[PATCH v7 4/9] pwm: rzg2l-gpt: Add prescale_mult variable to struct rzg2l_gpt_info

[Biju]

From: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>

RZ/G3E GPT IP has prescale factor power of 2 where as that of RZ/G2L is 4.
Add prescale_mult variable to struct rzg2l_gpt_info for handling this
difference.

Reviewed-by: Tommaso Merciai <tommaso.merciai.xr@xxxxxxxxxxxxxx>
Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
---
v6->v7:
 * No change.
v5->v6:
 * Dropped extra parameter rzg2l_gpt from rzg2l_gpt_calculate_prescale()
   in rzg2l_gpt_round_waveform_tohw().
 * Updated comment in rzg2l_gpt_calculate_period_or_duty().
v4->v5:
 * No change.
v3->v4:
 * Updated commit header and description
 * Renamed prescale_pow_of_two_mult_factor->prescale_mult
v2->v3:
 * No change.
v1->v2:
 * Collected tag.
---
 drivers/pwm/pwm-rzg2l-gpt.c | 28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/drivers/pwm/pwm-rzg2l-gpt.c b/drivers/pwm/pwm-rzg2l-gpt.c
index da2645a42608..fc77c27f0a97 100644
--- a/drivers/pwm/pwm-rzg2l-gpt.c
+++ b/drivers/pwm/pwm-rzg2l-gpt.c
@@ -79,6 +79,7 @@
 
 struct rzg2l_gpt_info {
 	u32 gtcr_tpcs;
+	u8 prescale_mult;
 };
 
 struct rzg2l_gpt_chip {
@@ -220,24 +221,29 @@ static void rzg2l_gpt_disable(struct rzg2l_gpt_chip *rzg2l_gpt,
 static u64 rzg2l_gpt_calculate_period_or_duty(struct rzg2l_gpt_chip *rzg2l_gpt,
 					      u32 val, u8 prescale)
 {
+	const struct rzg2l_gpt_info *info = rzg2l_gpt->info;
 	u64 tmp;
 
 	/*
-	 * The calculation doesn't overflow an u64 because prescale ≤ 5 and so
-	 * tmp = val << (2 * prescale) * NSEC_PER_MSEC
+	 * The calculation doesn't overflow a u64 because,
+	 * prescale ≤ 5 for info->prescale_mult = 2 and so
+	 * tmp = val << (info->prescale_mult * prescale) * NSEC_PER_MSEC
 	 *     < 2^32 * 2^10 * 10^6
 	 *     < 2^32 * 2^10 * 2^20
 	 *     = 2^62
 	 */
-	tmp = (u64)val << (2 * prescale);
+	tmp = (u64)val << (info->prescale_mult * prescale);
 	tmp *= NSEC_PER_MSEC;
 
 	return DIV64_U64_ROUND_UP(tmp, rzg2l_gpt->rate_khz);
 }
 
-static u32 rzg2l_gpt_calculate_pv_or_dc(u64 period_or_duty_cycle, u8 prescale)
+static u32 rzg2l_gpt_calculate_pv_or_dc(const struct rzg2l_gpt_info *info,
+					u64 period_or_duty_cycle, u8 prescale)
 {
-	return min_t(u64, DIV_ROUND_DOWN_ULL(period_or_duty_cycle, 1 << (2 * prescale)),
+	return min_t(u64,
+		     DIV_ROUND_DOWN_ULL(period_or_duty_cycle,
+					1 << (info->prescale_mult * prescale)),
 		     U32_MAX);
 }
 
@@ -247,6 +253,7 @@ static int rzg2l_gpt_round_waveform_tohw(struct pwm_chip *chip,
 					 void *_wfhw)
 {
 	struct rzg2l_gpt_chip *rzg2l_gpt = to_rzg2l_gpt_chip(chip);
+	const struct rzg2l_gpt_info *info = rzg2l_gpt->info;
 	struct rzg2l_gpt_waveform *wfhw = _wfhw;
 	bool is_small_second_period = false;
 	u8 ch = RZG2L_GET_CH(pwm->hwpwm);
@@ -287,7 +294,7 @@ static int rzg2l_gpt_round_waveform_tohw(struct pwm_chip *chip,
 		wfhw->prescale = rzg2l_gpt_calculate_prescale(period_ticks);
 	}
 
-	wfhw->gtpr = rzg2l_gpt_calculate_pv_or_dc(period_ticks, wfhw->prescale);
+	wfhw->gtpr = rzg2l_gpt_calculate_pv_or_dc(info, period_ticks, wfhw->prescale);
 	if (is_small_second_period) {
 		wfhw->gtccr = 0;
 		return 1;
@@ -296,7 +303,7 @@ static int rzg2l_gpt_round_waveform_tohw(struct pwm_chip *chip,
 	duty_ticks = mul_u64_u64_div_u64(wf->duty_length_ns, rzg2l_gpt->rate_khz, NSEC_PER_MSEC);
 	if (duty_ticks > period_ticks)
 		duty_ticks = period_ticks;
-	wfhw->gtccr = rzg2l_gpt_calculate_pv_or_dc(duty_ticks, wfhw->prescale);
+	wfhw->gtccr = rzg2l_gpt_calculate_pv_or_dc(info, duty_ticks, wfhw->prescale);
 
 	return 0;
 }
@@ -342,9 +349,9 @@ static int rzg2l_gpt_read_waveform(struct pwm_chip *chip,
 	return 0;
 }
 
-static u64 rzg2l_gpt_calculate_cycles(u32 value, u8 prescale)
+static u64 rzg2l_gpt_calculate_cycles(u32 value, u8 mult, u8 prescale)
 {
-	return (u64)value << (2 * prescale);
+	return (u64)value << (mult * prescale);
 }
 
 static int rzg2l_gpt_write_waveform(struct pwm_chip *chip,
@@ -352,6 +359,7 @@ static int rzg2l_gpt_write_waveform(struct pwm_chip *chip,
 				    const void *_wfhw)
 {
 	struct rzg2l_gpt_chip *rzg2l_gpt = to_rzg2l_gpt_chip(chip);
+	const struct rzg2l_gpt_info *info = rzg2l_gpt->info;
 	const struct rzg2l_gpt_waveform *wfhw = _wfhw;
 	u8 sub_ch = rzg2l_gpt_subchannel(pwm->hwpwm);
 	u8 ch = RZG2L_GET_CH(pwm->hwpwm);
@@ -407,6 +415,7 @@ static int rzg2l_gpt_write_waveform(struct pwm_chip *chip,
 		 * value for both channels.
 		 */
 		rzg2l_gpt->period_ticks[ch] = rzg2l_gpt_calculate_cycles(wfhw->gtpr,
+									 info->prescale_mult,
 									 wfhw->prescale);
 	} else if (!wfhw->gtpr && rzg2l_gpt_is_ch_enabled(rzg2l_gpt, pwm->hwpwm, NULL)) {
 		rzg2l_gpt_disable(rzg2l_gpt, pwm);
@@ -490,6 +499,7 @@ static int rzg2l_gpt_probe(struct platform_device *pdev)
 
 static const struct rzg2l_gpt_info rzg2l_data = {
 	.gtcr_tpcs = RZG2L_GTCR_TPCS,
+	.prescale_mult = 2,
 };
 
 static const struct of_device_id rzg2l_gpt_of_table[] = {
-- 
2.43.0