1// SPDX-License-Identifier: GPL-2.0+ 2/* 3 * Renesas RCar IIC driver 4 * 5 * Copyright (C) 2017 Marek Vasut <marek.vasut@gmail.com> 6 * 7 * Based on 8 * Copyright (C) 2011, 2013 Renesas Solutions Corp. 9 * Copyright (C) 2011, 2013 Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com> 10 */ 11 12#include <common.h> 13#include <clk.h> 14#include <dm.h> 15#include <i2c.h> 16#include <asm/io.h> 17#include <linux/bitops.h> 18#include <linux/delay.h> 19 20struct rcar_iic_priv { 21 void __iomem *base; 22 struct clk clk; 23 u8 iccl; 24 u8 icch; 25}; 26 27#define RCAR_IIC_ICDR 0x00 28#define RCAR_IIC_ICCR 0x04 29#define RCAR_IIC_ICSR 0x08 30#define RCAR_IIC_ICIC 0x0c 31#define RCAR_IIC_ICCL 0x10 32#define RCAR_IIC_ICCH 0x14 33 34/* ICCR */ 35#define RCAR_IIC_ICCR_ICE BIT(7) 36#define RCAR_IIC_ICCR_RACK BIT(6) 37#define RCAR_IIC_ICCR_RTS BIT(4) 38#define RCAR_IIC_ICCR_BUSY BIT(2) 39#define RCAR_IIC_ICCR_SCP BIT(0) 40 41/* ICSR / ICIC */ 42#define RCAR_IC_BUSY BIT(4) 43#define RCAR_IC_TACK BIT(2) 44#define RCAR_IC_DTE BIT(0) 45 46#define IRQ_WAIT 1000 47 48static void sh_irq_dte(struct udevice *dev) 49{ 50 struct rcar_iic_priv *priv = dev_get_priv(dev); 51 int i; 52 53 for (i = 0; i < IRQ_WAIT; i++) { 54 if (RCAR_IC_DTE & readb(priv->base + RCAR_IIC_ICSR)) 55 break; 56 udelay(10); 57 } 58} 59 60static int sh_irq_dte_with_tack(struct udevice *dev) 61{ 62 struct rcar_iic_priv *priv = dev_get_priv(dev); 63 u8 icsr; 64 int i; 65 66 for (i = 0; i < IRQ_WAIT; i++) { 67 icsr = readb(priv->base + RCAR_IIC_ICSR); 68 if (RCAR_IC_DTE & icsr) 69 break; 70 if (RCAR_IC_TACK & icsr) 71 return -ETIMEDOUT; 72 udelay(10); 73 } 74 return 0; 75} 76 77static void sh_irq_busy(struct udevice *dev) 78{ 79 struct rcar_iic_priv *priv = dev_get_priv(dev); 80 int i; 81 82 for (i = 0; i < IRQ_WAIT; i++) { 83 if (!(RCAR_IC_BUSY & readb(priv->base + RCAR_IIC_ICSR))) 84 break; 85 udelay(10); 86 } 87} 88 89static int rcar_iic_set_addr(struct udevice *dev, u8 chip, u8 read) 90{ 91 struct rcar_iic_priv *priv = dev_get_priv(dev); 92 93 clrbits_8(priv->base + RCAR_IIC_ICCR, RCAR_IIC_ICCR_ICE); 94 setbits_8(priv->base + RCAR_IIC_ICCR, RCAR_IIC_ICCR_ICE); 95 96 writeb(priv->iccl, priv->base + RCAR_IIC_ICCL); 97 writeb(priv->icch, priv->base + RCAR_IIC_ICCH); 98 writeb(RCAR_IC_TACK, priv->base + RCAR_IIC_ICIC); 99 100 writeb(RCAR_IIC_ICCR_ICE | RCAR_IIC_ICCR_RTS | RCAR_IIC_ICCR_BUSY, 101 priv->base + RCAR_IIC_ICCR); 102 sh_irq_dte(dev); 103 104 clrbits_8(priv->base + RCAR_IIC_ICSR, RCAR_IC_TACK); 105 writeb(chip << 1 | read, priv->base + RCAR_IIC_ICDR); 106 return sh_irq_dte_with_tack(dev); 107} 108 109static void rcar_iic_finish(struct udevice *dev) 110{ 111 struct rcar_iic_priv *priv = dev_get_priv(dev); 112 113 writeb(0, priv->base + RCAR_IIC_ICSR); 114 clrbits_8(priv->base + RCAR_IIC_ICCR, RCAR_IIC_ICCR_ICE); 115} 116 117static int rcar_iic_read_common(struct udevice *dev, struct i2c_msg *msg) 118{ 119 struct rcar_iic_priv *priv = dev_get_priv(dev); 120 int i, ret = -EREMOTEIO; 121 122 if (rcar_iic_set_addr(dev, msg->addr, 1) != 0) 123 goto err; 124 125 udelay(10); 126 127 writeb(RCAR_IIC_ICCR_ICE | RCAR_IIC_ICCR_SCP, 128 priv->base + RCAR_IIC_ICCR); 129 130 for (i = 0; i < msg->len; i++) { 131 if (sh_irq_dte_with_tack(dev) != 0) 132 goto err; 133 134 msg->buf[i] = readb(priv->base + RCAR_IIC_ICDR) & 