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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Coral-P(A)/Lime I2C adapter driver4 *5 * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>6 */7 8#include <linux/fb.h>9#include <linux/i2c.h>10#include <linux/io.h>11#include <linux/delay.h>12#include <linux/export.h>13 14#include "mb862xxfb.h"15#include "mb862xx_reg.h"16 17static int mb862xx_i2c_wait_event(struct i2c_adapter *adap)18{19 struct mb862xxfb_par *par = adap->algo_data;20 u32 reg;21 22 do {23 udelay(10);24 reg = inreg(i2c, GC_I2C_BCR);25 if (reg & (I2C_INT | I2C_BER))26 break;27 } while (1);28 29 return (reg & I2C_BER) ? 0 : 1;30}31 32static int mb862xx_i2c_do_address(struct i2c_adapter *adap, int addr)33{34 struct mb862xxfb_par *par = adap->algo_data;35 36 outreg(i2c, GC_I2C_DAR, addr);37 outreg(i2c, GC_I2C_CCR, I2C_CLOCK_AND_ENABLE);38 outreg(i2c, GC_I2C_BCR, par->i2c_rs ? I2C_REPEATED_START : I2C_START);39 if (!mb862xx_i2c_wait_event(adap))40 return -EIO;41 par->i2c_rs = !(inreg(i2c, GC_I2C_BSR) & I2C_LRB);42 return par->i2c_rs;43}44 45static int mb862xx_i2c_write_byte(struct i2c_adapter *adap, u8 byte)46{47 struct mb862xxfb_par *par = adap->algo_data;48 49 outreg(i2c, GC_I2C_DAR, byte);50 outreg(i2c, GC_I2C_BCR, I2C_START);51 if (!mb862xx_i2c_wait_event(adap))52 return -EIO;53 return !(inreg(i2c, GC_I2C_BSR) & I2C_LRB);54}55 56static int mb862xx_i2c_read_byte(struct i2c_adapter *adap, u8 *byte, int last)57{58 struct mb862xxfb_par *par = adap->algo_data;59 60 outreg(i2c, GC_I2C_BCR, I2C_START | (last ? 0 : I2C_ACK));61 if (!mb862xx_i2c_wait_event(adap))62 return 0;63 *byte = inreg(i2c, GC_I2C_DAR);64 return 1;65}66 67static void mb862xx_i2c_stop(struct i2c_adapter *adap)68{69 struct mb862xxfb_par *par = adap->algo_data;70 71 outreg(i2c, GC_I2C_BCR, I2C_STOP);72 outreg(i2c, GC_I2C_CCR, I2C_DISABLE);73 par->i2c_rs = 0;74}75 76static int mb862xx_i2c_read(struct i2c_adapter *adap, struct i2c_msg *m)77{78 int i, ret = 0;79 int last = m->len - 1;80 81 for (i = 0; i < m->len; i++) {82 if (!mb862xx_i2c_read_byte(adap, &m->buf[i], i == last)) {83 ret = -EIO;84 break;85 }86 }87 return ret;88}89 90static int mb862xx_i2c_write(struct i2c_adapter *adap, struct i2c_msg *m)91{92 int i, ret = 0;93 94 for (i = 0; i < m->len; i++) {95 if (!mb862xx_i2c_write_byte(adap, m->buf[i])) {96 ret = -EIO;97 break;98 }99 }100 return ret;101}102 103static int mb862xx_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,104 int num)105{106 struct mb862xxfb_par *par = adap->algo_data;107 struct i2c_msg *m;108 int addr;109 int i = 0, err = 0;110 111 dev_dbg(par->dev, "%s: %d msgs\n", __func__, num);112 113 for (i = 0; i < num; i++) {114 m = &msgs[i];115 if (!m->len) {116 dev_dbg(par->dev, "%s: null msgs\n", __func__);117 continue;118 }119 addr = m->addr;120 if (m->flags & I2C_M_RD)121 addr |= 1;122 123 err = mb862xx_i2c_do_address(adap, addr);124 if (err < 0)125 break;126 if (m->flags & I2C_M_RD)127 err = mb862xx_i2c_read(adap, m);128 else129 err = mb862xx_i2c_write(adap, m);130 }131 132 if (i)133 mb862xx_i2c_stop(adap);134 135 return (err < 0) ? err : i;136}137 138static u32 mb862xx_func(struct i2c_adapter *adap)139{140 return I2C_FUNC_SMBUS_BYTE_DATA;141}142 143static const struct i2c_algorithm mb862xx_algo = {144 .master_xfer = mb862xx_xfer,145 .functionality = mb862xx_func,146};147 148static struct i2c_adapter mb862xx_i2c_adapter = {149 .name = "MB862xx I2C adapter",150 .algo = &mb862xx_algo,151 .owner = THIS_MODULE,152};153 154int mb862xx_i2c_init(struct mb862xxfb_par *par)155{156 mb862xx_i2c_adapter.algo_data = par;157 par->adap = &mb862xx_i2c_adapter;158 159 return i2c_add_adapter(par->adap);160}161 162void mb862xx_i2c_exit(struct mb862xxfb_par *par)163{164 if (par->adap) {165 i2c_del_adapter(par->adap);166 par->adap = NULL;167 }168}169