Re: [PATCH v2 1/3] rtc: tps6594: add driver for TPS6594 PMIC RTC

From: Alexandre Belloni <alexandre.belloni@bootlin.com>
To: Esteban Blanc <eblanc@baylibre.com>
Cc: linus.walleij@linaro.org, lgirdwood@gmail.com,
	broonie@kernel.org, a.zummo@towertech.it,
	linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org,
	linux-rtc@vger.kernel.org, jpanis@baylibre.com,
	jneanne@baylibre.com, sterzik@ti.com, u-kumar1@ti.com
Subject: Re: [PATCH v2 1/3] rtc: tps6594: add driver for TPS6594 PMIC RTC
Date: Tue, 28 Mar 2023 11:29:44 +0200	[thread overview]
Message-ID: <202303280929448e41808d@mail.local> (raw)
In-Reply-To: <20230328091448.648452-2-eblanc@baylibre.com>

Hello,

On 28/03/2023 11:14:46+0200, Esteban Blanc wrote:
> +	/* Start rtc */
> +	ret = regmap_set_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1,
> +			      TPS6594_BIT_STOP_RTC);
> +	if (ret < 0)
> +		return ret;
> +
> +	mdelay(100);
> +
> +	/*
> +	 * RTC should be running now. Check if this is the case.
> +	 * If not it might be a missing oscillator.
> +	 */
> +	ret = regmap_test_bits(tps->regmap, TPS6594_REG_RTC_STATUS,
> +			       TPS6594_BIT_RUN);
> +	if (ret < 0)
> +		return ret;
> +	if (ret == 0)
> +		return -ENODEV;
> +
> +	/* Stop RTC until first call to `tps6594_rtc_set_time */
> +	ret = regmap_clear_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1,
> +				TPS6594_BIT_STOP_RTC);
> +	if (ret < 0)
> +		return ret;
> +

This whole block must not be executed when the RTC is already running,
else, you are stopping a perfectly running RTC.

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