pwm: stm32: Implementation of the waveform callbacks

Convert the stm32 pwm driver to use the new callbacks for hardware
programming.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/332d4f736d8360038d03f109c013441c655eea23.1726819463.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
This commit is contained in:
Uwe Kleine-König 2024-09-20 10:58:02 +02:00 committed by Uwe Kleine-König
parent eb18504ca5
commit deaba9cff8

View File

@ -51,6 +51,391 @@ static u32 active_channels(struct stm32_pwm *dev)
return ccer & TIM_CCER_CCXE;
}
struct stm32_pwm_waveform {
u32 ccer;
u32 psc;
u32 arr;
u32 ccr;
};
static int stm32_pwm_round_waveform_tohw(struct pwm_chip *chip,
struct pwm_device *pwm,
const struct pwm_waveform *wf,
void *_wfhw)
{
struct stm32_pwm_waveform *wfhw = _wfhw;
struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
unsigned int ch = pwm->hwpwm;
unsigned long rate;
u64 ccr, duty;
int ret;
if (wf->period_length_ns == 0) {
*wfhw = (struct stm32_pwm_waveform){
.ccer = 0,
};
return 0;
}
ret = clk_enable(priv->clk);
if (ret)
return ret;
wfhw->ccer = TIM_CCER_CCxE(ch + 1);
if (priv->have_complementary_output)
wfhw->ccer = TIM_CCER_CCxNE(ch + 1);
rate = clk_get_rate(priv->clk);
if (active_channels(priv) & ~(1 << ch * 4)) {
u64 arr;
/*
* Other channels are already enabled, so the configured PSC and
* ARR must be used for this channel, too.
*/
ret = regmap_read(priv->regmap, TIM_PSC, &wfhw->psc);
if (ret)
goto out;
ret = regmap_read(priv->regmap, TIM_ARR, &wfhw->arr);
if (ret)
goto out;
/*
* calculate the best value for ARR for the given PSC, refuse if
* the resulting period gets bigger than the requested one.
*/
arr = mul_u64_u64_div_u64(wf->period_length_ns, rate,
(u64)NSEC_PER_SEC * (wfhw->psc + 1));
if (arr <= wfhw->arr) {
/*
* requested period is small than the currently
* configured and unchangable period, report back the smallest
* possible period, i.e. the current state; Initialize
* ccr to anything valid.
*/
wfhw->ccr = 0;
ret = 1;
goto out;
}
} else {
/*
* .probe() asserted that clk_get_rate() is not bigger than 1 GHz, so
* the calculations here won't overflow.
* First we need to find the minimal value for prescaler such that
*
* period_ns * clkrate
* ------------------------------ < max_arr + 1
* NSEC_PER_SEC * (prescaler + 1)
*
* This equation is equivalent to
*
* period_ns * clkrate
* ---------------------------- < prescaler + 1
* NSEC_PER_SEC * (max_arr + 1)
*
* Using integer division and knowing that the right hand side is
* integer, this is further equivalent to
*
* (period_ns * clkrate) // (NSEC_PER_SEC * (max_arr + 1)) ≤ prescaler
*/
u64 psc = mul_u64_u64_div_u64(wf->period_length_ns, rate,
(u64)NSEC_PER_SEC * ((u64)priv->max_arr + 1));
u64 arr;
wfhw->psc = min_t(u64, psc, MAX_TIM_PSC);
arr = mul_u64_u64_div_u64(wf->period_length_ns, rate,
(u64)NSEC_PER_SEC * (wfhw->psc + 1));
if (!arr) {
/*
* requested period is too small, report back the smallest
* possible period, i.e. ARR = 0. The only valid CCR
* value is then zero, too.
*/
wfhw->arr = 0;
wfhw->ccr = 0;
ret = 1;
goto out;
}
/*
* ARR is limited intentionally to values less than
* priv->max_arr to allow 100% duty cycle.
