[PATCH V2 3/4] drivers: pwm: pwm-bcm-kona: Add cygnus-pwm support
From: Sheetal Tigadoli
Date: Wed Jan 16 2019 - 15:15:25 EST
From: Praveen Kumar B <praveen.b@xxxxxxxxxxxx>
Add support for new version of pwm-cygnus.
Add support to make PWM changes configured and stable.
Signed-off-by: Praveen Kumar B <praveen.b@xxxxxxxxxxxx>
Reviewed-by: Ray Jui <ray.jui@xxxxxxxxxxxx>
Reviewed-by: Scott Branden <scott.branden@xxxxxxxxxxxx>
Signed-off-by: Sheetal Tigadoli <sheetal.tigadoli@xxxxxxxxxxxx>
---
drivers/pwm/pwm-bcm-kona.c | 95 ++++++++++++++++++++++++++++++++++++----------
1 file changed, 76 insertions(+), 19 deletions(-)
diff --git a/drivers/pwm/pwm-bcm-kona.c b/drivers/pwm/pwm-bcm-kona.c
index fe63289..143843f 100644
--- a/drivers/pwm/pwm-bcm-kona.c
+++ b/drivers/pwm/pwm-bcm-kona.c
@@ -15,6 +15,7 @@
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/io.h>
+#include <linux/iopoll.h>
#include <linux/ioport.h>
#include <linux/math64.h>
#include <linux/module.h>
@@ -65,10 +66,19 @@
#define DUTY_CYCLE_HIGH_MIN (0x00000000)
#define DUTY_CYCLE_HIGH_MAX (0x00ffffff)
+#define PWM_MONITOR_OFFSET 0xb0
+#define PWM_MONITOR_TIMEOUT_US 5
+
+enum kona_pwmc_ver {
+ KONA_PWM = 1,
+ CYGNUS_PWM
+};
+
struct kona_pwmc {
struct pwm_chip chip;
void __iomem *base;
struct clk *clk;
+ enum kona_pwmc_ver version;
};
static inline struct kona_pwmc *to_kona_pwmc(struct pwm_chip *_chip)
@@ -76,10 +86,36 @@ static inline struct kona_pwmc *to_kona_pwmc(struct pwm_chip *_chip)
return container_of(_chip, struct kona_pwmc, chip);
}
+static int kona_pwmc_wait_stable(struct pwm_chip *chip, unsigned int chan,
+ unsigned int kona_ver)
+{
+ struct kona_pwmc *kp = to_kona_pwmc(chip);
+ unsigned int value;
+
+ switch (kona_ver) {
+ case KONA_PWM:
+ /*
+ * There must be a min 400ns delay between clearing trigger and
+ * settingit. Failing to do this may result in no PWM signal.
+ */
+ ndelay(400);
+ return 0;
+
+ case CYGNUS_PWM:
+ return readl_poll_timeout(kp->base + PWM_MONITOR_OFFSET, value,
+ !(value & (BIT(chan))), 0,
+ PWM_MONITOR_TIMEOUT_US);
+
+ default:
+ return -ENODEV;
+
+ }
+}
+
/*
* Clear trigger bit but set smooth bit to maintain old output.
*/
-static void kona_pwmc_prepare_for_settings(struct kona_pwmc *kp,
+static int kona_pwmc_prepare_for_settings(struct kona_pwmc *kp,
unsigned int chan)
{
unsigned int value = readl(kp->base + PWM_CONTROL_OFFSET);
@@ -88,14 +124,10 @@ static void kona_pwmc_prepare_for_settings(struct kona_pwmc *kp,
value &= ~(1 << PWM_CONTROL_TRIGGER_SHIFT(chan));
writel(value, kp->base + PWM_CONTROL_OFFSET);
- /*
- * There must be a min 400ns delay between clearing trigger and setting
- * it. Failing to do this may result in no PWM signal.
