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-rw-r--r--drivers/iio/amplifiers/hmc425a.c274
1 files changed, 216 insertions, 58 deletions
diff --git a/drivers/iio/amplifiers/hmc425a.c b/drivers/iio/amplifiers/hmc425a.c
index ed4d729226..2ee4c0d702 100644
--- a/drivers/iio/amplifiers/hmc425a.c
+++ b/drivers/iio/amplifiers/hmc425a.c
@@ -2,9 +2,10 @@
/*
* HMC425A and similar Gain Amplifiers
*
- * Copyright 2020 Analog Devices Inc.
+ * Copyright 2020, 2024 Analog Devices Inc.
*/
+#include <linux/bits.h>
#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/err.h>
@@ -12,6 +13,7 @@
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/kernel.h>
+#include <linux/math.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
@@ -20,10 +22,24 @@
#include <linux/regulator/consumer.h>
#include <linux/sysfs.h>
+/*
+ * The LTC6373 amplifier supports configuring gain using GPIO's with the following
+ * values (OUTPUT_V / INPUT_V): 0(shutdown), 0.25, 0.5, 1, 2, 4, 8, 16
+ *
+ * Except for the shutdown value, all can be converted to dB using 20 * log10(x)
+ * From here, it is observed that all values are multiples of the '2' gain setting,
+ * with the correspondent of 6.020dB.
+ */
+#define LTC6373_CONVERSION_CONSTANT 6020
+#define LTC6373_MIN_GAIN_CODE 0x6
+#define LTC6373_CONVERSION_MASK GENMASK(2, 0)
+#define LTC6373_SHUTDOWN GENMASK(2, 0)
+
enum hmc425a_type {
ID_HMC425A,
ID_HMC540S,
- ID_ADRF5740
+ ID_ADRF5740,
+ ID_LTC6373,
};
struct hmc425a_chip_info {
@@ -34,16 +50,110 @@ struct hmc425a_chip_info {
int gain_min;
int gain_max;
int default_gain;
+ int powerdown_val;
+ bool has_powerdown;
+
+ int (*gain_dB_to_code)(int gain, int *code);
+ int (*code_to_gain_dB)(int code, int *val, int *val2);
};
struct hmc425a_state {
struct mutex lock; /* protect sensor state */
- struct hmc425a_chip_info *chip_info;
+ const struct hmc425a_chip_info *chip_info;
struct gpio_descs *gpios;
- enum hmc425a_type type;
u32 gain;
+ bool powerdown;
};
+static int gain_dB_to_code(struct hmc425a_state *st, int val, int val2, int *code)
+{
+ const struct hmc425a_chip_info *inf = st->chip_info;
+ int gain;
+
+ if (val < 0)
+ gain = (val * 1000) - (val2 / 1000);
+ else
+ gain = (val * 1000) + (val2 / 1000);
+
+ if (gain > inf->gain_max || gain < inf->gain_min)
+ return -EINVAL;
+ if (st->powerdown)
+ return -EPERM;
+
+ return st->chip_info->gain_dB_to_code(gain, code);
+}
+
+static int hmc425a_gain_dB_to_code(int gain, int *code)
+{
+ *code = ~((abs(gain) / 500) & 0x3F);
+ return 0;
+}
+
+static int hmc540s_gain_dB_to_code(int gain, int *code)
+{
+ *code = ~((abs(gain) / 1000) & 0xF);
+ return 0;
+}
+
+static int adrf5740_gain_dB_to_code(int gain, int *code)
+{
+ int temp = (abs(gain) / 2000) & 0xF;
+
+ /* Bit [0-3]: 2dB 4dB 8dB 8dB */
+ *code = temp & BIT(3) ? temp | BIT(2) : temp;
+ return 0;
+}
+
+static int ltc6373_gain_dB_to_code(int gain, int *code)
+{
+ *code = ~(DIV_ROUND_CLOSEST(gain, LTC6373_CONVERSION_CONSTANT) + 3)
+ & LTC6373_CONVERSION_MASK;
+ return 0;
+}
+
+static int code_to_gain_dB(struct hmc425a_state *st, int *val, int *val2)
+{
+ if (st->powerdown)
+ return -EPERM;
+ return st->chip_info->code_to_gain_dB(st->gain, val, val2);
+}
+
+static int hmc425a_code_to_gain_dB(int code, int *val, int *val2)
+{
+ *val = (~code * -500) / 1000;
+ *val2 = ((~code * -500) % 1000) * 1000;
+ return 0;
+}
+
+static int hmc540s_code_to_gain_dB(int code, int *val, int *val2)
+{
+ *val = (~code * -1000) / 1000;
+ *val2 = ((~code * -1000) % 1000) * 1000;
+ return 0;
+}
+
+static int adrf5740_code_to_gain_dB(int code, int *val, int *val2)
