Keith Packard | a4fc5ed | 2009-04-07 16:16:42 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright © 2009 Keith Packard |
| 3 | * |
| 4 | * Permission to use, copy, modify, distribute, and sell this software and its |
| 5 | * documentation for any purpose is hereby granted without fee, provided that |
| 6 | * the above copyright notice appear in all copies and that both that copyright |
| 7 | * notice and this permission notice appear in supporting documentation, and |
| 8 | * that the name of the copyright holders not be used in advertising or |
| 9 | * publicity pertaining to distribution of the software without specific, |
| 10 | * written prior permission. The copyright holders make no representations |
| 11 | * about the suitability of this software for any purpose. It is provided "as |
| 12 | * is" without express or implied warranty. |
| 13 | * |
| 14 | * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, |
| 15 | * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO |
| 16 | * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR |
| 17 | * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, |
| 18 | * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER |
| 19 | * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE |
| 20 | * OF THIS SOFTWARE. |
| 21 | */ |
| 22 | |
| 23 | #include <linux/kernel.h> |
| 24 | #include <linux/module.h> |
| 25 | #include <linux/delay.h> |
Keith Packard | a4fc5ed | 2009-04-07 16:16:42 -0700 | [diff] [blame] | 26 | #include <linux/init.h> |
| 27 | #include <linux/errno.h> |
| 28 | #include <linux/sched.h> |
| 29 | #include <linux/i2c.h> |
David Howells | 760285e | 2012-10-02 18:01:07 +0100 | [diff] [blame] | 30 | #include <drm/drm_dp_helper.h> |
| 31 | #include <drm/drmP.h> |
Keith Packard | a4fc5ed | 2009-04-07 16:16:42 -0700 | [diff] [blame] | 32 | |
| 33 | /* Run a single AUX_CH I2C transaction, writing/reading data as necessary */ |
Keith Packard | a4fc5ed | 2009-04-07 16:16:42 -0700 | [diff] [blame] | 34 | static int |
| 35 | i2c_algo_dp_aux_transaction(struct i2c_adapter *adapter, int mode, |
| 36 | uint8_t write_byte, uint8_t *read_byte) |
| 37 | { |
| 38 | struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data; |
Keith Packard | a4fc5ed | 2009-04-07 16:16:42 -0700 | [diff] [blame] | 39 | int ret; |
Daniel Vetter | 00ae9a4 | 2012-10-18 10:15:23 +0200 | [diff] [blame] | 40 | |
Dave Airlie | ab2c067 | 2009-12-04 10:55:24 +1000 | [diff] [blame] | 41 | ret = (*algo_data->aux_ch)(adapter, mode, |
| 42 | write_byte, read_byte); |
| 43 | return ret; |
Keith Packard | a4fc5ed | 2009-04-07 16:16:42 -0700 | [diff] [blame] | 44 | } |
| 45 | |
| 46 | /* |
| 47 | * I2C over AUX CH |
| 48 | */ |
| 49 | |
| 50 | /* |
| 51 | * Send the address. If the I2C link is running, this 'restarts' |
| 52 | * the connection with the new address, this is used for doing |
| 53 | * a write followed by a read (as needed for DDC) |
| 54 | */ |
| 55 | static int |
| 56 | i2c_algo_dp_aux_address(struct i2c_adapter *adapter, u16 address, bool reading) |
| 57 | { |
| 58 | struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data; |
