ASoC: sgtl5000: Do a sanity check on SYS_MCLK

According to the sgtl5000 datasheet the valid range for SYS_MCLK is from 8 to
27 MHz.

Add a sanity check prior to enabling SYS_MCLK.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/sound/soc/codecs/sgtl5000.c b/sound/soc/codecs/sgtl5000.c
index 7ef2687b396f..3e9db43ed760 100644
--- a/sound/soc/codecs/sgtl5000.c
+++ b/sound/soc/codecs/sgtl5000.c
@@ -1445,6 +1445,7 @@ static int sgtl5000_i2c_probe(struct i2c_client *client,
 {
         struct sgtl5000_priv *sgtl5000;
         int ret, reg, rev;
+        unsigned int mclk;
 
         sgtl5000 = devm_kzalloc(&client->dev, sizeof(struct sgtl5000_priv),
                                                                 GFP_KERNEL);
@@ -1468,6 +1469,14 @@ static int sgtl5000_i2c_probe(struct i2c_client *client,
                 return ret;
         }
 
+        /* SGTL5000 SYS_MCLK should be between 8 and 27 MHz */
+        mclk = clk_get_rate(sgtl5000->mclk);
+        if (mclk < 8000000 || mclk > 27000000) {
+                dev_err(&client->dev, "Invalid SYS_CLK frequency: %u.%03uMHz\n",
+                        mclk / 1000000, mclk / 1000 % 1000);
+                return -EINVAL;
+        }
+
         ret = clk_prepare_enable(sgtl5000->mclk);
         if (ret)
                 return ret;