*/
wfhw->arr = min_t(u64, arr, priv->max_arr) - 1;
}
duty = mul_u64_u64_div_u64(wf->duty_length_ns, rate,
(u64)NSEC_PER_SEC * (wfhw->psc + 1));
duty = min_t(u64, duty, wfhw->arr + 1);
if (wf->duty_length_ns && wf->duty_offset_ns &&
wf->duty_length_ns + wf->duty_offset_ns >= wf->period_length_ns) {
wfhw->ccer |= TIM_CCER_CCxP(ch + 1);
if (priv->have_complementary_output)
wfhw->ccer |= TIM_CCER_CCxNP(ch + 1);
ccr = wfhw->arr + 1 - duty;
} else {
ccr = duty;
}
wfhw->ccr = min_t(u64, ccr, wfhw->arr + 1);
dev_dbg(&chip->dev, "pwm#%u: %lld/%lld [+%lld] @%lu -> CCER: %08x, PSC: %08x, ARR: %08x, CCR: %08x\n",
pwm->hwpwm, wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns,
rate, wfhw->ccer, wfhw->psc, wfhw->arr, wfhw->ccr);
out:
clk_disable(priv->clk);
return ret;
}
/*
* This should be moved to lib/math/div64.c. Currently there are some changes
* pending to mul_u64_u64_div_u64. Uwe will care for that when the dust settles.
*/
static u64 stm32_pwm_mul_u64_u64_div_u64_roundup(u64 a, u64 b, u64 c)
{
u64 res = mul_u64_u64_div_u64(a, b, c);
/* Those multiplications might overflow but it doesn't matter */
u64 rem = a * b - c * res;
if (rem)
res += 1;
return res;
}
static int stm32_pwm_round_waveform_fromhw(struct pwm_chip *chip,
struct pwm_device *pwm,
const void *_wfhw,
struct pwm_waveform *wf)
{
const struct stm32_pwm_waveform *wfhw = _wfhw;
struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
unsigned int ch = pwm->hwpwm;
if (wfhw->ccer & TIM_CCER_CCxE(ch + 1)) {
unsigned long rate = clk_get_rate(priv->clk);
u64 ccr_ns;
/* The result doesn't overflow for rate >= 15259 */
wf->period_length_ns = stm32_pwm_mul_u64_u64_div_u64_roundup(((u64)wfhw->psc + 1) * (wfhw->arr + 1),
NSEC_PER_SEC, rate);
ccr_ns = stm32_pwm_mul_u64_u64_div_u64_roundup(((u64)wfhw->psc + 1) * wfhw->ccr,
NSEC_PER_SEC, rate);
if (wfhw->ccer & TIM_CCER_CCxP(ch + 1)) {
wf->duty_length_ns =
stm32_pwm_mul_u64_u64_div_u64_roundup(((u64)wfhw->psc + 1) * (wfhw->arr + 1 - wfhw->ccr),
NSEC_PER_SEC, rate);
wf->duty_offset_ns = ccr_ns;
} else {
wf->duty_length_ns = ccr_ns;
wf->duty_offset_ns = 0;
}
dev_dbg(&chip->dev, "pwm#%u: CCER: %08x, PSC: %08x, ARR: %08x, CCR: %08x @%lu -> %lld/%lld [+%lld]\n",
pwm->hwpwm, wfhw->ccer, wfhw->psc, wfhw->arr, wfhw->ccr, rate,
wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns);
} else {
*wf = (struct pwm_waveform){
.period_length_ns = 0,
};
}
return 0;
}
static int stm32_pwm_read_waveform(struct pwm_chip *chip,
struct pwm_device *pwm,
void *_wfhw)
{
struct stm32_pwm_waveform *wfhw = _wfhw;
struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
unsigned int ch = pwm->hwpwm;
int ret;
ret = clk_enable(priv->clk);
if (ret)
return ret;
ret = regmap_read(priv->regmap, TIM_CCER, &wfhw->ccer);
if (ret)
goto out;
if (wfhw->ccer & TIM_CCER_CCxE(ch + 1)) {
ret = regmap_read(priv->regmap, TIM_PSC, &wfhw->psc);
if (ret)
goto out;
ret = regmap_read(priv->regmap, TIM_ARR, &wfhw->arr);
if (ret)
goto out;
if (wfhw->arr == U32_MAX)
wfhw->arr -= 1;
ret = regmap_read(priv->regmap, TIM_CCRx(ch + 1), &wfhw->ccr);
if (ret)
goto out;
if (wfhw->ccr > wfhw->arr + 1)
wfhw->ccr = wfhw->arr + 1;
}
out:
clk_disable(priv->clk);
return ret;
}
static int stm32_pwm_write_waveform(struct pwm_chip *chip,
