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1// SPDX-License-Identifier: MIT2/*3 * Permission is hereby granted, free of charge, to any person obtaining a4 * copy of this software and associated documentation files (the5 * "Software"), to deal in the Software without restriction, including6 * without limitation the rights to use, copy, modify, merge, publish,7 * distribute, sub license, and/or sell copies of the Software, and to8 * permit persons to whom the Software is furnished to do so, subject to9 * the following conditions:10 *11 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR12 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,13 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL14 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,15 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR16 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE17 * USE OR OTHER DEALINGS IN THE SOFTWARE.18 *19 * The above copyright notice and this permission notice (including the20 * next paragraph) shall be included in all copies or substantial portions21 * of the Software.22 */23 24#include <linux/i2c-algo-bit.h>25#include <linux/i2c.h>26 27#include <drm/drm_managed.h>28#include <drm/drm_print.h>29 30#include "ast_ddc.h"31#include "ast_drv.h"32 33struct ast_ddc {34 struct ast_device *ast;35 36 struct i2c_algo_bit_data bit;37 struct i2c_adapter adapter;38};39 40static void ast_ddc_algo_bit_data_setsda(void *data, int state)41{42 struct ast_ddc *ddc = data;43 struct ast_device *ast = ddc->ast;44 int i;45 u8 ujcrb7, jtemp;46 47 for (i = 0; i < 0x10000; i++) {48 ujcrb7 = ((state & 0x01) ? 0 : 1) << 2;49 ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xb7, 0xf1, ujcrb7);50 jtemp = ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xb7, 0x04);51 if (ujcrb7 == jtemp)52 break;53 }54}55 56static void ast_ddc_algo_bit_data_setscl(void *data, int state)57{58 struct ast_ddc *ddc = data;59 struct ast_device *ast = ddc->ast;60 int i;61 u8 ujcrb7, jtemp;62 63 for (i = 0; i < 0x10000; i++) {64 ujcrb7 = ((state & 0x01) ? 0 : 1);65 ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xb7, 0xf4, ujcrb7);66 jtemp = ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xb7, 0x01);67 if (ujcrb7 == jtemp)68 break;69 }70}71 72static int ast_ddc_algo_bit_data_pre_xfer(struct i2c_adapter *adapter)73{74 struct ast_ddc *ddc = i2c_get_adapdata(adapter);75 struct ast_device *ast = ddc->ast;76 77 /*78 * Protect access to I/O registers from concurrent modesetting79 * by acquiring the I/O-register lock.80 */81 mutex_lock(&ast->modeset_lock);82 83 return 0;84}85 86static void ast_ddc_algo_bit_data_post_xfer(struct i2c_adapter *adapter)87{88 struct ast_ddc *ddc = i2c_get_adapdata(adapter);89 struct ast_device *ast = ddc->ast;90 91 mutex_unlock(&ast->modeset_lock);92}93 94static int ast_ddc_algo_bit_data_getsda(void *data)95{96 struct ast_ddc *ddc = data;97 struct ast_device *ast = ddc->ast;98 uint32_t val, val2, count, pass;99 100 count = 0;101 pass = 0;102 val = (ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xb7, 0x20) >> 5) & 0x01;103 do {104 val2 = (ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xb7, 0x20) >> 5) & 0x01;105 if (val == val2) {106 pass++;107 } else {108 pass = 0;109 val = (ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xb7, 0x20) >> 5) & 0x01;110 }111 } while ((pass < 5) && (count++ < 0x10000));112 113 return val & 1 ? 1 : 0;114}115 116static int ast_ddc_algo_bit_data_getscl(void *data)117{118 struct ast_ddc *ddc = data;119 struct ast_device *ast = ddc->ast;120 uint32_t val, val2, count, pass;121 122 count = 0;123 pass = 0;124 val = (ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xb7, 0x10) >> 4) & 0x01;125 do {126 val2 = (ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xb7, 0x10) >> 4) & 0x01;127 if (val == val2) {128 pass++;129 } else {130 pass = 0;131 val = (ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xb7, 0x10) >> 4) & 0x01;132 }133 } while ((pass < 5) && (count++ < 0x10000));134 135 return val & 1 ? 1 : 0;136}137 138static void ast_ddc_release(struct drm_device *dev, void *res)139{140 struct ast_ddc *ddc = res;141 142 i2c_del_adapter(&ddc->adapter);143}144 145struct i2c_adapter *ast_ddc_create(struct ast_device *ast)146{147 struct drm_device *dev = &ast->base;148 struct ast_ddc *ddc;149 struct i2c_adapter *adapter;150 struct i2c_algo_bit_data *bit;151 int ret;152 153 ddc = drmm_kzalloc(dev, sizeof(*ddc), GFP_KERNEL);154 if (!ddc)155 return ERR_PTR(-ENOMEM);156 ddc->ast = ast;157 158 bit = &ddc->bit;159 bit->data = ddc;160 bit->setsda = ast_ddc_algo_bit_data_setsda;161 bit->setscl = ast_ddc_algo_bit_data_setscl;162 bit->getsda = ast_ddc_algo_bit_data_getsda;163 bit->getscl = ast_ddc_algo_bit_data_getscl;164 bit->pre_xfer = ast_ddc_algo_bit_data_pre_xfer;165 bit->post_xfer = ast_ddc_algo_bit_data_post_xfer;166 bit->udelay = 20;167 bit->timeout = usecs_to_jiffies(2200);168 169 adapter = &ddc->adapter;170 adapter->owner = THIS_MODULE;171 adapter->algo_data = bit;172 adapter->dev.parent = dev->dev;173 snprintf(adapter->name, sizeof(adapter->name), "AST DDC bus");174 i2c_set_adapdata(adapter, ddc);175 176 ret = i2c_bit_add_bus(adapter);177 if (ret) {178 drm_err(dev, "Failed to register bit i2c\n");179 return ERR_PTR(ret);180 }181 182 ret = drmm_add_action_or_reset(dev, ast_ddc_release, ddc);183 if (ret)184 return ERR_PTR(ret);185 186 return &ddc->adapter;187}188