linux-kernel - [PATCH RESEND v6] backlight: lp855x: Switch to atomic PWM API

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Message-Id: <20220714215334.78226-1-mairacanal@riseup.net>
Date:   Thu, 14 Jul 2022 18:53:34 -0300
From:   Maíra Canal <mairacanal@...eup.net>
To:     daniel.thompson@...aro.org, lee.jones@...aro.org,
        jingoohan1@...il.com, thierry.reding@...il.com,
        u.kleine-koenig@...gutronix.de
Cc:     dri-devel@...ts.freedesktop.org, linux-fbdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-pwm@...r.kernel.org,
        Maíra Canal <mairacanal@...eup.net>
Subject: [PATCH RESEND v6] backlight: lp855x: Switch to atomic PWM API

Remove legacy PWM interface (pwm_config, pwm_enable, pwm_disable) and
replace it for the atomic PWM API.

Reviewed-by: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
Reviewed-by: Daniel Thompson <daniel.thompson@...aro.org>
Signed-off-by: Maíra Canal <mairacanal@...eup.net>
---
V1 -> V2: Initialize variable and simplify conditional loop
V2 -> V3: Fix assignment of NULL variable
V3 -> V4: Replace division for pwm_set_relative_duty_cycle
V4 -> V5: Fix overwrite of state.period
V5 -> V6: Fix duty cycle rounding and set period outside conditional loop
---
 drivers/video/backlight/lp855x_bl.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c
index 2b9e2bbbb03e..fc02c5c16055 100644
--- a/drivers/video/backlight/lp855x_bl.c
+++ b/drivers/video/backlight/lp855x_bl.c
@@ -218,9 +218,8 @@ static int lp855x_configure(struct lp855x *lp)
 
 static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
 {
-	unsigned int period = lp->pdata->period_ns;
-	unsigned int duty = br * period / max_br;
 	struct pwm_device *pwm;
+	struct pwm_state state;
 
 	/* request pwm device with the consumer name */
 	if (!lp->pwm) {
@@ -230,18 +229,16 @@ static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
 
 		lp->pwm = pwm;
 
-		/*
-		 * FIXME: pwm_apply_args() should be removed when switching to
-		 * the atomic PWM API.
-		 */
-		pwm_apply_args(pwm);
+		pwm_init_state(lp->pwm, &state);
+	} else {
+		pwm_get_state(lp->pwm, &state);
 	}
 
-	pwm_config(lp->pwm, duty, period);
-	if (duty)
-		pwm_enable(lp->pwm);
-	else
-		pwm_disable(lp->pwm);
+	state.period = lp->pdata->period_ns;
+	state.duty_cycle = div_u64(br * state.period, max_br);
+	state.enabled = state.duty_cycle;
+
+	pwm_apply_state(lp->pwm, &state);
 }
 
 static int lp855x_bl_update_status(struct backlight_device *bl)
-- 
2.36.1