drivers/staging/media/s5p-cec/s5p_cec.c

   1 /* drivers/media/platform/s5p-cec/s5p_cec.c
   2  *
   3  * Samsung S5P CEC driver
   4  *
   5  * Copyright (c) 2014 Samsung Electronics Co., Ltd.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This driver is based on the "cec interface driver for exynos soc" by
  13  * SangPil Moon.
  14  */
  15
  16 #include <linux/clk.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/kernel.h>
  19 #include <linux/mfd/syscon.h>
  20 #include <linux/module.h>
  21 #include <linux/of.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/pm_runtime.h>
  24 #include <linux/timer.h>
  25 #include <linux/workqueue.h>
  26 #include <media/cec.h>
  27
  28 #include "exynos_hdmi_cec.h"
  29 #include "regs-cec.h"
  30 #include "s5p_cec.h"
  31
  32 #define CEC_NAME        "s5p-cec"
  33
  34 static int debug;
  35 module_param(debug, int, 0644);
  36 MODULE_PARM_DESC(debug, "debug level (0-2)");
  37
  38 static int s5p_cec_adap_enable(struct cec_adapter *adap, bool enable)
  39 {
  40         struct s5p_cec_dev *cec = cec_get_drvdata(adap);
  41
  42         if (enable) {
  43                 pm_runtime_get_sync(cec->dev);
  44
  45                 s5p_cec_reset(cec);
  46
  47                 s5p_cec_set_divider(cec);
  48                 s5p_cec_threshold(cec);
  49
  50                 s5p_cec_unmask_tx_interrupts(cec);
  51                 s5p_cec_unmask_rx_interrupts(cec);
  52                 s5p_cec_enable_rx(cec);
  53         } else {
  54                 s5p_cec_mask_tx_interrupts(cec);
  55                 s5p_cec_mask_rx_interrupts(cec);
  56                 pm_runtime_disable(cec->dev);
  57         }
  58
  59         return 0;
  60 }
  61
  62 static int s5p_cec_adap_log_addr(struct cec_adapter *adap, u8 addr)
  63 {
  64         struct s5p_cec_dev *cec = cec_get_drvdata(adap);
  65
  66         s5p_cec_set_addr(cec, addr);
  67         return 0;
  68 }
  69
  70 static int s5p_cec_adap_transmit(struct cec_adapter *adap, u8 attempts,
  71                                  u32 signal_free_time, struct cec_msg *msg)
  72 {
  73         struct s5p_cec_dev *cec = cec_get_drvdata(adap);
  74
  75         /*
  76          * Unclear if 0 retries are allowed by the hardware, so have 1 as
  77          * the minimum.
  78          */
  79         s5p_cec_copy_packet(cec, msg->msg, msg->len, max(1, attempts - 1));
  80         return 0;
  81 }
  82
  83 static irqreturn_t s5p_cec_irq_handler(int irq, void *priv)
  84 {
  85         struct s5p_cec_dev *cec = priv;
  86         u32 status = 0;
  87
  88         status = s5p_cec_get_status(cec);
  89
  90         dev_dbg(cec->dev, "irq received\n");
  91
  92         if (status & CEC_STATUS_TX_DONE) {
  93                 if (status & CEC_STATUS_TX_ERROR) {
  94                         dev_dbg(cec->dev, "CEC_STATUS_TX_ERROR set\n");
  95                         cec->tx = STATE_ERROR;
  96                 } else {
  97                         dev_dbg(cec->dev, "CEC_STATUS_TX_DONE\n");
  98                         cec->tx = STATE_DONE;
  99                 }
 100                 s5p_clr_pending_tx(cec);
 101         }
 102
 103         if (status & CEC_STATUS_RX_DONE) {
 104                 if (status & CEC_STATUS_RX_ERROR) {
 105                         dev_dbg(cec->dev, "CEC_STATUS_RX_ERROR set\n");
 106                         s5p_cec_rx_reset(cec);
 107                         s5p_cec_enable_rx(cec);
 108                 } else {
 109                         dev_dbg(cec->dev, "CEC_STATUS_RX_DONE set\n");
 110                         if (cec->rx != STATE_IDLE)
 111                                 dev_dbg(cec->dev, "Buffer overrun (worker did not process previous message)\n");
 112                         cec->rx = STATE_BUSY;
 113                         cec->msg.len = status >> 24;
 114                         cec->msg.rx_status = CEC_RX_STATUS_OK;
 115                         s5p_cec_get_rx_buf(cec, cec->msg.len,
 116                                         cec->msg.msg);
 117                         cec->rx = STATE_DONE;
 118                         s5p_cec_enable_rx(cec);
 119                 }
 120                 /* Clear interrupt pending bit */
 121                 s5p_clr_pending_rx(cec);
 122         }
 123         return IRQ_WAKE_THREAD;
 124 }
 125
 126 static irqreturn_t s5p_cec_irq_handler_thread(int irq, void *priv)
 127 {
 128         struct s5p_cec_dev *cec = priv;
 129
 130         dev_dbg(cec->dev, "irq processing thread\n");
 131         switch (cec->tx) {
 132         case STATE_DONE:
 133                 cec_transmit_done(cec->adap, CEC_TX_STATUS_OK, 0, 0, 0, 0);
 134                 cec->tx = STATE_IDLE;
 135                 break;
 136         case STATE_ERROR:
 137                 cec_transmit_done(cec->adap,
