From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
To: linux-amlogic@lists.infradead.org, linux-pwm@vger.kernel.org,
thierry.reding@gmail.com
Cc: linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
u.kleine-koenig@pengutronix.de, narmstrong@baylibre.com,
Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Subject: [PATCH v3 11/14] pwm: meson: read the full hardware state in meson_pwm_get_state()
Date: Wed, 12 Jun 2019 21:59:08 +0200 [thread overview]
Message-ID: <20190612195911.4442-12-martin.blumenstingl@googlemail.com> (raw)
In-Reply-To: <20190612195911.4442-1-martin.blumenstingl@googlemail.com>
Update the meson_pwm_get_state() implementation to take care of all
information in the registers instead of only reading the "enabled"
state.
The PWM output is only enabled if two conditions are met:
1. the per-channel clock is enabled
2. the PWM output is enabled
Calculate the PWM period and duty cycle using the reverse formula which
we already have in meson_pwm_calc() and update struct pwm_state with the
results.
As result of this /sys/kernel/debug/pwm now shows the PWM state set by
the bootloader (or firmware) after booting Linux.
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
drivers/pwm/pwm-meson.c | 52 ++++++++++++++++++++++++++++++++++++++---
1 file changed, 49 insertions(+), 3 deletions(-)
diff --git a/drivers/pwm/pwm-meson.c b/drivers/pwm/pwm-meson.c
index 9afa1e5aaebf..010212166d5d 100644
--- a/drivers/pwm/pwm-meson.c
+++ b/drivers/pwm/pwm-meson.c
@@ -287,19 +287,65 @@ static int meson_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
return 0;
}
+static unsigned int meson_pwm_cnt_to_ns(struct pwm_chip *chip,
+ struct pwm_device *pwm, u32 cnt)
+{
+ struct meson_pwm *meson = to_meson_pwm(chip);
+ struct meson_pwm_channel *channel;
+ unsigned long fin_freq;
+ u32 fin_ns;
+
+ /* to_meson_pwm() can only be used after .get_state() is called */
+ channel = &meson->channels[pwm->hwpwm];
+
+ fin_freq = clk_get_rate(channel->clk);
+ if (fin_freq == 0)
+ return 0;
+
+ fin_ns = div_u64(NSEC_PER_SEC, fin_freq);
+
+ return cnt * fin_ns * (channel->pre_div + 1);
+}
+
static void meson_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
{
struct meson_pwm *meson = to_meson_pwm(chip);
- u32 value, mask;
+ struct meson_pwm_channel_data *channel_data;
+ struct meson_pwm_channel *channel;
+ u32 value, tmp;
if (!state)
return;
- mask = meson_pwm_per_channel_data[pwm->hwpwm].pwm_en_mask;
+ channel = &meson->channels[pwm->hwpwm];
+ channel_data = &meson_pwm_per_channel_data[pwm->hwpwm];
value = readl(meson->base + REG_MISC_AB);
- state->enabled = (value & mask) != 0;
+
+ tmp = channel_data->pwm_en_mask | channel_data->clk_en_mask;
+ state->enabled = (value & tmp) == tmp;
+
+ tmp = value >> channel_data->clk_div_shift;
+ channel->pre_div = FIELD_GET(MISC_CLK_DIV_MASK, tmp);
+
+ value = readl(meson->base + channel_data->reg_offset);
+
+ channel->lo = FIELD_GET(PWM_LOW_MASK, value);
+ channel->hi = FIELD_GET(PWM_HIGH_MASK, value);
+
+ if (channel->lo == 0) {
+ state->period = meson_pwm_cnt_to_ns(chip, pwm, channel->hi);
+ state->duty_cycle = state->period;
+ } else if (channel->lo >= channel->hi) {
+ state->period = meson_pwm_cnt_to_ns(chip, pwm,
+ channel->lo + channel->hi);
+ state->duty_cycle = meson_pwm_cnt_to_ns(chip, pwm,
+ channel->hi);
+ } else {
+ state->period = 0;
+ state->duty_cycle = 0;
+ }
}
static const struct pwm_ops meson_pwm_ops = {
--
2.22.0
next prev parent reply other threads:[~2019-06-12 20:00 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-12 19:58 [PATCH v3 00/14] pwm-meson: cleanups and improvements Martin Blumenstingl
2019-06-12 19:58 ` [PATCH v3 01/14] pwm: meson: unify the parameter list of meson_pwm_{enable,disable} Martin Blumenstingl
2019-06-12 19:58 ` [PATCH v3 02/14] pwm: meson: use devm_clk_get_optional() to get the input clock Martin Blumenstingl
2019-06-12 19:59 ` [PATCH v3 03/14] pwm: meson: use GENMASK and FIELD_PREP for the lo and hi values Martin Blumenstingl
2019-06-12 19:59 ` [PATCH v3 04/14] pwm: meson: change MISC_CLK_SEL_WIDTH to MISC_CLK_SEL_MASK Martin Blumenstingl
2019-06-12 19:59 ` [PATCH v3 05/14] pwm: meson: don't duplicate the polarity internally Martin Blumenstingl
2019-06-12 19:59 ` [PATCH v3 06/14] pwm: meson: pass struct pwm_device to meson_pwm_calc() Martin Blumenstingl
2019-06-12 19:59 ` [PATCH v3 07/14] pwm: meson: add the meson_pwm_channel data to struct meson_pwm Martin Blumenstingl
2019-06-12 19:59 ` [PATCH v3 08/14] pwm: meson: add the per-channel register offsets and bits in a struct Martin Blumenstingl
2019-06-12 19:59 ` [PATCH v3 09/14] pwm: meson: move pwm_set_chip_data() to meson_pwm_request() Martin Blumenstingl
2019-06-12 19:59 ` [PATCH v3 10/14] pwm: meson: simplify the calculation of the pre-divider and count Martin Blumenstingl
2019-06-12 19:59 ` Martin Blumenstingl [this message]
2019-06-12 19:59 ` [PATCH v3 12/14] pwm: meson: don't cache struct pwm_state internally Martin Blumenstingl
2019-06-12 19:59 ` [PATCH v3 13/14] pwm: meson: add support PWM_POLARITY_INVERSED when disabling Martin Blumenstingl
2019-06-12 19:59 ` [PATCH v3 14/14] pwm: meson: add documentation to the driver Martin Blumenstingl
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