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Subject[PATCH v6 1/2] pwm: Convert drivers to use 64-bit period and duty cycle
Date
Because period and duty cycle are defined in the PWM framework structs
as ints with units of nanoseconds, the maximum time duration that can be
set is limited to ~2.147 seconds. Redefining them as u64 values will
enable larger time durations to be set.

As a first step, prepare drivers to handle the switch to u64 period and
duty_cycle by making the relevant fixes to those drivers that use the
period and duty_cycle pwm struct members in division operations, viz.
replacing the division operations with 64-bit division macros as
appropriate. The actual switch to u64 period and duty_cycle follows as a
separate patch.

Where the dividend is 64-bit but the divisor is 32-bit, use *_ULL
macros:
- DIV_ROUND_UP_ULL
- DIV_ROUND_CLOSEST_ULL
- div_u64

Where the divisor is 64-bit (dividend may be 32-bit or 64-bit), use
DIV64_* macros:
- DIV64_U64_ROUND_CLOSEST
- div64_u64

The kbuild test robot helped to improve this patch by catching a couple
of code sites that had to be adapted.

Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
---
drivers/clk/clk-pwm.c | 2 +-
drivers/gpu/drm/i915/display/intel_panel.c | 2 +-
drivers/hwmon/pwm-fan.c | 2 +-
drivers/media/rc/ir-rx51.c | 3 ++-
drivers/pwm/pwm-clps711x.c | 2 +-
drivers/pwm/pwm-imx-tpm.c | 2 +-
drivers/pwm/pwm-imx27.c | 5 ++---
drivers/pwm/pwm-sifive.c | 2 +-
drivers/pwm/pwm-sti.c | 5 +++--
drivers/pwm/pwm-stm32-lp.c | 2 +-
drivers/pwm/pwm-sun4i.c | 2 +-
drivers/video/backlight/pwm_bl.c | 3 ++-
12 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/drivers/clk/clk-pwm.c b/drivers/clk/clk-pwm.c
index 87fe0b0e..7b1f7a0 100644
--- a/drivers/clk/clk-pwm.c
+++ b/drivers/clk/clk-pwm.c
@@ -89,7 +89,7 @@ static int clk_pwm_probe(struct platform_device *pdev)
}

if (of_property_read_u32(node, "clock-frequency", &clk_pwm->fixed_rate))
- clk_pwm->fixed_rate = NSEC_PER_SEC / pargs.period;
+ clk_pwm->fixed_rate = div64_u64(NSEC_PER_SEC, pargs.period);

if (pargs.period != NSEC_PER_SEC / clk_pwm->fixed_rate &&
pargs.period != DIV_ROUND_UP(NSEC_PER_SEC, clk_pwm->fixed_rate)) {
diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c
index bc14e9c..843cac1 100644
--- a/drivers/gpu/drm/i915/display/intel_panel.c
+++ b/drivers/gpu/drm/i915/display/intel_panel.c
@@ -1868,7 +1868,7 @@ static int pwm_setup_backlight(struct intel_connector *connector,

panel->backlight.min = 0; /* 0% */
panel->backlight.max = 100; /* 100% */
- panel->backlight.level = DIV_ROUND_UP(
+ panel->backlight.level = DIV_ROUND_UP_ULL(
pwm_get_duty_cycle(panel->backlight.pwm) * 100,
CRC_PMIC_PWM_PERIOD_NS);
panel->backlight.enabled = panel->backlight.level != 0;
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index 42ffd2e..283423a 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -437,7 +437,7 @@ static int pwm_fan_resume(struct device *dev)
return 0;

pwm_get_args(ctx->pwm, &pargs);
- duty = DIV_ROUND_UP(ctx->pwm_value * (pargs.period - 1), MAX_PWM);
+ duty = DIV_ROUND_UP_ULL(ctx->pwm_value * (pargs.period - 1), MAX_PWM);
ret = pwm_config(ctx->pwm, duty, pargs.period);
if (ret)
return ret;
diff --git a/drivers/media/rc/ir-rx51.c b/drivers/media/rc/ir-rx51.c
index 8574eda..9a5dfd7 100644
--- a/drivers/media/rc/ir-rx51.c
+++ b/drivers/media/rc/ir-rx51.c
@@ -241,7 +241,8 @@ static int ir_rx51_probe(struct platform_device *dev)
}

/* Use default, in case userspace does not set the carrier */
- ir_rx51.freq = DIV_ROUND_CLOSEST(pwm_get_period(pwm), NSEC_PER_SEC);
+ ir_rx51.freq = DIV_ROUND_CLOSEST_ULL(pwm_get_period(pwm),
+ NSEC_PER_SEC);
pwm_put(pwm);

hrtimer_init(&ir_rx51.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
diff --git a/drivers/pwm/pwm-clps711x.c b/drivers/pwm/pwm-clps711x.c
index 924d39a..ba9500a 100644
--- a/drivers/pwm/pwm-clps711x.c
+++ b/drivers/pwm/pwm-clps711x.c
@@ -43,7 +43,7 @@ static void clps711x_pwm_update_val(struct clps711x_chip *priv, u32 n, u32 v)
static unsigned int clps711x_get_duty(struct pwm_device *pwm, unsigned int v)
{
/* Duty cycle 0..15 max */
- return DIV_ROUND_CLOSEST(v * 0xf, pwm->args.period);
+ return DIV64_U64_ROUND_CLOSEST(v * 0xf, pwm->args.period);
}

