[U-Boot] [PATCH v2 1/2] power: regulator: pwm: support pwm polarity setting
The latest kernel PWM drivers enable the polarity settings. When system run from U-Boot to kerenl, if there are differences in polarity set or duty cycle, the PMW will re-init: close -> set polarity and duty cycle -> enable the PWM. The power supply controled by pwm regulator may have voltage shaking, which lead to the system not stable.
Signed-off-by: Elaine Zhang zhangqing@rock-chips.com Signed-off-by: Kever Yang kever.yang@rock-chips.com ---
Changes in v2: - use pwm_set_invert() instead of pwm_set_init() - add comment for polarity
drivers/power/regulator/pwm_regulator.c | 16 ++++++++++++++-- drivers/pwm/pwm-uclass.c | 10 ++++++++++ drivers/pwm/rk_pwm.c | 17 ++++++++++++++++- include/pwm.h | 9 +++++++++ 4 files changed, 49 insertions(+), 3 deletions(-)
diff --git a/drivers/power/regulator/pwm_regulator.c b/drivers/power/regulator/pwm_regulator.c index 4875238..3ffe3a1 100644 --- a/drivers/power/regulator/pwm_regulator.c +++ b/drivers/power/regulator/pwm_regulator.c @@ -24,6 +24,12 @@ struct pwm_regulator_info { int pwm_id; /* the period of one PWM cycle */ int period_ns; + /* + * the polarity of one PWM + * 0: normal polarity + * 1: inverted polarity + */ + int polarity; struct udevice *pwm; /* initialize voltage of regulator */ unsigned int init_voltage; @@ -49,7 +55,7 @@ static int pwm_voltage_to_duty_cycle_percentage(struct udevice *dev, int req_uV) int max_uV = priv->max_voltage; int diff = max_uV - min_uV;
- return 100 - (((req_uV * 100) - (min_uV * 100)) / diff); + return ((req_uV * 100) - (min_uV * 100)) / diff; }
static int pwm_regulator_get_voltage(struct udevice *dev) @@ -67,6 +73,12 @@ static int pwm_regulator_set_voltage(struct udevice *dev, int uvolt)
duty_cycle = pwm_voltage_to_duty_cycle_percentage(dev, uvolt);
+ ret = pwm_set_invert(priv->pwm, priv->pwm_id, priv->polarity); + if (ret) { + dev_err(dev, "Failed to init PWM\n"); + return ret; + } + ret = pwm_set_config(priv->pwm, priv->pwm_id, (priv->period_ns / 100) * duty_cycle, priv->period_ns); if (ret) { @@ -97,9 +109,9 @@ static int pwm_regulator_ofdata_to_platdata(struct udevice *dev) debug("%s: Cannot get PWM phandle: ret=%d\n", __func__, ret); return ret; } - /* TODO: pwm_id here from device tree if needed */
priv->period_ns = args.args[1]; + priv->polarity = args.args[2];
priv->init_voltage = fdtdec_get_int(blob, node, "regulator-init-microvolt", -1); diff --git a/drivers/pwm/pwm-uclass.c b/drivers/pwm/pwm-uclass.c index c2200af..d1d7fce 100644 --- a/drivers/pwm/pwm-uclass.c +++ b/drivers/pwm/pwm-uclass.c @@ -9,6 +9,16 @@ #include <dm.h> #include <pwm.h>
+int pwm_set_invert(struct udevice *dev, uint channel, uint polarity) +{ + struct pwm_ops *ops = pwm_get_ops(dev); + + if (!ops->set_invert) + return -ENOSYS; + + return ops->set_invert(dev, channel, polarity); +} + int pwm_set_config(struct udevice *dev, uint channel, uint period_ns, uint duty_ns) { diff --git a/drivers/pwm/rk_pwm.c b/drivers/pwm/rk_pwm.c index 9254f5b..f003d09 100644 --- a/drivers/pwm/rk_pwm.c +++ b/drivers/pwm/rk_pwm.c @@ -21,8 +21,22 @@ DECLARE_GLOBAL_DATA_PTR; struct rk_pwm_priv { struct rk3288_pwm *regs; ulong freq; + uint enable_conf; };
+static int rk_pwm_set_invert(struct udevice *dev, uint channel, uint polarity) +{ + struct rk_pwm_priv *priv = dev_get_priv(dev); + + debug("%s: polarity=%u\n", __func__, polarity); + if (polarity) + priv->enable_conf |= PWM_DUTY_NEGATIVE | PWM_INACTIVE_POSTIVE; + else + priv->enable_conf |= PWM_DUTY_POSTIVE | PWM_INACTIVE_NEGATIVE; + + return 0; +} + static int rk_pwm_set_config(struct udevice *dev, uint channel, uint period_ns, uint duty_ns) { @@ -32,7 +46,7 @@ static int rk_pwm_set_config(struct udevice *dev, uint channel, uint period_ns,
debug("%s: period_ns=%u, duty_ns=%u\n", __func__, period_ns, duty_ns); writel(PWM_SEL_SRC_CLK | PWM_OUTPUT_LEFT | PWM_LP_DISABLE | - PWM_CONTINUOUS | PWM_DUTY_POSTIVE | PWM_INACTIVE_POSTIVE | + PWM_CONTINUOUS | priv->enable_conf | RK_PWM_DISABLE, ®s->ctrl);
@@ -83,6 +97,7 @@ static int rk_pwm_probe(struct udevice *dev) }
static const struct pwm_ops rk_pwm_ops = { + .set_invert = rk_pwm_set_invert, .set_config = rk_pwm_set_config, .set_enable = rk_pwm_set_enable, }; diff --git a/include/pwm.h b/include/pwm.h index 851915e..66c6bf0 100644 --- a/include/pwm.h +++ b/include/pwm.h @@ -14,6 +14,15 @@ /* struct pwm_ops: Operations for the PWM uclass */ struct pwm_ops { /** + * set_invert() - Set the PWM invert + * + * @dev: PWM device to update + * @channel: PWM channel to update + * @polarity: PWM invert polarity + * @return 0 if OK, -ve on error + */ + int (*set_invert)(struct udevice *dev, uint channel, uint polarity); + /** * set_config() - Set the PWM configuration * * @dev: PWM device to update
This is a copy from kernel.
