/**
* 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)
*/
struct stm32f7_i2c_spec {
u32 rate;
- u32 rate_min;
- u32 rate_max;
u32 fall_max;
u32 rise_max;
u32 hddat_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)
* @fmp_clr_offset: Fast Mode Plus clear register offset from set register
*/
struct stm32f7_i2c_setup {
- enum stm32_i2c_speed speed;
u32 speed_freq;
u32 clock_src;
u32 rise_time;
* @base: virtual memory area
* @complete: completion of I2C message
* @clk: hw i2c clock
- * @speed: I2C clock frequency of the controller. Standard, Fast or Fast+
+ * @bus_rate: I2C clock frequency of the controller
* @msg: Pointer to data to be written
* @msg_num: number of I2C messages to be executed
* @msg_id: message identifiant
void __iomem *base;
struct completion complete;
struct clk *clk;
- int speed;
+ unsigned int bus_rate;
struct i2c_msg *msg;
unsigned int msg_num;
unsigned int msg_id;
* 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] = {
+static struct stm32f7_i2c_spec stm32f7_i2c_specs[] = {
+ {
.rate = I2C_MAX_STANDARD_MODE_FREQ,
- .rate_min = I2C_MAX_STANDARD_MODE_FREQ * 8 / 10, /* 80% */
- .rate_max = I2C_MAX_STANDARD_MODE_FREQ,
.fall_max = 300,
.rise_max = 1000,
.hddat_min = 0,
.l_min = 4700,
.h_min = 4000,
},
- [STM32_I2C_SPEED_FAST] = {
+ {
.rate = I2C_MAX_FAST_MODE_FREQ,
- .rate_min = I2C_MAX_FAST_MODE_FREQ * 8 / 10, /* 80% */
- .rate_max = I2C_MAX_FAST_MODE_FREQ,
.fall_max = 300,
.rise_max = 300,
.hddat_min = 0,
.l_min = 1300,
.h_min = 600,
},
- [STM32_I2C_SPEED_FAST_PLUS] = {
+ {
.rate = I2C_MAX_FAST_MODE_PLUS_FREQ,
- .rate_min = I2C_MAX_FAST_MODE_PLUS_FREQ * 8 / 10, /* 80% */
- .rate_max = I2C_MAX_FAST_MODE_PLUS_FREQ,
.fall_max = 100,
.rise_max = 120,
.hddat_min = 0,
stm32f7_i2c_clr_bits(i2c_dev->base + STM32F7_I2C_CR1, mask);
}
+static struct stm32f7_i2c_spec *stm32f7_get_specs(u32 rate)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(stm32f7_i2c_specs); i++)
+ if (rate <= stm32f7_i2c_specs[i].rate)
+ return &stm32f7_i2c_specs[i];
+
+ return ERR_PTR(-EINVAL);
+}
+
+#define RATE_MIN(rate) ((rate) * 8 / 10)
static int stm32f7_i2c_compute_timing(struct stm32f7_i2c_dev *i2c_dev,
struct stm32f7_i2c_setup *setup,
struct stm32f7_i2c_timings *output)
{
+ struct stm32f7_i2c_spec *specs;
u32 p_prev = STM32F7_PRESC_MAX;
u32 i2cclk = DIV_ROUND_CLOSEST(NSEC_PER_SEC,
setup->clock_src);
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);
+ specs = stm32f7_get_specs(setup->speed_freq);
+ if (specs == ERR_PTR(-EINVAL)) {
+ dev_err(i2c_dev->dev, "speed out of bound {%d}\n",
+ setup->speed_freq);
return -EINVAL;
}
- if ((setup->rise_time > i2c_specs[setup->speed].rise_max) ||
- (setup->fall_time > i2c_specs[setup->speed].fall_max)) {
+ if ((setup->rise_time > specs->rise_max) ||
+ (setup->fall_time > specs->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);
+ setup->rise_time, specs->rise_max,
+ setup->fall_time, specs->fall_max);
return -EINVAL;
}
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_MAX : 0);
dnf_delay = setup->dnf * i2cclk;
