diff --git a/drivers/i2c/stm32f7_i2c.c b/drivers/i2c/stm32f7_i2c.c index 7d046c1a1e..fc5c1221e1 100644 --- a/drivers/i2c/stm32f7_i2c.c +++ b/drivers/i2c/stm32f7_i2c.c @@ -7,10 +7,10 @@ #include #include #include -#include #include #include +#include #include /* STM32 I2C registers */ @@ -145,7 +145,6 @@ struct stm32_i2c_spec { /** * struct stm32_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) @@ -154,7 +153,6 @@ struct stm32_i2c_spec { * @analog_filter: Analog filter delay (On/Off) */ struct stm32_i2c_setup { - enum i2c_speed_mode speed; u32 speed_freq; u32 clock_src; u32 rise_time; @@ -184,10 +182,11 @@ struct stm32_i2c_priv { struct stm32_i2c_regs *regs; struct clk clk; struct stm32_i2c_setup *setup; - int speed; + 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, @@ -200,6 +199,7 @@ static const struct stm32_i2c_spec i2c_specs[] = { .l_min = 4700, .h_min = 4000, }, + /* Fast speed - 400 KHz */ [IC_SPEED_MODE_FAST] = { .rate = I2C_SPEED_FAST_RATE, .rate_min = 320000, @@ -212,6 +212,7 @@ static const struct stm32_i2c_spec i2c_specs[] = { .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, @@ -474,6 +475,7 @@ static int stm32_i2c_xfer(struct udevice *bus, struct i2c_msg *msg, } 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; @@ -490,13 +492,13 @@ static int stm32_i2c_compute_solutions(struct stm32_i2c_setup *setup, af_delay_max = setup->analog_filter ? STM32_I2C_ANALOG_FILTER_DELAY_MAX : 0; - 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; @@ -548,6 +550,7 @@ static int stm32_i2c_compute_solutions(struct stm32_i2c_setup *setup, } 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) { @@ -570,8 +573,8 @@ static int stm32_i2c_choose_solution(struct stm32_i2c_setup *setup, dnf_delay = setup->dnf * i2cclk; tsync = af_delay_min + dnf_delay + (2 * i2cclk); - clk_max = STM32_NSEC_PER_SEC / i2c_specs[setup->speed].rate_min; - clk_min = STM32_NSEC_PER_SEC / i2c_specs[setup->speed].rate_max; + 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 @@ -589,7 +592,7 @@ static int stm32_i2c_choose_solution(struct stm32_i2c_setup *setup, for (l = 0; l < STM32_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; @@ -601,7 +604,7 @@ static int stm32_i2c_choose_solution(struct stm32_i2c_setup *setup, 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)) { u32 clk_error; @@ -630,26 +633,40 @@ static int stm32_i2c_choose_solution(struct stm32_i2c_setup *setup, 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; - if (setup->speed >= ARRAY_SIZE(i2c_specs)) { - pr_err("%s: speed out of bound {%d/%d}\n", __func__, - setup->speed, ARRAY_SIZE(i2c_specs) - 1); + 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 > 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) { pr_err("%s :timings out of bound Rise{%d>%d}/Fall{%d>%d}\n", __func__, - 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; } @@ -659,18 +676,12 @@ static int stm32_i2c_compute_timing(struct stm32_i2c_priv *i2c_priv, return -EINVAL; } - if (setup->speed_freq > i2c_specs[setup->speed].rate) { - pr_err("%s: Freq {%d/%d}\n", __func__, - setup->speed_freq, i2c_specs[setup->speed].rate); - return -EINVAL; - } - INIT_LIST_HEAD(&solutions); - ret = stm32_i2c_compute_solutions(setup, &solutions); + ret = stm32_i2c_compute_solutions(setup, specs, &solutions); if (ret) goto exit; - ret = stm32_i2c_choose_solution(setup, &solutions, output); + ret = stm32_i2c_choose_solution(setup, specs, &solutions, output); if (ret) goto exit; @@ -689,14 +700,24 @@ exit: 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 = i2c_priv->speed; - setup->speed_freq = i2c_specs[setup->speed].rate; + setup->speed_freq = i2c_priv->speed; setup->clock_src = clk_get_rate(&i2c_priv->clk); if (!setup->clock_src) { @@ -709,13 +730,11 @@ static int stm32_i2c_setup_timing(struct stm32_i2c_priv *i2c_priv, if (ret) { debug("%s: failed to compute I2C timings.\n", __func__); - if (i2c_priv->speed > IC_SPEED_MODE_STANDARD) { - i2c_priv->speed--; - setup->speed = i2c_priv->speed; + if (setup->speed_freq > I2C_SPEED_STANDARD_RATE) { setup->speed_freq = - i2c_specs[setup->speed].rate; + get_lower_rate(setup->speed_freq); debug("%s: downgrade I2C Speed Freq to (%i)\n", - __func__, i2c_specs[setup->speed].rate); + __func__, setup->speed_freq); } else { break; } @@ -727,13 +746,15 @@ static int stm32_i2c_setup_timing(struct stm32_i2c_priv *i2c_priv, return ret; } - debug("%s: I2C Speed(%i), Freq(%i), Clk Source(%i)\n", __func__, - setup->speed, setup->speed_freq, setup->clock_src); + 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; } @@ -773,21 +794,13 @@ static int stm32_i2c_set_bus_speed(struct udevice *bus, unsigned int speed) { struct stm32_i2c_priv *i2c_priv = dev_get_priv(bus); - switch (speed) { - case I2C_SPEED_STANDARD_RATE: - i2c_priv->speed = IC_SPEED_MODE_STANDARD; - break; - case I2C_SPEED_FAST_RATE: - i2c_priv->speed = IC_SPEED_MODE_FAST; - break; - case I2C_SPEED_FAST_PLUS_RATE: - i2c_priv->speed = IC_SPEED_MODE_FAST_PLUS; - break; - default: + 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); }