Re: [PATCH v2 3/3] rtc: ds1307: Add driver for Epson RX8901CE

[Alexandre Belloni]

On 20/05/2026 16:48:55+0200, Fredrik M Olsson wrote:
> +static int do_trickle_setup_rx8901(struct ds1307 *ds1307, u32 ohms __always_unused, bool diode)
> +{
> +	int ret;
> +	unsigned int setup;
> +
> +	ret = regmap_read(ds1307->regmap, RX8901_REG_PWSW_CFG, &setup);
> +	if (ret) {
> +		dev_err(ds1307->dev, "Failed to read PWSW_CFG register\n");
> +		return ret;
> +	}
> +
> +	/* Enable low battery voltage detection */
> +	setup |= RX8901_REG_PWSW_CFG_VBATLDETEN;
> +
> +	if (diode)
> +		setup |= RX8901_REG_PWSW_CFG_CHGEN;

When diode is false, you need to explicitly clear
RX8901_REG_PWSW_CFG_CHGEN so it is possible to actually disable trickle
charging once it has been enabled has the register is battery backed.


-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com