drivers/gpu/drm/mediatek/mtk_hdmi_ddc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2014 MediaTek Inc.
   4  * Author: Jie Qiu <[email protected]>
   5  */
   6 #include <linux/kernel.h>
   7 #include <linux/module.h>
   8 #include <linux/i2c.h>
   9 #include <linux/time.h>
  10 #include <linux/delay.h>
  11 #include <linux/errno.h>
  12 #include <linux/err.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/clk.h>
  15 #include <linux/slab.h>
  16 #include <linux/io.h>
  17 #include <linux/iopoll.h>
  18 #include <linux/of_address.h>
  19 #include <linux/of_irq.h>
  20 #include <linux/of_platform.h>
  21
  22 #include "mtk_drm_drv.h"
  23 #include "mtk_hdmi.h"
  24
  25 #define SIF1_CLOK               (288)
  26 #define DDC_DDCMCTL0            (0x0)
  27 #define DDCM_ODRAIN                     BIT(31)
  28 #define DDCM_CLK_DIV_OFFSET             (16)
  29 #define DDCM_CLK_DIV_MASK               (0xfff << 16)
  30 #define DDCM_CS_STATUS                  BIT(4)
  31 #define DDCM_SCL_STATE                  BIT(3)
  32 #define DDCM_SDA_STATE                  BIT(2)
  33 #define DDCM_SM0EN                      BIT(1)
  34 #define DDCM_SCL_STRECH                 BIT(0)
  35 #define DDC_DDCMCTL1            (0x4)
  36 #define DDCM_ACK_OFFSET                 (16)
  37 #define DDCM_ACK_MASK                   (0xff << 16)
  38 #define DDCM_PGLEN_OFFSET               (8)
  39 #define DDCM_PGLEN_MASK                 (0x7 << 8)
  40 #define DDCM_SIF_MODE_OFFSET            (4)
  41 #define DDCM_SIF_MODE_MASK              (0x7 << 4)
  42 #define DDCM_START                      (0x1)
  43 #define DDCM_WRITE_DATA                 (0x2)
  44 #define DDCM_STOP                       (0x3)
  45 #define DDCM_READ_DATA_NO_ACK           (0x4)
  46 #define DDCM_READ_DATA_ACK              (0x5)
  47 #define DDCM_TRI                        BIT(0)
  48 #define DDC_DDCMD0              (0x8)
  49 #define DDCM_DATA3                      (0xff << 24)
  50 #define DDCM_DATA2                      (0xff << 16)
  51 #define DDCM_DATA1                      (0xff << 8)
  52 #define DDCM_DATA0                      (0xff << 0)
  53 #define DDC_DDCMD1              (0xc)
  54 #define DDCM_DATA7                      (0xff << 24)
  55 #define DDCM_DATA6                      (0xff << 16)
  56 #define DDCM_DATA5                      (0xff << 8)
  57 #define DDCM_DATA4                      (0xff << 0)
  58
  59 struct mtk_hdmi_ddc {
  60         struct i2c_adapter adap;
  61         struct clk *clk;
  62         void __iomem *regs;
  63 };
  64
  65 static inline void sif_set_bit(struct mtk_hdmi_ddc *ddc, unsigned int offset,
  66                                unsigned int val)
  67 {
  68         writel(readl(ddc->regs + offset) | val, ddc->regs + offset);
  69 }
  70
  71 static inline void sif_clr_bit(struct mtk_hdmi_ddc *ddc, unsigned int offset,
  72                                unsigned int val)
  73 {
  74         writel(readl(ddc->regs + offset) & ~val, ddc->regs + offset);
