ASoC: sgtl5000: Fix wrong register name in restore

Correct SGTL5000_CHIP_CLK_CTRL to SGTL5000_CHIP_REF_CTRL in
sgtl5000_restore_regs(), and add comment to explain the
restore order.

Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Zeng Zhaoming <zengzm.kernel@gmail.com>
Acked-by: Dong Aisheng <dong.aisheng@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 13 insertions, 4 deletions

diff --git a/sound/soc/codecs/sgtl5000.c b/sound/soc/codecs/sgtl5000.c
index f8863ebb4304..7f4ba819a9f6 100644
--- a/sound/soc/codecs/sgtl5000.c
+++ b/sound/soc/codecs/sgtl5000.c
@@ -987,12 +987,12 @@ static int sgtl5000_restore_regs(struct snd_soc_codec *codec)
         /* restore regular registers */
         for (reg = 0; reg <= SGTL5000_CHIP_SHORT_CTRL; reg += 2) {
 
-                /* this regs depends on the others */
+                /* These regs should restore in particular order */
                 if (reg == SGTL5000_CHIP_ANA_POWER ||
                         reg == SGTL5000_CHIP_CLK_CTRL ||
                         reg == SGTL5000_CHIP_LINREG_CTRL ||
                         reg == SGTL5000_CHIP_LINE_OUT_CTRL ||
-                        reg == SGTL5000_CHIP_CLK_CTRL)
+                        reg == SGTL5000_CHIP_REF_CTRL)
                         continue;
 
                 snd_soc_write(codec, reg, cache[reg]);
@@ -1003,8 +1003,17 @@ static int sgtl5000_restore_regs(struct snd_soc_codec *codec)
                 snd_soc_write(codec, reg, cache[reg]);
 
         /*
-         * restore power and other regs according
-         * to set_power() and set_clock()
+         * restore these regs according to the power setting sequence in
+         * sgtl5000_set_power_regs() and clock setting sequence in
+         * sgtl5000_set_clock().
+         *
+         * The order of restore is:
+         * 1. SGTL5000_CHIP_CLK_CTRL MCLK_FREQ bits (1:0) should be restore after
+         *    SGTL5000_CHIP_ANA_POWER PLL bits set
+         * 2. SGTL5000_CHIP_LINREG_CTRL should be set before
+         *    SGTL5000_CHIP_ANA_POWER LINREG_D restored
+         * 3. SGTL5000_CHIP_REF_CTRL controls Analog Ground Voltage,
+         *    prefer to resotre it after SGTL5000_CHIP_ANA_POWER restored
          */
         snd_soc_write(codec, SGTL5000_CHIP_LINREG_CTRL,
                         cache[SGTL5000_CHIP_LINREG_CTRL]);