struct pwm_device *pwm,
const void *_wfhw)
{
const struct stm32_pwm_waveform *wfhw = _wfhw;
struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
unsigned int ch = pwm->hwpwm;
int ret;
ret = clk_enable(priv->clk);
if (ret)
return ret;
if (wfhw->ccer & TIM_CCER_CCxE(ch + 1)) {
u32 ccer, mask;
unsigned int shift;
u32 ccmr;
ret = regmap_read(priv->regmap, TIM_CCER, &ccer);
if (ret)
goto out;
/* If there are other channels enabled, don't update PSC and ARR */
if (ccer & ~TIM_CCER_CCxE(ch + 1) & TIM_CCER_CCXE) {
u32 psc, arr;
ret = regmap_read(priv->regmap, TIM_PSC, &psc);
if (ret)
goto out;
if (psc != wfhw->psc) {
ret = -EBUSY;
goto out;
}
regmap_read(priv->regmap, TIM_ARR, &arr);
if (ret)
goto out;
if (arr != wfhw->arr) {
ret = -EBUSY;
goto out;
}
} else {
ret = regmap_write(priv->regmap, TIM_PSC, wfhw->psc);
if (ret)
goto out;
ret = regmap_write(priv->regmap, TIM_ARR, wfhw->arr);
if (ret)
goto out;
ret = regmap_set_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE);
if (ret)
goto out;
}
/* set polarity */
mask = TIM_CCER_CCxP(ch + 1) | TIM_CCER_CCxNP(ch + 1);
ret = regmap_update_bits(priv->regmap, TIM_CCER, mask, wfhw->ccer);
if (ret)
goto out;
ret = regmap_write(priv->regmap, TIM_CCRx(ch + 1), wfhw->ccr);
if (ret)
goto out;
/* Configure output mode */
shift = (ch & 0x1) * CCMR_CHANNEL_SHIFT;
ccmr = (TIM_CCMR_PE | TIM_CCMR_M1) << shift;
mask = CCMR_CHANNEL_MASK << shift;
if (ch < 2)
ret = regmap_update_bits(priv->regmap, TIM_CCMR1, mask, ccmr);
else
ret = regmap_update_bits(priv->regmap, TIM_CCMR2, mask, ccmr);
if (ret)
goto out;
ret = regmap_set_bits(priv->regmap, TIM_BDTR, TIM_BDTR_MOE);
if (ret)
goto out;
if (!(ccer & TIM_CCER_CCxE(ch + 1))) {
mask = TIM_CCER_CCxE(ch + 1) | TIM_CCER_CCxNE(ch + 1);
ret = clk_enable(priv->clk);
if (ret)
goto out;
ccer = (ccer & ~mask) | (wfhw->ccer & mask);
regmap_write(priv->regmap, TIM_CCER, ccer);
/* Make sure that registers are updated */
regmap_set_bits(priv->regmap, TIM_EGR, TIM_EGR_UG);
/* Enable controller */
regmap_set_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN);
}
} else {
/* disable channel */
u32 mask, ccer;
mask = TIM_CCER_CCxE(ch + 1);
if (priv->have_complementary_output)
mask |= TIM_CCER_CCxNE(ch + 1);
ret = regmap_read(priv->regmap, TIM_CCER, &ccer);
if (ret)
goto out;
if (ccer & mask) {
ccer = ccer & ~mask;
ret = regmap_write(priv->regmap, TIM_CCER, ccer);
if (ret)
goto out;
if (!(ccer & TIM_CCER_CCXE)) {
/* When all channels are disabled, we can disable the controller */
ret = regmap_clear_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN);
if (ret)
goto out;
}
clk_disable(priv->clk);
}
}
out:
clk_disable(priv->clk);
return ret;
}
#define TIM_CCER_CC12P (TIM_CCER_CC1P | TIM_CCER_CC2P)
#define TIM_CCER_CC12E (TIM_CCER_CC1E | TIM_CCER_CC2E)
#define TIM_CCER_CC34P (TIM_CCER_CC3P | TIM_CCER_CC4P)
@ -308,228 +693,13 @@ static int stm32_pwm_capture(struct pwm_chip *chip, struct pwm_device *pwm,
return ret;
}
static int stm32_pwm_config(struct stm32_pwm *priv, unsigned int ch,
u64 duty_ns, u64 period_ns)
{
unsigned long long prd, dty;
unsigned long long prescaler;
u32 ccmr, mask, shift;
/*
* .probe() asserted that clk_get_rate() is not bigger than 1 GHz, so
* the calculations here won't overflow.
