Hello Binbin,
On Tue, Dec 10, 2024 at 08:37:06PM +0800, Binbin Zhou wrote:
> +static int pwm_loongson_probe(struct platform_device *pdev)
> +{
> + int ret;
> + struct pwm_chip *chip;
> + struct pwm_loongson_ddata *ddata;
> + struct device *dev = &pdev->dev;
> +
> + chip = devm_pwmchip_alloc(dev, 1, sizeof(*ddata));
> + if (IS_ERR(chip))
> + return PTR_ERR(chip);
> + ddata = to_pwm_loongson_ddata(chip);
> +
> + ddata->base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(ddata->base))
> + return PTR_ERR(ddata->base);
> +
> + ddata->clk = devm_clk_get_optional_enabled(dev, NULL);
> + if (IS_ERR(ddata->clk))
> + return dev_err_probe(dev, PTR_ERR(ddata->clk),
> + "failed to get pwm clock\n");
> + if (ddata->clk) {
> + ret = devm_clk_rate_exclusive_get(dev, ddata->clk);
> + if (ret)
> + return ret;
Error message please. Also please make all errors start with a capital
letter.
> + ddata->clk_rate = clk_get_rate(ddata->clk);
> + } else {
> + ddata->clk_rate = LOONGSON_PWM_FREQ_DEFAULT;
> + }
> +
> + /* Explicitly initialize the CTRL register */
> + pwm_loongson_writel(ddata, 0, LOONGSON_PWM_REG_CTRL);
This disables all outputs, right? Ideally the driver takes over running
channels. Consider the bootloader initialized a display with a splash
screen. Disabling the PWM might disable the backlight of the display
which hurts the visual experience.
> + chip->ops = &pwm_loongson_ops;
> + chip->atomic = true;
> + dev_set_drvdata(dev, chip);
> +
> + ret = devm_pwmchip_add(dev, chip);
> + if (ret < 0)
> + return dev_err_probe(dev, ret, "failed to add PWM chip\n");
> +
> + return 0;
> +}
> +
> +static int pwm_loongson_suspend(struct device *dev)
> +{
> + struct pwm_chip *chip = dev_get_drvdata(dev);
> + struct pwm_loongson_ddata *ddata = to_pwm_loongson_ddata(chip);
> +
> + ddata->lss.ctrl = pwm_loongson_readl(ddata, LOONGSON_PWM_REG_CTRL);
> + ddata->lss.duty = pwm_loongson_readl(ddata, LOONGSON_PWM_REG_DUTY);
> + ddata->lss.period = pwm_loongson_readl(ddata, LOONGSON_PWM_REG_PERIOD);
> +
> + clk_disable_unprepare(ddata->clk);
> +
> + return 0;
Is this needed assuming that before suspend the consumer stopped the
PWM?
Best regards
Uwe
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