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Message-Id: <1464942192-25967-8-git-send-email-boris.brezillon@free-electrons.com>
Date: Fri, 3 Jun 2016 10:23:05 +0200
From: Boris Brezillon <boris.brezillon@...e-electrons.com>
To: Thierry Reding <thierry.reding@...il.com>,
linux-pwm@...r.kernel.org, Mark Brown <broonie@...nel.org>,
Liam Girdwood <lgirdwood@...il.com>
Cc: Heiko Stuebner <heiko@...ech.de>,
linux-rockchip@...ts.infradead.org,
Rob Herring <robh+dt@...nel.org>,
Pawel Moll <pawel.moll@....com>,
Mark Rutland <mark.rutland@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...eaurora.org>, devicetree@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
Milo Kim <milo.kim@...com>,
Doug Anderson <dianders@...gle.com>,
Caesar Wang <wxt@...k-chips.com>,
Stephen Barber <smbarber@...omium.org>,
Brian Norris <briannorris@...omium.org>,
Ajit Pal Singh <ajitpal.singh@...com>,
Srinivas Kandagatla <srinivas.kandagatla@...il.com>,
Maxime Coquelin <maxime.coquelin@...com>,
Patrice Chotard <patrice.chotard@...com>, kernel@...inux.com,
Boris Brezillon <boris.brezillon@...e-electrons.com>
Subject: [PATCH 07/14] pwm: sti: Add support for hardware readout
Implement ->get_state() to provide support for initial state retrieval.
Signed-off-by: Boris Brezillon <boris.brezillon@...e-electrons.com>
---
drivers/pwm/pwm-sti.c | 38 ++++++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)
diff --git a/drivers/pwm/pwm-sti.c b/drivers/pwm/pwm-sti.c
index 92abbd5..6300d3e 100644
--- a/drivers/pwm/pwm-sti.c
+++ b/drivers/pwm/pwm-sti.c
@@ -238,6 +238,43 @@ static void sti_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
mutex_unlock(&pc->sti_pwm_lock);
}
+static void sti_pwm_get_state(struct pwm_chip *chip,
+ struct pwm_device *pwm,
+ struct pwm_state *state)
+{
+ struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
+ unsigned int regval, prescaler;
+ int ret;
+
+ /* The clock has to be enabled to access PWM registers */
+ ret = clk_enable(pc->clk);
+ if (ret) {
+ dev_err(chip->dev, "Failed to enable PWM clk");
+ return;
+ }
+
+ regmap_field_read(pc->prescale_high, ®val);
+ prescaler = regval << 4;
+ regmap_field_read(pc->prescale_low, ®val);
+ prescaler |= regval;
+ state->period = DIV_ROUND_CLOSEST_ULL((u64)(prescaler + 1) *
+ NSEC_PER_SEC *
+ (pc->cdata->max_pwm_cnt + 1),
+ pc->clk_rate);
+
+ regmap_read(pc->regmap, STI_DS_REG(pwm->hwpwm), ®val);
+ state->duty_cycle = DIV_ROUND_CLOSEST_ULL((u64)(regval + 1) *
+ state->period,
+ pc->cdata->max_pwm_cnt + 1);
+
+ regmap_field_read(pc->pwm_en, ®val);
+ state->enabled = regval;
+
+ state->polarity = PWM_POLARITY_NORMAL;
+
+ clk_disable(pc->clk);
+}
+
static void sti_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
@@ -249,6 +286,7 @@ static const struct pwm_ops sti_pwm_ops = {
.config = sti_pwm_config,
.enable = sti_pwm_enable,
.disable = sti_pwm_disable,
+ .get_state = sti_pwm_get_state,
.free = sti_pwm_free,
.owner = THIS_MODULE,
};
--
2.7.4
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