drivers/rtc/i2c_rtc_emul.c

   1 /*
   2  * Simulate an I2C real time clock
   3  *
   4  * Copyright (c) 2015 Google, Inc
   5  * Written by Simon Glass <sjg@chromium.org>
   6  *
   7  * SPDX-License-Identifier:     GPL-2.0+
   8  */
   9
  10 /*
  11  * This is a test driver. It starts off with the current time of the machine,
  12  * but also supports setting the time, using an offset from the current
  13  * clock. This driver is only intended for testing, not accurate
  14  * time-keeping. It does not change the system time.
  15  */
  16
  17 #include <common.h>
  18 #include <dm.h>
  19 #include <i2c.h>
  20 #include <os.h>
  21 #include <rtc.h>
  22 #include <asm/rtc.h>
  23 #include <asm/test.h>
  24
  25 #ifdef DEBUG
  26 #define debug_buffer print_buffer
  27 #else
  28 #define debug_buffer(x, ...)
  29 #endif
  30
  31 DECLARE_GLOBAL_DATA_PTR;
  32
  33 /**
  34  * struct sandbox_i2c_rtc_plat_data - platform data for the RTC
  35  *
  36  * @base_time:          Base system time when RTC device was bound
  37  * @offset:             RTC offset from current system time
  38  * @use_system_time:    true to use system time, false to use @base_time
  39  * @reg:                Register values
  40  */
  41 struct sandbox_i2c_rtc_plat_data {
  42         long base_time;
  43         long offset;
  44         bool use_system_time;
  45         u8 reg[REG_COUNT];
  46 };
  47
  48 struct sandbox_i2c_rtc {
  49         unsigned int offset_secs;
  50 };
  51
  52 long sandbox_i2c_rtc_set_offset(struct udevice *dev, bool use_system_time,
  53                                 int offset)
  54 {
  55         struct sandbox_i2c_rtc_plat_data *plat = dev_get_platdata(dev);
  56         long old_offset;
  57
  58         old_offset = plat->offset;
  59         plat->use_system_time = use_system_time;
  60         if (offset != -1)
  61                 plat->offset = offset;
  62
  63         return old_offset;
  64 }
  65
  66 long sandbox_i2c_rtc_get_set_base_time(struct udevice *dev, long base_time)
  67 {
  68         struct sandbox_i2c_rtc_plat_data *plat = dev_get_platdata(dev);
  69         long old_base_time;
  70
  71         old_base_time = plat->base_time;
  72         if (base_time != -1)
  73                 plat->base_time = base_time;
  74
  75         return old_base_time;
  76 }
  77
  78 static void reset_time(struct udevice *dev)
  79 {
  80         struct sandbox_i2c_rtc_plat_data *plat = dev_get_platdata(dev);
  81         struct rtc_time now;
  82
  83         os_localtime(&now);
  84         plat->base_time = rtc_mktime(&now);
  85         plat->offset = 0;
  86         plat->use_system_time = true;
  87 }
  88
  89 static int sandbox_i2c_rtc_get(struct udevice *dev, struct rtc_time *time)
  90 {
  91         struct sandbox_i2c_rtc_plat_data *plat = dev_get_platdata(dev);
  92         struct rtc_time tm_now;
  93         long now;
  94
  95         if (plat->use_system_time) {
  96                 os_localtime(&tm_now);
  97                 now = rtc_mktime(&tm_now);
  98         } else {
  99                 now = plat->base_time;
 100         }
 101
 102         return rtc_to_tm(now + plat->offset, time);
 103 }
 104
 105 static int sandbox_i2c_rtc_set(struct udevice *dev, const struct rtc_time *time)
 106 {
 107         struct sandbox_i2c_rtc_plat_data *plat = dev_get_platdata(dev);
 108         struct rtc_time tm_now;
 109         long now;
 110
 111         if (plat->use_system_time) {
 112                 os_localtime(&tm_now);
 113                 now = rtc_mktime(&tm_now);
 114         } else {
 115                 now = plat->base_time;
 116         }
 117         plat->offset = rtc_mktime(time) - now;
 118
 119         return 0;
 120 }
 121
 122 /* Update the current time in the registers */
 123 static int sandbox_i2c_rtc_prepare_read(struct udevice *emul)
 124 {
 125         struct sandbox_i2c_rtc_plat_data *plat = dev_get_platdata(emul);
 126         struct rtc_time time;
