patch "staging: iio: adc: ad7192: fix external frequency setting" added to staging-linus

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    staging: iio: adc: ad7192: fix external frequency setting

to my staging git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


>From e31b617d0a63c6558485aaa730fd162faa95a766 Mon Sep 17 00:00:00 2001
From: Alexandru Ardelean <alexandru.ardelean@analog.com>
Date: Mon, 22 Jan 2018 11:53:12 +0200
Subject: staging: iio: adc: ad7192: fix external frequency setting

The external clock frequency was set only when selecting
the internal clock, which is fixed at 4.9152 Mhz.

This is incorrect, since it should be set when any of
the external clock or crystal settings is selected.

Added range validation for the external (crystal/clock)
frequency setting.
Valid values are between 2.4576 and 5.12 Mhz.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/staging/iio/adc/ad7192.c | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/drivers/staging/iio/adc/ad7192.c b/drivers/staging/iio/adc/ad7192.c
index f01595593ce2..425e8b82533b 100644
--- a/drivers/staging/iio/adc/ad7192.c
+++ b/drivers/staging/iio/adc/ad7192.c
@@ -141,6 +141,8 @@
 #define AD7192_GPOCON_P1DAT	BIT(1) /* P1 state */
 #define AD7192_GPOCON_P0DAT	BIT(0) /* P0 state */
 
+#define AD7192_EXT_FREQ_MHZ_MIN	2457600
+#define AD7192_EXT_FREQ_MHZ_MAX	5120000
 #define AD7192_INT_FREQ_MHZ	4915200
 
 /* NOTE:
@@ -218,6 +220,12 @@ static int ad7192_calibrate_all(struct ad7192_state *st)
 				ARRAY_SIZE(ad7192_calib_arr));
 }
 
+static inline bool ad7192_valid_external_frequency(u32 freq)
+{
+	return (freq >= AD7192_EXT_FREQ_MHZ_MIN &&
+		freq <= AD7192_EXT_FREQ_MHZ_MAX);
+}
+
 static int ad7192_setup(struct ad7192_state *st,
 			const struct ad7192_platform_data *pdata)
 {
@@ -243,17 +251,20 @@ static int ad7192_setup(struct ad7192_state *st,
 			 id);
 
 	switch (pdata->clock_source_sel) {
-	case AD7192_CLK_EXT_MCLK1_2:
-	case AD7192_CLK_EXT_MCLK2:
-		st->mclk = AD7192_INT_FREQ_MHZ;
-		break;
 	case AD7192_CLK_INT:
 	case AD7192_CLK_INT_CO:
-		if (pdata->ext_clk_hz)
-			st->mclk = pdata->ext_clk_hz;
-		else
-			st->mclk = AD7192_INT_FREQ_MHZ;
+		st->mclk = AD7192_INT_FREQ_MHZ;
 		break;
+	case AD7192_CLK_EXT_MCLK1_2:
+	case AD7192_CLK_EXT_MCLK2:
+		if (ad7192_valid_external_frequency(pdata->ext_clk_hz)) {
+			st->mclk = pdata->ext_clk_hz;
+			break;
+		}
+		dev_err(&st->sd.spi->dev, "Invalid frequency setting %u\n",
+			pdata->ext_clk_hz);
+		ret = -EINVAL;
+		goto out;
 	default:
 		ret = -EINVAL;
 		goto out;
-- 
2.16.2