git.sur5r.net Git - u-boot/blob - 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         int i;
  62
  63         for (i = 0; i < IRQ_WAIT; i++) {
  64                 if (RCAR_IC_DTE & readb(priv->base + RCAR_IIC_ICSR))
  65                         break;
  66                 if (RCAR_IC_TACK & readb(priv->base + RCAR_IIC_ICSR))
  67                         return -ETIMEDOUT;
  68                 udelay(10);
  69         }
  70         return 0;
  71 }
  72
  73 static void sh_irq_busy(struct udevice *dev)
  74 {
  75         struct rcar_iic_priv *priv = dev_get_priv(dev);
  76         int i;
  77
  78         for (i = 0; i < IRQ_WAIT; i++) {
  79                 if (!(RCAR_IC_BUSY & readb(priv->base + RCAR_IIC_ICSR)))
  80                         break;
  81                 udelay(10);
  82         }
  83 }
  84
  85 static int rcar_iic_set_addr(struct udevice *dev, u8 chip, u8 read)
  86 {
  87         struct rcar_iic_priv *priv = dev_get_priv(dev);
  88
  89         clrbits_8(priv->base + RCAR_IIC_ICCR, RCAR_IIC_ICCR_ICE);
  90         setbits_8(priv->base + RCAR_IIC_ICCR, RCAR_IIC_ICCR_ICE);
  91
  92         writeb(priv->iccl, priv->base + RCAR_IIC_ICCL);
  93         writeb(priv->icch, priv->base + RCAR_IIC_ICCH);
  94         writeb(RCAR_IC_TACK, priv->base + RCAR_IIC_ICIC);
  95
  96         writeb(RCAR_IIC_ICCR_ICE | RCAR_IIC_ICCR_RTS | RCAR_IIC_ICCR_BUSY,
  97                priv->base + RCAR_IIC_ICCR);
  98         sh_irq_dte(dev);
  99
 100         clrbits_8(priv->base + RCAR_IIC_ICSR, RCAR_IC_TACK);
 101         writeb(chip << 1 | read, priv->base + RCAR_IIC_ICDR);
 102         return sh_irq_dte_with_tack(dev);
 103 }
 104
 105 static void rcar_iic_finish(struct udevice *dev)
 106 {
 107         struct rcar_iic_priv *priv = dev_get_priv(dev);
 108
 109         writeb(0, priv->base + RCAR_IIC_ICSR);
 110         clrbits_8(priv->base + RCAR_IIC_ICCR, RCAR_IIC_ICCR_ICE);
 111 }
 112
 113 static int rcar_iic_read_common(struct udevice *dev, struct i2c_msg *msg)
 114 {
 115         struct rcar_iic_priv *priv = dev_get_priv(dev);
 116         int i, ret = -EREMOTEIO;
 117
 118         if (rcar_iic_set_addr(dev, msg->addr, 1) != 0)
 119                 goto err;
 120
 121         udelay(10);
 122
 123         writeb(RCAR_IIC_ICCR_ICE | RCAR_IIC_ICCR_SCP,
 124                priv->base + RCAR_IIC_ICCR);
 125
 126         for (i = 0; i < msg->len; i++) {
 127                 if (sh_irq_dte_with_tack(dev) != 0)
 128                         goto err;
 129
 130                 msg->buf[i] = readb(priv->base + RCAR_IIC_ICDR) & 0xff;
 131
 132                 if (msg->len - 1 == i) {
 133                         writeb(RCAR_IIC_ICCR_ICE | RCAR_IIC_ICCR_RACK,
 134                                priv->base + RCAR_IIC_ICCR);
 135                 }
 136         }
 137
 138         sh_irq_busy(dev);
 139         ret = 0;
 140
 141 err:
 142         rcar_iic_finish(dev);
 143         return ret;
 144 }
 145
 146 static int rcar_iic_write_common(struct udevice *dev, struct i2c_msg *msg)
 147 {
 148         struct rcar_iic_priv *priv = dev_get_priv(dev);
 149         int i, ret = -EREMOTEIO;
 150
 151         if (rcar_iic_set_addr(dev, msg->addr, 0) != 0)
 152                 goto err;
 153
 154         udelay(10);
 155
 156         for (i = 0; i < msg->len; i++) {
 157                 writeb(msg->buf[i], priv->base + RCAR_IIC_ICDR);
 158                 if (sh_irq_dte_with_tack(dev) != 0)
 159                         goto err;
 160         }
 161