| 59 | int mode = MODE_I2C_START; |
| 60 | int ret; |
| 61 | |
| 62 | if (reading) |
| 63 | mode |= MODE_I2C_READ; |
| 64 | else |
| 65 | mode |= MODE_I2C_WRITE; |
| 66 | algo_data->address = address; |
| 67 | algo_data->running = true; |
| 68 | ret = i2c_algo_dp_aux_transaction(adapter, mode, 0, NULL); |
| 69 | return ret; |
| 70 | } |
| 71 | |
| 72 | /* |
| 73 | * Stop the I2C transaction. This closes out the link, sending |
| 74 | * a bare address packet with the MOT bit turned off |
| 75 | */ |
| 76 | static void |
| 77 | i2c_algo_dp_aux_stop(struct i2c_adapter *adapter, bool reading) |
| 78 | { |
| 79 | struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data; |
| 80 | int mode = MODE_I2C_STOP; |
| 81 | |
| 82 | if (reading) |
| 83 | mode |= MODE_I2C_READ; |
| 84 | else |
| 85 | mode |= MODE_I2C_WRITE; |
| 86 | if (algo_data->running) { |
| 87 | (void) i2c_algo_dp_aux_transaction(adapter, mode, 0, NULL); |
| 88 | algo_data->running = false; |
| 89 | } |
| 90 | } |
| 91 | |
| 92 | /* |
| 93 | * Write a single byte to the current I2C address, the |
| 94 | * the I2C link must be running or this returns -EIO |
| 95 | */ |
| 96 | static int |
| 97 | i2c_algo_dp_aux_put_byte(struct i2c_adapter *adapter, u8 byte) |
| 98 | { |
| 99 | struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data; |
| 100 | int ret; |
| 101 | |
| 102 | if (!algo_data->running) |
| 103 | return -EIO; |
| 104 | |
| 105 | ret = i2c_algo_dp_aux_transaction(adapter, MODE_I2C_WRITE, byte, NULL); |
| 106 | return ret; |
| 107 | } |
| 108 | |
| 109 | /* |
| 110 | * Read a single byte from the current I2C address, the |
| 111 | * I2C link must be running or this returns -EIO |
| 112 | */ |
| 113 | static int |
| 114 | i2c_algo_dp_aux_get_byte(struct i2c_adapter *adapter, u8 *byte_ret) |
| 115 | { |
| 116 | struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data; |
| 117 | int ret; |
| 118 | |
| 119 | if (!algo_data->running) |
| 120 | return -EIO; |
| 121 | |
| 122 | ret = i2c_algo_dp_aux_transaction(adapter, MODE_I2C_READ, 0, byte_ret); |
| 123 | return ret; |
| 124 | } |
| 125 | |
| 126 | static int |
| 127 | i2c_algo_dp_aux_xfer(struct i2c_adapter *adapter, |
| 128 | struct i2c_msg *msgs, |
| 129 | int num) |
| 130 | { |
| 131 | int ret = 0; |
| 132 | bool reading = false; |
| 133 | int m; |
| 134 | int b; |
| 135 | |
| 136 | for (m = 0; m < num; m++) { |
| 137 | u16 len = msgs[m].len; |
| 138 | u8 *buf = msgs[m].buf; |
| 139 | reading = (msgs[m].flags & I2C_M_RD) != 0; |
| 140 | ret = i2c_algo_dp_aux_address(adapter, msgs[m].addr, reading); |
| 141 | if (ret < 0) |
| 142 | break; |
| 143 | if (reading) { |
| 144 | for (b = 0; b < len; b++) { |
| 145 | ret = i2c_algo_dp_aux_get_byte(adapter, &buf[b]); |
| 146 | if (ret < 0) |
| 147 | break; |
| 148 | } |
| 149 | } else { |
| 150 | for (b = 0; b < len; b++) { |
| 151 | ret = i2c_algo_dp_aux_put_byte(adapter, buf[b]); |
| 152 | if (ret < 0) |
| 153 | break; |
| 154 | } |
| 155 | } |
| 156 | if (ret < 0) |
| 157 | break; |
| 158 | } |
| 159 | if (ret >= 0) |
| 160 | ret = num; |
