drivers/i2c/cros_ec_ldo.c

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