| 0,0 → 1,348 |
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| /* |
| * Copyright © 2009 Keith Packard |
| * |
| * Permission to use, copy, modify, distribute, and sell this software and its |
| * documentation for any purpose is hereby granted without fee, provided that |
| * the above copyright notice appear in all copies and that both that copyright |
| * notice and this permission notice appear in supporting documentation, and |
| * that the name of the copyright holders not be used in advertising or |
| * publicity pertaining to distribution of the software without specific, |
| * written prior permission. The copyright holders make no representations |
| * about the suitability of this software for any purpose. It is provided "as |
| * is" without express or implied warranty. |
| * |
| * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, |
| * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO |
| * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR |
| * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, |
| * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER |
| * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE |
| * OF THIS SOFTWARE. |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| //#include <linux/delay.h> |
| //#include <linux/init.h> |
| #include <linux/errno.h> |
| #include <linux/sched.h> |
| #include <linux/i2c.h> |
| #include <drm/drm_dp_helper.h> |
| #include <drm/drmP.h> |
| |
| /** |
| * DOC: dp helpers |
| * |
| * These functions contain some common logic and helpers at various abstraction |
| * levels to deal with Display Port sink devices and related things like DP aux |
| * channel transfers, EDID reading over DP aux channels, decoding certain DPCD |
| * blocks, ... |
| */ |
| |
| /* Run a single AUX_CH I2C transaction, writing/reading data as necessary */ |
| static int |
| i2c_algo_dp_aux_transaction(struct i2c_adapter *adapter, int mode, |
| uint8_t write_byte, uint8_t *read_byte) |
| { |
| struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data; |
| int ret; |
| |
| ret = (*algo_data->aux_ch)(adapter, mode, |
| write_byte, read_byte); |
| return ret; |
| } |
| |
| /* |
| * I2C over AUX CH |
| */ |
| |
| /* |
| * Send the address. If the I2C link is running, this 'restarts' |
| * the connection with the new address, this is used for doing |
| * a write followed by a read (as needed for DDC) |
| */ |
| static int |
| i2c_algo_dp_aux_address(struct i2c_adapter *adapter, u16 address, bool reading) |
| { |
| struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data; |
| int mode = MODE_I2C_START; |
| int ret; |
| |
| if (reading) |
| mode |= MODE_I2C_READ; |
| else |
| mode |= MODE_I2C_WRITE; |
| algo_data->address = address; |
| algo_data->running = true; |
| ret = i2c_algo_dp_aux_transaction(adapter, mode, 0, NULL); |
| return ret; |
| } |
| |
| /* |
| * Stop the I2C transaction. This closes out the link, sending |
| * a bare address packet with the MOT bit turned off |
| */ |
| static void |
| i2c_algo_dp_aux_stop(struct i2c_adapter *adapter, bool reading) |
| { |
| struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data; |
| int mode = MODE_I2C_STOP; |
| |
| if (reading) |
| mode |= MODE_I2C_READ; |
| else |
| mode |= MODE_I2C_WRITE; |
| if (algo_data->running) { |
| (void) i2c_algo_dp_aux_transaction(adapter, mode, 0, NULL); |
| algo_data->running = false; |
