include/media/cec-pin.h

   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  *
 101  * These operations are used by the cec pin framework to manipulate
 102  * the CEC pin.
 103  */
 104 struct cec_pin_ops {
 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);
 112 };
 113
 114 #define CEC_NUM_PIN_EVENTS 128
 115
 116 #define CEC_PIN_IRQ_UNCHANGED   0
 117 #define CEC_PIN_IRQ_DISABLE     1
 118 #define CEC_PIN_IRQ_ENABLE      2
 119
 120 struct cec_pin {
 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;
 126         ktime_t                         ts;
 127         unsigned int                    wait_usecs;
 128         u16                             la_mask;
 129         bool                            enabled;
 130         bool                            monitor_all;
 131         bool                            rx_eom;
 132         bool                            enable_irq_failed;
 133         enum cec_pin_state              state;
 134         struct cec_msg                  tx_msg;
 135         u32                             tx_bit;
 136         bool                            tx_nacked;
 137         u32                             tx_signal_free_time;
 138         struct cec_msg                  rx_msg;
 139         u32                             rx_bit;
 140
 141         struct cec_msg                  work_rx_msg;
 142         u8                              work_tx_status;
 143         ktime_t                         work_tx_ts;
 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];
 150         ktime_t                         timer_ts;
 151         u32                             timer_cnt;
 152         u32                             timer_100ms_overruns;
 153         u32                             timer_300ms_overruns;
 154         u32                             timer_max_overrun;
 155         u32                             timer_sum_overrun;
 156 };
 157
 158 /**
 159  * cec_pin_changed() - update pin state from interrupt
 160  *
 161  * @adap:       pointer to the cec adapter
 162  * @value:      when true the pin is high, otherwise it is low
 163  *
 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.
 166  */
 167 void cec_pin_changed(struct cec_adapter *adap, bool value);
 168
 169 /**
 170  * cec_pin_allocate_adapter() - allocate a pin-based cec adapter
 171  *
 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.
 178  *
 179  * Allocate a cec adapter using the cec pin framework.
 180  *
 181  * Return: a pointer to the cec adapter or an error pointer
 182  */
 183 struct cec_adapter *cec_pin_allocate_adapter(const struct cec_pin_ops *pin_ops,
 184                                         void *priv, const char *name, u32 caps);
 185
 186 #endif