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1b9ee2882e
This PWM is used in rk3399-gru-bob and rk3399-gru-kevin to control
the display brightness. We can only change the duty cycle, so on
set_config() we just try to match the duty cycle that dividing duty_ns
by period_ns gives us. To disable, we set the duty cycle to zero while
keeping the old value for when we want to re-enable it.
The cros_ec_set_pwm_duty() function is taken from Depthcharge's
cros_ec_set_bl_pwm_duty() but modified to use the generic pwm type.
The driver itself is very loosely based on rk_pwm.c for the general pwm
driver structure.
The devicetree binding file is from Linux, before it was converted to
YAML at 5df5a577a6b4 ("dt-bindings: pwm: Convert google,cros-ec-pwm.txt
to YAML format") in their repo.
Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
84 lines
1.8 KiB
C
84 lines
1.8 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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#include <common.h>
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#include <cros_ec.h>
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#include <dm.h>
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#include <errno.h>
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#include <log.h>
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#include <pwm.h>
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struct cros_ec_pwm_priv {
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bool enabled;
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uint duty;
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};
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static int cros_ec_pwm_set_config(struct udevice *dev, uint channel,
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uint period_ns, uint duty_ns)
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{
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struct cros_ec_pwm_priv *priv = dev_get_priv(dev);
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uint duty;
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int ret;
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debug("%s: period_ns=%u, duty_ns=%u asked\n", __func__,
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period_ns, duty_ns);
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/* No way to set the period, only a relative duty cycle */
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duty = EC_PWM_MAX_DUTY * duty_ns / period_ns;
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if (duty > EC_PWM_MAX_DUTY)
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duty = EC_PWM_MAX_DUTY;
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if (!priv->enabled) {
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priv->duty = duty;
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debug("%s: duty=%#x to-be-set\n", __func__, duty);
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return 0;
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}
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ret = cros_ec_set_pwm_duty(dev->parent, channel, duty);
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if (ret) {
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debug("%s: duty=%#x failed\n", __func__, duty);
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return ret;
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}
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priv->duty = duty;
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debug("%s: duty=%#x set\n", __func__, duty);
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return 0;
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}
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static int cros_ec_pwm_set_enable(struct udevice *dev, uint channel,
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bool enable)
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{
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struct cros_ec_pwm_priv *priv = dev_get_priv(dev);
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int ret;
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ret = cros_ec_set_pwm_duty(dev->parent, channel,
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enable ? priv->duty : 0);
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if (ret) {
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debug("%s: enable=%d failed\n", __func__, enable);
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return ret;
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}
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priv->enabled = enable;
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debug("%s: enable=%d (duty=%#x) set\n", __func__,
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enable, priv->duty);
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return 0;
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}
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static const struct pwm_ops cros_ec_pwm_ops = {
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.set_config = cros_ec_pwm_set_config,
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.set_enable = cros_ec_pwm_set_enable,
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};
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static const struct udevice_id cros_ec_pwm_ids[] = {
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{ .compatible = "google,cros-ec-pwm" },
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{ }
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};
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U_BOOT_DRIVER(cros_ec_pwm) = {
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.name = "cros_ec_pwm",
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.id = UCLASS_PWM,
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.of_match = cros_ec_pwm_ids,
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.ops = &cros_ec_pwm_ops,
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.priv_auto_alloc_size = sizeof(struct cros_ec_pwm_priv),
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};
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