  75 }
  76
  77 static inline bool sif_bit_is_set(struct mtk_hdmi_ddc *ddc, unsigned int offset,
  78                                   unsigned int val)
  79 {
  80         return (readl(ddc->regs + offset) & val) == val;
  81 }
  82
  83 static inline void sif_write_mask(struct mtk_hdmi_ddc *ddc, unsigned int offset,
  84                                   unsigned int mask, unsigned int shift,
  85                                   unsigned int val)
  86 {
  87         unsigned int tmp;
  88
  89         tmp = readl(ddc->regs + offset);
  90         tmp &= ~mask;
  91         tmp |= (val << shift) & mask;
  92         writel(tmp, ddc->regs + offset);
  93 }
  94
  95 static inline unsigned int sif_read_mask(struct mtk_hdmi_ddc *ddc,
  96                                          unsigned int offset, unsigned int mask,
  97                                          unsigned int shift)
  98 {
  99         return (readl(ddc->regs + offset) & mask) >> shift;
 100 }
 101
 102 static void ddcm_trigger_mode(struct mtk_hdmi_ddc *ddc, int mode)
 103 {
 104         u32 val;
 105
 106         sif_write_mask(ddc, DDC_DDCMCTL1, DDCM_SIF_MODE_MASK,
 107                        DDCM_SIF_MODE_OFFSET, mode);
 108         sif_set_bit(ddc, DDC_DDCMCTL1, DDCM_TRI);
 109         readl_poll_timeout(ddc->regs + DDC_DDCMCTL1, val,
 110                            (val & DDCM_TRI) != DDCM_TRI, 4, 20000);
 111 }
 112
 113 static int mtk_hdmi_ddc_read_msg(struct mtk_hdmi_ddc *ddc, struct i2c_msg *msg)
 114 {
 115         struct device *dev = ddc->adap.dev.parent;
 116         u32 remain_count, ack_count, ack_final, read_count, temp_count;
 117         u32 index = 0;
 118         u32 ack;
 119         int i;
 120
 121         ddcm_trigger_mode(ddc, DDCM_START);
 122         sif_write_mask(ddc, DDC_DDCMD0, 0xff, 0, (msg->addr << 1) | 0x01);
 123         sif_write_mask(ddc, DDC_DDCMCTL1, DDCM_PGLEN_MASK, DDCM_PGLEN_OFFSET,
 124                        0x00);
 125         ddcm_trigger_mode(ddc, DDCM_WRITE_DATA);
 126         ack = sif_read_mask(ddc, DDC_DDCMCTL1, DDCM_ACK_MASK, DDCM_ACK_OFFSET);
 127         dev_dbg(dev, "ack = 0x%x\n", ack);
 128         if (ack != 0x01) {
 129                 dev_err(dev, "i2c ack err!\n");
 130                 return -ENXIO;
 131         }
 132
 133         remain_count = msg->len;
 134         ack_count = (msg->len - 1) / 8;
 135         ack_final = 0;
 136
 137         while (remain_count > 0) {
 138                 if (ack_count > 0) {
 139                         read_count = 8;
 140                         ack_final = 0;
 141                         ack_count--;
 142                 } else {
 143                         read_count = remain_count;
 144                         ack_final = 1;
 145                 }
 146
 147                 sif_write_mask(ddc, DDC_DDCMCTL1, DDCM_PGLEN_MASK,
 148                                DDCM_PGLEN_OFFSET, read_count - 1);
 149                 ddcm_trigger_mode(ddc, (ack_final == 1) ?