 127         int ret;
 128
 129         ret = sandbox_i2c_rtc_get(emul, &time);
 130         if (ret)
 131                 return ret;
 132
 133         plat->reg[REG_SEC] = time.tm_sec;
 134         plat->reg[REG_MIN] = time.tm_min;
 135         plat->reg[REG_HOUR] = time.tm_hour;
 136         plat->reg[REG_MDAY] = time.tm_mday;
 137         plat->reg[REG_MON] = time.tm_mon;
 138         plat->reg[REG_YEAR] = time.tm_year - 1900;
 139         plat->reg[REG_WDAY] = time.tm_wday;
 140
 141         return 0;
 142 }
 143
 144 static int sandbox_i2c_rtc_complete_write(struct udevice *emul)
 145 {
 146         struct sandbox_i2c_rtc_plat_data *plat = dev_get_platdata(emul);
 147         struct rtc_time time;
 148         int ret;
 149
 150         time.tm_sec = plat->reg[REG_SEC];
 151         time.tm_min = plat->reg[REG_MIN];
 152         time.tm_hour = plat->reg[REG_HOUR];
 153         time.tm_mday = plat->reg[REG_MDAY];
 154         time.tm_mon = plat->reg[REG_MON];
 155         time.tm_year = plat->reg[REG_YEAR] + 1900;
 156         time.tm_wday = plat->reg[REG_WDAY];
 157
 158         ret = sandbox_i2c_rtc_set(emul, &time);
 159         if (ret)
 160                 return ret;
 161
 162         return 0;
 163 }
 164
 165 static int sandbox_i2c_rtc_xfer(struct udevice *emul, struct i2c_msg *msg,
 166                                 int nmsgs)
 167 {
 168         struct sandbox_i2c_rtc_plat_data *plat = dev_get_platdata(emul);
 169         uint offset = 0;
 170         int ret;
 171
 172         debug("\n%s\n", __func__);
 173         ret = sandbox_i2c_rtc_prepare_read(emul);
 174         if (ret)
 175                 return ret;
 176         for (; nmsgs > 0; nmsgs--, msg++) {
 177                 int len;
 178                 u8 *ptr;
 179
 180                 len = msg->len;
 181                 debug("   %s: msg->len=%d",
 182                       msg->flags & I2C_M_RD ? "read" : "write",
 183                       msg->len);
 184                 if (msg->flags & I2C_M_RD) {
 185                         debug(", offset %x, len %x: ", offset, len);
 186
 187                         /* Read the register */
 188                         memcpy(msg->buf, plat->reg + offset, len);
 189                         memset(msg->buf + len, '\xff', msg->len - len);
 190                         debug_buffer(0, msg->buf, 1, msg->len, 0);
 191                 } else if (len >= 1) {
 192                         ptr = msg->buf;
 193                         offset = *ptr++ & (REG_COUNT - 1);
 194                         len--;
 195                         debug(", set offset %x: ", offset);
 196                         debug_buffer(0, msg->buf, 1, msg->len, 0);
 197
 198                         /* Write the register */
 199                         memcpy(plat->reg + offset, ptr, len);
 200                         if (offset == REG_RESET)
 201                                 reset_time(emul);
 202                 }
 203         }
 204         ret = sandbox_i2c_rtc_complete_write(emul);
 205         if (ret)
 206                 return ret;
 207
 208         return 0;
 209 }
 210
 211 struct dm_i2c_ops sandbox_i2c_rtc_emul_ops = {
 212         .xfer = sandbox_i2c_rtc_xfer,
 213 };
 214
 215 static int sandbox_i2c_rtc_bind(struct udevice *dev)
 216 {
 217         reset_time(dev);
 218
 219         return 0;
 220 }
 221
 222 static const struct udevice_id sandbox_i2c_rtc_ids[] = {
 223         { .compatible = "sandbox,i2c-rtc" },
 224         { }
 225 };
 226
 227 U_BOOT_DRIVER(sandbox_i2c_rtc_emul) = {
 228         .name           = "sandbox_i2c_rtc_emul",
 229         .id             = UCLASS_I2C_EMUL,
 230         .of_match       = sandbox_i2c_rtc_ids,
 231         .bind           = sandbox_i2c_rtc_bind,
 232         .priv_auto_alloc_size = sizeof(struct sandbox_i2c_rtc),
 233         .platdata_auto_alloc_size = sizeof(struct sandbox_i2c_rtc_plat_data),
 234         .ops            = &sandbox_i2c_rtc_emul_ops,
 235 };