Signed-off-by: Kever Yang kever.yang@rock-chips.com ---
Changes in v2: None
doc/device-tree-bindings/pwm/pwm.txt | 69 ++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) create mode 100644 doc/device-tree-bindings/pwm/pwm.txt
diff --git a/doc/device-tree-bindings/pwm/pwm.txt b/doc/device-tree-bindings/pwm/pwm.txt new file mode 100644 index 0000000..8556263 --- /dev/null +++ b/doc/device-tree-bindings/pwm/pwm.txt @@ -0,0 +1,69 @@ +Specifying PWM information for devices +====================================== + +1) PWM user nodes +----------------- + +PWM users should specify a list of PWM devices that they want to use +with a property containing a 'pwm-list': + + pwm-list ::= <single-pwm> [pwm-list] + single-pwm ::= <pwm-phandle> <pwm-specifier> + pwm-phandle : phandle to PWM controller node + pwm-specifier : array of #pwm-cells specifying the given PWM + (controller specific) + +PWM properties should be named "pwms". The exact meaning of each pwms +property must be documented in the device tree binding for each device. +An optional property "pwm-names" may contain a list of strings to label +each of the PWM devices listed in the "pwms" property. If no "pwm-names" +property is given, the name of the user node will be used as fallback. + +Drivers for devices that use more than a single PWM device can use the +"pwm-names" property to map the name of the PWM device requested by the +pwm_get() call to an index into the list given by the "pwms" property. + +The following example could be used to describe a PWM-based backlight +device: + + pwm: pwm { + #pwm-cells = <2>; + }; + + [...] + + bl: backlight { + pwms = <&pwm 0 5000000>; + pwm-names = "backlight"; + }; + +Note that in the example above, specifying the "pwm-names" is redundant +because the name "backlight" would be used as fallback anyway. + +pwm-specifier typically encodes the chip-relative PWM number and the PWM +period in nanoseconds. + +Optionally, the pwm-specifier can encode a number of flags (defined in +<dt-bindings/pwm/pwm.h>) in a third cell: +- PWM_POLARITY_INVERTED: invert the PWM signal polarity + +Example with optional PWM specifier for inverse polarity + + bl: backlight { + pwms = <&pwm 0 5000000 PWM_POLARITY_INVERTED>; + pwm-names = "backlight"; + }; + +2) PWM controller nodes +----------------------- + +PWM controller nodes must specify the number of cells used for the +specifier using the '#pwm-cells' property. + +An example PWM controller might look like this: + + pwm: pwm@7000a000 { + compatible = "nvidia,tegra20-pwm"; + reg = <0x7000a000 0x100>; + #pwm-cells = <2>; + };
Hi Kever,
On 11 April 2017 at 02:35, Kever Yang kever.yang@rock-chips.com wrote:
The latest kernel PWM drivers enable the polarity settings. When system run from U-Boot to kerenl, if there are differences in polarity set or duty cycle, the PMW will re-init: close -> set polarity and duty cycle -> enable the PWM. The power supply controled by pwm regulator may have voltage shaking, which lead to the system not stable.