 150                                   DDCM_READ_DATA_NO_ACK :
 151                                   DDCM_READ_DATA_ACK);
 152
 153                 ack = sif_read_mask(ddc, DDC_DDCMCTL1, DDCM_ACK_MASK,
 154                                     DDCM_ACK_OFFSET);
 155                 temp_count = 0;
 156                 while (((ack & (1 << temp_count)) != 0) && (temp_count < 8))
 157                         temp_count++;
 158                 if (((ack_final == 1) && (temp_count != (read_count - 1))) ||
 159                     ((ack_final == 0) && (temp_count != read_count))) {
 160                         dev_err(dev, "Address NACK! ACK(0x%x)\n", ack);
 161                         break;
 162                 }
 163
 164                 for (i = read_count; i >= 1; i--) {
 165                         int shift;
 166                         int offset;
 167
 168                         if (i > 4) {
 169                                 offset = DDC_DDCMD1;
 170                                 shift = (i - 5) * 8;
 171                         } else {
 172                                 offset = DDC_DDCMD0;
 173                                 shift = (i - 1) * 8;
 174                         }
 175
 176                         msg->buf[index + i - 1] = sif_read_mask(ddc, offset,
 177                                                                 0xff << shift,
 178                                                                 shift);
 179                 }
 180
 181                 remain_count -= read_count;
 182                 index += read_count;
 183         }
 184
 185         return 0;
 186 }
 187
 188 static int mtk_hdmi_ddc_write_msg(struct mtk_hdmi_ddc *ddc, struct i2c_msg *msg)
 189 {
 190         struct device *dev = ddc->adap.dev.parent;
 191         u32 ack;
 192
 193         ddcm_trigger_mode(ddc, DDCM_START);
 194         sif_write_mask(ddc, DDC_DDCMD0, DDCM_DATA0, 0, msg->addr << 1);
 195         sif_write_mask(ddc, DDC_DDCMD0, DDCM_DATA1, 8, msg->buf[0]);
 196         sif_write_mask(ddc, DDC_DDCMCTL1, DDCM_PGLEN_MASK, DDCM_PGLEN_OFFSET,
 197                        0x1);
 198         ddcm_trigger_mode(ddc, DDCM_WRITE_DATA);
 199
 200         ack = sif_read_mask(ddc, DDC_DDCMCTL1, DDCM_ACK_MASK, DDCM_ACK_OFFSET);
 201         dev_dbg(dev, "ack = %d\n", ack);
 202
 203         if (ack != 0x03) {
 204                 dev_err(dev, "i2c ack err!\n");
 205                 return -EIO;
 206         }
 207
 208         return 0;
 209 }
 210
 211 static int mtk_hdmi_ddc_xfer(struct i2c_adapter *adapter,
 212                              struct i2c_msg *msgs, int num)
 213 {
 214         struct mtk_hdmi_ddc *ddc = adapter->algo_data;
 215         struct device *dev = adapter->dev.parent;
 216         int ret;
 217         int i;
 218
 219         if (!ddc) {
 220                 dev_err(dev, "invalid arguments\n");
 221                 return -EINVAL;
 222         }
 223
 224         sif_set_bit(ddc, DDC_DDCMCTL0, DDCM_SCL_STRECH);
 225         sif_set_bit(ddc, DDC_DDCMCTL0, DDCM_SM0EN);
 226         sif_clr_bit(ddc, DDC_DDCMCTL0, DDCM_ODRAIN);
 227
 228         if (sif_bit_is_set(ddc, DDC_DDCMCTL1, DDCM_TRI)) {
 229                 dev_err(dev, "ddc line is busy!\n");
 230                 return -EBUSY;
 231         }
 232
 233         sif_write_mask(ddc, DDC_DDCMCTL0, DDCM_CLK_DIV_MASK,
 234                        DDCM_CLK_DIV_OFFSET, SIF1_CLOK);
 235
 236         for (i = 0; i < num; i++) {
 237                 struct i2c_msg *msg = &msgs[i];
 238
 239                 dev_dbg(dev, "i2c msg, adr:0x%x, flags:%d, len :0x%x\n",
