linux-kernel - [PATCH v2 5/5] pwm-stm32: Make use of parametrised register definitions

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Date: Wed, 19 Jun 2024 12:11:46 +0200
From: Uwe Kleine-König <u.kleine-koenig@...libre.com>
To: Fabrice Gasnier <fabrice.gasnier@...s.st.com>,
	William Breathitt Gray <wbg@...nel.org>,
	Lee Jones <lee@...nel.org>,
	Maxime Coquelin <mcoquelin.stm32@...il.com>,
	Alexandre Torgue <alexandre.torgue@...s.st.com>
Cc: linux-pwm@...r.kernel.org,
	linux-stm32@...md-mailman.stormreply.com,
	linux-iio@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	Thorsten Scherer <T.Scherer@...elmann.de>
Subject: [PATCH v2 5/5] pwm-stm32: Make use of parametrised register definitions

There is no semantic change, but it is a nicer on the eyes of a reader,
because

	TIM_CCR1 + 4 * ch

encodes internal register knowledge, while

	TIM_CCRx(ch + 1)

keeps that information completely in the header defining the registers.

While I expected this to not result in any changes in the binary, gcc 13
(as provided by Debian in the gcc-13-arm-linux-gnueabihf 13.2.0-12cross1
package) compiles the new version with an allmodconfig to more compact
code:

	$ source/scripts/bloat-o-meter drivers/pwm/pwm-stm32.o-pre drivers/pwm/pwm-stm32.o
	add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-488 (-488)
	Function                                     old     new   delta
	stm32_pwm_get_state                          968     936     -32
	stm32_pwm_apply_locked                      1920    1464    -456

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@...libre.com>
---
 drivers/pwm/pwm-stm32.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c
index a2f231d13a9f..49a76514b83e 100644
--- a/drivers/pwm/pwm-stm32.c
+++ b/drivers/pwm/pwm-stm32.c
@@ -360,7 +360,7 @@ static int stm32_pwm_config(struct stm32_pwm *priv, unsigned int ch,
 	dty = mul_u64_u64_div_u64(duty_ns, clk_get_rate(priv->clk),
 				  (u64)NSEC_PER_SEC * (prescaler + 1));
 
-	regmap_write(priv->regmap, TIM_CCR1 + 4 * ch, dty);
+	regmap_write(priv->regmap, TIM_CCRx(ch + 1), dty);
 
 	/* Configure output mode */
 	shift = (ch & 0x1) * CCMR_CHANNEL_SHIFT;
@@ -382,9 +382,9 @@ static int stm32_pwm_set_polarity(struct stm32_pwm *priv, unsigned int ch,
 {
 	u32 mask;
 
-	mask = TIM_CCER_CC1P << (ch * 4);
+	mask = TIM_CCER_CCxP(ch + 1);
 	if (priv->have_complementary_output)
-		mask |= TIM_CCER_CC1NP << (ch * 4);
+		mask |= TIM_CCER_CCxNP(ch + 1);
 
 	regmap_update_bits(priv->regmap, TIM_CCER, mask,
 			   polarity == PWM_POLARITY_NORMAL ? 0 : mask);
@@ -402,9 +402,9 @@ static int stm32_pwm_enable(struct stm32_pwm *priv, unsigned int ch)
 		return ret;
 
 	/* Enable channel */
-	mask = TIM_CCER_CC1E << (ch * 4);
+	mask = TIM_CCER_CCxE(ch + 1);
 	if (priv->have_complementary_output)
-		mask |= TIM_CCER_CC1NE << (ch * 4);
+		mask |= TIM_CCER_CCxNE(ch);
 
 	regmap_set_bits(priv->regmap, TIM_CCER, mask);
 
@@ -422,9 +422,9 @@ static void stm32_pwm_disable(struct stm32_pwm *priv, unsigned int ch)
 	u32 mask;
 
 	/* Disable channel */
-	mask = TIM_CCER_CC1E << (ch * 4);
+	mask = TIM_CCER_CCxE(ch + 1);
 	if (priv->have_complementary_output)
-		mask |= TIM_CCER_CC1NE << (ch * 4);
+		mask |= TIM_CCER_CCxNE(ch + 1);
 
 	regmap_clear_bits(priv->regmap, TIM_CCER, mask);
 
@@ -493,8 +493,8 @@ static int stm32_pwm_get_state(struct pwm_chip *chip,
 	if (ret)
 		goto out;
 
-	state->enabled = ccer & (TIM_CCER_CC1E << (ch * 4));
-	state->polarity = (ccer & (TIM_CCER_CC1P << (ch * 4))) ?
+	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)
@@ -502,7 +502,7 @@ static int stm32_pwm_get_state(struct pwm_chip *chip,
 	ret = regmap_read(priv->regmap, TIM_ARR, &arr);
 	if (ret)
 		goto out;
-	ret = regmap_read(priv->regmap, TIM_CCR1 + 4 * ch, &ccr);
+	ret = regmap_read(priv->regmap, TIM_CCRx(ch + 1), &ccr);
 	if (ret)
 		goto out;
 
@@ -702,7 +702,7 @@ static int stm32_pwm_suspend(struct device *dev)
 	ccer = active_channels(priv);
 
 	for (i = 0; i < chip->npwm; i++) {
-		mask = TIM_CCER_CC1E << (i * 4);
+		mask = TIM_CCER_CCxE(i + 1);
 		if (ccer & mask) {
 			dev_err(dev, "PWM %u still in use by consumer %s\n",
 				i, chip->pwms[i].label);
-- 
2.43.0