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authorJavier Martinez Canillas <javier.martinez@collabora.co.uk>2015-06-09 13:04:44 +0200
committerLee Jones <lee.jones@linaro.org>2015-06-15 13:18:20 +0100
commit062476f24aa7cf714169342cc50626fd9bbb93da (patch)
tree5af8fcb6bacea36579c79929a57b572d14982691 /drivers/platform/chrome
parent256ab950bdaa8797b7bac8fc11a567030d486304 (diff)
downloadlinux-062476f24aa7cf714169342cc50626fd9bbb93da.tar.bz2
mfd: cros_ec: Move protocol helpers out of the MFD driver
The MFD driver should only have the logic to instantiate its child devices and setup any shared resources that will be used by the subdevices drivers. The cros_ec MFD is more complex than expected since it also has helpers to communicate with the EC. So the driver will only get more bigger as other protocols are supported in the future. So move the communication protocol helpers to its own driver as drivers/platform/chrome/cros_ec_proto.c. Suggested-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk> Tested-by: Heiko Stuebner <heiko@sntech.de> Acked-by: Lee Jones <lee.jones@linaro.org> Acked-by: Olof Johansson <olof@lixom.net> Signed-off-by: Lee Jones <lee.jones@linaro.org>
Diffstat (limited to 'drivers/platform/chrome')
-rw-r--r--drivers/platform/chrome/Kconfig9
-rw-r--r--drivers/platform/chrome/Makefile1
-rw-r--r--drivers/platform/chrome/cros_ec_proto.c115
3 files changed, 123 insertions, 2 deletions
diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
index 2a6531a5fde8..cb1329919527 100644
--- a/drivers/platform/chrome/Kconfig
+++ b/drivers/platform/chrome/Kconfig
@@ -40,7 +40,7 @@ config CHROMEOS_PSTORE
config CROS_EC_CHARDEV
tristate "Chrome OS Embedded Controller userspace device interface"
- depends on MFD_CROS_EC
+ depends on CROS_EC_PROTO
---help---
This driver adds support to talk with the ChromeOS EC from userspace.
@@ -49,7 +49,7 @@ config CROS_EC_CHARDEV
config CROS_EC_LPC
tristate "ChromeOS Embedded Controller (LPC)"
- depends on MFD_CROS_EC && (X86 || COMPILE_TEST)
+ depends on MFD_CROS_EC && CROS_EC_PROTO && (X86 || COMPILE_TEST)
help
If you say Y here, you get support for talking to the ChromeOS EC
over an LPC bus. This uses a simple byte-level protocol with a
@@ -59,4 +59,9 @@ config CROS_EC_LPC
To compile this driver as a module, choose M here: the
module will be called cros_ec_lpc.
+config CROS_EC_PROTO
+ bool
+ help
+ ChromeOS EC communication protocol helpers.
+
endif # CHROMEOS_PLATFORMS
diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
index bd8d8601e875..4a11b010f5d8 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -4,3 +4,4 @@ obj-$(CONFIG_CHROMEOS_PSTORE) += chromeos_pstore.o
cros_ec_devs-objs := cros_ec_dev.o cros_ec_sysfs.o cros_ec_lightbar.o
obj-$(CONFIG_CROS_EC_CHARDEV) += cros_ec_devs.o
obj-$(CONFIG_CROS_EC_LPC) += cros_ec_lpc.o
+obj-$(CONFIG_CROS_EC_PROTO) += cros_ec_proto.o
diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
new file mode 100644
index 000000000000..58e98a24fd08
--- /dev/null
+++ b/drivers/platform/chrome/cros_ec_proto.c
@@ -0,0 +1,115 @@
+/*
+ * ChromeOS EC communication protocol helper functions
+ *
+ * Copyright (C) 2015 Google, Inc
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/mfd/cros_ec.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#define EC_COMMAND_RETRIES 50
+
+int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
+ struct cros_ec_command *msg)
+{
+ uint8_t *out;
+ int csum, i;
+
+ BUG_ON(msg->outsize > EC_PROTO2_MAX_PARAM_SIZE);
+ out = ec_dev->dout;
+ out[0] = EC_CMD_VERSION0 + msg->version;
+ out[1] = msg->command;
+ out[2] = msg->outsize;
+ csum = out[0] + out[1] + out[2];
+ for (i = 0; i < msg->outsize; i++)
+ csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->data[i];
+ out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = (uint8_t)(csum & 0xff);
+
+ return EC_MSG_TX_PROTO_BYTES + msg->outsize;
+}
+EXPORT_SYMBOL(cros_ec_prepare_tx);
+
+int cros_ec_check_result(struct cros_ec_device *ec_dev,
+ struct cros_ec_command *msg)
+{
+ switch (msg->result) {
+ case EC_RES_SUCCESS:
+ return 0;
+ case EC_RES_IN_PROGRESS:
+ dev_dbg(ec_dev->dev, "command 0x%02x in progress\n",
+ msg->command);
+ return -EAGAIN;
+ default:
+ dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n",
+ msg->command, msg->result);
+ return 0;
+ }
+}
+EXPORT_SYMBOL(cros_ec_check_result);
+
+int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
+ struct cros_ec_command *msg)
+{
+ int ret;
+
+ mutex_lock(&ec_dev->lock);
+ ret = ec_dev->cmd_xfer(ec_dev, msg);
+ if (msg->result == EC_RES_IN_PROGRESS) {
+ int i;
+ struct cros_ec_command *status_msg;
+ struct ec_response_get_comms_status *status;
+
+ status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status),
+ GFP_KERNEL);
+ if (!status_msg) {
+ ret = -ENOMEM;
+ goto exit;
+ }
+
+ status_msg->version = 0;
+ status_msg->command = EC_CMD_GET_COMMS_STATUS;
+ status_msg->insize = sizeof(*status);
+ status_msg->outsize = 0;
+
+ /*
+ * Query the EC's status until it's no longer busy or
+ * we encounter an error.
+ */
+ for (i = 0; i < EC_COMMAND_RETRIES; i++) {
+ usleep_range(10000, 11000);
+
+ ret = ec_dev->cmd_xfer(ec_dev, status_msg);
+ if (ret < 0)
+ break;
+
+ msg->result = status_msg->result;
+ if (status_msg->result != EC_RES_SUCCESS)
+ break;
+
+ status = (struct ec_response_get_comms_status *)
+ status_msg->data;
+ if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
+ break;
+ }
+
+ kfree(status_msg);
+ }
+exit:
+ mutex_unlock(&ec_dev->lock);
+
+ return ret;
+}
+EXPORT_SYMBOL(cros_ec_cmd_xfer);