 240                         msg->addr, msg->flags, msg->len);
 241
 242                 if (msg->flags & I2C_M_RD)
 243                         ret = mtk_hdmi_ddc_read_msg(ddc, msg);
 244                 else
 245                         ret = mtk_hdmi_ddc_write_msg(ddc, msg);
 246                 if (ret < 0)
 247                         goto xfer_end;
 248         }
 249
 250         ddcm_trigger_mode(ddc, DDCM_STOP);
 251
 252         return i;
 253
 254 xfer_end:
 255         ddcm_trigger_mode(ddc, DDCM_STOP);
 256         dev_err(dev, "ddc failed!\n");
 257         return ret;
 258 }
 259
 260 static u32 mtk_hdmi_ddc_func(struct i2c_adapter *adapter)
 261 {
 262         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 263 }
 264
 265 static const struct i2c_algorithm mtk_hdmi_ddc_algorithm = {
 266         .master_xfer = mtk_hdmi_ddc_xfer,
 267         .functionality = mtk_hdmi_ddc_func,
 268 };
 269
 270 static int mtk_hdmi_ddc_probe(struct platform_device *pdev)
 271 {
 272         struct device *dev = &pdev->dev;
 273         struct mtk_hdmi_ddc *ddc;
 274         struct resource *mem;
 275         int ret;
 276
 277         ddc = devm_kzalloc(dev, sizeof(struct mtk_hdmi_ddc), GFP_KERNEL);
 278         if (!ddc)
 279                 return -ENOMEM;
 280
 281         ddc->clk = devm_clk_get(dev, "ddc-i2c");
 282         if (IS_ERR(ddc->clk))
 283                 return dev_err_probe(dev, PTR_ERR(ddc->clk),
 284                                      "get ddc_clk failed\n");
 285
 286         ddc->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &mem);
 287         if (IS_ERR(ddc->regs))
 288                 return PTR_ERR(ddc->regs);
 289
 290         ret = clk_prepare_enable(ddc->clk);
 291         if (ret)
 292                 return dev_err_probe(dev, ret, "enable ddc clk failed!\n");
 293
 294         strscpy(ddc->adap.name, "mediatek-hdmi-ddc", sizeof(ddc->adap.name));
 295         ddc->adap.owner = THIS_MODULE;
 296         ddc->adap.algo = &mtk_hdmi_ddc_algorithm;
 297         ddc->adap.retries = 3;
 298         ddc->adap.dev.of_node = dev->of_node;
 299         ddc->adap.algo_data = ddc;
 300         ddc->adap.dev.parent = &pdev->dev;
 301
 302         ret = i2c_add_adapter(&ddc->adap);
 303         if (ret < 0) {
 304                 clk_disable_unprepare(ddc->clk);
 305                 return dev_err_probe(dev, ret, "failed to add bus to i2c core\n");
 306         }
 307
 308         platform_set_drvdata(pdev, ddc);
 309
 310         dev_dbg(dev, "ddc->adap: %p\n", &ddc->adap);
 311         dev_dbg(dev, "ddc->clk: %p\n", ddc->clk);
 312         dev_dbg(dev, "physical adr: %pa, end: %pa\n", &mem->start,
 313                 &mem->end);
 314
 315         return 0;
 316 }
 317
 318 static void mtk_hdmi_ddc_remove(struct platform_device *pdev)
 319 {
 320         struct mtk_hdmi_ddc *ddc = platform_get_drvdata(pdev);
 321
 322         i2c_del_adapter(&ddc->adap);
 323         clk_disable_unprepare(ddc->clk);
 324 }
 325
 326 static const struct of_device_id mtk_hdmi_ddc_match[] = {
 327         { .compatible = "mediatek,mt8173-hdmi-ddc", },
 328         {},
 329 };
 330 MODULE_DEVICE_TABLE(of, mtk_hdmi_ddc_match);
 331
 332 struct platform_driver mtk_hdmi_ddc_driver = {
 333         .probe = mtk_hdmi_ddc_probe,
 334         .remove = mtk_hdmi_ddc_remove,
 335         .driver = {
 336                 .name = "mediatek-hdmi-ddc",
 337                 .of_match_table = mtk_hdmi_ddc_match,
 338         },
 339 };
 340
 341 MODULE_AUTHOR("Jie Qiu <[email protected]>");
 342 MODULE_DESCRIPTION("MediaTek HDMI DDC Driver");
 343 MODULE_LICENSE("GPL v2");