goto clk_free;
platform_set_drvdata(pdev, i2c_dev);
clk_disable(i2c_dev->clk);
dev_info(i2c_dev->dev, "STM32F7 I2C-%d bus adapter\n", adap->nr);
return 0;
clk_free:
clk_disable_unprepare(i2c_dev->clk);
return ret;
}
static int stm32f7_i2c_remove(struct platform_device *pdev)
{
struct stm32f7_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
i2c_del_adapter(&i2c_dev->adap);
clk_unprepare(i2c_dev->clk);
return 0;
}
static const struct of_device_id stm32f7_i2c_match[] = {
{ .compatible = "st,stm32f7-i2c", .data = &stm32f7_setup},
{},
};
MODULE_DEVICE_TABLE(of, stm32f7_i2c_match);
static struct platform_driver stm32f7_i2c_driver = {
.driver = {
.name = "stm32f7-i2c",
.of_match_table = stm32f7_i2c_match,
},
.probe = stm32f7_i2c_probe,
.remove = stm32f7_i2c_remove,
};
module_platform_driver(stm32f7_i2c_driver);
MODULE_AUTHOR("M'boumba Cedric Madianga <cedric.madianga@gmail.com>");
MODULE_DESCRIPTION("STMicroelectronics STM32F7 I2C driver");
MODULE_LICENSE("GPL v2");