linux-kernel - [PATCH v3 3/3] pwm: mtk_disp: implement atomic API .get

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Date:   Wed, 26 May 2021 10:48:46 +0800
From:   Jitao Shi <jitao.shi@...iatek.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Matthias Brugger <matthias.bgg@...il.com>
CC:     <linux-pwm@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <srv_heupstream@...iatek.com>,
        <yingjoe.chen@...iatek.com>, <eddie.huang@...iatek.com>,
        <cawa.cheng@...iatek.com>, <bibby.hsieh@...iatek.com>,
        <ck.hu@...iatek.com>, <stonea168@....com>,
        <huijuan.xie@...iatek.com>, Jitao Shi <jitao.shi@...iatek.com>
Subject: [PATCH v3 3/3] pwm: mtk_disp: implement atomic API .get_state()

Change-Id: Ie1618b90e77989ae558f59554d55d0d18754b091
Signed-off-by: Jitao Shi <jitao.shi@...iatek.com>
---
 drivers/pwm/pwm-mtk-disp.c | 44 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
index 9c95b9af417f..d7535f24364a 100644
--- a/drivers/pwm/pwm-mtk-disp.c
+++ b/drivers/pwm/pwm-mtk-disp.c
@@ -179,8 +179,52 @@ static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	return mtk_disp_pwm_enable(chip, state);
 }
 
+static void mtk_disp_pwm_get_state(struct pwm_chip *chip,
+				   struct pwm_device *pwm,
+				   struct pwm_state *state)
+{
+	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
+	u32 clk_div, period, high_width, con0, con1;
+	u64 rate;
+	int err;
+
+	err = clk_prepare_enable(mdp->clk_main);
+	if (err < 0) {
+		dev_err(chip->dev, "Can't enable mdp->clk_main: %d\n", err);
+		return;
+	}
+	err = clk_prepare_enable(mdp->clk_mm);
+	if (err < 0) {
+		dev_err(chip->dev, "Can't enable mdp->clk_mm: %d\n", err);
+		clk_disable_unprepare(mdp->clk_main);
+		return;
+	}
+
+	rate = clk_get_rate(mdp->clk_main);
+
+	con0 = readl(mdp->base + mdp->data->con0);
+	con1 = readl(mdp->base + mdp->data->con1);
+
+	state->polarity = con0 & PWM_POLARITY ?
+			  PWM_POLARITY_INVERSED : PWM_POLARITY_NORMAL;
+	state->enabled = !!(con0 & BIT(0));
+
+	clk_div = (con0 & PWM_CLKDIV_MASK) >> PWM_CLKDIV_SHIFT;
+	period = con1 & PWM_PERIOD_MASK;
+	state->period = div_u64(period * (clk_div + 1) * NSEC_PER_SEC, rate);
+	high_width = (con1 & PWM_HIGH_WIDTH_MASK) >> PWM_HIGH_WIDTH_SHIFT;
+	state->duty_cycle = div_u64(high_width * (clk_div + 1) * NSEC_PER_SEC,
+				    rate);
+
+	clk_disable_unprepare(mdp->clk_mm);
+	clk_disable_unprepare(mdp->clk_main);
+
+	mdp->enabled = state->enabled;
+}
+
 static const struct pwm_ops mtk_disp_pwm_ops = {
 	.apply = mtk_disp_pwm_apply,
+	.get_state = mtk_disp_pwm_get_state,
 	.owner = THIS_MODULE,
 };
 
-- 
2.25.1