Signed-off-by: Elaine Zhang zhangqing@rock-chips.com Signed-off-by: Kever Yang kever.yang@rock-chips.com
Changes in v2:
- use pwm_set_invert() instead of pwm_set_init()
- add comment for polarity
drivers/power/regulator/pwm_regulator.c | 16 ++++++++++++++-- drivers/pwm/pwm-uclass.c | 10 ++++++++++ drivers/pwm/rk_pwm.c | 17 ++++++++++++++++- include/pwm.h | 9 +++++++++ 4 files changed, 49 insertions(+), 3 deletions(-)
diff --git a/drivers/power/regulator/pwm_regulator.c b/drivers/power/regulator/pwm_regulator.c index 4875238..3ffe3a1 100644 --- a/drivers/power/regulator/pwm_regulator.c +++ b/drivers/power/regulator/pwm_regulator.c @@ -24,6 +24,12 @@ struct pwm_regulator_info { int pwm_id; /* the period of one PWM cycle */ int period_ns;
/** the polarity of one PWM* 0: normal polarity* 1: inverted polarity*/int polarity; struct udevice *pwm; /* initialize voltage of regulator */ unsigned int init_voltage;@@ -49,7 +55,7 @@ static int pwm_voltage_to_duty_cycle_percentage(struct udevice *dev, int req_uV) int max_uV = priv->max_voltage; int diff = max_uV - min_uV;
return 100 - (((req_uV * 100) - (min_uV * 100)) / diff);
return ((req_uV * 100) - (min_uV * 100)) / diff;}
static int pwm_regulator_get_voltage(struct udevice *dev) @@ -67,6 +73,12 @@ static int pwm_regulator_set_voltage(struct udevice *dev, int uvolt)
duty_cycle = pwm_voltage_to_duty_cycle_percentage(dev, uvolt);
ret = pwm_set_invert(priv->pwm, priv->pwm_id, priv->polarity);if (ret) {dev_err(dev, "Failed to init PWM\n");return ret;}ret = pwm_set_config(priv->pwm, priv->pwm_id, (priv->period_ns / 100) * duty_cycle, priv->period_ns); if (ret) {@@ -97,9 +109,9 @@ static int pwm_regulator_ofdata_to_platdata(struct udevice *dev) debug("%s: Cannot get PWM phandle: ret=%d\n", __func__, ret); return ret; }
/* TODO: pwm_id here from device tree if needed */ priv->period_ns = args.args[1];
priv->polarity = args.args[2]; priv->init_voltage = fdtdec_get_int(blob, node, "regulator-init-microvolt", -1);diff --git a/drivers/pwm/pwm-uclass.c b/drivers/pwm/pwm-uclass.c index c2200af..d1d7fce 100644 --- a/drivers/pwm/pwm-uclass.c +++ b/drivers/pwm/pwm-uclass.c @@ -9,6 +9,16 @@ #include <dm.h> #include <pwm.h>
+int pwm_set_invert(struct udevice *dev, uint channel, uint polarity) +{
struct pwm_ops *ops = pwm_get_ops(dev);if (!ops->set_invert)return -ENOSYS;return ops->set_invert(dev, channel, polarity);+}
int pwm_set_config(struct udevice *dev, uint channel, uint period_ns, uint duty_ns) { diff --git a/drivers/pwm/rk_pwm.c b/drivers/pwm/rk_pwm.c index 9254f5b..f003d09 100644 --- a/drivers/pwm/rk_pwm.c +++ b/drivers/pwm/rk_pwm.c @@ -21,8 +21,22 @@ DECLARE_GLOBAL_DATA_PTR; struct rk_pwm_priv { struct rk3288_pwm *regs; ulong freq;
uint enable_conf;};
+static int rk_pwm_set_invert(struct udevice *dev, uint channel, uint polarity) +{
struct rk_pwm_priv *priv = dev_get_priv(dev);debug("%s: polarity=%u\n", __func__, polarity);if (polarity)priv->enable_conf |= PWM_DUTY_NEGATIVE | PWM_INACTIVE_POSTIVE;elsepriv->enable_conf |= PWM_DUTY_POSTIVE | PWM_INACTIVE_NEGATIVE;return 0;+}
static int rk_pwm_set_config(struct udevice *dev, uint channel, uint period_ns, uint duty_ns) { @@ -32,7 +46,7 @@ static int rk_pwm_set_config(struct udevice *dev, uint channel, uint period_ns,
debug("%s: period_ns=%u, duty_ns=%u\n", __func__, period_ns, duty_ns); writel(PWM_SEL_SRC_CLK | PWM_OUTPUT_LEFT | PWM_LP_DISABLE |
PWM_CONTINUOUS | PWM_DUTY_POSTIVE | PWM_INACTIVE_POSTIVE |
PWM_CONTINUOUS | priv->enable_conf | RK_PWM_DISABLE, ®s->ctrl);@@ -83,6 +97,7 @@ static int rk_pwm_probe(struct udevice *dev) }
static const struct pwm_ops rk_pwm_ops = {
.set_invert = rk_pwm_set_invert, .set_config = rk_pwm_set_config, .set_enable = rk_pwm_set_enable,}; diff --git a/include/pwm.h b/include/pwm.h index 851915e..66c6bf0 100644 --- a/include/pwm.h +++ b/include/pwm.h @@ -14,6 +14,15 @@ /* struct pwm_ops: Operations for the PWM uclass */ struct pwm_ops { /**
* set_invert() - Set the PWM invert** @dev: PWM device to update* @channel: PWM channel to update* @polarity: PWM invert polarity
Please document the meaning of this parameter.
* @return 0 if OK, -ve on error*/int (*set_invert)(struct udevice *dev, uint channel, uint polarity);/** * set_config() - Set the PWM configuration * * @dev: PWM device to update-- 1.9.1
Can you also please write a test in test/dm/pwm.c with a sandbox pwm driver? A recent example is:
http://patchwork.ozlabs.org/patch/750796/
Regards, Simon
participants (2)
-
Kever Yang -
Simon Glass