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Diffstat (limited to 'include/media/cec-pin.h')
| -rw-r--r-- | include/media/cec-pin.h | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/include/media/cec-pin.h b/include/media/cec-pin.h new file mode 100644 index 000000000000..f09cc9579d53 --- /dev/null +++ b/include/media/cec-pin.h @@ -0,0 +1,186 @@ +/* + * cec-pin.h - low-level CEC pin control + * + * Copyright 2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved. + * + * This program is free software; you may redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +#ifndef LINUX_CEC_PIN_H +#define LINUX_CEC_PIN_H + +#include <linux/types.h> +#include <linux/atomic.h> +#include <media/cec.h> + +enum cec_pin_state { + /* CEC is off */ + CEC_ST_OFF, + /* CEC is idle, waiting for Rx or Tx */ + CEC_ST_IDLE, + + /* Tx states */ + + /* Pending Tx, waiting for Signal Free Time to expire */ + CEC_ST_TX_WAIT, + /* Low-drive was detected, wait for bus to go high */ + CEC_ST_TX_WAIT_FOR_HIGH, + /* Drive CEC low for the start bit */ + CEC_ST_TX_START_BIT_LOW, + /* Drive CEC high for the start bit */ + CEC_ST_TX_START_BIT_HIGH, + /* Drive CEC low for the 0 bit */ + CEC_ST_TX_DATA_BIT_0_LOW, + /* Drive CEC high for the 0 bit */ + CEC_ST_TX_DATA_BIT_0_HIGH, + /* Drive CEC low for the 1 bit */ + CEC_ST_TX_DATA_BIT_1_LOW, + /* Drive CEC high for the 1 bit */ + CEC_ST_TX_DATA_BIT_1_HIGH, + /* + * Wait for start of sample time to check for Ack bit or first + * four initiator bits to check for Arbitration Lost. + */ + CEC_ST_TX_DATA_BIT_1_HIGH_PRE_SAMPLE, + /* Wait for end of bit period after sampling */ + CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE, + + /* Rx states */ + + /* Start bit low detected */ + CEC_ST_RX_START_BIT_LOW, + /* Start bit high detected */ + CEC_ST_RX_START_BIT_HIGH, + /* Wait for bit sample time */ + CEC_ST_RX_DATA_SAMPLE, + /* Wait for earliest end of bit period after sampling */ + CEC_ST_RX_DATA_POST_SAMPLE, + /* Wait for CEC to go high (i.e. end of bit period */ + CEC_ST_RX_DATA_HIGH, + /* Drive CEC low to send 0 Ack bit */ + CEC_ST_RX_ACK_LOW, + /* End of 0 Ack time, wait for earliest end of bit period */ + CEC_ST_RX_ACK_LOW_POST, + /* Wait for CEC to go high (i.e. end of bit period */ + CEC_ST_RX_ACK_HIGH_POST, + /* Wait for earliest end of bit period and end of message */ + CEC_ST_RX_ACK_FINISH, + + /* Start low drive */ + CEC_ST_LOW_DRIVE, + /* Monitor pin using interrupts */ + CEC_ST_RX_IRQ, + + /* Total number of pin states */ + CEC_PIN_STATES +}; + +/** + * struct cec_pin_ops - low-level CEC pin operations + * @read: read the CEC pin. Return true if high, false if low. + * @low: drive the CEC pin low. + * @high: stop driving the CEC pin. The pull-up will drive the pin + * high, unless someone else is driving the pin low. + * @enable_irq: optional, enable the interrupt to detect pin voltage changes. + * @disable_irq: optional, disable the interrupt. + * @free: optional. Free any allocated resources. Called when the + * adapter is deleted. + * @status: optional, log status information. + * + * These operations are used by the cec pin framework to manipulate + * the CEC pin. + */ +struct cec_pin_ops { + bool (*read)(struct cec_adapter *adap); + void (*low)(struct cec_adapter *adap); + void (*high)(struct cec_adapter *adap); + bool (*enable_irq)(struct cec_adapter *adap); + void (*disable_irq)(struct cec_adapter *adap); + void (*free)(struct cec_adapter *adap); + void (*status)(struct cec_adapter *adap, struct seq_file *file); +}; + +#define CEC_NUM_PIN_EVENTS 128 + +#define CEC_PIN_IRQ_UNCHANGED 0 +#define CEC_PIN_IRQ_DISABLE 1 +#define CEC_PIN_IRQ_ENABLE 2 + +struct cec_pin { + struct cec_adapter *adap; + const struct cec_pin_ops *ops; + struct task_struct *kthread; + wait_queue_head_t kthread_waitq; + struct hrtimer timer; + ktime_t ts; + unsigned int wait_usecs; + u16 la_mask; + bool enabled; + bool monitor_all; + bool rx_eom; + bool enable_irq_failed; + enum cec_pin_state state; + struct cec_msg tx_msg; + u32 tx_bit; + bool tx_nacked; + u32 tx_signal_free_time; + struct cec_msg rx_msg; + u32 rx_bit; + + struct cec_msg work_rx_msg; + u8 work_tx_status; + ktime_t work_tx_ts; + atomic_t work_irq_change; + atomic_t work_pin_events; + unsigned int work_pin_events_wr; + unsigned int work_pin_events_rd; + ktime_t work_pin_ts[CEC_NUM_PIN_EVENTS]; + bool work_pin_is_high[CEC_NUM_PIN_EVENTS]; + ktime_t timer_ts; + u32 timer_cnt; + u32 timer_100ms_overruns; + u32 timer_300ms_overruns; + u32 timer_max_overrun; + u32 timer_sum_overrun; +}; + +/** + * cec_pin_changed() - update pin state from interrupt + * + * @adap: pointer to the cec adapter + * @value: when true the pin is high, otherwise it is low + * + * If changes of the CEC voltage are detected via an interrupt, then + * cec_pin_changed is called from the interrupt with the new value. + */ +void cec_pin_changed(struct cec_adapter *adap, bool value); + +/** + * cec_pin_allocate_adapter() - allocate a pin-based cec adapter + * + * @pin_ops: low-level pin operations + * @priv: will be stored in adap->priv and can be used by the adapter ops. + * Use cec_get_drvdata(adap) to get the priv pointer. + * @name: the name of the CEC adapter. Note: this name will be copied. + * @caps: capabilities of the CEC adapter. This will be ORed with + * CEC_CAP_MONITOR_ALL and CEC_CAP_MONITOR_PIN. + * + * Allocate a cec adapter using the cec pin framework. + * + * Return: a pointer to the cec adapter or an error pointer + */ +struct cec_adapter *cec_pin_allocate_adapter(const struct cec_pin_ops *pin_ops, + void *priv, const char *name, u32 caps); + +#endif |