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Diffstat (limited to 'drivers/hwmon/pmbus/delta-ahe50dc-fan.c')
-rw-r--r--drivers/hwmon/pmbus/delta-ahe50dc-fan.c130
1 files changed, 130 insertions, 0 deletions
diff --git a/drivers/hwmon/pmbus/delta-ahe50dc-fan.c b/drivers/hwmon/pmbus/delta-ahe50dc-fan.c
new file mode 100644
index 0000000000..4dd3b6686d
--- /dev/null
+++ b/drivers/hwmon/pmbus/delta-ahe50dc-fan.c
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Delta AHE-50DC power shelf fan control module driver
+ *
+ * Copyright 2021 Zev Weiss <zev@bewilderbeest.net>
+ */
+
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pmbus.h>
+
+#include "pmbus.h"
+
+#define AHE50DC_PMBUS_READ_TEMP4 0xd0
+
+static int ahe50dc_fan_write_byte(struct i2c_client *client, int page, u8 value)
+{
+ /*
+ * The CLEAR_FAULTS operation seems to sometimes (unpredictably, perhaps
+ * 5% of the time or so) trigger a problematic phenomenon in which the
+ * fan speeds surge momentarily and at least some (perhaps all?) of the
+ * system's power outputs experience a glitch.
+ *
+ * However, according to Delta it should be OK to simply not send any
+ * CLEAR_FAULTS commands (the device doesn't seem to be capable of
+ * reporting any faults anyway), so just blackhole them unconditionally.
+ */
+ return value == PMBUS_CLEAR_FAULTS ? -EOPNOTSUPP : -ENODATA;
+}
+
+static int ahe50dc_fan_read_word_data(struct i2c_client *client, int page, int phase, int reg)
+{
+ /* temp1 in (virtual) page 1 is remapped to mfr-specific temp4 */
+ if (page == 1) {
+ if (reg == PMBUS_READ_TEMPERATURE_1)
+ return i2c_smbus_read_word_data(client, AHE50DC_PMBUS_READ_TEMP4);
+ return -EOPNOTSUPP;
+ }
+
+ /*
+ * There's a fairly limited set of commands this device actually
+ * supports, so here we block attempts to read anything else (which
+ * return 0xffff and would cause confusion elsewhere).
+ */
+ switch (reg) {
+ case PMBUS_STATUS_WORD:
+ case PMBUS_FAN_COMMAND_1:
+ case PMBUS_FAN_COMMAND_2:
+ case PMBUS_FAN_COMMAND_3:
+ case PMBUS_FAN_COMMAND_4:
+ case PMBUS_STATUS_FAN_12:
+ case PMBUS_STATUS_FAN_34:
+ case PMBUS_READ_VIN:
+ case PMBUS_READ_TEMPERATURE_1:
+ case PMBUS_READ_TEMPERATURE_2:
+ case PMBUS_READ_TEMPERATURE_3:
+ case PMBUS_READ_FAN_SPEED_1:
+ case PMBUS_READ_FAN_SPEED_2:
+ case PMBUS_READ_FAN_SPEED_3:
+ case PMBUS_READ_FAN_SPEED_4:
+ return -ENODATA;
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static struct pmbus_driver_info ahe50dc_fan_info = {
+ .pages = 2,
+ .format[PSC_FAN] = direct,
+ .format[PSC_TEMPERATURE] = direct,
+ .format[PSC_VOLTAGE_IN] = direct,
+ .m[PSC_FAN] = 1,
+ .b[PSC_FAN] = 0,
+ .R[PSC_FAN] = 0,
+ .m[PSC_TEMPERATURE] = 1,
+ .b[PSC_TEMPERATURE] = 0,
+ .R[PSC_TEMPERATURE] = 1,
+ .m[PSC_VOLTAGE_IN] = 1,
+ .b[PSC_VOLTAGE_IN] = 0,
+ .R[PSC_VOLTAGE_IN] = 3,
+ .func[0] = PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_TEMP3 |
+ PMBUS_HAVE_VIN | PMBUS_HAVE_FAN12 | PMBUS_HAVE_FAN34 |
+ PMBUS_HAVE_STATUS_FAN12 | PMBUS_HAVE_STATUS_FAN34 | PMBUS_PAGE_VIRTUAL,
+ .func[1] = PMBUS_HAVE_TEMP | PMBUS_PAGE_VIRTUAL,
+ .write_byte = ahe50dc_fan_write_byte,
+ .read_word_data = ahe50dc_fan_read_word_data,
+};
+
+/*
+ * CAPABILITY returns 0xff, which appears to be this device's way indicating
+ * it doesn't support something (and if we enable I2C_CLIENT_PEC on seeing bit
+ * 7 being set it generates bad PECs, so let's not go there).
+ */
+static struct pmbus_platform_data ahe50dc_fan_data = {
+ .flags = PMBUS_NO_CAPABILITY,
+};
+
+static int ahe50dc_fan_probe(struct i2c_client *client)
+{
+ client->dev.platform_data = &ahe50dc_fan_data;
+ return pmbus_do_probe(client, &ahe50dc_fan_info);
+}
+
+static const struct i2c_device_id ahe50dc_fan_id[] = {
+ { "ahe50dc_fan" },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, ahe50dc_fan_id);
+
+static const struct of_device_id __maybe_unused ahe50dc_fan_of_match[] = {
+ { .compatible = "delta,ahe50dc-fan" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, ahe50dc_fan_of_match);
+
+static struct i2c_driver ahe50dc_fan_driver = {
+ .driver = {
+ .name = "ahe50dc_fan",
+ .of_match_table = of_match_ptr(ahe50dc_fan_of_match),
+ },
+ .probe = ahe50dc_fan_probe,
+ .id_table = ahe50dc_fan_id,
+};
+module_i2c_driver(ahe50dc_fan_driver);
+
+MODULE_AUTHOR("Zev Weiss <zev@bewilderbeest.net>");
+MODULE_DESCRIPTION("Driver for Delta AHE-50DC power shelf fan control module");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(PMBUS);