1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2013 Red Hat 4 * Author: Rob Clark <robdclark@gmail.com> 5 */ 6 7 #include "hdmi.h" 8 9 struct hdmi_i2c_adapter { 10 struct i2c_adapter base; 11 struct hdmi *hdmi; 12 bool sw_done; 13 wait_queue_head_t ddc_event; 14 }; 15 #define to_hdmi_i2c_adapter(x) container_of(x, struct hdmi_i2c_adapter, base) 16 17 static void init_ddc(struct hdmi_i2c_adapter *hdmi_i2c) 18 { 19 struct hdmi *hdmi = hdmi_i2c->hdmi; 20 21 hdmi_write(hdmi, REG_HDMI_DDC_CTRL, 22 HDMI_DDC_CTRL_SW_STATUS_RESET); 23 hdmi_write(hdmi, REG_HDMI_DDC_CTRL, 24 HDMI_DDC_CTRL_SOFT_RESET); 25 26 hdmi_write(hdmi, REG_HDMI_DDC_SPEED, 27 HDMI_DDC_SPEED_THRESHOLD(2) | 28 HDMI_DDC_SPEED_PRESCALE(10)); 29 30 hdmi_write(hdmi, REG_HDMI_DDC_SETUP, 31 HDMI_DDC_SETUP_TIMEOUT(0xff)); 32 33 /* enable reference timer for 27us */ 34 hdmi_write(hdmi, REG_HDMI_DDC_REF, 35 HDMI_DDC_REF_REFTIMER_ENABLE | 36 HDMI_DDC_REF_REFTIMER(27)); 37 } 38 39 static int ddc_clear_irq(struct hdmi_i2c_adapter *hdmi_i2c) 40 { 41 struct hdmi *hdmi = hdmi_i2c->hdmi; 42 struct drm_device *dev = hdmi->dev; 43 uint32_t retry = 0xffff; 44 uint32_t ddc_int_ctrl; 45 46 do { 47 --retry; 48 49 hdmi_write(hdmi, REG_HDMI_DDC_INT_CTRL, 50 HDMI_DDC_INT_CTRL_SW_DONE_ACK | 51 HDMI_DDC_INT_CTRL_SW_DONE_MASK); 52 53 ddc_int_ctrl = hdmi_read(hdmi, REG_HDMI_DDC_INT_CTRL); 54 55 } while ((ddc_int_ctrl & HDMI_DDC_INT_CTRL_SW_DONE_INT) && retry); 56 57 if (!retry) { 58 DRM_DEV_ERROR(dev->dev, "timeout waiting for DDC\n"); 59 return -ETIMEDOUT; 60 } 61 62 hdmi_i2c->sw_done = false; 63 64 return 0; 65 } 66 67 #define MAX_TRANSACTIONS 4 68 69 static bool sw_done(struct hdmi_i2c_adapter *hdmi_i2c) 70 { 71 struct hdmi *hdmi = hdmi_i2c->hdmi; 72 73 if (!hdmi_i2c->sw_done) { 74 uint32_t ddc_int_ctrl; 75 76 ddc_int_ctrl = hdmi_read(hdmi, REG_HDMI_DDC_INT_CTRL); 77 78 if ((ddc_int_ctrl & HDMI_DDC_INT_CTRL_SW_DONE_MASK) && 79 (ddc_int_ctrl & HDMI_DDC_INT_CTRL_SW_DONE_INT)) { 80 hdmi_i2c->sw_done = true; 81 hdmi_write(hdmi, REG_HDMI_DDC_INT_CTRL, 82 HDMI_DDC_INT_CTRL_SW_DONE_ACK); 83 } 84 } 85 86 return hdmi_i2c->sw_done; 87 } 88 89 static int msm_hdmi_i2c_xfer(struct i2c_adapter *i2c, 90 struct i2c_msg *msgs, int num) 91 { 92 struct hdmi_i2c_adapter *hdmi_i2c = to_hdmi_i2c_adapter(i2c); 93 struct hdmi *hdmi = hdmi_i2c->hdmi; 94 struct drm_device *dev = hdmi->dev; 95 static const uint32_t nack[] = { 96 HDMI_DDC_SW_STATUS_NACK0, HDMI_DDC_SW_STATUS_NACK1, 97 HDMI_DDC_SW_STATUS_NACK2, HDMI_DDC_SW_STATUS_NACK3, 98 }; 99 int indices[MAX_TRANSACTIONS]; 100 int ret, i, j, index = 0; 101 uint32_t ddc_status, ddc_data, i2c_trans; 102 103 num = min(num, MAX_TRANSACTIONS); 104 105 WARN_ON(!(hdmi_read(hdmi, REG_HDMI_CTRL) & HDMI_CTRL_ENABLE)); 106 107 if (num == 0) 108 return num; 109 110 init_ddc(hdmi_i2c); 111 112 ret = ddc_clear_irq(hdmi_i2c); 113 if (ret) 114 return ret; 115 116 for (i = 0; i < num; i++) { 117 struct i2c_msg *p = &msgs[i]; 118 uint32_t raw_addr = p->addr << 1; 119 120 if (p->flags & I2C_M_RD) 121 raw_addr |= 1; 122 123 ddc_data = HDMI_DDC_DATA_DATA(raw_addr) | 124 HDMI_DDC_DATA_DATA_RW(DDC_WRITE); 125 126 if (i == 0) { 127 ddc_data |= HDMI_DDC_DATA_INDEX(0) | 128 HDMI_DDC_DATA_INDEX_WRITE; 129 } 130 131 hdmi_write(hdmi, REG_HDMI_DDC_DATA, ddc_data); 132 index++; 133 134 indices[i] = index; 135 136 if (p->flags & I2C_M_RD) { 137 index += p->len; 138 } else { 139 for (j = 0; j < p->len; j++) { 140 ddc_data = HDMI_DDC_DATA_DATA(p->buf[j]) | 141 HDMI_DDC_DATA_DATA_RW(DDC_WRITE); 142 hdmi_write(hdmi, REG_HDMI_DDC_DATA, ddc_data); 143 index++; 144 } 145 } 146 147 i2c_trans = HDMI_I2C_TRANSACTION_REG_CNT(p->len) | 148 HDMI_I2C_TRANSACTION_REG_RW( 149 (p->flags & I2C_M_RD) ? DDC_READ : DDC_WRITE) | 150 HDMI_I2C_TRANSACTION_REG_START; 151 152 if (i == (num - 1)) 153 i2c_trans |= HDMI_I2C_TRANSACTION_REG_STOP; 154 155 hdmi_write(hdmi, REG_HDMI_I2C_TRANSACTION(i), i2c_trans); 156 } 157 158 /* trigger the transfer: */ 159 hdmi_write(hdmi, REG_HDMI_DDC_CTRL, 160 HDMI_DDC_CTRL_TRANSACTION_CNT(num - 1) | 161 HDMI_DDC_CTRL_GO); 162 163 ret = wait_event_timeout(hdmi_i2c->ddc_event, sw_done(hdmi_i2c), HZ/4); 164 if (ret <= 0) { 165 if (ret == 0) 166 ret = -ETIMEDOUT; 167 dev_warn(dev->dev, "DDC timeout: %d\n", ret); 168 DBG("sw_status=%08x, hw_status=%08x, int_ctrl=%08x", 169 hdmi_read(hdmi, REG_HDMI_DDC_SW_STATUS), 170 hdmi_read(hdmi, REG_HDMI_DDC_HW_STATUS), 171 hdmi_read(hdmi, REG_HDMI_DDC_INT_CTRL)); 172 return ret; 173 } 174 175 ddc_status = hdmi_read(hdmi, REG_HDMI_DDC_SW_STATUS); 176 177 /* read back results of any read transactions: */ 178 for (i = 0; i < num; i++) { 179 struct i2c_msg *p = &msgs[i]; 180 181 if (!(p->flags & I2C_M_RD)) 182 continue; 183 184 /* check for NACK: */ 185 if (ddc_status & nack[i]) { 186 DBG("ddc_status=%08x", ddc_status); 187 break; 188 } 189 190 ddc_data = HDMI_DDC_DATA_DATA_RW(DDC_READ) | 191 HDMI_DDC_DATA_INDEX(indices[i]) | 192 HDMI_DDC_DATA_INDEX_WRITE; 193 194 hdmi_write(hdmi, REG_HDMI_DDC_DATA, ddc_data); 195 196 /* discard first byte: */ 197 hdmi_read(hdmi, REG_HDMI_DDC_DATA); 198 199 for (j = 0; j < p->len; j++) { 200 ddc_data = hdmi_read(hdmi, REG_HDMI_DDC_DATA); 201 p->buf[j] = FIELD(ddc_data, HDMI_DDC_DATA_DATA); 202 } 203 } 204 205 return i; 206 } 207 208 static u32 msm_hdmi_i2c_func(struct i2c_adapter *adapter) 209 { 210 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; 211 } 212 213 static const struct i2c_algorithm msm_hdmi_i2c_algorithm = { 214 .master_xfer = msm_hdmi_i2c_xfer, 215 .functionality = msm_hdmi_i2c_func, 216 }; 217 218 void msm_hdmi_i2c_irq(struct i2c_adapter *i2c) 219 { 220 struct hdmi_i2c_adapter *hdmi_i2c = to_hdmi_i2c_adapter(i2c); 221 222 if (sw_done(hdmi_i2c)) 223 wake_up_all(&hdmi_i2c->ddc_event); 224 } 225 226 void msm_hdmi_i2c_destroy(struct i2c_adapter *i2c) 227 { 228 struct hdmi_i2c_adapter *hdmi_i2c = to_hdmi_i2c_adapter(i2c); 229 i2c_del_adapter(i2c); 230 kfree(hdmi_i2c); 231 } 232 233 struct i2c_adapter *msm_hdmi_i2c_init(struct hdmi *hdmi) 234 { 235 struct hdmi_i2c_adapter *hdmi_i2c; 236 struct i2c_adapter *i2c = NULL; 237 int ret; 238 239 hdmi_i2c = kzalloc(sizeof(*hdmi_i2c), GFP_KERNEL); 240 if (!hdmi_i2c) { 241 ret = -ENOMEM; 242 goto fail; 243 } 244 245 i2c = &hdmi_i2c->base; 246 247 hdmi_i2c->hdmi = hdmi; 248 init_waitqueue_head(&hdmi_i2c->ddc_event); 249 250 251 i2c->owner = THIS_MODULE; 252 snprintf(i2c->name, sizeof(i2c->name), "msm hdmi i2c"); 253 i2c->dev.parent = &hdmi->pdev->dev; 254 i2c->algo = &msm_hdmi_i2c_algorithm; 255 256 ret = i2c_add_adapter(i2c); 257 if (ret) 258 goto fail; 259 260 return i2c; 261 262 fail: 263 if (i2c) 264 msm_hdmi_i2c_destroy(i2c); 265 return ERR_PTR(ret); 266 } 267