| } |
| } |
| |
| /* |
| * Write a single byte to the current I2C address, the |
| * the I2C link must be running or this returns -EIO |
| */ |
| static int |
| i2c_algo_dp_aux_put_byte(struct i2c_adapter *adapter, u8 byte) |
| { |
| struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data; |
| int ret; |
| |
| if (!algo_data->running) |
| return -EIO; |
| |
| ret = i2c_algo_dp_aux_transaction(adapter, MODE_I2C_WRITE, byte, NULL); |
| return ret; |
| } |
| |
| /* |
| * Read a single byte from the current I2C address, the |
| * I2C link must be running or this returns -EIO |
| */ |
| static int |
| i2c_algo_dp_aux_get_byte(struct i2c_adapter *adapter, u8 *byte_ret) |
| { |
| struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data; |
| int ret; |
| |
| if (!algo_data->running) |
| return -EIO; |
| |
| ret = i2c_algo_dp_aux_transaction(adapter, MODE_I2C_READ, 0, byte_ret); |
| return ret; |
| } |
| |
| static int |
| i2c_algo_dp_aux_xfer(struct i2c_adapter *adapter, |
| struct i2c_msg *msgs, |
| int num) |
| { |
| int ret = 0; |
| bool reading = false; |
| int m; |
| int b; |
| |
| for (m = 0; m < num; m++) { |
| u16 len = msgs[m].len; |
| u8 *buf = msgs[m].buf; |
| reading = (msgs[m].flags & I2C_M_RD) != 0; |
| ret = i2c_algo_dp_aux_address(adapter, msgs[m].addr, reading); |
| if (ret < 0) |
| break; |
| if (reading) { |
| for (b = 0; b < len; b++) { |
| ret = i2c_algo_dp_aux_get_byte(adapter, &buf[b]); |
| if (ret < 0) |
| break; |
| } |
| } else { |
| for (b = 0; b < len; b++) { |
| ret = i2c_algo_dp_aux_put_byte(adapter, buf[b]); |
| if (ret < 0) |
| break; |
| } |
| } |
| if (ret < 0) |
| break; |
| } |
| if (ret >= 0) |
| ret = num; |
| i2c_algo_dp_aux_stop(adapter, reading); |
| DRM_DEBUG_KMS("dp_aux_xfer return %d\n", ret); |
| return ret; |
| } |
| |
| static u32 |
| i2c_algo_dp_aux_functionality(struct i2c_adapter *adapter) |
| { |
| return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | |
| I2C_FUNC_SMBUS_READ_BLOCK_DATA | |
| I2C_FUNC_SMBUS_BLOCK_PROC_CALL | |
| I2C_FUNC_10BIT_ADDR; |
| } |
| |
| static const struct i2c_algorithm i2c_dp_aux_algo = { |
| .master_xfer = i2c_algo_dp_aux_xfer, |
| .functionality = i2c_algo_dp_aux_functionality, |
| }; |
| |
| static void |
| i2c_dp_aux_reset_bus(struct i2c_adapter *adapter) |
| { |
| (void) i2c_algo_dp_aux_address(adapter, 0, false); |
| (void) i2c_algo_dp_aux_stop(adapter, false); |
| } |
| |
| static int |
| i2c_dp_aux_prepare_bus(struct i2c_adapter *adapter) |
| { |
| adapter->algo = &i2c_dp_aux_algo; |
| adapter->retries = 3; |
| i2c_dp_aux_reset_bus(adapter); |
| return 0; |
| } |
| |
| /** |
| * i2c_dp_aux_add_bus() - register an i2c adapter using the aux ch helper |
| * @adapter: i2c adapter to register |
| * |
| * This registers an i2c adapater that uses dp aux channel as it's underlaying |
| * transport. The driver needs to fill out the &i2c_algo_dp_aux_data structure |
| * and store it in the algo_data member of the @adapter argument. This will be |
| * used by the i2c over dp aux algorithm to drive the hardware. |
| * |
| * RETURNS: |
| * 0 on success, -ERRNO on failure. |
| */ |
| int |
| i2c_dp_aux_add_bus(struct i2c_adapter *adapter) |
| { |
| int error; |
| |
| error = i2c_dp_aux_prepare_bus(adapter); |
| if (error) |
| return error; |
| error = i2c_add_adapter(adapter); |
| return error; |
| } |
| EXPORT_SYMBOL(i2c_dp_aux_add_bus); |
| |
| /* Helpers for DP link training */ |
