drivers/i2c/cros_ec_ldo.c

   1 /*
   2  * Copyright (c) 2015 Google, Inc
   3  * Written by Simon Glass <sjg@chromium.org>
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #include <common.h>
   9 #include <dm.h>
  10 #include <cros_ec.h>
  11 #include <errno.h>
  12 #include <i2c.h>
  13 #include <power/tps65090.h>
  14
  15 static int cros_ec_ldo_set_bus_speed(struct udevice *dev, unsigned int speed)
  16 {
  17         return 0;
  18 }
  19
  20 static int cros_ec_ldo_xfer(struct udevice *dev, struct i2c_msg *msg,
  21                             int nmsgs)
  22 {
  23         bool is_read = nmsgs > 1;
  24         int fet_id, ret;
  25
  26         /*
  27          * Look for reads and writes of the LDO registers. In either case the
  28          * first message is a write with the register number as the first byte.
  29          */
  30         if (!nmsgs || !msg->len || (msg->flags & I2C_M_RD)) {
  31                 debug("%s: Invalid message\n", __func__);
  32                 goto err;
  33         }
  34
  35         fet_id = msg->buf[0] - REG_FET_BASE;
  36         if (fet_id < 1 || fet_id > MAX_FET_NUM) {
  37                 debug("%s: Invalid FET %d\n", __func__, fet_id);
  38                 goto err;
  39         }
  40
  41         if (is_read) {
  42                 uint8_t state;
  43
  44                 ret = cros_ec_get_ldo(dev->parent, fet_id, &state);
  45                 if (!ret)
  46                         msg[1].buf[0] = state ?
  47                                 FET_CTRL_ENFET | FET_CTRL_PGFET : 0;
  48         } else {
  49                 bool on = msg->buf[1] & FET_CTRL_ENFET;
  50
  51                 ret = cros_ec_set_ldo(dev->parent, fet_id, on);
  52         }
  53
  54         return ret;
  55
  56 err:
  57         /* Indicate that the message is unimplemented */
  58         return -ENOSYS;
  59 }
  60
  61 static const struct dm_i2c_ops cros_ec_i2c_ops = {
  62         .xfer           = cros_ec_ldo_xfer,
  63         .set_bus_speed  = cros_ec_ldo_set_bus_speed,
  64 };
  65
  66 static const struct udevice_id cros_ec_i2c_ids[] = {
  67         { .compatible = "google,cros-ec-ldo-tunnel" },
  68         { }
  69 };
  70
  71 U_BOOT_DRIVER(cros_ec_ldo) = {
  72         .name   = "cros_ec_ldo_tunnel",
  73         .id     = UCLASS_I2C,
  74         .of_match = cros_ec_i2c_ids,
  75         .ops    = &cros_ec_i2c_ops,
  76 };