 138                         CEC_TX_STATUS_MAX_RETRIES | CEC_TX_STATUS_ERROR,
 139                         0, 0, 0, 1);
 140                 cec->tx = STATE_IDLE;
 141                 break;
 142         case STATE_BUSY:
 143                 dev_err(cec->dev, "state set to busy, this should not occur here\n");
 144                 break;
 145         default:
 146                 break;
 147         }
 148
 149         switch (cec->rx) {
 150         case STATE_DONE:
 151                 cec_received_msg(cec->adap, &cec->msg);
 152                 cec->rx = STATE_IDLE;
 153                 break;
 154         default:
 155                 break;
 156         }
 157
 158         return IRQ_HANDLED;
 159 }
 160
 161 static const struct cec_adap_ops s5p_cec_adap_ops = {
 162         .adap_enable = s5p_cec_adap_enable,
 163         .adap_log_addr = s5p_cec_adap_log_addr,
 164         .adap_transmit = s5p_cec_adap_transmit,
 165 };
 166
 167 static int s5p_cec_probe(struct platform_device *pdev)
 168 {
 169         struct device *dev = &pdev->dev;
 170         struct resource *res;
 171         struct s5p_cec_dev *cec;
 172         int ret;
 173
 174         cec = devm_kzalloc(&pdev->dev, sizeof(*cec), GFP_KERNEL);
 175         if (!cec)
 176                 return -ENOMEM;
 177
 178         cec->dev = dev;
 179
 180         cec->irq = platform_get_irq(pdev, 0);
 181         if (cec->irq < 0)
 182                 return cec->irq;
 183
 184         ret = devm_request_threaded_irq(dev, cec->irq, s5p_cec_irq_handler,
 185                 s5p_cec_irq_handler_thread, 0, pdev->name, cec);
 186         if (ret)
 187                 return ret;
 188
 189         cec->clk = devm_clk_get(dev, "hdmicec");
 190         if (IS_ERR(cec->clk))
 191                 return PTR_ERR(cec->clk);
 192
 193         cec->pmu = syscon_regmap_lookup_by_phandle(dev->of_node,
 194                                                  "samsung,syscon-phandle");
 195         if (IS_ERR(cec->pmu))
 196                 return -EPROBE_DEFER;
 197
 198         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 199         cec->reg = devm_ioremap_resource(dev, res);
 200         if (IS_ERR(cec->reg))
 201                 return PTR_ERR(cec->reg);
 202
 203         cec->adap = cec_allocate_adapter(&s5p_cec_adap_ops, cec,
 204                 CEC_NAME,
 205                 CEC_CAP_PHYS_ADDR | CEC_CAP_LOG_ADDRS | CEC_CAP_TRANSMIT |
 206                 CEC_CAP_PASSTHROUGH | CEC_CAP_RC, 1);
 207         ret = PTR_ERR_OR_ZERO(cec->adap);
 208         if (ret)
 209                 return ret;
 210         ret = cec_register_adapter(cec->adap, &pdev->dev);
 211         if (ret) {
 212                 cec_delete_adapter(cec->adap);
 213                 return ret;
 214         }
 215
 216         platform_set_drvdata(pdev, cec);
 217         pm_runtime_enable(dev);
 218
 219         dev_dbg(dev, "successfuly probed\n");
 220         return 0;
 221 }
 222
 223 static int s5p_cec_remove(struct platform_device *pdev)
 224 {
 225         struct s5p_cec_dev *cec = platform_get_drvdata(pdev);
 226
 227         cec_unregister_adapter(cec->adap);
 228         pm_runtime_disable(&pdev->dev);
 229         return 0;
 230 }
 231
 232 static int __maybe_unused s5p_cec_runtime_suspend(struct device *dev)
 233 {
 234         struct s5p_cec_dev *cec = dev_get_drvdata(dev);
 235
 236         clk_disable_unprepare(cec->clk);
 237         return 0;
 238 }
 239
 240 static int __maybe_unused s5p_cec_runtime_resume(struct device *dev)
 241 {
 242         struct s5p_cec_dev *cec = dev_get_drvdata(dev);
 243         int ret;
 244
 245         ret = clk_prepare_enable(cec->clk);
 246         if (ret < 0)
 247                 return ret;
 248         return 0;
 249 }
 250
 251 static const struct dev_pm_ops s5p_cec_pm_ops = {
 252         SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
 253                                 pm_runtime_force_resume)
 254         SET_RUNTIME_PM_OPS(s5p_cec_runtime_suspend, s5p_cec_runtime_resume,
 255                            NULL)
 256 };
 257
 258 static const struct of_device_id s5p_cec_match[] = {
 259         {
 260                 .compatible     = "samsung,s5p-cec",
 261         },
 262         {},
 263 };
 264 MODULE_DEVICE_TABLE(of, s5p_cec_match);
 265
 266 static struct platform_driver s5p_cec_pdrv = {
 267         .probe  = s5p_cec_probe,
 268         .remove = s5p_cec_remove,
 269         .driver = {
 270                 .name           = CEC_NAME,
 271                 .of_match_table = s5p_cec_match,
 272                 .pm             = &s5p_cec_pm_ops,
 273         },
 274 };
 275
 276 module_platform_driver(s5p_cec_pdrv);
 277
 278 MODULE_AUTHOR("Kamil Debski <kamil@wypas.org>");
 279 MODULE_LICENSE("GPL");
 280 MODULE_DESCRIPTION("Samsung S5P CEC driver");