* First we need to find the minimal value for prescaler such that
*
* period_ns * clkrate
* ------------------------------ < max_arr + 1
* NSEC_PER_SEC * (prescaler + 1)
*
* This equation is equivalent to
*
* period_ns * clkrate
* ---------------------------- < prescaler + 1
* NSEC_PER_SEC * (max_arr + 1)
*
* Using integer division and knowing that the right hand side is
* integer, this is further equivalent to
*
* (period_ns * clkrate) // (NSEC_PER_SEC * (max_arr + 1)) ≤ prescaler
*/
prescaler = mul_u64_u64_div_u64(period_ns, clk_get_rate(priv->clk),
(u64)NSEC_PER_SEC * ((u64)priv->max_arr + 1));
if (prescaler > MAX_TIM_PSC)
return -EINVAL;
prd = mul_u64_u64_div_u64(period_ns, clk_get_rate(priv->clk),
(u64)NSEC_PER_SEC * (prescaler + 1));
if (!prd)
return -EINVAL;
/*
* All channels share the same prescaler and counter so when two
* channels are active at the same time we can't change them
*/
if (active_channels(priv) & ~(1 << ch * 4)) {
u32 psc, arr;
regmap_read(priv->regmap, TIM_PSC, &psc);
regmap_read(priv->regmap, TIM_ARR, &arr);
if ((psc != prescaler) || (arr != prd - 1))
return -EBUSY;
}
regmap_write(priv->regmap, TIM_PSC, prescaler);
regmap_write(priv->regmap, TIM_ARR, prd - 1);
regmap_set_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE);
/* Calculate the duty cycles */
dty = mul_u64_u64_div_u64(duty_ns, clk_get_rate(priv->clk),
(u64)NSEC_PER_SEC * (prescaler + 1));
regmap_write(priv->regmap, TIM_CCRx(ch + 1), dty);
/* Configure output mode */
shift = (ch & 0x1) * CCMR_CHANNEL_SHIFT;
ccmr = (TIM_CCMR_PE | TIM_CCMR_M1) << shift;
mask = CCMR_CHANNEL_MASK << shift;
if (ch < 2)
regmap_update_bits(priv->regmap, TIM_CCMR1, mask, ccmr);
else
regmap_update_bits(priv->regmap, TIM_CCMR2, mask, ccmr);
regmap_set_bits(priv->regmap, TIM_BDTR, TIM_BDTR_MOE);
return 0;
}
static int stm32_pwm_set_polarity(struct stm32_pwm *priv, unsigned int ch,
enum pwm_polarity polarity)
{
u32 mask;
mask = TIM_CCER_CCxP(ch + 1);
if (priv->have_complementary_output)
mask |= TIM_CCER_CCxNP(ch + 1);
regmap_update_bits(priv->regmap, TIM_CCER, mask,
polarity == PWM_POLARITY_NORMAL ? 0 : mask);
return 0;
}
static int stm32_pwm_enable(struct stm32_pwm *priv, unsigned int ch)
{
u32 mask;
int ret;
ret = clk_enable(priv->clk);
if (ret)
return ret;
/* Enable channel */
mask = TIM_CCER_CCxE(ch + 1);
if (priv->have_complementary_output)
mask |= TIM_CCER_CCxNE(ch + 1);
regmap_set_bits(priv->regmap, TIM_CCER, mask);
/* Make sure that registers are updated */
regmap_set_bits(priv->regmap, TIM_EGR, TIM_EGR_UG);
/* Enable controller */
regmap_set_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN);
return 0;
}
static void stm32_pwm_disable(struct stm32_pwm *priv, unsigned int ch)
