hwmon: Add support for ltc2947

The ltc2947 is a high precision power and energy monitor with an
internal sense resistor supporting up to +/- 30A. Three internal no
Latency ADCs ensure accurate measurement of voltage and current, while
high-bandwidth analog multiplication of voltage and current provides
accurate power measurement in a wide range of applications. Internal or
external clocking options enable precise charge and energy measurements.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20191021154115.319073-1-nuno.sa@analog.com
[groeck: Removed unnecessary checks when reading temperature and energy;
	 PAGE{0,1} -> LTC2947_PAGE_{0,1}]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

1 files changed, 50 insertions, 0 deletions

diff --git a/drivers/hwmon/ltc2947-spi.c b/drivers/hwmon/ltc2947-spi.c
new file mode 100644
index 000000000000..c24ca569db1b
--- /dev/null
+++ b/drivers/hwmon/ltc2947-spi.c
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Analog Devices LTC2947 high precision power and energy monitor over SPI
+ *
+ * Copyright 2019 Analog Devices Inc.
+ */
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+
+#include "ltc2947.h"
+
+static const struct regmap_config ltc2947_regmap_config = {
+	.reg_bits = 16,
+	.val_bits = 8,
+	.read_flag_mask = BIT(0),
+};
+
+static int ltc2947_probe(struct spi_device *spi)
+{
+	struct regmap *map;
+
+	map = devm_regmap_init_spi(spi, &ltc2947_regmap_config);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+
+	return ltc2947_core_probe(map, spi_get_device_id(spi)->name);
+}
+
+static const struct spi_device_id ltc2947_id[] = {
+	{"ltc2947", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(spi, ltc2947_id);
+
+static struct spi_driver ltc2947_driver = {
+	.driver = {
+		.name = "ltc2947",
+		.of_match_table = ltc2947_of_match,
+		.pm = &ltc2947_pm_ops,
+	},
+	.probe = ltc2947_probe,
+	.id_table = ltc2947_id,
+};
+module_spi_driver(ltc2947_driver);
+
+MODULE_AUTHOR("Nuno Sa <nuno.sa@analog.com>");
+MODULE_DESCRIPTION("LTC2947 SPI power and energy monitor driver");
+MODULE_LICENSE("GPL");