From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Brown Subject: [PATCH 12/21] ASoC: Actively manage the DC servo for WM8903 Date: Thu, 23 Apr 2009 20:55:46 +0100 Message-ID: <1240516555-22249-12-git-send-email-broonie@opensource.wolfsonmicro.com> References: <20090423195420.GA20863@sirena.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from cassiel.sirena.org.uk (cassiel.sirena.org.uk [80.68.93.111]) by alsa0.perex.cz (Postfix) with ESMTP id 7C17C1038AF for ; Thu, 23 Apr 2009 21:56:06 +0200 (CEST) In-Reply-To: <20090423195420.GA20863@sirena.org.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: alsa-devel-bounces@alsa-project.org Errors-To: alsa-devel-bounces@alsa-project.org To: Takashi Iwai Cc: alsa-devel@alsa-project.org, Mark Brown List-Id: alsa-devel@alsa-project.org Save a little extra power by enabling the DC servo offset correction for the output channels only when the relevant channels are enabled. Signed-off-by: Mark Brown --- sound/soc/codecs/wm8903.c | 14 ++++++++++++++ 1 files changed, 14 insertions(+), 0 deletions(-) diff --git a/sound/soc/codecs/wm8903.c b/sound/soc/codecs/wm8903.c index de0a585..0bab5c6 100644 --- a/sound/soc/codecs/wm8903.c +++ b/sound/soc/codecs/wm8903.c @@ -392,14 +392,18 @@ static int wm8903_output_event(struct snd_soc_dapm_widget *w, struct snd_soc_codec *codec = w->codec; u16 val; u16 reg; + u16 dcs_reg; + u16 dcs_bit; int shift; switch (w->reg) { case WM8903_POWER_MANAGEMENT_2: reg = WM8903_ANALOGUE_HP_0; + dcs_bit = 0 + w->shift; break; case WM8903_POWER_MANAGEMENT_3: reg = WM8903_ANALOGUE_LINEOUT_0; + dcs_bit = 2 + w->shift; break; default: BUG(); @@ -439,6 +443,11 @@ static int wm8903_output_event(struct snd_soc_dapm_widget *w, val |= (WM8903_OUTPUT_OUT << shift); wm8903_write(codec, reg, val); + /* Enable the DC servo */ + dcs_reg = wm8903_read(codec, WM8903_DC_SERVO_0); + dcs_reg |= dcs_bit; + wm8903_write(codec, WM8903_DC_SERVO_0, dcs_reg); + /* Remove the short */ val |= (WM8903_OUTPUT_SHORT << shift); wm8903_write(codec, reg, val); @@ -451,6 +460,11 @@ static int wm8903_output_event(struct snd_soc_dapm_widget *w, val &= ~(WM8903_OUTPUT_SHORT << shift); wm8903_write(codec, reg, val); + /* Disable the DC servo */ + dcs_reg = wm8903_read(codec, WM8903_DC_SERVO_0); + dcs_reg &= ~dcs_bit; + wm8903_write(codec, WM8903_DC_SERVO_0, dcs_reg); + /* Then disable the intermediate and output stages */ val &= ~((WM8903_OUTPUT_OUT | WM8903_OUTPUT_INT | WM8903_OUTPUT_IN) << shift); -- 1.5.6.3