[RESEND 08/11] pwm: sti: Add support for PWM Capture IRQs

Lee Jones
2016-03-02T15:35:58Z

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@linaro.org>
---
drivers/pwm/pwm-sti.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 90 insertions(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-sti.c b/drivers/pwm/pwm-sti.c
index fca692a..82a69e4 100644
--- a/drivers/pwm/pwm-sti.c
+++ b/drivers/pwm/pwm-sti.c
@@ -12,6 +12,7 @@

#include <linux/clk.h>
#include <linux/gpio.h>
+#include <linux/interrupt.h>
#include <linux/math64.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
@@ -94,7 +95,9 @@ 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;
@@ -314,6 +317,74 @@ 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_data *d;
+ int channel;
+ int cpt_int_stat;
+ 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) {
+ channel = ffs(cpt_int_stat) - 1;
+
+ d = pc->cpt_data[channel];
+
+ /*
+ * 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(channel), &d->snapshot[d->index]);
+
+ switch (d->index) {
+ case 0:
+ case 1:
+ regmap_read(pc->regmap, PWM_CPT_EDGE(channel), &reg);
+ reg ^= PWM_CPT_EDGE_MASK;
+ regmap_write(pc->regmap, PWM_CPT_EDGE(channel), reg);
+
+ d->index++;
+ break;
+ case 2:
+ regmap_write(pc->regmap,
+ PWM_CPT_EDGE(channel), CPT_EDGE_DISABLED);
+ wake_up(&d->wait);
+ break;
+ default:
+ dev_err(dev, "Internal error\n");
+ }
+
+ clear_bit(channel, (unsigned long int *)&cpt_int_stat);
+
+ 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;
@@ -354,6 +425,11 @@ 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 (IS_ERR(pc->pwm_cpt_int_stat))
+ return PTR_ERR(pc->pwm_cpt_int_stat);
+
return 0;
}

@@ -371,7 +447,7 @@ static int sti_pwm_probe(struct platform_device *pdev)
struct sti_pwm_chip *pc;
struct resource *res;
unsigned int chan;
- int ret;
+ int ret, irq;

pc = devm_kzalloc(dev, sizeof(*pc), GFP_KERNEL);
if (!pc)
@@ -392,6 +468,19 @@ 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 -ENODEV;
+ }
+
+ ret = devm_request_irq(&pdev->dev, irq, sti_pwm_interrupt,
+ 0, pdev->name, (void *) 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.
--
1.9.1