drivers/platform/chrome/wilco_ec/properties.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright 2019 Google LLC
   4  */
   5
   6 #include <linux/errno.h>
   7 #include <linux/export.h>
   8 #include <linux/platform_data/wilco-ec.h>
   9 #include <linux/string.h>
  10 #include <linux/types.h>
  11 #include <asm/unaligned.h>
  12
  13 /* Operation code; what the EC should do with the property */
  14 enum ec_property_op {
  15         EC_OP_GET = 0,
  16         EC_OP_SET = 1,
  17 };
  18
  19 struct ec_property_request {
  20         u8 op; /* One of enum ec_property_op */
  21         u8 property_id[4]; /* The 32 bit PID is stored Little Endian */
  22         u8 length;
  23         u8 data[WILCO_EC_PROPERTY_MAX_SIZE];
  24 } __packed;
  25
  26 struct ec_property_response {
  27         u8 reserved[2];
  28         u8 op; /* One of enum ec_property_op */
  29         u8 property_id[4]; /* The 32 bit PID is stored Little Endian */
  30         u8 length;
  31         u8 data[WILCO_EC_PROPERTY_MAX_SIZE];
  32 } __packed;
  33
  34 static int send_property_msg(struct wilco_ec_device *ec,
  35                              struct ec_property_request *rq,
  36                              struct ec_property_response *rs)
  37 {
  38         struct wilco_ec_message ec_msg;
  39         int ret;
  40
  41         memset(&ec_msg, 0, sizeof(ec_msg));
  42         ec_msg.type = WILCO_EC_MSG_PROPERTY;
  43         ec_msg.request_data = rq;
  44         ec_msg.request_size = sizeof(*rq);
  45         ec_msg.response_data = rs;
  46         ec_msg.response_size = sizeof(*rs);
  47
  48         ret = wilco_ec_mailbox(ec, &ec_msg);
  49         if (ret < 0)
  50                 return ret;
  51         if (rs->op != rq->op)
  52                 return -EBADMSG;
  53         if (memcmp(rq->property_id, rs->property_id, sizeof(rs->property_id)))
  54                 return -EBADMSG;
  55
  56         return 0;
  57 }
  58
  59 int wilco_ec_get_property(struct wilco_ec_device *ec,
  60                           struct wilco_ec_property_msg *prop_msg)
  61 {
  62         struct ec_property_request rq;
  63         struct ec_property_response rs;
  64         int ret;
  65
  66         memset(&rq, 0, sizeof(rq));
  67         rq.op = EC_OP_GET;
  68         put_unaligned_le32(prop_msg->property_id, rq.property_id);
  69
  70         ret = send_property_msg(ec, &rq, &rs);
  71         if (ret < 0)
  72                 return ret;
  73
  74         prop_msg->length = rs.length;
  75         memcpy(prop_msg->data, rs.data, rs.length);
  76
  77         return 0;
  78 }
  79 EXPORT_SYMBOL_GPL(wilco_ec_get_property);
  80
  81 int wilco_ec_set_property(struct wilco_ec_device *ec,
  82                           struct wilco_ec_property_msg *prop_msg)
  83 {
  84         struct ec_property_request rq;
  85         struct ec_property_response rs;
  86         int ret;
  87
  88         memset(&rq, 0, sizeof(rq));
  89         rq.op = EC_OP_SET;
  90         put_unaligned_le32(prop_msg->property_id, rq.property_id);
  91         rq.length = prop_msg->length;
  92         memcpy(rq.data, prop_msg->data, prop_msg->length);
  93
  94         ret = send_property_msg(ec, &rq, &rs);
  95         if (ret < 0)
  96                 return ret;
  97         if (rs.length != prop_msg->length)
  98                 return -EBADMSG;
  99
 100         return 0;
 101 }
 102 EXPORT_SYMBOL_GPL(wilco_ec_set_property);
 103
 104 int wilco_ec_get_byte_property(struct wilco_ec_device *ec, u32 property_id,
 105                                u8 *val)
 106 {
 107         struct wilco_ec_property_msg msg;
 108         int ret;
 109
 110         msg.property_id = property_id;
 111
 112         ret = wilco_ec_get_property(ec, &msg);
 113         if (ret < 0)
 114                 return ret;
 115         if (msg.length != 1)
 116                 return -EBADMSG;
 117
 118         *val = msg.data[0];
 119
 120         return 0;
 121 }
 122 EXPORT_SYMBOL_GPL(wilco_ec_get_byte_property);
 123
 124 int wilco_ec_set_byte_property(struct wilco_ec_device *ec, u32 property_id,
 125                                u8 val)
 126 {
 127         struct wilco_ec_property_msg msg;
 128
 129         msg.property_id = property_id;
 130         msg.data[0] = val;
 131         msg.length = 1;
 132
 133         return wilco_ec_set_property(ec, &msg);
 134 }
 135 EXPORT_SYMBOL_GPL(wilco_ec_set_byte_property);