1 files changed, 294 insertions, 0 deletions
diff --git a/drivers/hwmon/pmbus/fsp-3y.c b/drivers/hwmon/pmbus/fsp-3y.c
new file mode 100644
index 0000000000..72a7c261ef
--- /dev/null
+++ b/drivers/hwmon/pmbus/fsp-3y.c
@@ -0,0 +1,294 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Hardware monitoring driver for FSP 3Y-Power PSUs
+ *
+ * Copyright (c) 2021 Václav Kubernát, CESNET
+ *
+ * This driver is mostly reverse engineered with the help of a tool called pmbus_peek written by
+ * David Brownell (and later adopted by Jan Kundrát). The device has some sort of a timing issue
+ * when switching pages, details are explained in the code. The driver support is limited. It
+ * exposes only the values, that have been tested to work correctly. Unsupported values either
+ * aren't supported by the devices or their encondings are unknown.
+ */
+
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include "pmbus.h"
+
+#define YM2151_PAGE_12V_LOG	0x00
+#define YM2151_PAGE_12V_REAL	0x00
+#define YM2151_PAGE_5VSB_LOG	0x01
+#define YM2151_PAGE_5VSB_REAL	0x20
+#define YH5151E_PAGE_12V_LOG	0x00
+#define YH5151E_PAGE_12V_REAL	0x00
+#define YH5151E_PAGE_5V_LOG	0x01
+#define YH5151E_PAGE_5V_REAL	0x10
+#define YH5151E_PAGE_3V3_LOG	0x02
+#define YH5151E_PAGE_3V3_REAL	0x11
+
+enum chips {
+	ym2151e,
+	yh5151e
+};
+
+struct fsp3y_data {
+	struct pmbus_driver_info info;
+	int chip;
+	int page;
+
+	bool vout_linear_11;
+};
+
+#define to_fsp3y_data(x) container_of(x, struct fsp3y_data, info)
+
+static int page_log_to_page_real(int page_log, enum chips chip)
+{
+	switch (chip) {
+	case ym2151e:
+		switch (page_log) {
+		case YM2151_PAGE_12V_LOG:
+			return YM2151_PAGE_12V_REAL;
+		case YM2151_PAGE_5VSB_LOG:
+			return YM2151_PAGE_5VSB_REAL;
+		}
+		return -EINVAL;
+	case yh5151e:
+		switch (page_log) {
+		case YH5151E_PAGE_12V_LOG:
+			return YH5151E_PAGE_12V_REAL;
+		case YH5151E_PAGE_5V_LOG:
+			return YH5151E_PAGE_5V_REAL;
+		case YH5151E_PAGE_3V3_LOG:
+			return YH5151E_PAGE_3V3_REAL;
+		}
+		return -EINVAL;
+	}
+
+	return -EINVAL;
+}
+
+static int set_page(struct i2c_client *client, int page_log)
+{
+	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+	struct fsp3y_data *data = to_fsp3y_data(info);
+	int rv;
+	int page_real;
+
+	if (page_log < 0)
+		return 0;
+
+	page_real = page_log_to_page_real(page_log, data->chip);
+	if (page_real < 0)
+		return page_real;
+
+	if (data->page != page_real) {
+		rv = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page_real);
+		if (rv < 0)
+			return rv;
+
+		data->page = page_real;
+
+		/*
+		 * Testing showed that the device has a timing issue. After
+		 * setting a page, it takes a while, before the device actually
+		 * gives the correct values from the correct page. 20 ms was
+		 * tested to be enough to not give wrong values (15 ms wasn't
+		 * enough).
+		 */
+		usleep_range(20000, 30000);
+	}
+
+	return 0;
+}
+
+static int fsp3y_read_byte_data(struct i2c_client *client, int page, int reg)
+{
+	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+	struct fsp3y_data *data = to_fsp3y_data(info);
+	int rv;
+
+	/*
+	 * Inject an exponent for non-compliant YH5151-E.
+	 */
+	if (data->vout_linear_11 && reg == PMBUS_VOUT_MODE)
+		return 0x1A;
+
+	rv = set_page(client, page);
+	if (rv < 0)
+		return rv;
+
+	return i2c_smbus_read_byte_data(client, reg);
+}
+
+static int fsp3y_read_word_data(struct i2c_client *client, int page, int phase, int reg)
+{
+	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+	struct fsp3y_data *data = to_fsp3y_data(info);
+	int rv;
+
+	/*
+	 * This masks commands which weren't tested to work correctly. Some of
+	 * the masked commands return 0xFFFF. These would probably get tagged as
+	 * invalid by pmbus_core. Other ones do return values which might be
+	 * useful (that is, they are not 0xFFFF), but their encoding is unknown,
+	 * and so they are unsupported.
