aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/hwmon
diff options
context:
space:
mode:
authorAndrew Jeffery <andrew@aj.id.au>2017-11-20 15:12:06 +1030
committerGuenter Roeck <linux@roeck-us.net>2018-01-02 15:05:34 -0800
commitcf583b4275761754638c946ff777546d1a9b6744 (patch)
tree1148c9ee65f4f716352c7d9d2a8b5f79611d9453 /drivers/hwmon
parent464df6fa3766784b85b00d56cd4d7c706aee5375 (diff)
hwmon: (pmbus/max31785) Add dual tachometer support
The dual tachometer feature is implemented in hardware with a TACHSEL input to indicate the rotor under measurement, and exposed on the device by extending the READ_FAN_SPEED_1 word with two extra bytes*. The need to read the non-standard four-byte response leads to a cut-down implementation of i2c_smbus_xfer_emulated() included in the driver. Further, to expose the second rotor tachometer value to userspace the values are exposed through virtual pages. We re-route accesses to FAN_CONFIG_1_2 and READ_FAN_SPEED_1 on pages 23-28 (not defined by the hardware) to the same registers on pages 0-5, and with the latter command we extract the value from the second word of the four-byte response. * The documentation recommends the slower rotor be associated with TACHSEL=0, which corresponds to the first word of the response. The TACHSEL=0 measurement is used by the controller's closed-loop fan management to judge target fan rate. Signed-off-by: Andrew Jeffery <andrew@aj.id.au> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon')
-rw-r--r--drivers/hwmon/pmbus/max31785.c147
1 files changed, 147 insertions, 0 deletions
diff --git a/drivers/hwmon/pmbus/max31785.c b/drivers/hwmon/pmbus/max31785.c
index 8706a696c89a..bffab449be39 100644
--- a/drivers/hwmon/pmbus/max31785.c
+++ b/drivers/hwmon/pmbus/max31785.c
@@ -16,9 +16,79 @@
enum max31785_regs {
MFR_REVISION = 0x9b,
+ MFR_FAN_CONFIG = 0xf1,
};
+#define MAX31785 0x3030
+#define MAX31785A 0x3040
+
+#define MFR_FAN_CONFIG_DUAL_TACH BIT(12)
+
#define MAX31785_NR_PAGES 23
+#define MAX31785_NR_FAN_PAGES 6
+
+static int max31785_read_byte_data(struct i2c_client *client, int page,
+ int reg)
+{
+ if (page < MAX31785_NR_PAGES)
+ return -ENODATA;
+
+ switch (reg) {
+ case PMBUS_VOUT_MODE:
+ return -ENOTSUPP;
+ case PMBUS_FAN_CONFIG_12:
+ return pmbus_read_byte_data(client, page - MAX31785_NR_PAGES,
+ reg);
+ }
+
+ return -ENODATA;
+}
+
+static int max31785_write_byte(struct i2c_client *client, int page, u8 value)
+{
+ if (page < MAX31785_NR_PAGES)
+ return -ENODATA;
+
+ return -ENOTSUPP;
+}
+
+static int max31785_read_long_data(struct i2c_client *client, int page,
+ int reg, u32 *data)
+{
+ unsigned char cmdbuf[1];
+ unsigned char rspbuf[4];
+ int rc;
+
+ struct i2c_msg msg[2] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ .len = sizeof(cmdbuf),
+ .buf = cmdbuf,
+ },
+ {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = sizeof(rspbuf),
+ .buf = rspbuf,
+ },
+ };
+
+ cmdbuf[0] = reg;
+
+ rc = pmbus_set_page(client, page);
+ if (rc < 0)
+ return rc;
+
+ rc = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
+ if (rc < 0)
+ return rc;
+
+ *data = (rspbuf[0] << (0 * 8)) | (rspbuf[1] << (1 * 8)) |
+ (rspbuf[2] << (2 * 8)) | (rspbuf[3] << (3 * 8));
+
+ return rc;
+}
static int max31785_get_pwm(struct i2c_client *client, int page)
{
@@ -62,9 +132,30 @@ static int max31785_get_pwm_mode(struct i2c_client *client, int page)
static int max31785_read_word_data(struct i2c_client *client, int page,
int reg)
{
+ u32 val;
int rv;
switch (reg) {
+ case PMBUS_READ_FAN_SPEED_1:
+ if (page < MAX31785_NR_PAGES)
+ return -ENODATA;
+
+ rv = max31785_read_long_data(client, page - MAX31785_NR_PAGES,
+ reg, &val);
+ if (rv < 0)
+ return rv;
+
+ rv = (val >> 16) & 0xffff;
+ break;
+ case PMBUS_FAN_COMMAND_1:
+ /*
+ * PMBUS_FAN_COMMAND_x is probed to judge whether or not to
+ * expose fan control registers.
