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/*
* 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
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