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Subject[PATCH 1/3] iio: Add ADM1177 Hot Swap Controller and Digital Power Monitor driver
Date
From: Michael Hennerich <michael.hennerich@analog.com>

ADM1177 is a Hot Swap Controller and Digital Power Monitor with
Soft Start Pin.

Datasheet:
Link: https://www.analog.com/media/en/technical-documentation/data-sheets/ADM1177.pdf

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Co-developed-by: Beniamin Bia <beniamin.bia@analog.com>
Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>
---
drivers/iio/adc/Kconfig | 12 ++
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/adm1177.c | 257 ++++++++++++++++++++++++++++++++++++++
3 files changed, 270 insertions(+)
create mode 100644 drivers/iio/adc/adm1177.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 9554890a3200..4db8c6dcb595 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -228,6 +228,18 @@ config ASPEED_ADC
To compile this driver as a module, choose M here: the module will be
called aspeed_adc.

+config ADM1177
+ tristate "Analog Devices ADM1177 Digital Power Monitor driver"
+ depends on I2C
+ help
+ Say yes here to build support for Analog Devices:
+ ADM1177 Hot Swap Controller and Digital Power Monitor
+ with Soft Start Pin. Provides direct access
+ via sysfs.
+
+ To compile this driver as a module, choose M here: the
+ module will be called adm1177.
+
config AT91_ADC
tristate "Atmel AT91 ADC"
depends on ARCH_AT91
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 5ecc481c2967..7899d6a158f3 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_AD7887) += ad7887.o
obj-$(CONFIG_AD7949) += ad7949.o
obj-$(CONFIG_AD799X) += ad799x.o
obj-$(CONFIG_ASPEED_ADC) += aspeed_adc.o
+obj-$(CONFIG_ADM1177) += adm1177.o
obj-$(CONFIG_AT91_ADC) += at91_adc.o
obj-$(CONFIG_AT91_SAMA5D2_ADC) += at91-sama5d2_adc.o
obj-$(CONFIG_AXP20X_ADC) += axp20x_adc.o
diff --git a/drivers/iio/adc/adm1177.c b/drivers/iio/adc/adm1177.c
new file mode 100644
index 000000000000..daec34566a65
--- /dev/null
+++ b/drivers/iio/adc/adm1177.c
@@ -0,0 +1,257 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ADM1177 Hot Swap Controller and Digital Power Monitor with Soft Start Pin
+ *
+ * Copyright 2015-2019 Analog Devices Inc.
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/events.h>
+
+/* Command Byte Operations */
+#define ADM1177_CMD_V_CONT BIT(0)
+#define ADM1177_CMD_V_ONCE BIT(1)
+#define ADM1177_CMD_I_CONT BIT(2)
+#define ADM1177_CMD_I_ONCE BIT(3)
+#define ADM1177_CMD_VRANGE BIT(4)
+#define ADM1177_CMD_STATUS_RD BIT(6)
+
+/* Extended Register */
+#define ADM1177_REG_ALERT_EN 1
+#define ADM1177_REG_ALERT_TH 2
+#define ADM1177_REG_CONTROL 3
+
+/* ADM1177_REG_ALERT_EN */
+#define ADM1177_EN_ADC_OC1 BIT(0)
+#define ADM1177_EN_ADC_OC4 BIT(1)
+#define ADM1177_EN_HS_ALERT BIT(2)
+#define ADM1177_EN_OFF_ALERT BIT(3)
+#define ADM1177_CLEAR BIT(4)
+
+/* ADM1177_REG_CONTROL */
+#define ADM1177_SWOFF BIT(0)
+
+#define ADM1177_BITS 12
+
+/**
+ * struct adm1177_state - driver instance specific data
+ * @client pointer to i2c client
+ * @reg regulator info for the the power supply of the device
+ * @command internal control register
+ * @r_sense_uohm current sense resistor value
+ * @alert_threshold_ua current limit for shutdown
+ * @vrange_high internal voltage divider
+ */
+struct adm1177_state {
+ struct i2c_client *client;
+ struct regulator *reg;
+ u8 command;
+ u32 r_sense_uohm;
+ u32 alert_threshold_ua;
+ bool vrange_high;
+};
+
+static int adm1177_read(struct adm1177_state *st, u8 num, u8 *data)
+{
+ struct i2c_client *client = st->client;
+ int ret = 0;
+
+ ret = i2c_master_recv(client, data, num);
+ if (ret < 0) {
+ dev_err(&client->dev, "I2C read error\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static int adm1177_write_cmd(struct adm1177_state *st, u8 cmd)
+{
+ st->command = cmd;
+ return i2c_smbus_write_byte(st->client, cmd);
+}
+