static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
diff --git a/drivers/pwm/pwm-imx-tpm.c b/drivers/pwm/pwm-imx-tpm.c
index 9145f61..53bf364 100644
--- a/drivers/pwm/pwm-imx-tpm.c
+++ b/drivers/pwm/pwm-imx-tpm.c
@@ -126,7 +126,7 @@ static int pwm_imx_tpm_round_state(struct pwm_chip *chip,
real_state->duty_cycle = state->duty_cycle;

tmp = (u64)p->mod * real_state->duty_cycle;
- p->val = DIV_ROUND_CLOSEST_ULL(tmp, real_state->period);
+ p->val = DIV64_U64_ROUND_CLOSEST(tmp, real_state->period);

real_state->polarity = state->polarity;
real_state->enabled = state->enabled;
diff --git a/drivers/pwm/pwm-imx27.c b/drivers/pwm/pwm-imx27.c
index 35a7ac42..b7d38d0 100644
--- a/drivers/pwm/pwm-imx27.c
+++ b/drivers/pwm/pwm-imx27.c
@@ -208,7 +208,7 @@ static void pwm_imx27_wait_fifo_slot(struct pwm_chip *chip,
sr = readl(imx->mmio_base + MX3_PWMSR);
fifoav = FIELD_GET(MX3_PWMSR_FIFOAV, sr);
if (fifoav == MX3_PWMSR_FIFOAV_4WORDS) {
- period_ms = DIV_ROUND_UP(pwm_get_period(pwm),
+ period_ms = DIV_ROUND_UP_ULL(pwm_get_period(pwm),
NSEC_PER_MSEC);
msleep(period_ms);

@@ -240,8 +240,7 @@ static int pwm_imx27_apply(struct pwm_chip *chip, struct pwm_device *pwm,

period_cycles /= prescale;
c = (unsigned long long)period_cycles * state->duty_cycle;
- do_div(c, state->period);
- duty_cycles = c;
+ duty_cycles = div64_u64(c, state->period);

/*
* according to imx pwm RM, the real period value should be PERIOD
diff --git a/drivers/pwm/pwm-sifive.c b/drivers/pwm/pwm-sifive.c
index cc63f9b..62de0bb 100644
--- a/drivers/pwm/pwm-sifive.c
+++ b/drivers/pwm/pwm-sifive.c
@@ -181,7 +181,7 @@ static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm,
* consecutively
*/
num = (u64)duty_cycle * (1U << PWM_SIFIVE_CMPWIDTH);
- frac = DIV_ROUND_CLOSEST_ULL(num, state->period);
+ frac = DIV64_U64_ROUND_CLOSEST(num, state->period);
/* The hardware cannot generate a 100% duty cycle */
frac = min(frac, (1U << PWM_SIFIVE_CMPWIDTH) - 1);

diff --git a/drivers/pwm/pwm-sti.c b/drivers/pwm/pwm-sti.c
index 1508616..5a7f337 100644
--- a/drivers/pwm/pwm-sti.c
+++ b/drivers/pwm/pwm-sti.c
@@ -371,10 +371,11 @@ static int sti_pwm_capture(struct pwm_chip *chip, struct pwm_device *pwm,
effective_ticks = clk_get_rate(pc->cpt_clk);

result->period = (high + low) * NSEC_PER_SEC;
- result->period /= effective_ticks;
+ result->period = div_u64(result->period, effective_ticks);

result->duty_cycle = high * NSEC_PER_SEC;
- result->duty_cycle /= effective_ticks;
+ result->duty_cycle = div_u64(result->duty_cycle,
+ effective_ticks);

break;

diff --git a/drivers/pwm/pwm-stm32-lp.c b/drivers/pwm/pwm-stm32-lp.c
index 67fca62..134c146 100644
--- a/drivers/pwm/pwm-stm32-lp.c
+++ b/drivers/pwm/pwm-stm32-lp.c
@@ -61,7 +61,7 @@ static int stm32_pwm_lp_apply(struct pwm_chip *chip, struct pwm_device *pwm,
do_div(div, NSEC_PER_SEC);
if (!div) {
/* Clock is too slow to achieve requested period. */
- dev_dbg(priv->chip.dev, "Can't reach %u ns\n", state->period);
+ dev_dbg(priv->chip.dev, "Can't reach %llu ns\n", state->period);
return -EINVAL;
}

diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
index 3e3efa6..772fdf4 100644
--- a/drivers/pwm/pwm-sun4i.c
+++ b/drivers/pwm/pwm-sun4i.c
@@ -286,7 +286,7 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
val = (duty & PWM_DTY_MASK) | PWM_PRD(period);
sun4i_pwm_writel(sun4i_pwm, val, PWM_CH_PRD(pwm->hwpwm));
sun4i_pwm->next_period[pwm->hwpwm] = jiffies +
- usecs_to_jiffies(cstate.period / 1000 + 1);
+ usecs_to_jiffies(div_u64(cstate.period, 1000) + 1);
sun4i_pwm->needs_delay[pwm->hwpwm] = true;

if (state->polarity != PWM_POLARITY_NORMAL)
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index efb4efc..3e5dbcf 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -625,7 +625,8 @@ static int pwm_backlight_probe(struct platform_device *pdev)
pb->scale = data->max_brightness;
}

- pb->lth_brightness = data->lth_brightness * (state.period / pb->scale);
+ pb->lth_brightness = data->lth_brightness * (div_u64(state.period,
+ pb->scale));

props.type = BACKLIGHT_RAW;
props.max_brightness = data->max_brightness;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
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