+{
+ /*
+ * Bit [0-3]: 2dB 4dB 8dB 8dB
+ * When BIT(3) is set, unset BIT(2) and use 3 as double the place value
+ */
+ code = code & BIT(3) ? code & ~BIT(2) : code;
+ *val = (code * -2000) / 1000;
+ *val2 = ((code * -2000) % 1000) * 1000;
+ return 0;
+}
+
+static int ltc6373_code_to_gain_dB(int code, int *val, int *val2)
+{
+ int gain = ((~code & LTC6373_CONVERSION_MASK) - 3) *
+ LTC6373_CONVERSION_CONSTANT;
+
+ *val = gain / 1000;
+ *val2 = (gain % 1000) * 1000;
+ return 0;
+}
+
static int hmc425a_write(struct iio_dev *indio_dev, u32 value)
{
struct hmc425a_state *st = iio_priv(indio_dev);
@@ -61,30 +171,14 @@ static int hmc425a_read_raw(struct iio_dev *indio_dev,
int *val2, long m)
{
struct hmc425a_state *st = iio_priv(indio_dev);
- int code, gain = 0;
int ret;
mutex_lock(&st->lock);
switch (m) {
case IIO_CHAN_INFO_HARDWAREGAIN:
- code = st->gain;
-
- switch (st->type) {
- case ID_HMC425A:
- gain = ~code * -500;
+ ret = code_to_gain_dB(st, val, val2);
+ if (ret)
break;
- case ID_HMC540S:
- gain = ~code * -1000;
- break;
- case ID_ADRF5740:
- code = code & BIT(3) ? code & ~BIT(2) : code;
- gain = code * -2000;
- break;
- }
-
- *val = gain / 1000;
- *val2 = (gain % 1000) * 1000;
-
ret = IIO_VAL_INT_PLUS_MICRO_DB;
break;
default:
@@ -100,34 +194,14 @@ static int hmc425a_write_raw(struct iio_dev *indio_dev,
int val2, long mask)
{
struct hmc425a_state *st = iio_priv(indio_dev);
- struct hmc425a_chip_info *inf = st->chip_info;
- int code = 0, gain;
- int ret;
-
- if (val < 0)
- gain = (val * 1000) - (val2 / 1000);
- else
- gain = (val * 1000) + (val2 / 1000);
-
- if (gain > inf->gain_max || gain < inf->gain_min)
- return -EINVAL;
-
- switch (st->type) {
- case ID_HMC425A:
- code = ~((abs(gain) / 500) & 0x3F);
- break;
- case ID_HMC540S:
- code = ~((abs(gain) / 1000) & 0xF);
- break;
- case ID_ADRF5740:
- code = (abs(gain) / 2000) & 0xF;
- code = code & BIT(3) ? code | BIT(2) : code;
- break;
- }
+ int code = 0, ret;
mutex_lock(&st->lock);
switch (mask) {
case IIO_CHAN_INFO_HARDWAREGAIN:
+ ret = gain_dB_to_code(st, val, val2, &code);
+ if (ret)
+ break;
st->gain = code;
ret = hmc425a_write(indio_dev, st->gain);
@@ -158,6 +232,48 @@ static const struct iio_info hmc425a_info = {
.write_raw_get_fmt = &hmc425a_write_raw_get_fmt,
};
+static ssize_t ltc6373_read_powerdown(struct iio_dev *indio_dev,
+ uintptr_t private,
+ const struct iio_chan_spec *chan,
+ char *buf)
+{
+ struct hmc425a_state *st = iio_priv(indio_dev);
+
+ return sysfs_emit(buf, "%d\n", st->powerdown);
+}
+
+static ssize_t ltc6373_write_powerdown(struct iio_dev *indio_dev,
+ uintptr_t private,
+ const struct iio_chan_spec *chan,
+ const char *buf,
+ size_t len)
+{
+ struct hmc425a_state *st = iio_priv(indio_dev);
+ bool powerdown;
+ int code, ret;
+
+ ret = kstrtobool(buf, &powerdown);
+ if (ret)
+ return ret;
+
+ mutex_lock(&st->lock);
+ st->powerdown = powerdown;
+ code = (powerdown) ? LTC6373_SHUTDOWN : st->gain;
+ hmc425a_write(indio_dev, code);
+ mutex_unlock(&st->lock);
+ return len;
+}
+
+static const struct iio_chan_spec_ext_info ltc6373_ext_info[] = {
+ {
+ .name = "powerdown",
+ .read = ltc6373_read_powerdown,
+ .write = ltc6373_write_powerdown,
+ .shared = IIO_SEPARATE,
+ },
+ {}
+};
+
#define HMC425A_CHAN(_channel) \
{ \
.type = IIO_VOLTAGE, \
@@ -167,20 +283,25 @@ static const struct iio_info hmc425a_info = {
.info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN), \
}
+#define LTC6373_CHAN(_channel) \
+{ \
+ .type = IIO_VOLTAGE, \
+ .output = 1, \
+ .indexed = 1, \
+ .channel = _channel, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN), \