+	 */
+	switch (reg) {
+	case PMBUS_READ_FAN_SPEED_1:
+	case PMBUS_READ_IIN:
+	case PMBUS_READ_IOUT:
+	case PMBUS_READ_PIN:
+	case PMBUS_READ_POUT:
+	case PMBUS_READ_TEMPERATURE_1:
+	case PMBUS_READ_TEMPERATURE_2:
+	case PMBUS_READ_TEMPERATURE_3:
+	case PMBUS_READ_VIN:
+	case PMBUS_READ_VOUT:
+	case PMBUS_STATUS_WORD:
+		break;
+	default:
+		return -ENXIO;
+	}
+
+	rv = set_page(client, page);
+	if (rv < 0)
+		return rv;
+
+	rv = i2c_smbus_read_word_data(client, reg);
+	if (rv < 0)
+		return rv;
+
+	/*
+	 * Handle YH-5151E non-compliant linear11 vout voltage.
+	 */
+	if (data->vout_linear_11 && reg == PMBUS_READ_VOUT)
+		rv = sign_extend32(rv, 10) & 0xffff;
+
+	return rv;
+}
+
+static struct pmbus_driver_info fsp3y_info[] = {
+	[ym2151e] = {
+		.pages = 2,
+		.func[YM2151_PAGE_12V_LOG] =
+			PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
+			PMBUS_HAVE_PIN | PMBUS_HAVE_POUT  |
+			PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 |
+			PMBUS_HAVE_VIN | PMBUS_HAVE_IIN |
+			PMBUS_HAVE_FAN12,
+		.func[YM2151_PAGE_5VSB_LOG] =
+			PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT,
+		.read_word_data = fsp3y_read_word_data,
+		.read_byte_data = fsp3y_read_byte_data,
+	},
+	[yh5151e] = {
+		.pages = 3,
+		.func[YH5151E_PAGE_12V_LOG] =
+			PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
+			PMBUS_HAVE_POUT  |
+			PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_TEMP3,
+		.func[YH5151E_PAGE_5V_LOG] =
+			PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
+			PMBUS_HAVE_POUT,
+		.func[YH5151E_PAGE_3V3_LOG] =
+			PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
+			PMBUS_HAVE_POUT,
+		.read_word_data = fsp3y_read_word_data,
+		.read_byte_data = fsp3y_read_byte_data,
+	}
+};
+
+static int fsp3y_detect(struct i2c_client *client)
+{
+	int rv;
+	u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
+
+	rv = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
+	if (rv < 0)
+		return rv;
+
+	buf[rv] = '\0';
+
+	if (rv == 8) {
+		if (!strcmp(buf, "YM-2151E"))
+			return ym2151e;
+		else if (!strcmp(buf, "YH-5151E"))
+			return yh5151e;
+	}
+
+	dev_err(&client->dev, "Unsupported model %.*s\n", rv, buf);
+	return -ENODEV;
+}
+
+static const struct i2c_device_id fsp3y_id[] = {
+	{"ym2151e", ym2151e},
+	{"yh5151e", yh5151e},
+	{ }
+};
+
+static int fsp3y_probe(struct i2c_client *client)
+{
+	struct fsp3y_data *data;
+	const struct i2c_device_id *id;
+	int rv;
+
+	data = devm_kzalloc(&client->dev, sizeof(struct fsp3y_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->chip = fsp3y_detect(client);
+	if (data->chip < 0)
+		return data->chip;
+
+	id = i2c_match_id(fsp3y_id, client);
+	if (data->chip != id->driver_data)
+		dev_warn(&client->dev, "Device mismatch: Configured %s (%d), detected %d\n",
+			 id->name, (int)id->driver_data, data->chip);
+
+	rv = i2c_smbus_read_byte_data(client, PMBUS_PAGE);
+	if (rv < 0)
+		return rv;
+	data->page = rv;
+
+	data->info = fsp3y_info[data->chip];
+
+	/*
+	 * YH-5151E sometimes reports vout in linear11 and sometimes in
+	 * linear16. This depends on the exact individual piece of hardware. One
+	 * YH-5151E can use linear16 and another might use linear11 instead.
+	 *
+	 * The format can be recognized by reading VOUT_MODE - if it doesn't
+	 * report a valid exponent, then vout uses linear11. Otherwise, the
+	 * device is compliant and uses linear16.
+	 */
+	data->vout_linear_11 = false;
+	if (data->chip == yh5151e) {
+		rv = i2c_smbus_read_byte_data(client, PMBUS_VOUT_MODE);
+		if (rv < 0)
+			return rv;
+
+		if (rv == 0xFF)
+			data->vout_linear_11 = true;
+	}
+
+	return pmbus_do_probe(client, &data->info);
+}
+
+MODULE_DEVICE_TABLE(i2c, fsp3y_id);
+
+static struct i2c_driver fsp3y_driver = {
+	.driver = {
+		   .name = "fsp3y",
+		   },
+	.probe = fsp3y_probe,
+	.id_table = fsp3y_id
+};
+
+module_i2c_driver(fsp3y_driver);
+
+MODULE_AUTHOR("Václav Kubernát");
+MODULE_DESCRIPTION("PMBus driver for FSP/3Y-Power power supplies");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(PMBUS);