drivers/i2c/rcar_iic.c

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