drivers/pwm/pwm-clps711x.c

Source file repositories/reference/linux-study-clean/drivers/pwm/pwm-clps711x.c

File Facts

System
Linux kernel
Corpus path
drivers/pwm/pwm-clps711x.c
Extension
.c
Size
2584 bytes
Lines
111
Domain
Driver Families
Bucket
drivers/pwm
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct clps711x_chip {
	void __iomem *pmpcon;
	struct clk *clk;
};

static inline struct clps711x_chip *to_clps711x_chip(struct pwm_chip *chip)
{
	return pwmchip_get_drvdata(chip);
}

static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct clps711x_chip *priv = to_clps711x_chip(chip);
	unsigned int freq = clk_get_rate(priv->clk);

	if (!freq)
		return -EINVAL;

	/* Store constant period value */
	pwm->args.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq);

	return 0;
}

static int clps711x_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
			      const struct pwm_state *state)
{
	struct clps711x_chip *priv = to_clps711x_chip(chip);
	/* PWM0 - bits 4..7, PWM1 - bits 8..11 */
	u32 shift = (pwm->hwpwm + 1) * 4;
	u32 pmpcon, val;

	if (state->polarity != PWM_POLARITY_NORMAL)
		return -EINVAL;

	if (state->period != pwm->args.period)
		return -EINVAL;

	if (state->enabled)
		val = mul_u64_u64_div_u64(state->duty_cycle, 0xf, state->period);
	else
		val = 0;

	pmpcon = readl(priv->pmpcon);
	pmpcon &= ~(0xf << shift);
	pmpcon |= val << shift;
	writel(pmpcon, priv->pmpcon);

	return 0;
}

static const struct pwm_ops clps711x_pwm_ops = {
	.request = clps711x_pwm_request,
	.apply = clps711x_pwm_apply,
};

static int clps711x_pwm_probe(struct platform_device *pdev)
{
	struct pwm_chip *chip;
	struct clps711x_chip *priv;

	chip = devm_pwmchip_alloc(&pdev->dev, 2, sizeof(*priv));
	if (IS_ERR(chip))
		return PTR_ERR(chip);
	priv = to_clps711x_chip(chip);

	priv->pmpcon = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(priv->pmpcon))
		return PTR_ERR(priv->pmpcon);

	priv->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(priv->clk))
		return PTR_ERR(priv->clk);

	chip->ops = &clps711x_pwm_ops;

	return devm_pwmchip_add(&pdev->dev, chip);
}

static const struct of_device_id clps711x_pwm_dt_ids[] = {
	{ .compatible = "cirrus,ep7209-pwm", },
	{ }
};
MODULE_DEVICE_TABLE(of, clps711x_pwm_dt_ids);

static struct platform_driver clps711x_pwm_driver = {
	.driver = {
		.name = "clps711x-pwm",
		.of_match_table = clps711x_pwm_dt_ids,
	},

Annotation

Implementation Notes