Message-ID: <689ffdac-8d52-a76d-8a01-a43b8a7d9fa8@opensource.cirrus.com>
Date:   Wed, 22 Feb 2023 15:56:36 -0600
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Subject: Re: [PATCH v6 3/4] ALSA: cs35l41: Add shared boost feature
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To:     Lucas Tanure <lucas.tanure@collabora.com>,
        David Rhodes <david.rhodes@cirrus.com>,
        Charles Keepax <ckeepax@opensource.cirrus.com>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Mark Brown <broonie@kernel.org>,
        "Rob Herring" <robh+dt@kernel.org>,
        Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>
CC:     <alsa-devel@alsa-project.org>, <devicetree@vger.kernel.org>,
        <patches@opensource.cirrus.com>, <linux-kernel@vger.kernel.org>,
        <kernel@collabora.com>
References: <20230222093244.938156-1-lucas.tanure@collabora.com>
 <20230222093244.938156-4-lucas.tanure@collabora.com>
From:   David Rhodes <drhodes@opensource.cirrus.com>
In-Reply-To: <20230222093244.938156-4-lucas.tanure@collabora.com>
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Precedence: bulk

On 2/22/23 03:32, Lucas Tanure wrote:
> +static const struct reg_sequence cs35l41_actv_seq[] = {
> +	/* SYNC_BST_CTL_RX_EN = 1; SYNC_BST_CTL_TX_EN = 1 */
> +	{CS35L41_MDSYNC_EN,        0x00003000},
> +	/* BST_CTL_SEL = MDSYNC */
> +	{CS35L41_BSTCVRT_VCTRL2,    0x00000002},
> +};
> +
> +static const struct reg_sequence cs35l41_pass_seq[] = {
> +	/* SYNC_BST_CTL_RX_EN = 1; SYNC_BST_CTL_TX_EN = 0 */
> +	{CS35L41_MDSYNC_EN,        0x00002000},
> +	/* BST_EN = 0 */
> +	{CS35L41_PWR_CTRL2,        0x00003300},
> +	/* BST_CTL_SEL = MDSYNC */
> +	{CS35L41_BSTCVRT_VCTRL2,    0x00000002},
> +};
> +

The passive device only needs to use TX, not RX.
It is transmitting its boost target voltage to the bus so that the
active amp can boost according to the combined target.

Should be:
static const struct reg_sequence cs35l41_pass_seq[] = {
	/* SYNC_BST_CTL_RX_EN = 0; SYNC_BST_CTL_TX_EN = 1 */
	{CS35L41_MDSYNC_EN,        0x00001000},
...

Thanks,
David