+ .ext_info = ltc6373_ext_info, \
+}
+
static const struct iio_chan_spec hmc425a_channels[] = {
HMC425A_CHAN(0),
};
-/* Match table for of_platform binding */
-static const struct of_device_id hmc425a_of_match[] = {
- { .compatible = "adi,hmc425a", .data = (void *)ID_HMC425A },
- { .compatible = "adi,hmc540s", .data = (void *)ID_HMC540S },
- { .compatible = "adi,adrf5740", .data = (void *)ID_ADRF5740 },
- {},
+static const struct iio_chan_spec ltc6373_channels[] = {
+ LTC6373_CHAN(0),
};
-MODULE_DEVICE_TABLE(of, hmc425a_of_match);
-static struct hmc425a_chip_info hmc425a_chip_info_tbl[] = {
+static const struct hmc425a_chip_info hmc425a_chip_info_tbl[] = {
[ID_HMC425A] = {
.name = "hmc425a",
.channels = hmc425a_channels,
@@ -189,6 +310,8 @@ static struct hmc425a_chip_info hmc425a_chip_info_tbl[] = {
.gain_min = -31500,
.gain_max = 0,
.default_gain = -0x40, /* set default gain -31.5db*/
+ .gain_dB_to_code = hmc425a_gain_dB_to_code,
+ .code_to_gain_dB = hmc425a_code_to_gain_dB,
},
[ID_HMC540S] = {
.name = "hmc540s",
@@ -198,6 +321,8 @@ static struct hmc425a_chip_info hmc425a_chip_info_tbl[] = {
.gain_min = -15000,
.gain_max = 0,
.default_gain = -0x10, /* set default gain -15.0db*/
+ .gain_dB_to_code = hmc540s_gain_dB_to_code,
+ .code_to_gain_dB = hmc540s_code_to_gain_dB,
},
[ID_ADRF5740] = {
.name = "adrf5740",
@@ -207,6 +332,21 @@ static struct hmc425a_chip_info hmc425a_chip_info_tbl[] = {
.gain_min = -22000,
.gain_max = 0,
.default_gain = 0xF, /* set default gain -22.0db*/
+ .gain_dB_to_code = adrf5740_gain_dB_to_code,
+ .code_to_gain_dB = adrf5740_code_to_gain_dB,
+ },
+ [ID_LTC6373] = {
+ .name = "ltc6373",
+ .channels = ltc6373_channels,
+ .num_channels = ARRAY_SIZE(ltc6373_channels),
+ .num_gpios = 3,
+ .gain_min = -12041, /* gain setting x0.25*/
+ .gain_max = 24082, /* gain setting x16 */
+ .default_gain = LTC6373_MIN_GAIN_CODE,
+ .powerdown_val = LTC6373_SHUTDOWN,
+ .has_powerdown = true,
+ .gain_dB_to_code = ltc6373_gain_dB_to_code,
+ .code_to_gain_dB = ltc6373_code_to_gain_dB,
},
};
@@ -221,9 +361,8 @@ static int hmc425a_probe(struct platform_device *pdev)
return -ENOMEM;
st = iio_priv(indio_dev);
- st->type = (uintptr_t)device_get_match_data(&pdev->dev);
- st->chip_info = &hmc425a_chip_info_tbl[st->type];
+ st->chip_info = device_get_match_data(&pdev->dev);
indio_dev->num_channels = st->chip_info->num_channels;
indio_dev->channels = st->chip_info->channels;
indio_dev->name = st->chip_info->name;
@@ -249,12 +388,31 @@ static int hmc425a_probe(struct platform_device *pdev)
indio_dev->info = &hmc425a_info;
indio_dev->modes = INDIO_DIRECT_MODE;
- /* Set default gain */
- hmc425a_write(indio_dev, st->gain);
+ if (st->chip_info->has_powerdown) {
+ st->powerdown = true;
+ hmc425a_write(indio_dev, st->chip_info->powerdown_val);
+ } else {
+ /* Set default gain */
+ hmc425a_write(indio_dev, st->gain);
+ }
return devm_iio_device_register(&pdev->dev, indio_dev);
}
+/* Match table for of_platform binding */
+static const struct of_device_id hmc425a_of_match[] = {
+ { .compatible = "adi,hmc425a",
+ .data = &hmc425a_chip_info_tbl[ID_HMC425A]},
+ { .compatible = "adi,hmc540s",
+ .data = &hmc425a_chip_info_tbl[ID_HMC540S]},
+ { .compatible = "adi,adrf5740",
+ .data = &hmc425a_chip_info_tbl[ID_ADRF5740]},
+ { .compatible = "adi,ltc6373",
+ .data = &hmc425a_chip_info_tbl[ID_LTC6373]},
+ {}
+};
+MODULE_DEVICE_TABLE(of, hmc425a_of_match);
+
static struct platform_driver hmc425a_driver = {
.driver = {
.name = KBUILD_MODNAME,
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-03 22:35:03 +0000