| 161 | i2c_algo_dp_aux_stop(adapter, reading); |
Zhao Yakui | 28c9773 | 2009-10-09 11:39:41 +0800 | [diff] [blame] | 162 | DRM_DEBUG_KMS("dp_aux_xfer return %d\n", ret); |
Keith Packard | a4fc5ed | 2009-04-07 16:16:42 -0700 | [diff] [blame] | 163 | return ret; |
| 164 | } |
| 165 | |
| 166 | static u32 |
| 167 | i2c_algo_dp_aux_functionality(struct i2c_adapter *adapter) |
| 168 | { |
| 169 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | |
| 170 | I2C_FUNC_SMBUS_READ_BLOCK_DATA | |
| 171 | I2C_FUNC_SMBUS_BLOCK_PROC_CALL | |
| 172 | I2C_FUNC_10BIT_ADDR; |
| 173 | } |
| 174 | |
| 175 | static const struct i2c_algorithm i2c_dp_aux_algo = { |
| 176 | .master_xfer = i2c_algo_dp_aux_xfer, |
| 177 | .functionality = i2c_algo_dp_aux_functionality, |
| 178 | }; |
| 179 | |
| 180 | static void |
| 181 | i2c_dp_aux_reset_bus(struct i2c_adapter *adapter) |
| 182 | { |
| 183 | (void) i2c_algo_dp_aux_address(adapter, 0, false); |
| 184 | (void) i2c_algo_dp_aux_stop(adapter, false); |
Keith Packard | a4fc5ed | 2009-04-07 16:16:42 -0700 | [diff] [blame] | 185 | } |
| 186 | |
| 187 | static int |
| 188 | i2c_dp_aux_prepare_bus(struct i2c_adapter *adapter) |
| 189 | { |
| 190 | adapter->algo = &i2c_dp_aux_algo; |
| 191 | adapter->retries = 3; |
| 192 | i2c_dp_aux_reset_bus(adapter); |
| 193 | return 0; |
| 194 | } |
| 195 | |
| 196 | int |
| 197 | i2c_dp_aux_add_bus(struct i2c_adapter *adapter) |
| 198 | { |
| 199 | int error; |
Daniel Vetter | 00ae9a4 | 2012-10-18 10:15:23 +0200 | [diff] [blame] | 200 | |
Keith Packard | a4fc5ed | 2009-04-07 16:16:42 -0700 | [diff] [blame] | 201 | error = i2c_dp_aux_prepare_bus(adapter); |
| 202 | if (error) |
| 203 | return error; |
| 204 | error = i2c_add_adapter(adapter); |
| 205 | return error; |
| 206 | } |
| 207 | EXPORT_SYMBOL(i2c_dp_aux_add_bus); |
Daniel Vetter | 1ffdff1 | 2012-10-18 10:15:24 +0200 | [diff] [blame] | 208 | |
| 209 | /* Helpers for DP link training */ |
| 210 | static u8 dp_link_status(u8 link_status[DP_LINK_STATUS_SIZE], int r) |
| 211 | { |
| 212 | return link_status[r - DP_LANE0_1_STATUS]; |
| 213 | } |
| 214 | |
| 215 | static u8 dp_get_lane_status(u8 link_status[DP_LINK_STATUS_SIZE], |
| 216 | int lane) |
| 217 | { |
| 218 | int i = DP_LANE0_1_STATUS + (lane >> 1); |
| 219 | int s = (lane & 1) * 4; |
| 220 | u8 l = dp_link_status(link_status, i); |
| 221 | return (l >> s) & 0xf; |
| 222 | } |
| 223 | |
| 224 | bool drm_dp_channel_eq_ok(u8 link_status[DP_LINK_STATUS_SIZE], |
| 225 | int lane_count) |
| 226 | { |
| 227 | u8 lane_align; |
| 228 | u8 lane_status; |
| 229 | int lane; |
| 230 | |
| 231 | lane_align = dp_link_status(link_status, |
| 232 | DP_LANE_ALIGN_STATUS_UPDATED); |
| 233 | if ((lane_align & DP_INTERLANE_ALIGN_DONE) == 0) |
| 234 | return false; |
| 235 | for (lane = 0; lane < lane_count; lane++) { |
| 236 | lane_status = dp_get_lane_status(link_status, lane); |
| 237 | if ((lane_status & DP_CHANNEL_EQ_BITS) != DP_CHANNEL_EQ_BITS) |
| 238 | return false; |
| 239 | } |
| 240 | return true; |
| 241 | } |
| 242 | EXPORT_SYMBOL(drm_dp_channel_eq_ok); |
| 243 | |
| 244 | bool drm_dp_clock_recovery_ok(u8 link_status[DP_LINK_STATUS_SIZE], |
