linux-kernel - [PATCH v1 10/15] iio: adc: ad7768-1: Add support for variable VCM

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <a6999fc24a4c61498e55f23861997382df2ab4f4.1736201898.git.Jonathan.Santos@analog.com>
Date: Tue, 7 Jan 2025 12:26:17 -0300
From: Jonathan Santos <Jonathan.Santos@...log.com>
To: <linux-iio@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
CC: Sergiu Cuciurean <sergiu.cuciurean@...log.com>, <lars@...afoo.de>,
        <Michael.Hennerich@...log.com>, <jic23@...nel.org>, <robh@...nel.org>,
        <krzk+dt@...nel.org>, <conor+dt@...nel.org>,
        <marcelo.schmitt1@...il.com>
Subject: [PATCH v1 10/15] iio: adc: ad7768-1: Add support for variable VCM

From: Sergiu Cuciurean <sergiu.cuciurean@...log.com>

The VCM output voltage can be used as a common-mode voltage within the
amplifier preconditioning circuits external to the AD7768-1.

This change exports the VCM as an iio attribute and makes it available
for configuration.

Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@...log.com>
---
 drivers/iio/adc/ad7768-1.c | 56 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c
index eaa9a12737ac..574d735f2c3a 100644
--- a/drivers/iio/adc/ad7768-1.c
+++ b/drivers/iio/adc/ad7768-1.c
@@ -119,6 +119,17 @@ struct ad7768_clk_configuration {
 	enum ad7768_pwrmode pwrmode;
 };
 
+static const char * const ad7768_vcm_modes[] = {
+	"(AVDD1-AVSS)/2",
+	"2V5",
+	"2V05",
+	"1V9",
+	"1V65",
+	"1V1",
+	"0V9",
+	"OFF",
+};
+
 static const struct ad7768_clk_configuration ad7768_clk_config[] = {
 	{ AD7768_MCLK_DIV_2, AD7768_DEC_RATE_8, 16,  AD7768_FAST_MODE },
 	{ AD7768_MCLK_DIV_2, AD7768_DEC_RATE_16, 32,  AD7768_FAST_MODE },
@@ -133,12 +144,34 @@ static const struct ad7768_clk_configuration ad7768_clk_config[] = {
 	{ AD7768_MCLK_DIV_16, AD7768_DEC_RATE_1024, 16384, AD7768_ECO_MODE },
 };
 
+static int ad7768_get_vcm(struct iio_dev *dev, const struct iio_chan_spec *chan);
+static int ad7768_set_vcm(struct iio_dev *dev, const struct iio_chan_spec *chan,
+			  unsigned int mode);
+
+static const struct iio_enum ad7768_vcm_mode_enum = {
+	.items = ad7768_vcm_modes,
+	.num_items = ARRAY_SIZE(ad7768_vcm_modes),
+	.set = ad7768_set_vcm,
+	.get = ad7768_get_vcm,
+};
+
+static struct iio_chan_spec_ext_info ad7768_ext_info[] = {
+	IIO_ENUM("common_mode_voltage",
+		 IIO_SHARED_BY_ALL,
+		 &ad7768_vcm_mode_enum),
+	IIO_ENUM_AVAILABLE("common_mode_voltage",
+			   IIO_SHARED_BY_ALL,
+			   &ad7768_vcm_mode_enum),
+	{ },
+};
+
 static const struct iio_chan_spec ad7768_channels[] = {
 	{
 		.type = IIO_VOLTAGE,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.ext_info = ad7768_ext_info,
 		.indexed = 1,
 		.channel = 0,
 		.scan_index = 0,
@@ -159,6 +192,7 @@ struct ad7768_state {
 	struct clk *mclk;
 	unsigned int mclk_freq;
 	unsigned int samp_freq;
+	unsigned int common_mode_voltage;
 	struct completion completion;
 	struct iio_trigger *trig;
 	struct gpio_desc *gpio_sync_in;
@@ -329,6 +363,28 @@ static int ad7768_set_freq(struct ad7768_state *st,
 	return 0;
 }
 
+static int ad7768_get_vcm(struct iio_dev *dev, const struct iio_chan_spec *chan)
+{
+	struct ad7768_state *st = iio_priv(dev);
+
+	return st->common_mode_voltage;
+}
+
+static int ad7768_set_vcm(struct iio_dev *dev,
+			  const struct iio_chan_spec *chan,
+			  unsigned int mode)
+{
+	int ret;
+	struct ad7768_state *st = iio_priv(dev);
+
+	ret = ad7768_spi_reg_write(st, AD7768_REG_ANALOG2, mode);
+
+	if (ret == 0)
+		st->common_mode_voltage = mode;
+
+	return ret;
+}
+
 static ssize_t ad7768_sampling_freq_avail(struct device *dev,
 					  struct device_attribute *attr,
 					  char *buf)
-- 
2.34.1