+ *
+ * Don't expose fan_target attribute for virtual pages.
+ */
+ rv = (page >= MAX31785_NR_PAGES) ? -ENOTSUPP : -ENODATA;
+ break;
case PMBUS_VIRT_PWM_1:
rv = max31785_get_pwm(client, page);
break;
@@ -157,11 +248,15 @@ static int max31785_write_word_data(struct i2c_client *client, int page,
#define MAX31785_VOUT_FUNCS \
(PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT)
+#define MAX37185_NUM_FAN_PAGES 6
+
static const struct pmbus_driver_info max31785_info = {
.pages = MAX31785_NR_PAGES,
.write_word_data = max31785_write_word_data,
+ .read_byte_data = max31785_read_byte_data,
.read_word_data = max31785_read_word_data,
+ .write_byte = max31785_write_byte,
/* RPM */
.format[PSC_FAN] = direct,
@@ -208,13 +303,46 @@ static const struct pmbus_driver_info max31785_info = {
.func[22] = MAX31785_VOUT_FUNCS,
};
+static int max31785_configure_dual_tach(struct i2c_client *client,
+ struct pmbus_driver_info *info)
+{
+ int ret;
+ int i;
+
+ for (i = 0; i < MAX31785_NR_FAN_PAGES; i++) {
+ ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, i);
+ if (ret < 0)
+ return ret;
+
+ ret = i2c_smbus_read_word_data(client, MFR_FAN_CONFIG);
+ if (ret < 0)
+ return ret;
+
+ if (ret & MFR_FAN_CONFIG_DUAL_TACH) {
+ int virtual = MAX31785_NR_PAGES + i;
+
+ info->pages = virtual + 1;
+ info->func[virtual] |= PMBUS_HAVE_FAN12;
+ info->func[virtual] |= PMBUS_PAGE_VIRTUAL;
+ }
+ }
+
+ return 0;
+}
+
static int max31785_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct device *dev = &client->dev;
struct pmbus_driver_info *info;
+ bool dual_tach = false;
s64 ret;
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_BYTE_DATA |
+ I2C_FUNC_SMBUS_WORD_DATA))
+ return -ENODEV;
+
info = devm_kzalloc(dev, sizeof(struct pmbus_driver_info), GFP_KERNEL);
if (!info)
return -ENOMEM;
@@ -225,6 +353,25 @@ static int max31785_probe(struct i2c_client *client,
if (ret < 0)
return ret;
+ ret = i2c_smbus_read_word_data(client, MFR_REVISION);
+ if (ret < 0)
+ return ret;
+
+ if (ret == MAX31785A) {
+ dual_tach = true;
+ } else if (ret == MAX31785) {
+ if (!strcmp("max31785a", id->name))
+ dev_warn(dev, "Expected max3175a, found max31785: cannot provide secondary tachometer readings\n");
+ } else {
+ return -ENODEV;
+ }
+
+ if (dual_tach) {
+ ret = max31785_configure_dual_tach(client, info);
+ if (ret < 0)
+ return ret;
+ }
+
return pmbus_do_probe(client, id, info);
}

Privacy Policy