| static u8 dp_link_status(u8 link_status[DP_LINK_STATUS_SIZE], int r) |
| { |
| return link_status[r - DP_LANE0_1_STATUS]; |
| } |
| |
| static u8 dp_get_lane_status(u8 link_status[DP_LINK_STATUS_SIZE], |
| int lane) |
| { |
| int i = DP_LANE0_1_STATUS + (lane >> 1); |
| int s = (lane & 1) * 4; |
| u8 l = dp_link_status(link_status, i); |
| return (l >> s) & 0xf; |
| } |
| |
| bool drm_dp_channel_eq_ok(u8 link_status[DP_LINK_STATUS_SIZE], |
| int lane_count) |
| { |
| u8 lane_align; |
| u8 lane_status; |
| int lane; |
| |
| lane_align = dp_link_status(link_status, |
| DP_LANE_ALIGN_STATUS_UPDATED); |
| if ((lane_align & DP_INTERLANE_ALIGN_DONE) == 0) |
| return false; |
| for (lane = 0; lane < lane_count; lane++) { |
| lane_status = dp_get_lane_status(link_status, lane); |
| if ((lane_status & DP_CHANNEL_EQ_BITS) != DP_CHANNEL_EQ_BITS) |
| return false; |
| } |
| return true; |
| } |
| EXPORT_SYMBOL(drm_dp_channel_eq_ok); |
| |
| bool drm_dp_clock_recovery_ok(u8 link_status[DP_LINK_STATUS_SIZE], |
| int lane_count) |
| { |
| int lane; |
| u8 lane_status; |
| |
| for (lane = 0; lane < lane_count; lane++) { |
| lane_status = dp_get_lane_status(link_status, lane); |
| if ((lane_status & DP_LANE_CR_DONE) == 0) |
| return false; |
| } |
| return true; |
| } |
| EXPORT_SYMBOL(drm_dp_clock_recovery_ok); |
| |
| u8 drm_dp_get_adjust_request_voltage(u8 link_status[DP_LINK_STATUS_SIZE], |
| int lane) |
| { |
| int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1); |
| int s = ((lane & 1) ? |
| DP_ADJUST_VOLTAGE_SWING_LANE1_SHIFT : |
| DP_ADJUST_VOLTAGE_SWING_LANE0_SHIFT); |
| u8 l = dp_link_status(link_status, i); |
| |
| return ((l >> s) & 0x3) << DP_TRAIN_VOLTAGE_SWING_SHIFT; |
| } |
| EXPORT_SYMBOL(drm_dp_get_adjust_request_voltage); |
| |
| u8 drm_dp_get_adjust_request_pre_emphasis(u8 link_status[DP_LINK_STATUS_SIZE], |
| int lane) |
| { |
| int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1); |
| int s = ((lane & 1) ? |
| DP_ADJUST_PRE_EMPHASIS_LANE1_SHIFT : |
| DP_ADJUST_PRE_EMPHASIS_LANE0_SHIFT); |
| u8 l = dp_link_status(link_status, i); |
| |
| return ((l >> s) & 0x3) << DP_TRAIN_PRE_EMPHASIS_SHIFT; |
| } |
| EXPORT_SYMBOL(drm_dp_get_adjust_request_pre_emphasis); |
| |
| void drm_dp_link_train_clock_recovery_delay(u8 dpcd[DP_RECEIVER_CAP_SIZE]) { |
| if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0) |
| udelay(100); |
| else |
| mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4); |
| } |
| EXPORT_SYMBOL(drm_dp_link_train_clock_recovery_delay); |
| |
| void drm_dp_link_train_channel_eq_delay(u8 dpcd[DP_RECEIVER_CAP_SIZE]) { |
| if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0) |
| udelay(400); |
| else |
| mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4); |
| } |
| EXPORT_SYMBOL(drm_dp_link_train_channel_eq_delay); |
| |
| u8 drm_dp_link_rate_to_bw_code(int link_rate) |
| { |
| switch (link_rate) { |
| case 162000: |
| default: |
| return DP_LINK_BW_1_62; |
| case 270000: |
| return DP_LINK_BW_2_7; |
| case 540000: |
| return DP_LINK_BW_5_4; |
| } |
| } |
| EXPORT_SYMBOL(drm_dp_link_rate_to_bw_code); |
| |
| int drm_dp_bw_code_to_link_rate(u8 link_bw) |
| { |
| switch (link_bw) { |
| case DP_LINK_BW_1_62: |
| default: |
| return 162000; |
| case DP_LINK_BW_2_7: |
| return 270000; |
| case DP_LINK_BW_5_4: |
| return 540000; |
| } |
| } |
| EXPORT_SYMBOL(drm_dp_bw_code_to_link_rate); |