0xff; 135 136 if (msg->len - 1 == i) { 137 writeb(RCAR_IIC_ICCR_ICE | RCAR_IIC_ICCR_RACK, 138 priv->base + RCAR_IIC_ICCR); 139 } 140 } 141 142 sh_irq_busy(dev); 143 ret = 0; 144 145err: 146 rcar_iic_finish(dev); 147 return ret; 148} 149 150static int rcar_iic_write_common(struct udevice *dev, struct i2c_msg *msg) 151{ 152 struct rcar_iic_priv *priv = dev_get_priv(dev); 153 int i, ret = -EREMOTEIO; 154 155 if (rcar_iic_set_addr(dev, msg->addr, 0) != 0) 156 goto err; 157 158 udelay(10); 159 160 for (i = 0; i < msg->len; i++) { 161 writeb(msg->buf[i], priv->base + RCAR_IIC_ICDR); 162 if (sh_irq_dte_with_tack(dev) != 0) 163 goto err; 164 } 165 166 if (msg->flags & I2C_M_STOP) { 167 writeb(RCAR_IIC_ICCR_ICE | RCAR_IIC_ICCR_RTS, 168 priv->base + RCAR_IIC_ICCR); 169 if (sh_irq_dte_with_tack(dev) != 0) 170 goto err; 171 } 172 173 sh_irq_busy(dev); 174 ret = 0; 175 176err: 177 rcar_iic_finish(dev); 178 return ret; 179} 180 181static int rcar_iic_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs) 182{ 183 int ret; 184 185 for (; nmsgs > 0; nmsgs--, msg++) { 186 if (msg->flags & I2C_M_RD) 187 ret = rcar_iic_read_common(dev, msg); 188 else 189 ret = rcar_iic_write_common(dev, msg); 190 191 if (ret) 192 return -EREMOTEIO; 193 } 194 195 return ret; 196} 197 198static int rcar_iic_set_speed(struct udevice *dev, uint speed) 199{ 200 struct rcar_iic_priv *priv = dev_get_priv(dev); 201 const unsigned int ratio_high = 4; 202 const unsigned int ratio_low = 5; 203 int clkrate, denom; 204 205 clkrate = clk_get_rate(&priv->clk); 206 if (clkrate < 0) 207 return clkrate; 208 209 /* 210 * Calculate the value for ICCL and ICCH. From the data sheet: 211 * iccl = (p-clock / transfer-rate) * (L / (L + H)) 212 * icch = (p clock / transfer rate) * (H / (L + H)) 213 * where L and H are the SCL low and high ratio. 214 */ 215 denom = speed * (ratio_high + ratio_low); 216 priv->iccl = DIV_ROUND_CLOSEST(clkrate * ratio_low, denom); 217 priv->icch = DIV_ROUND_CLOSEST(clkrate * ratio_high, denom); 218 219 return 0; 220} 221 222static int rcar_iic_probe_chip(struct udevice *dev, uint addr, uint flags) 223{ 224 struct rcar_iic_priv *priv = dev_get_priv(dev); 225 int ret; 226 227 rcar_iic_set_addr(dev, addr, 1); 228 writeb(RCAR_IIC_ICCR_ICE | RCAR_IIC_ICCR_SCP, 229 priv->base + RCAR_IIC_ICCR); 230 ret = sh_irq_dte_with_tack(dev); 231 rcar_iic_finish(dev); 232 233 return ret; 234} 235 236static int rcar_iic_probe(struct udevice *dev) 237{ 238 struct rcar_iic_priv *priv = dev_get_priv(dev); 239 int ret; 240 241 priv->base = dev_read_addr_ptr(dev); 242 243 ret = clk_get_by_index(dev, 0, &priv->clk); 244 if (ret) 245 return ret; 246 247 ret = clk_enable(&priv->clk); 248 if (ret) 249 return ret; 250 251 rcar_iic_finish(dev); 252 253 return rcar_iic_set_speed(dev, I2C_SPEED_STANDARD_RATE); 254} 255 256static const struct dm_i2c_ops rcar_iic_ops = { 257 .xfer = rcar_iic_xfer, 258 .probe_chip = rcar_iic_probe_chip, 259 .set_bus_speed = rcar_iic_set_speed, 260}; 261 262static const struct udevice_id rcar_iic_ids[] = { 263 { .compatible = "renesas,rmobile-iic" }, 264 { } 265}; 266 267U_BOOT_DRIVER(iic_rcar) = { 268 .name = "iic_rcar", 269 .id = UCLASS_I2C, 270 .of_match = rcar_iic_ids, 271 .probe = rcar_iic_probe, 272 .priv_auto = sizeof(struct rcar_iic_priv), 273 .ops = &rcar_iic_ops, 274}; 275