From: George Stark <gnstark@sberdevices.ru>
To: <thierry.reding@gmail.com>, <u.kleine-koenig@pengutronix.de>,
<neil.armstrong@linaro.org>, <khilman@baylibre.com>,
<jbrunet@baylibre.com>, <martin.blumenstingl@googlemail.com>,
<hkallweit1@gmail.com>
Cc: <linux-iio@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>,
<linux-amlogic@lists.infradead.org>, <kernel@sberdevices.ru>,
George Stark <GNStark@sberdevices.ru>,
Dmitry Rokosov <ddrokosov@sberdevices.ru>
Subject: [PATCH] pwm: meson: compute cnt register value in proper way
Date: Fri, 2 Jun 2023 13:32:11 +0300 [thread overview]
Message-ID: <20230602103211.2199283-1-gnstark@sberdevices.ru> (raw)
According to the datasheet, the PWM high and low clock count values
should be set to at least one. Therefore, setting the clock count
register to 0 actually means 1 clock count.
Signed-off-by: George Stark <GNStark@sberdevices.ru>
Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
---
This patch is based on currently unmerged patch by Heiner Kallweit
https://lore.kernel.org/linux-amlogic/23fe625e-dc23-4db8-3dce-83167cd3b206@gmail.com
---
diff --git a/drivers/pwm/pwm-meson.c b/drivers/pwm/pwm-meson.c
index 834acd7..57e7d9c 100644
--- a/drivers/pwm/pwm-meson.c
+++ b/drivers/pwm/pwm-meson.c
@@ -206,6 +206,11 @@
channel->pre_div = pre_div;
channel->hi = duty_cnt;
channel->lo = cnt - duty_cnt;
+
+ if (channel->hi)
+ channel->hi--;
+ if (channel->lo)
+ channel->lo--;
}
return 0;
@@ -340,7 +345,8 @@
channel->lo = FIELD_GET(PWM_LOW_MASK, value);
channel->hi = FIELD_GET(PWM_HIGH_MASK, value);
- state->period = meson_pwm_cnt_to_ns(chip, pwm, channel->lo + channel->hi);
+ state->period = meson_pwm_cnt_to_ns(chip, pwm,
+ channel->lo + 1 + channel->hi + 1);
state->duty_cycle = meson_pwm_cnt_to_ns(chip, pwm, channel->hi);
return 0;
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next reply other threads:[~2023-06-02 10:33 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-02 10:32 George Stark [this message]
2023-06-02 20:52 ` [PATCH] pwm: meson: compute cnt register value in proper way Heiner Kallweit
2023-06-05 7:11 ` George Stark
2023-06-05 21:01 ` Heiner Kallweit
2023-06-06 8:14 ` Uwe Kleine-König
2023-06-06 7:38 ` Uwe Kleine-König
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