| 245 | int lane_count) |
| 246 | { |
| 247 | int lane; |
| 248 | u8 lane_status; |
| 249 | |
| 250 | for (lane = 0; lane < lane_count; lane++) { |
| 251 | lane_status = dp_get_lane_status(link_status, lane); |
| 252 | if ((lane_status & DP_LANE_CR_DONE) == 0) |
| 253 | return false; |
| 254 | } |
| 255 | return true; |
| 256 | } |
| 257 | EXPORT_SYMBOL(drm_dp_clock_recovery_ok); |
Daniel Vetter | 0f037bd | 2012-10-18 10:15:27 +0200 | [diff] [blame] | 258 | |
| 259 | u8 drm_dp_get_adjust_request_voltage(u8 link_status[DP_LINK_STATUS_SIZE], |
| 260 | int lane) |
| 261 | { |
| 262 | int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1); |
| 263 | int s = ((lane & 1) ? |
| 264 | DP_ADJUST_VOLTAGE_SWING_LANE1_SHIFT : |
| 265 | DP_ADJUST_VOLTAGE_SWING_LANE0_SHIFT); |
| 266 | u8 l = dp_link_status(link_status, i); |
| 267 | |
| 268 | return ((l >> s) & 0x3) << DP_TRAIN_VOLTAGE_SWING_SHIFT; |
| 269 | } |
| 270 | EXPORT_SYMBOL(drm_dp_get_adjust_request_voltage); |
| 271 | |
| 272 | u8 drm_dp_get_adjust_request_pre_emphasis(u8 link_status[DP_LINK_STATUS_SIZE], |
| 273 | int lane) |
| 274 | { |
| 275 | int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1); |
| 276 | int s = ((lane & 1) ? |
| 277 | DP_ADJUST_PRE_EMPHASIS_LANE1_SHIFT : |
| 278 | DP_ADJUST_PRE_EMPHASIS_LANE0_SHIFT); |
| 279 | u8 l = dp_link_status(link_status, i); |
| 280 | |
| 281 | return ((l >> s) & 0x3) << DP_TRAIN_PRE_EMPHASIS_SHIFT; |
| 282 | } |
| 283 | EXPORT_SYMBOL(drm_dp_get_adjust_request_pre_emphasis); |
| 284 | |
Daniel Vetter | 1a644cd | 2012-10-18 15:32:40 +0200 | [diff] [blame] | 285 | void drm_dp_link_train_clock_recovery_delay(u8 dpcd[DP_RECEIVER_CAP_SIZE]) { |
| 286 | if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0) |
| 287 | udelay(100); |
| 288 | else |
| 289 | mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4); |
| 290 | } |
| 291 | EXPORT_SYMBOL(drm_dp_link_train_clock_recovery_delay); |
| 292 | |
| 293 | void drm_dp_link_train_channel_eq_delay(u8 dpcd[DP_RECEIVER_CAP_SIZE]) { |
| 294 | if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0) |
| 295 | udelay(400); |
| 296 | else |
| 297 | mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4); |
| 298 | } |
| 299 | EXPORT_SYMBOL(drm_dp_link_train_channel_eq_delay); |
Daniel Vetter | 3b5c662 | 2012-10-18 10:15:31 +0200 | [diff] [blame^] | 300 | |
| 301 | u8 drm_dp_link_rate_to_bw_code(int link_rate) |
| 302 | { |
| 303 | switch (link_rate) { |
| 304 | case 162000: |
| 305 | default: |
| 306 | return DP_LINK_BW_1_62; |
| 307 | case 270000: |
| 308 | return DP_LINK_BW_2_7; |
| 309 | case 540000: |
| 310 | return DP_LINK_BW_5_4; |
| 311 | } |
| 312 | } |
| 313 | EXPORT_SYMBOL(drm_dp_link_rate_to_bw_code); |
| 314 | |
| 315 | int drm_dp_bw_code_to_link_rate(u8 link_bw) |
| 316 | { |
| 317 | switch (link_bw) { |
| 318 | case DP_LINK_BW_1_62: |
| 319 | default: |
| 320 | return 162000; |
| 321 | case DP_LINK_BW_2_7: |
| 322 | return 270000; |
| 323 | case DP_LINK_BW_5_4: |
| 324 | return 540000; |
| 325 | } |
| 326 | } |
| 327 | EXPORT_SYMBOL(drm_dp_bw_code_to_link_rate); |