docs: hwmon: add emc2305.rst to docs

Add description of emc2305 driver.
Signed-off-by: Michael Shych <michaelsh@nvidia.com>
Reviewed-by: Vadim Pasternak <vadimp@nvidia.com>
Link: https://lore.kernel.org/r/20220810171552.56417-4-michaelsh@nvidia.com
[groeck: Fixed htmldocs warnings]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/emc2305.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver emc2305
+=====================
+
+Supported chips:
+   Microchip EMC2305, EMC2303, EMC2302, EMC2301
+
+   Addresses scanned: I2C 0x27, 0x2c, 0x2d, 0x2e, 0x2f, 0x4c, 0x4d
+   Prefixes: 'emc2305'
+
+   Datasheet: Publicly available at the Microchip website :
+      https://www.microchip.com/en-us/product/EMC2305
+
+Description:
+------------
+This driver implements support for Microchip EMC2301/2/3/5 RPM-based PWM Fan Controller.
+The EMC2305 Fan Controller supports up to 5 independently controlled PWM fan drives.
+Fan rotation speeds are reported in RPM.
+The driver supports the RPM-based PWM control to keep a fan at the desired speed.
+The driver provides the possibility to have one common PWM interface for all FANs
+or up to the maximum available or configured independent PWMs.
+
+The driver provides the following sysfs interfaces in hwmon subsystem:
+
+================= == ===================================================
+fan[1-5]_fault    RO files for tachometers TACH1-TACH5 fault indication
+fan[1-5]_input    RO files for tachometers TACH1-TACH5 input (in RPM)
+pwm[1-5]          RW file for fan[1-5] target duty cycle (0..255)
+================= == ===================================================
+
+sysfs interfaces in thermal subsystem:
+
+================= == ========================================================================
+cur_state         RW file for the current cooling state of the cooling device (0..max_state)
+max_state         RO file for the maximum cooling state of the cooling device
+================= == ========================================================================

Documentation/hwmon/index.rst

@@ -62,6 +62,7 @@ Hardware Monitoring Kernel Drivers
    ds620
    emc1403
    emc2103
+   emc2305
    emc6w201
    f71805f
    f71882fg