drivers/rtc/i2c_rtc_emul.c

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