[PATCH v4 13/17] pwm: sti: Add support for PWM Capture IRQs

From: Lee Jones
Date: Tue Aug 16 2016 - 05:37:18 EST


Here we're requesting the PWM Capture IRQ and supplying the
handler which will be called in the event of an IRQ fire to
handle it.

Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
---
drivers/pwm/pwm-sti.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 91 insertions(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-sti.c b/drivers/pwm/pwm-sti.c
index 16c3f4d..4686ba0 100644
--- a/drivers/pwm/pwm-sti.c
+++ b/drivers/pwm/pwm-sti.c
@@ -91,7 +91,9 @@ struct sti_pwm_chip {
struct regmap_field *prescale_low;
struct regmap_field *prescale_high;
struct regmap_field *pwm_out_en;
+ struct regmap_field *pwm_cpt_en;
struct regmap_field *pwm_cpt_int_en;
+ struct regmap_field *pwm_cpt_int_stat;
struct pwm_chip chip;
struct pwm_device *cur;
unsigned long configured;
@@ -311,6 +313,76 @@ static const struct pwm_ops sti_pwm_ops = {
.owner = THIS_MODULE,
};

+static irqreturn_t sti_pwm_interrupt(int irq, void *data)
+{
+ struct sti_pwm_chip *pc = data;
+ struct device *dev = pc->dev;
+ struct sti_cpt_ddata *ddata;
+ int devicenum;
+ unsigned int cpt_int_stat;
+ unsigned int reg;
+ int ret = IRQ_NONE;
+
+ ret = regmap_field_read(pc->pwm_cpt_int_stat, &cpt_int_stat);
+ if (ret)
+ return ret;
+
+ while (cpt_int_stat) {
+ devicenum = ffs(cpt_int_stat) - 1;
+
+ ddata = pwm_get_chip_data(&pc->chip.pwms[devicenum]);
+
+ /*
+ * Capture input:
+ * _______ _______
+ * | | | |
+ * __| |_________________| |________
+ * ^0 ^1 ^2
+ *
+ * Capture start by the first available rising edge
+ * When a capture event occurs, capture value (CPT_VALx)
+ * is stored, index incremented, capture edge changed.
+ *
+ * After the capture, if the index > 1, we have collected
+ * the necessary data so we signal the thread waiting for it
+ * and disable the capture by setting capture edge to none
+ *
+ */
+
+ regmap_read(pc->regmap,
+ PWM_CPT_VAL(devicenum),
+ &ddata->snapshot[ddata->index]);
+
+ switch (ddata->index) {
+ case 0:
+ case 1:
+ regmap_read(pc->regmap, PWM_CPT_EDGE(devicenum), &reg);
+ reg ^= PWM_CPT_EDGE_MASK;
+ regmap_write(pc->regmap, PWM_CPT_EDGE(devicenum), reg);
+
+ ddata->index++;
+ break;
+ case 2:
+ regmap_write(pc->regmap,
+ PWM_CPT_EDGE(devicenum),
+ CPT_EDGE_DISABLED);
+ wake_up(&ddata->wait);
+ break;
+ default:
+ dev_err(dev, "Internal error\n");
+ }
+
+ cpt_int_stat &= ~BIT_MASK(devicenum);
+
+ ret = IRQ_HANDLED;
+ }
+
+ /* Just ACK everything */
+ regmap_write(pc->regmap, PWM_INT_ACK, PWM_INT_ACK_MASK);
+
+ return ret;
+}
+
static int sti_pwm_probe_dt(struct sti_pwm_chip *pc)
{
struct device *dev = pc->dev;
@@ -351,6 +423,11 @@ static int sti_pwm_probe_dt(struct sti_pwm_chip *pc)
if (IS_ERR(pc->pwm_cpt_int_en))
return PTR_ERR(pc->pwm_cpt_int_en);

+ pc->pwm_cpt_int_stat = devm_regmap_field_alloc(dev, pc->regmap,
+ reg_fields[PWM_CPT_INT_STAT]);
+ if (PTR_ERR_OR_ZERO(pc->pwm_cpt_int_stat))
+ return PTR_ERR(pc->pwm_cpt_int_stat);
+
return 0;
}

@@ -367,7 +444,7 @@ static int sti_pwm_probe(struct platform_device *pdev)
struct sti_pwm_chip *pc;
struct resource *res;
unsigned int devnum;
- int ret;
+ int irq, ret;

pc = devm_kzalloc(dev, sizeof(*pc), GFP_KERNEL);
if (!pc)
@@ -388,6 +465,19 @@ static int sti_pwm_probe(struct platform_device *pdev)
if (IS_ERR(pc->regmap))
return PTR_ERR(pc->regmap);

+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(&pdev->dev, "Failed to obtain IRQ\n");
+ return irq;
+ }
+
+ ret = devm_request_irq(&pdev->dev, irq, sti_pwm_interrupt,
+ 0, pdev->name, pc);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Failed to request IRQ\n");
+ return ret;
+ }
+
/*
* Setup PWM data with default values: some values could be replaced
* with specific ones provided from Device Tree.
--
2.9.0