{
u32 mask;
/* Disable channel */
mask = TIM_CCER_CCxE(ch + 1);
if (priv->have_complementary_output)
mask |= TIM_CCER_CCxNE(ch + 1);
regmap_clear_bits(priv->regmap, TIM_CCER, mask);
/* When all channels are disabled, we can disable the controller */
if (!active_channels(priv))
regmap_clear_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN);
clk_disable(priv->clk);
}
static int stm32_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_state *state)
{
bool enabled;
struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
int ret;
enabled = pwm->state.enabled;
if (!state->enabled) {
if (enabled)
stm32_pwm_disable(priv, pwm->hwpwm);
return 0;
}
if (state->polarity != pwm->state.polarity)
stm32_pwm_set_polarity(priv, pwm->hwpwm, state->polarity);
ret = stm32_pwm_config(priv, pwm->hwpwm,
state->duty_cycle, state->period);
if (ret)
return ret;
if (!enabled && state->enabled)
ret = stm32_pwm_enable(priv, pwm->hwpwm);
return ret;
}
static int stm32_pwm_apply_locked(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_state *state)
{
struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
int ret;
/* protect common prescaler for all active channels */
mutex_lock(&priv->lock);
ret = stm32_pwm_apply(chip, pwm, state);
mutex_unlock(&priv->lock);
return ret;
}
static int stm32_pwm_get_state(struct pwm_chip *chip,
struct pwm_device *pwm, struct pwm_state *state)
{
struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
int ch = pwm->hwpwm;
unsigned long rate;
u32 ccer, psc, arr, ccr;
u64 dty, prd;
int ret;
mutex_lock(&priv->lock);
ret = regmap_read(priv->regmap, TIM_CCER, &ccer);
if (ret)
goto out;
state->enabled = ccer & TIM_CCER_CCxE(ch + 1);
state->polarity = (ccer & TIM_CCER_CCxP(ch + 1)) ?
PWM_POLARITY_INVERSED : PWM_POLARITY_NORMAL;
ret = regmap_read(priv->regmap, TIM_PSC, &psc);
if (ret)
goto out;
ret = regmap_read(priv->regmap, TIM_ARR, &arr);
if (ret)
goto out;
ret = regmap_read(priv->regmap, TIM_CCRx(ch + 1), &ccr);
if (ret)
goto out;
rate = clk_get_rate(priv->clk);
prd = (u64)NSEC_PER_SEC * (psc + 1) * (arr + 1);
state->period = DIV_ROUND_UP_ULL(prd, rate);
dty = (u64)NSEC_PER_SEC * (psc + 1) * ccr;
state->duty_cycle = DIV_ROUND_UP_ULL(dty, rate);
out:
mutex_unlock(&priv->lock);
return ret;
}
static const struct pwm_ops stm32pwm_ops = {
.apply = stm32_pwm_apply_locked,
.get_state = stm32_pwm_get_state,
.sizeof_wfhw = sizeof(struct stm32_pwm_waveform),
.round_waveform_tohw = stm32_pwm_round_waveform_tohw,
.round_waveform_fromhw = stm32_pwm_round_waveform_fromhw,
.read_waveform = stm32_pwm_read_waveform,
.write_waveform = stm32_pwm_write_waveform,
.capture = IS_ENABLED(CONFIG_DMA_ENGINE) ? stm32_pwm_capture : NULL,
};