!3 feat(pwm): support pwm capture

Merge pull request !3 from Ilikara/feat/pwm-capture

drivers/pwm/pwm-loongson.c

@@ -22,12 +22,16 @@
 #include <linux/device.h>
 #include <linux/init.h>
 #include <linux/io.h>
+#include <linux/iopoll.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/pwm.h>
 #include <linux/units.h>
 #include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/delay.h>
 
 /* Loongson PWM registers */
 #define LOONGSON_PWM_REG_DUTY		0x4 /* Low Pulse Buffer Register */
@@ -57,8 +61,11 @@ struct pwm_loongson_suspend_store {
 struct pwm_loongson_ddata {
 	struct clk *clk;
 	void __iomem *base;
+	u32 irq;
+	u32 int_count;
 	u64 clk_rate;
 	struct pwm_loongson_suspend_store lss;
+    struct wait_queue_head capture_wait_queue;
 };
 
 static inline struct pwm_loongson_ddata *to_pwm_loongson_ddata(struct pwm_chip *chip)
@@ -77,6 +84,64 @@ static inline void pwm_loongson_writel(struct pwm_loongson_ddata *ddata,
 	writel(val, ddata->base + offset);
 }
 
+static irqreturn_t pwm_loongson_isr(int irq, void *dev)
+{
+	u32 val;
+	struct pwm_chip *chip = dev_get_drvdata(dev);
+	struct pwm_loongson_ddata *ddata = to_pwm_loongson_ddata(chip);
+
+	val = pwm_loongson_readl(ddata, LOONGSON_PWM_REG_CTRL);
+	if ((val & LOONGSON_PWM_CTRL_INT) == 0) {
+		return IRQ_NONE;
+	}
+	val |= LOONGSON_PWM_CTRL_INT;
+	pwm_loongson_writel(ddata, val, LOONGSON_PWM_REG_CTRL);
+
+	ddata->int_count++;
+
+	dev_info(dev, "pwm_loongson_isr count %u\n", ddata->int_count);
+
+	return IRQ_HANDLED;
+}
+
+static int pwm_loongson_capture(struct pwm_chip *chip, struct pwm_device *pwm,
+				struct pwm_capture *result,
+				unsigned long timeout)
+{
+	u32 val;
+	struct device *dev = pwmchip_parent(chip);
+	struct pwm_loongson_ddata *ddata = to_pwm_loongson_ddata(chip);
+	int ret;
+
+	pwm_loongson_writel(ddata, 0, LOONGSON_PWM_REG_PERIOD);
+
+	val = pwm_loongson_readl(ddata, LOONGSON_PWM_REG_CTRL);
+	val |= LOONGSON_PWM_CTRL_EN | LOONGSON_PWM_CTRL_CAPTE |
+	       LOONGSON_PWM_CTRL_OE;
+	pwm_loongson_writel(ddata, val, LOONGSON_PWM_REG_CTRL);
+	ret = readl_poll_timeout(ddata->base + LOONGSON_PWM_REG_PERIOD, val,
+				 val, 10, timeout * 1000);
+	if (ret < 0)
+		return -ETIMEDOUT;
+
+	dev_dbg(dev, "get first period: %u\n", val);
+
+	usleep_range(val * 4 / 100 + 1, val * 4 / 100 + 2);
+
+	val = pwm_loongson_readl(ddata, LOONGSON_PWM_REG_PERIOD);
+	result->period = DIV64_U64_ROUND_UP((u64)val * NSEC_PER_SEC, ddata->clk_rate);
+	dev_dbg(dev, "get second period: %u\n", val);
+	val = pwm_loongson_readl(ddata, LOONGSON_PWM_REG_DUTY);
+	result->duty_cycle = DIV64_U64_ROUND_UP((u64)val * NSEC_PER_SEC, ddata->clk_rate);
+
+	val = pwm_loongson_readl(ddata, LOONGSON_PWM_REG_CTRL);
+	val &= ~(LOONGSON_PWM_CTRL_EN | LOONGSON_PWM_CTRL_CAPTE |
+		 LOONGSON_PWM_CTRL_OE);
+	pwm_loongson_writel(ddata, val, LOONGSON_PWM_REG_CTRL);
+
+	return 0;
+}
+
 static int pwm_loongson_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
 				     enum pwm_polarity polarity)
 {
@@ -207,6 +272,7 @@ static int pwm_loongson_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
 }
 
 static const struct pwm_ops pwm_loongson_ops = {
+	.capture = pwm_loongson_capture,
 	.apply = pwm_loongson_apply,
 	.get_state = pwm_loongson_get_state,
 };
@@ -219,12 +285,23 @@ static int pwm_loongson_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node;
 	u32 of_clk_freq = 0;
+	u32 irq;
+
+	irq = platform_get_irq(pdev, 0);
+	dev_info(dev, "irq get:%u\n", irq);
+	if (irq <= 0) {
+	    dev_err(&pdev->dev, "no irq resource?\n");
+	    return -ENODEV;
+	}
 
 	chip = devm_pwmchip_alloc(dev, 1, sizeof(*ddata));
 	if (IS_ERR(chip))
 		return PTR_ERR(chip);
 	ddata = to_pwm_loongson_ddata(chip);
 
+    // 初始化等待队列
+    init_waitqueue_head(&ddata->capture_wait_queue);
+
 	ddata->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(ddata->base))
 		return PTR_ERR(ddata->base);
@@ -247,6 +324,14 @@ static int pwm_loongson_probe(struct platform_device *pdev)
 #endif
 	}
 
+	ddata->irq = irq;
+
+	ret = devm_request_irq(dev, ddata->irq, pwm_loongson_isr, IRQF_SHARED,
+			       dev_name(dev), dev);
+
+	if (ret)
+		dev_err(dev, "failure requesting irq %d\n", ret);
+
 	/* Explicitly initialize the CTRL register */
 	pwm_loongson_writel(ddata, 0, LOONGSON_PWM_REG_CTRL);