1 /* 2 * cec-pin.h - low-level CEC pin control 3 * 4 * Copyright 2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved. 5 * 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. 9 * 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 17 * SOFTWARE. 18 */ 19 20 #ifndef LINUX_CEC_PIN_H 21 #define LINUX_CEC_PIN_H 22 23 #include <linux/types.h> 24 #include <linux/atomic.h> 25 #include <media/cec.h> 26 27 enum cec_pin_state { 28 /* CEC is off */ 29 CEC_ST_OFF, 30 /* CEC is idle, waiting for Rx or Tx */ 31 CEC_ST_IDLE, 32 33 /* Tx states */ 34 35 /* Pending Tx, waiting for Signal Free Time to expire */ 36 CEC_ST_TX_WAIT, 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, 51 /* 52 * Wait for start of sample time to check for Ack bit or first 53 * four initiator bits to check for Arbitration Lost. 54 */ 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, 58 59 /* Rx states */ 60 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 */ 70 CEC_ST_RX_DATA_HIGH, 71 /* Drive CEC low to send 0 Ack bit */ 72 CEC_ST_RX_ACK_LOW, 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 */ 78 CEC_ST_RX_ACK_FINISH, 79 80 /* Start low drive */ 81 CEC_ST_LOW_DRIVE, 82 /* Monitor pin using interrupts */ 83 CEC_ST_RX_IRQ, 84 85 /* Total number of pin states */ 86 CEC_PIN_STATES 87 }; 88 89 /** 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 98 * adapter is deleted. 99 * @status: optional, log status information. 100 * @read_hpd: read the HPD pin. Return true if high, false if low or 101 * an error if negative. If NULL or -ENOTTY is returned, 102 * then this is not supported. 103 * 104 * These operations are used by the cec pin framework to manipulate 105 * the CEC pin. 106 */ 107 struct cec_pin_ops { 108 bool (*read)(struct cec_adapter *adap); 109 void (*low)(struct cec_adapter *adap); 110 void (*high)(struct cec_adapter *adap); 111 bool (*enable_irq)(struct cec_adapter *adap); 112 void (*disable_irq)(struct cec_adapter *adap); 113 void (*free)(struct cec_adapter *adap); 114 void (*status)(struct cec_adapter *adap, struct seq_file *file); 115 int (*read_hpd)(struct cec_adapter *adap); 116 }; 117 118 #define CEC_NUM_PIN_EVENTS 128 119 120 #define CEC_PIN_IRQ_UNCHANGED 0 121 #define CEC_PIN_IRQ_DISABLE 1 122 #define CEC_PIN_IRQ_ENABLE 2 123 124 struct cec_pin { 125 struct cec_adapter *adap; 126 const struct cec_pin_ops *ops; 127 struct task_struct *kthread; 128 wait_queue_head_t kthread_waitq; 129 struct hrtimer timer; 130 ktime_t ts; 131 unsigned int wait_usecs; 132 u16 la_mask; 133 bool enabled; 134 bool monitor_all; 135 bool rx_eom; 136 bool enable_irq_failed; 137 enum cec_pin_state state; 138 struct cec_msg tx_msg; 139 u32 tx_bit; 140 bool tx_nacked; 141 u32 tx_signal_free_time; 142 struct cec_msg rx_msg; 143 u32 rx_bit; 144 145 struct cec_msg work_rx_msg; 146 u8 work_tx_status; 147 ktime_t work_tx_ts; 148 atomic_t work_irq_change; 149 atomic_t work_pin_events; 150 unsigned int work_pin_events_wr; 151 unsigned int work_pin_events_rd; 152 ktime_t work_pin_ts[CEC_NUM_PIN_EVENTS]; 153 bool work_pin_is_high[CEC_NUM_PIN_EVENTS]; 154 ktime_t timer_ts; 155 u32 timer_cnt; 156 u32 timer_100ms_overruns; 157 u32 timer_300ms_overruns; 158 u32 timer_max_overrun; 159 u32 timer_sum_overrun; 160 }; 161 162 /** 163 * cec_pin_changed() - update pin state from interrupt 164 * 165 * @adap: pointer to the cec adapter 166 * @value: when true the pin is high, otherwise it is low 167 * 168 * If changes of the CEC voltage are detected via an interrupt, then 169 * cec_pin_changed is called from the interrupt with the new value. 170 */ 171 void cec_pin_changed(struct cec_adapter *adap, bool value); 172 173 /** 174 * cec_pin_allocate_adapter() - allocate a pin-based cec adapter 175 * 176 * @pin_ops: low-level pin operations 177 * @priv: will be stored in adap->priv and can be used by the adapter ops. 178 * Use cec_get_drvdata(adap) to get the priv pointer. 179 * @name: the name of the CEC adapter. Note: this name will be copied. 180 * @caps: capabilities of the CEC adapter. This will be ORed with 181 * CEC_CAP_MONITOR_ALL and CEC_CAP_MONITOR_PIN. 182 * 183 * Allocate a cec adapter using the cec pin framework. 184 * 185 * Return: a pointer to the cec adapter or an error pointer 186 */ 187 struct cec_adapter *cec_pin_allocate_adapter(const struct cec_pin_ops *pin_ops, 188 void *priv, const char *name, u32 caps); 189 190 #endif 191