2 * cec-pin.h - low-level CEC pin control
4 * Copyright 2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
6 * This program is free software; you may redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; version 2 of the License.
10 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
11 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
12 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
13 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
14 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
15 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
16 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
20 #ifndef LINUX_CEC_PIN_H
21 #define LINUX_CEC_PIN_H
23 #include <linux/types.h>
24 #include <linux/atomic.h>
25 #include <media/cec.h>
30 /* CEC is idle, waiting for Rx or Tx */
35 /* Pending Tx, waiting for Signal Free Time to expire */
37 /* Low-drive was detected, wait for bus to go high */
38 CEC_ST_TX_WAIT_FOR_HIGH,
39 /* Drive CEC low for the start bit */
40 CEC_ST_TX_START_BIT_LOW,
41 /* Drive CEC high for the start bit */
42 CEC_ST_TX_START_BIT_HIGH,
43 /* Drive CEC low for the 0 bit */
44 CEC_ST_TX_DATA_BIT_0_LOW,
45 /* Drive CEC high for the 0 bit */
46 CEC_ST_TX_DATA_BIT_0_HIGH,
47 /* Drive CEC low for the 1 bit */
48 CEC_ST_TX_DATA_BIT_1_LOW,
49 /* Drive CEC high for the 1 bit */
50 CEC_ST_TX_DATA_BIT_1_HIGH,
52 * Wait for start of sample time to check for Ack bit or first
53 * four initiator bits to check for Arbitration Lost.
55 CEC_ST_TX_DATA_BIT_1_HIGH_PRE_SAMPLE,
56 /* Wait for end of bit period after sampling */
57 CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE,
61 /* Start bit low detected */
62 CEC_ST_RX_START_BIT_LOW,
63 /* Start bit high detected */
64 CEC_ST_RX_START_BIT_HIGH,
65 /* Wait for bit sample time */
66 CEC_ST_RX_DATA_SAMPLE,
67 /* Wait for earliest end of bit period after sampling */
68 CEC_ST_RX_DATA_POST_SAMPLE,
69 /* Wait for CEC to go high (i.e. end of bit period */
71 /* Drive CEC low to send 0 Ack bit */
73 /* End of 0 Ack time, wait for earliest end of bit period */
74 CEC_ST_RX_ACK_LOW_POST,
75 /* Wait for CEC to go high (i.e. end of bit period */
76 CEC_ST_RX_ACK_HIGH_POST,
77 /* Wait for earliest end of bit period and end of message */
82 /* Monitor pin using interrupts */
85 /* Total number of pin states */
90 * struct cec_pin_ops - low-level CEC pin operations
91 * @read: read the CEC pin. Return true if high, false if low.
92 * @low: drive the CEC pin low.
93 * @high: stop driving the CEC pin. The pull-up will drive the pin
94 * high, unless someone else is driving the pin low.
95 * @enable_irq: optional, enable the interrupt to detect pin voltage changes.
96 * @disable_irq: optional, disable the interrupt.
97 * @free: optional. Free any allocated resources. Called when the
99 * @status: optional, log status information.
101 * These operations are used by the cec pin framework to manipulate
105 bool (*read)(struct cec_adapter *adap);
106 void (*low)(struct cec_adapter *adap);
107 void (*high)(struct cec_adapter *adap);
108 bool (*enable_irq)(struct cec_adapter *adap);
109 void (*disable_irq)(struct cec_adapter *adap);
110 void (*free)(struct cec_adapter *adap);
111 void (*status)(struct cec_adapter *adap, struct seq_file *file);
114 #define CEC_NUM_PIN_EVENTS 128
116 #define CEC_PIN_IRQ_UNCHANGED 0
117 #define CEC_PIN_IRQ_DISABLE 1
118 #define CEC_PIN_IRQ_ENABLE 2
121 struct cec_adapter *adap;
122 const struct cec_pin_ops *ops;
123 struct task_struct *kthread;
124 wait_queue_head_t kthread_waitq;
125 struct hrtimer timer;
127 unsigned int wait_usecs;
132 bool enable_irq_failed;
133 enum cec_pin_state state;
134 struct cec_msg tx_msg;
137 u32 tx_signal_free_time;
138 struct cec_msg rx_msg;
141 struct cec_msg work_rx_msg;
144 atomic_t work_irq_change;
145 atomic_t work_pin_events;
146 unsigned int work_pin_events_wr;
147 unsigned int work_pin_events_rd;
148 ktime_t work_pin_ts[CEC_NUM_PIN_EVENTS];
149 bool work_pin_is_high[CEC_NUM_PIN_EVENTS];
152 u32 timer_100ms_overruns;
153 u32 timer_300ms_overruns;
154 u32 timer_max_overrun;
155 u32 timer_sum_overrun;
159 * cec_pin_changed() - update pin state from interrupt
161 * @adap: pointer to the cec adapter
162 * @value: when true the pin is high, otherwise it is low
164 * If changes of the CEC voltage are detected via an interrupt, then
165 * cec_pin_changed is called from the interrupt with the new value.
167 void cec_pin_changed(struct cec_adapter *adap, bool value);
170 * cec_pin_allocate_adapter() - allocate a pin-based cec adapter
172 * @pin_ops: low-level pin operations
173 * @priv: will be stored in adap->priv and can be used by the adapter ops.
174 * Use cec_get_drvdata(adap) to get the priv pointer.
175 * @name: the name of the CEC adapter. Note: this name will be copied.
176 * @caps: capabilities of the CEC adapter. This will be ORed with
177 * CEC_CAP_MONITOR_ALL and CEC_CAP_MONITOR_PIN.
179 * Allocate a cec adapter using the cec pin framework.
181 * Return: a pointer to the cec adapter or an error pointer
183 struct cec_adapter *cec_pin_allocate_adapter(const struct cec_pin_ops *pin_ops,
184 void *priv, const char *name, u32 caps);