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>

diff --git a/sound/soc/codecs/sgtl5000.c b/sound/soc/codecs/sgtl5000.c
index f8863eb..7f4ba81 100644 (file)
--- 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]);