ASoC: sgtl5000: Calculate Lineout Channel Output Level (1f39d939) · Commits · 戴 / test

sound/soc/codecs/sgtl5000.c

+38 −0

Original line number	Diff line number	Diff line
		@@ -1091,6 +1091,19 @@ static bool sgtl5000_readable(struct device *dev, unsigned int reg)
		}
		}

		/*
		* This precalculated table contains all (vag_val * 100 / lo_calcntrl) results
		* to select an appropriate lo_vol_* in SGTL5000_CHIP_LINE_OUT_VOL
		* The calculatation was done for all possible register values which
		* is the array index and the following formula: 10^((idx−15)/40) * 100
		*/
		static const u8 vol_quot_table[] = {
		42, 45, 47, 50, 53, 56, 60, 63,
		67, 71, 75, 79, 84, 89, 94, 100,
		106, 112, 119, 126, 133, 141, 150, 158,
		168, 178, 188, 200, 211, 224, 237, 251
		};

		/*
		* sgtl5000 has 3 internal power supplies:
		* 1. VAG, normally set to vdda/2
		@@ -1112,6 +1125,9 @@ static int sgtl5000_set_power_regs(struct snd_soc_codec *codec)
		u16 lreg_ctrl;
		int vag;
		int lo_vag;
		int vol_quot;
		int lo_vol;
		size_t i;
		struct sgtl5000_priv *sgtl5000 = snd_soc_codec_get_drvdata(codec);

		vdda = regulator_get_voltage(sgtl5000->supplies[VDDA].consumer);
		@@ -1216,6 +1232,28 @@ static int sgtl5000_set_power_regs(struct snd_soc_codec *codec)
		SGTL5000_LINE_OUT_CURRENT_360u <<
		SGTL5000_LINE_OUT_CURRENT_SHIFT);

		/*
		* Set lineout output level in range (0..31)
		* the same value is used for right and left channel
		*
		* Searching for a suitable index solving this formula:
		* idx = 40 * log10(vag_val / lo_cagcntrl) + 15
		*/
		vol_quot = (vag * 100) / lo_vag;
		lo_vol = 0;
		for (i = 0; i < ARRAY_SIZE(vol_quot_table); i++) {
		if (vol_quot >= vol_quot_table[i])
		lo_vol = i;
		else
		break;
		}

		snd_soc_update_bits(codec, SGTL5000_CHIP_LINE_OUT_VOL,
		SGTL5000_LINE_OUT_VOL_RIGHT_MASK \|
		SGTL5000_LINE_OUT_VOL_LEFT_MASK,
		lo_vol << SGTL5000_LINE_OUT_VOL_RIGHT_SHIFT \|
		lo_vol << SGTL5000_LINE_OUT_VOL_LEFT_SHIFT);

		return 0;
		}

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