- */
- ndelay(400);
+ return kona_pwmc_wait_stable(&kp->chip, chan, kp->version);
}
-static void kona_pwmc_apply_settings(struct kona_pwmc *kp, unsigned int chan)
+static int kona_pwmc_apply_settings(struct kona_pwmc *kp, unsigned int chan)
{
unsigned int value = readl(kp->base + PWM_CONTROL_OFFSET);
@@ -104,8 +136,7 @@ static void kona_pwmc_apply_settings(struct kona_pwmc *kp, unsigned int chan)
value |= 1 << PWM_CONTROL_TRIGGER_SHIFT(chan);
writel(value, kp->base + PWM_CONTROL_OFFSET);
- /* Trigger bit must be held high for at least 400 ns. */
- ndelay(400);
+ return kona_pwmc_wait_stable(&kp->chip, chan, kp->version);
}
static void kona_pwmc_disable(struct pwm_chip *chip, struct pwm_device *pwm)
@@ -113,8 +144,13 @@ static void kona_pwmc_disable(struct pwm_chip *chip, struct pwm_device *pwm)
struct kona_pwmc *kp = to_kona_pwmc(chip);
unsigned int chan = pwm->hwpwm;
unsigned int value;
+ int ret;
- kona_pwmc_prepare_for_settings(kp, chan);
+ ret = kona_pwmc_prepare_for_settings(kp, chan);
+ if (ret < 0) {
+ dev_err(chip->dev, "failed to prepare pwm settings: %d\n", ret);
+ return;
+ }
/* Simulate a disable by configuring for zero duty */
writel(0, kp->base + DUTY_CYCLE_HIGH_OFFSET(chan));
@@ -125,7 +161,11 @@ static void kona_pwmc_disable(struct pwm_chip *chip, struct pwm_device *pwm)
value &= ~PRESCALE_MASK(chan);
writel(value, kp->base + PRESCALE_OFFSET);
- kona_pwmc_apply_settings(kp, chan);
+ ret = kona_pwmc_apply_settings(kp, chan);
+ if (ret < 0) {
+ dev_err(chip->dev, "failed to apply pwm settings: %d\n", ret);
+ return;
+ }
clk_disable_unprepare(kp->clk);
}
@@ -188,7 +228,12 @@ static int kona_pwmc_apply(struct pwm_chip *chip, struct pwm_device *pwm,
}
}
- kona_pwmc_prepare_for_settings(kp, chan);
+ ret = kona_pwmc_prepare_for_settings(kp, chan);
+ if (ret < 0) {
+ dev_err(chip->dev,
+ "failed to prepare pwm settings: %d\n", ret);
+ return ret;
+ }
value = readl(kp->base + PRESCALE_OFFSET);
value &= ~PRESCALE_MASK(chan);
@@ -208,7 +253,12 @@ static int kona_pwmc_apply(struct pwm_chip *chip, struct pwm_device *pwm,
writel(value, kp->base + PWM_CONTROL_OFFSET);
}
- kona_pwmc_apply_settings(kp, chan);
+ ret = kona_pwmc_apply_settings(kp, chan);
+ if (ret < 0) {
+ dev_err(chip->dev,
+ "failed to prepare pwm settings: %d\n", ret);
+ return ret;
+ }
} else if (cstate.enabled) {
kona_pwmc_disable(chip, pwm);
}
@@ -221,14 +271,26 @@ static int kona_pwmc_apply(struct pwm_chip *chip, struct pwm_device *pwm,
.owner = THIS_MODULE,
};
+static const struct of_device_id bcm_kona_pwmc_dt[] = {
+ { .compatible = "brcm,kona-pwm", .data = (void *)KONA_PWM},
+ { .compatible = "brcm,cygnus-pwm", .data = (void *)CYGNUS_PWM},
+ { },
+};
+MODULE_DEVICE_TABLE(of, bcm_kona_pwmc_dt);
+
static int kona_pwmc_probe(struct platform_device *pdev)
{
struct kona_pwmc *kp;
struct resource *res;
+ const struct of_device_id *of_id;
unsigned int chan;
unsigned int value = 0;
int ret = 0;
+ of_id = of_match_node(bcm_kona_pwmc_dt, pdev->dev.of_node);
+ if (!of_id)
+ return -ENODEV;
+
kp = devm_kzalloc(&pdev->dev, sizeof(*kp), GFP_KERNEL);
if (kp == NULL)
return -ENOMEM;
@@ -241,6 +303,7 @@ static int kona_pwmc_probe(struct platform_device *pdev)
kp->chip.npwm = 6;
kp->chip.of_xlate = of_pwm_xlate_with_flags;
kp->chip.of_pwm_n_cells = 3;
+ kp->version = (enum kona_pwmc_ver)of_id->data;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
kp->base = devm_ioremap_resource(&pdev->dev, res);
@@ -287,12 +350,6 @@ static int kona_pwmc_remove(struct platform_device *pdev)
return pwmchip_remove(&kp->chip);
}
-static const struct of_device_id bcm_kona_pwmc_dt[] = {
- { .compatible = "brcm,kona-pwm" },
- { },
-};
-MODULE_DEVICE_TABLE(of, bcm_kona_pwmc_dt);
-
static struct platform_driver kona_pwmc_driver = {
.driver = {
.name = "bcm-kona-pwm",
--
1.9.1