+static int adm1177_write_reg(struct adm1177_state *st, u8 reg, u8 val)
+{
+ return i2c_smbus_write_byte_data(st->client, reg, val);
+}
+
+static int adm1177_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val,
+ int *val2,
+ long mask)
+{
+ struct adm1177_state *st = iio_priv(indio_dev);
+ u8 data[3];
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ adm1177_read(st, 3, data);
+ switch (chan->type) {
+ case IIO_VOLTAGE:
+ *val = (data[0] << 4) | (data[2] >> 4);
+ return IIO_VAL_INT;
+ case IIO_CURRENT:
+ *val = (data[1] << 4) | (data[2] & 0xF);
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+
+ case IIO_CHAN_INFO_SCALE:
+ switch (chan->type) {
+ case IIO_VOLTAGE:
+ if (st->command & ADM1177_CMD_VRANGE)
+ *val = 6650;
+ else
+ *val = 26350;
+
+ *val2 = ADM1177_BITS;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ case IIO_CURRENT:
+ *val = 105840 / st->r_sense_uohm;
+
+ *val2 = ADM1177_BITS;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ default:
+ return -EINVAL;
+ }
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_chan_spec adm1177_channels[] = {
+ {
+ .type = IIO_VOLTAGE,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ .indexed = 1,
+ .channel = 0,
+ },
+ {
+ .type = IIO_CURRENT,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ .indexed = 1,
+ .channel = 0,
+ },
+};
+
+static const struct iio_info adm1177_info = {
+ .read_raw = &adm1177_read_raw,
+};
+static void adm1177_remove(void *data)
+{
+ struct adm1177_state *st = data;
+
+ if (st->reg)
+ regulator_disable(st->reg);
+}
+
+static int adm1177_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int ret;
+ struct device_node *np;
+ struct adm1177_state *st;
+ struct iio_dev *indio_dev;
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*st));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ st = iio_priv(indio_dev);
+ i2c_set_clientdata(client, indio_dev);
+ st->client = client;
+
+ np = client->dev.of_node;
+
+ st->reg = devm_regulator_get_optional(&client->dev, "vref");
+ if (IS_ERR(st->reg)) {
+ if (PTR_ERR(st->reg) == EPROBE_DEFER)
+ return -EPROBE_DEFER;
+
+ st->reg = NULL;
+ } else {
+ ret = regulator_enable(st->reg);
+ if (ret)
+ return ret;
+ ret = devm_add_action_or_reset(&client->dev, adm1177_remove,
+ st);
+ if (ret)
+ return ret;
+ }
+
+ of_property_read_u32(np, "adi,r-sense-micro-ohms", &st->r_sense_uohm);
+ of_property_read_u32(np, "adi,shutdown-threshold-microamp",
+ &st->alert_threshold_ua);
+ st->vrange_high = of_property_read_bool(np,
+ "adi,vrange-high-enable");
+ if (st->alert_threshold_ua) {
+ unsigned int val;
+
+ val = (st->alert_threshold_ua * st->r_sense_uohm * 0xFF);
+ val /= 105840000U;
+ if (val > 0xFF) {
+ dev_err(&client->dev,
+ "Requested shutdown current %d uA above limit\n",
+ st->alert_threshold_ua);
+
+ val = 0xFF;
+ }
+ adm1177_write_reg(st, ADM1177_REG_ALERT_TH, val);
+ }
+
+ adm1177_write_cmd(st, ADM1177_CMD_V_CONT |
+ ADM1177_CMD_I_CONT |
+ (st->vrange_high ? 0 : ADM1177_CMD_VRANGE));
+
+ indio_dev->name = id->name;
+ indio_dev->channels = adm1177_channels;
+ indio_dev->num_channels = ARRAY_SIZE(adm1177_channels);
+
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->info = &adm1177_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id adm1177_ids[] = {
+ { "adm1177", 0 },
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, adm1177_ids);
+
+static const struct of_device_id adm1177_dt_ids[] = {
+ { .compatible = "adi,adm1177" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, adm1177_dt_ids);
+
+static struct i2c_driver adm1177_driver = {
+ .driver = {
+ .name = "adm1177",
+ .of_match_table = adm1177_dt_ids,
+ },
+ .probe = adm1177_probe,
+ .id_table = adm1177_ids,
+};
+module_i2c_driver(adm1177_driver);
+
+MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
+MODULE_DESCRIPTION("Analog Devices ADM1177 ADC driver");
+MODULE_LICENSE("GPL v2");
--
2.17.1
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