- sdadel_min = i2c_specs[setup->speed].hddat_min + setup->fall_time -
+ sdadel_min = specs->hddat_min + setup->fall_time -
af_delay_min - (setup->dnf + 3) * i2cclk;
- sdadel_max = i2c_specs[setup->speed].vddat_max - setup->rise_time -
+ sdadel_max = specs->vddat_max - setup->rise_time -
af_delay_max - (setup->dnf + 4) * i2cclk;
- scldel_min = setup->rise_time + i2c_specs[setup->speed].sudat_min;
+ scldel_min = setup->rise_time + specs->sudat_min;
if (sdadel_min < 0)
sdadel_min = 0;
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;
+ clk_max = NSEC_PER_SEC / RATE_MIN(setup->speed_freq);
+ clk_min = NSEC_PER_SEC / setup->speed_freq;
/*
* Among Prescaler possibilities discovered above figures out SCL Low
for (l = 0; l < STM32F7_SCLL_MAX; l++) {
u32 tscl_l = (l + 1) * prescaler + tsync;
- if ((tscl_l < i2c_specs[setup->speed].l_min) ||
+ if ((tscl_l < specs->l_min) ||
(i2cclk >=
((tscl_l - af_delay_min - dnf_delay) / 4))) {
continue;
setup->rise_time + setup->fall_time;
if ((tscl >= clk_min) && (tscl <= clk_max) &&
- (tscl_h >= i2c_specs[setup->speed].h_min) &&
+ (tscl_h >= specs->h_min) &&
(i2cclk < tscl_h)) {
int clk_error = tscl - i2cbus;
return ret;
}
+static u32 stm32f7_get_lower_rate(u32 rate)
+{
+ int i = ARRAY_SIZE(stm32f7_i2c_specs);
+
+ while (i--)
+ if (stm32f7_i2c_specs[i].rate < rate)
+ break;
+
+ return stm32f7_i2c_specs[i].rate;
+}
+
static int stm32f7_i2c_setup_timing(struct stm32f7_i2c_dev *i2c_dev,
struct stm32f7_i2c_setup *setup)
{
i2c_parse_fw_timings(i2c_dev->dev, t, false);
- if (t->bus_freq_hz >= I2C_MAX_FAST_MODE_PLUS_FREQ)
- i2c_dev->speed = STM32_I2C_SPEED_FAST_PLUS;
- else if (t->bus_freq_hz >= I2C_MAX_FAST_MODE_FREQ)
- i2c_dev->speed = STM32_I2C_SPEED_FAST;
- else
- i2c_dev->speed = STM32_I2C_SPEED_STANDARD;
+ if (t->bus_freq_hz > I2C_MAX_FAST_MODE_PLUS_FREQ) {
+ dev_err(i2c_dev->dev, "Invalid bus speed (%i>%i)\n",
+ t->bus_freq_hz, I2C_MAX_FAST_MODE_PLUS_FREQ);
+ return -EINVAL;
+ }
+ setup->speed_freq = t->bus_freq_hz;
i2c_dev->setup.rise_time = t->scl_rise_ns;
i2c_dev->setup.fall_time = t->scl_fall_ns;
-
- 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) {
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 {
+ if (setup->speed_freq <= I2C_MAX_STANDARD_MODE_FREQ)
break;
- }
+ setup->speed_freq =
+ stm32f7_get_lower_rate(setup->speed_freq);
+ dev_warn(i2c_dev->dev,
+ "downgrade I2C Speed Freq to (%i)\n",
+ setup->speed_freq);
}
} while (ret);
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 Speed(%i), Clk Source(%i)\n",
+ 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);
+ i2c_dev->bus_rate = setup->speed_freq;
+
return 0;
}
{
int ret;
- if (i2c_dev->speed != STM32_I2C_SPEED_FAST_PLUS ||
+ if (i2c_dev->bus_rate <= I2C_MAX_FAST_MODE_FREQ ||
IS_ERR_OR_NULL(i2c_dev->regmap))
/* Optional */
return 0;
if (ret)
goto clk_free;
- if (i2c_dev->speed == STM32_I2C_SPEED_FAST_PLUS) {
+ /* Setup Fast mode plus if necessary */
+ if (i2c_dev->bus_rate > I2C_MAX_FAST_MODE_FREQ) {
ret = stm32f7_i2c_setup_fm_plus_bits(pdev, i2c_dev);
if (ret)
goto clk_free;
projects / linux-2.6-microblaze.git / blobdiff