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Subject[PATCH INTERNAL V3 2/3] drivers: pwm: pwm-bcm-kona: Add pwm-kona-v2 support
Date
From: Praveen Kumar B <praveen.b@broadcom.com>

Add support for new version of pwm-kona.
Add support to make PWM changes configured and stable.

Signed-off-by: Praveen Kumar B <praveen.b@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Sheetal Tigadoli <sheetal.tigadoli@broadcom.com>
---
drivers/pwm/pwm-bcm-kona.c | 128 ++++++++++++++++++++++++++++++++++-----------
1 file changed, 98 insertions(+), 30 deletions(-)

diff --git a/drivers/pwm/pwm-bcm-kona.c b/drivers/pwm/pwm-bcm-kona.c
index 09a95ae..2b44ad8 100644
--- a/drivers/pwm/pwm-bcm-kona.c
+++ b/drivers/pwm/pwm-bcm-kona.c
@@ -45,30 +45,39 @@
* high or low depending on its state at that exact instant.
*/

-#define PWM_CONTROL_OFFSET (0x00000000)
+#define PWM_CONTROL_OFFSET 0x00000000
#define PWM_CONTROL_SMOOTH_SHIFT(chan) (24 + (chan))
#define PWM_CONTROL_TYPE_SHIFT(chan) (16 + (chan))
#define PWM_CONTROL_POLARITY_SHIFT(chan) (8 + (chan))
#define PWM_CONTROL_TRIGGER_SHIFT(chan) (chan)

-#define PRESCALE_OFFSET (0x00000004)
+#define PRESCALE_OFFSET 0x00000004
#define PRESCALE_SHIFT(chan) ((chan) << 2)
#define PRESCALE_MASK(chan) (0x7 << PRESCALE_SHIFT(chan))
-#define PRESCALE_MIN (0x00000000)
-#define PRESCALE_MAX (0x00000007)
+#define PRESCALE_MIN 0x00000000
+#define PRESCALE_MAX 0x00000007

#define PERIOD_COUNT_OFFSET(chan) (0x00000008 + ((chan) << 3))
-#define PERIOD_COUNT_MIN (0x00000002)
-#define PERIOD_COUNT_MAX (0x00ffffff)
+#define PERIOD_COUNT_MIN 0x00000002
+#define PERIOD_COUNT_MAX 0x00ffffff

#define DUTY_CYCLE_HIGH_OFFSET(chan) (0x0000000c + ((chan) << 3))
-#define DUTY_CYCLE_HIGH_MIN (0x00000000)
-#define DUTY_CYCLE_HIGH_MAX (0x00ffffff)
+#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_V1 = 1,
+ KONA_PWM_V2
+};

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)
@@ -76,11 +85,40 @@ 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;
+ unsigned int count = PWM_MONITOR_TIMEOUT_US * 1000;
+
+ switch (kona_ver) {
+ case KONA_PWM_V1:
+ /*
+ * 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 KONA_PWM_V2:
+ do {
+ value = readl(kp->base + PWM_MONITOR_OFFSET);
+ if (!(value & (BIT(chan))))
+ return 0;
+ ndelay(1);
+ } while (count--);
+
+ return -ETIMEDOUT;
+ 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,
- unsigned int chan)
+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 +126,10 @@ 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 +138,7 @@ 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 int kona_pwmc_config(struct pwm_chip *chip, struct pwm_device *pwm,
@@ -115,6 +148,7 @@ static int kona_pwmc_config(struct pwm_chip *chip, struct pwm_device *pwm,
u64 val, div, rate;
unsigned long prescale = PRESCALE_MIN, pc, dc;
unsigned int value, chan = pwm->hwpwm;
+ int ret;

/*
* Find period count, duty count and prescale to suit duty_ns and
@@ -156,7 +190,12 @@ static int kona_pwmc_config(struct pwm_chip *chip, struct pwm_device *pwm,
* validated immediately instead of on enable.
*/
if (pwm_is_enabled(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);
@@ -167,7 +206,12 @@ static int kona_pwmc_config(struct pwm_chip *chip, struct pwm_device *pwm,

writel(dc, kp->base + DUTY_CYCLE_HIGH_OFFSET(chan));

- kona_pwmc_apply_settings(kp, chan);
+ ret = kona_pwmc_apply_settings(kp, chan);
+ if (ret < 0) {
+ dev_err(chip->dev, "failed to apply settings: %d\n",
+ ret);
+ return ret;
+ }
}

return 0;
@@ -187,7 +231,11 @@ static int kona_pwmc_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
return 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 ret;
+ }

value = readl(kp->base + PWM_CONTROL_OFFSET);

@@ -198,7 +246,11 @@ static int kona_pwmc_set_polarity(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 apply pwm settings: %d\n", ret);
+ return ret;
+ }

clk_disable_unprepare(kp->clk);

@@ -231,8 +283,13 @@ 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));
@@ -243,7 +300,11 @@ 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 prepare pwm settings: %d\n", ret);
+ return;
+ }

clk_disable_unprepare(kp->clk);
}
@@ -256,14 +317,26 @@ static void kona_pwmc_disable(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_V1},
+ { .compatible = "brcm,kona-pwm-v2", .data = (void *)KONA_PWM_V2},
+ { },
+};
+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;
@@ -276,6 +349,7 @@ 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);
@@ -322,12 +396,6 @@ 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
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