Re: [PATCH] rtc: sun6i: Add NVMEM provider

From: Jernej Škrabec
Date: Fri Apr 15 2022 - 14:26:55 EST


Dne četrtek, 14. april 2022 ob 01:17:30 CEST je Samuel Holland napisal(a):
> The sun6i RTC provides 32 bytes of general-purpose data registers.
> They can be used to save data in the always-on RTC power domain.
> The registers are writable via 32-bit MMIO accesses only.
>
> Expose them with a NVMEM provider so they can be used by other drivers.
>
> Signed-off-by: Samuel Holland <samuel@xxxxxxxxxxxx>

Acked-by: Jernej Skrabec <jernej.skrabec@xxxxxxxxx>

Best regards,
Jernej

> ---
>
> drivers/rtc/rtc-sun6i.c | 42 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 42 insertions(+)
>
> diff --git a/drivers/rtc/rtc-sun6i.c b/drivers/rtc/rtc-sun6i.c
> index 5b3e4da63406..755aeb82a285 100644
> --- a/drivers/rtc/rtc-sun6i.c
> +++ b/drivers/rtc/rtc-sun6i.c
> @@ -71,6 +71,10 @@
> #define SUN6I_LOSC_OUT_GATING 0x0060
> #define SUN6I_LOSC_OUT_GATING_EN_OFFSET 0
>
> +/* General-purpose data */
> +#define SUN6I_GP_DATA 0x0100
> +#define SUN6I_GP_DATA_SIZE 0x20
> +
> /*
> * Get date values
> */
> @@ -662,6 +666,39 @@ static const struct rtc_class_ops sun6i_rtc_ops = {
> .alarm_irq_enable = sun6i_rtc_alarm_irq_enable
> };
>
> +static int sun6i_rtc_nvmem_read(void *priv, unsigned int offset, void
> *_val, size_t bytes) +{
> + struct sun6i_rtc_dev *chip = priv;
> + u32 *val = _val;
> + int i;
> +
> + for (i = 0; i < bytes / 4; ++i)
> + val[i] = readl(chip->base + SUN6I_GP_DATA + offset + 4 *
i);
> +
> + return 0;
> +}
> +
> +static int sun6i_rtc_nvmem_write(void *priv, unsigned int offset, void
> *_val, size_t bytes) +{
> + struct sun6i_rtc_dev *chip = priv;
> + u32 *val = _val;
> + int i;
> +
> + for (i = 0; i < bytes / 4; ++i)
> + writel(val[i], chip->base + SUN6I_GP_DATA + offset + 4 *
i);
> +
> + return 0;
> +}
> +
> +static struct nvmem_config sun6i_rtc_nvmem_cfg = {
> + .type = NVMEM_TYPE_BATTERY_BACKED,
> + .reg_read = sun6i_rtc_nvmem_read,
> + .reg_write = sun6i_rtc_nvmem_write,
> + .size = SUN6I_GP_DATA_SIZE,
> + .word_size = 4,
> + .stride = 4,
> +};
> +
> #ifdef CONFIG_PM_SLEEP
> /* Enable IRQ wake on suspend, to wake up from RTC. */
> static int sun6i_rtc_suspend(struct device *dev)
> @@ -795,6 +832,11 @@ static int sun6i_rtc_probe(struct platform_device
> *pdev) if (ret)
> return ret;
>
> + sun6i_rtc_nvmem_cfg.priv = chip;
> + ret = devm_rtc_nvmem_register(chip->rtc, &sun6i_rtc_nvmem_cfg);
> + if (ret)
> + return ret;
> +
> dev_info(&pdev->dev, "RTC enabled\n");
>
> return 0;