1What:		/sys/class/tty/console/active
2Date:		Nov 2010
3Contact:	Kay Sievers <kay.sievers@vrfy.org>
4Description:
5		 Shows the list of currently configured
6		 console devices, like 'tty1 ttyS0'.
7		 The last entry in the file is the active
8		 device connected to /dev/console.
9		 The file supports poll() to detect virtual
10		 console switches.
11
12What:		/sys/class/tty/tty<x>/active
13Date:		Nov 2010
14Contact:	Kay Sievers <kay.sievers@vrfy.org>
15Description:
16		 Shows the currently active virtual console
17		 device, like 'tty1'.
18		 The file supports poll() to detect virtual
19		 console switches.
20
21What:		/sys/class/tty/ttyS<x>/uartclk
22Date:		Sep 2012
23Contact:	Tomas Hlavacek <tmshlvck@gmail.com>
24Description:
25		 Shows the current uartclk value associated with the
26		 UART port in serial_core, that is bound to TTY like ttyS0.
27		 uartclk = 16 * baud_base
28
29		 These sysfs values expose the TIOCGSERIAL interface via
30		 sysfs rather than via ioctls.
31
32What:		/sys/class/tty/ttyS<x>/type
33Date:		October 2012
34Contact:	Alan Cox <alan@linux.intel.com>
35Description:
36		 Shows the current tty type for this port.
37
38		 These sysfs values expose the TIOCGSERIAL interface via
39		 sysfs rather than via ioctls.
40
41What:		/sys/class/tty/ttyS<x>/line
42Date:		October 2012
43Contact:	Alan Cox <alan@linux.intel.com>
44Description:
45		 Shows the current tty line number for this port.
46
47		 These sysfs values expose the TIOCGSERIAL interface via
48		 sysfs rather than via ioctls.
49
50What:		/sys/class/tty/ttyS<x>/port
51Date:		October 2012
52Contact:	Alan Cox <alan@linux.intel.com>
53Description:
54		 Shows the current tty port I/O address for this port.
55
56		 These sysfs values expose the TIOCGSERIAL interface via
57		 sysfs rather than via ioctls.
58
59What:		/sys/class/tty/ttyS<x>/irq
60Date:		October 2012
61Contact:	Alan Cox <alan@linux.intel.com>
62Description:
63		 Shows the current primary interrupt for this port.
64
65		 These sysfs values expose the TIOCGSERIAL interface via
66		 sysfs rather than via ioctls.
67
68What:		/sys/class/tty/ttyS<x>/flags
69Date:		October 2012
70Contact:	Alan Cox <alan@linux.intel.com>
71Description:
72		 Show the tty port status flags for this port.
73
74		 These sysfs values expose the TIOCGSERIAL interface via
75		 sysfs rather than via ioctls.
76
77What:		/sys/class/tty/ttyS<x>/xmit_fifo_size
78Date:		October 2012
79Contact:	Alan Cox <alan@linux.intel.com>
80Description:
81		 Show the transmit FIFO size for this port.
82
83		 These sysfs values expose the TIOCGSERIAL interface via
84		 sysfs rather than via ioctls.
85
86What:		/sys/class/tty/ttyS<x>/close_delay
87Date:		October 2012
88Contact:	Alan Cox <alan@linux.intel.com>
89Description:
90		Show the closing delay time for this port in centiseconds.
91
92		These sysfs values expose the TIOCGSERIAL interface via
93		sysfs rather than via ioctls.
94
95What:		/sys/class/tty/ttyS<x>/closing_wait
96Date:		October 2012
97Contact:	Alan Cox <alan@linux.intel.com>
98Description:
99		Show the close wait time for this port in centiseconds.
100
101		Waiting forever is represented as 0. If waiting on close is
102		disabled then the value is 65535.
103
104		These sysfs values expose the TIOCGSERIAL interface via
105		sysfs rather than via ioctls.
106
107What:		/sys/class/tty/ttyS<x>/custom_divisor
108Date:		October 2012
109Contact:	Alan Cox <alan@linux.intel.com>
110Description:
111		 Show the custom divisor if any that is set on this port.
112
113		 These sysfs values expose the TIOCGSERIAL interface via
114		 sysfs rather than via ioctls.
115
116What:		/sys/class/tty/ttyS<x>/io_type
117Date:		October 2012
118Contact:	Alan Cox <alan@linux.intel.com>
119Description:
120		 Show the I/O type that is to be used with the iomem base
121		 address.
122
123		 These sysfs values expose the TIOCGSERIAL interface via
124		 sysfs rather than via ioctls.
125
126What:		/sys/class/tty/ttyS<x>/iomem_base
127Date:		October 2012
128Contact:	Alan Cox <alan@linux.intel.com>
129Description:
130		 The I/O memory base for this port.
131
132		 These sysfs values expose the TIOCGSERIAL interface via
133		 sysfs rather than via ioctls.
134
135What:		/sys/class/tty/ttyS<x>/iomem_reg_shift
136Date:		October 2012
137Contact:	Alan Cox <alan@linux.intel.com>
138Description:
139		 Show the register shift indicating the spacing to be used
140		 for accesses on this iomem address.
141
142		 These sysfs values expose the TIOCGSERIAL interface via
143		 sysfs rather than via ioctls.
144
145What:		/sys/class/tty/ttyS<x>/rx_trig_bytes
146Date:		May 2014
147Contact:	Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
148Description:
149		 Shows current RX interrupt trigger bytes or sets the
150		 user specified value to change it for the FIFO buffer.
151		 Users can show or set this value regardless of opening the
152		 serial device file or not.
153
154		 The RX trigger can be set one of four kinds of values for UART
155		 serials. When users input a meaning less value to this I/F,
156		 the RX trigger is changed to the nearest lower value for the
157		 device specification. For example, when user sets 7bytes on
158		 16550A, which has 1/4/8/14 bytes trigger, the RX trigger is
159		 automatically changed to 4 bytes.
160
161What:		/sys/class/tty/ttyS<x>/console
162Date:		February 2020
163Contact:	Andy Shevchenko <andriy.shevchenko@linux.intel.com>
164Description:
165		 Allows user to detach or attach back the given device as
166		 kernel console. It shows and accepts a boolean variable.
167