 162         if (msg->flags & I2C_M_STOP) {
 163                 writeb(RCAR_IIC_ICCR_ICE | RCAR_IIC_ICCR_RTS,
 164                        priv->base + RCAR_IIC_ICCR);
 165                 if (sh_irq_dte_with_tack(dev) != 0)
 166                         goto err;
 167         }
 168
 169         sh_irq_busy(dev);
 170         ret = 0;
 171
 172 err:
 173         rcar_iic_finish(dev);
 174         return ret;
 175 }
 176
 177 static int rcar_iic_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs)
 178 {
 179         int ret;
 180
 181         for (; nmsgs > 0; nmsgs--, msg++) {
 182                 if (msg->flags & I2C_M_RD)
 183                         ret = rcar_iic_read_common(dev, msg);
 184                 else
 185                         ret = rcar_iic_write_common(dev, msg);
 186
 187                 if (ret)
 188                         return -EREMOTEIO;
 189         }
 190
 191         return ret;
 192 }
 193
 194 static int rcar_iic_set_speed(struct udevice *dev, uint speed)
 195 {
 196         struct rcar_iic_priv *priv = dev_get_priv(dev);
 197         const unsigned int ratio_high = 4;
 198         const unsigned int ratio_low = 5;
 199         int clkrate, denom;
 200
 201         clkrate = clk_get_rate(&priv->clk);
 202         if (clkrate < 0)
 203                 return clkrate;
 204
 205         /*
 206          * Calculate the value for ICCL and ICCH. From the data sheet:
 207          * iccl = (p-clock / transfer-rate) * (L / (L + H))
 208          * icch = (p clock / transfer rate) * (H / (L + H))
 209          * where L and H are the SCL low and high ratio.
 210          */
 211         denom = speed * (ratio_high + ratio_low);
 212         priv->iccl = DIV_ROUND_CLOSEST(clkrate * ratio_low, denom);
 213         priv->icch = DIV_ROUND_CLOSEST(clkrate * ratio_high, denom);
 214
 215         return 0;
 216 }
 217
 218 static int rcar_iic_probe_chip(struct udevice *dev, uint addr, uint flags)
 219 {
 220         struct rcar_iic_priv *priv = dev_get_priv(dev);
 221         int ret;
 222
 223         rcar_iic_set_addr(dev, addr, 1);
 224         writeb(RCAR_IIC_ICCR_ICE | RCAR_IIC_ICCR_SCP,
 225                priv->base + RCAR_IIC_ICCR);
 226         ret = sh_irq_dte_with_tack(dev);
 227         rcar_iic_finish(dev);
 228
 229         return ret;
 230 }
 231
 232 static int rcar_iic_probe(struct udevice *dev)
 233 {
 234         struct rcar_iic_priv *priv = dev_get_priv(dev);
 235         int ret;
 236
 237         priv->base = dev_read_addr_ptr(dev);
 238
 239         ret = clk_get_by_index(dev, 0, &priv->clk);
 240         if (ret)
 241                 return ret;
 242
 243         ret = clk_enable(&priv->clk);
 244         if (ret)
 245                 return ret;
 246
 247         rcar_iic_finish(dev);
 248
 249         return rcar_iic_set_speed(dev, 100000);
 250 }
 251
 252 static const struct dm_i2c_ops rcar_iic_ops = {
 253         .xfer           = rcar_iic_xfer,
 254         .probe_chip     = rcar_iic_probe_chip,
 255         .set_bus_speed  = rcar_iic_set_speed,
 256 };
 257
 258 static const struct udevice_id rcar_iic_ids[] = {
 259         { .compatible = "renesas,rmobile-iic" },
 260         { }
 261 };
 262
 263 U_BOOT_DRIVER(iic_rcar) = {
 264         .name           = "iic_rcar",
 265         .id             = UCLASS_I2C,
 266         .of_match       = rcar_iic_ids,
 267         .probe          = rcar_iic_probe,
 268         .priv_auto_alloc_size = sizeof(struct rcar_iic_priv),
 269         .ops            = &rcar_iic_ops,
 270 };