Commit 4ab6174e authored by Simon Glass's avatar Simon Glass Committed by Samuel Ortiz

mfd: Add ChromeOS EC implementation

This is the base EC implementation, which provides a high level
interface to the EC for use by the rest of the kernel. The actual
communcations is dealt with by a separate protocol driver which
registers itself with this interface.

Interrupts are passed on through a notifier.

A simple message structure is used to pass messages to the
protocol driver.
Signed-off-by: default avatarSimon Glass <sjg@chromium.org>
Signed-off-by: default avatarChe-Liang Chiou <clchiou@chromium.org>
Signed-off-by: default avatarJonathan Kliegman <kliegs@chromium.org>
Signed-off-by: default avatarLuigi Semenzato <semenzato@chromium.org>
Signed-off-by: default avatarOlof Johansson <olofj@chromium.org>
Signed-off-by: default avatarVincent Palatin <vpalatin@chromium.org>
Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
parent deaf39ef
ChromeOS Embedded Controller
Google's ChromeOS EC is a Cortex-M device which talks to the AP and
implements various function such as keyboard and battery charging.
The EC can be connect through various means (I2C, SPI, LPC) and the
compatible string used depends on the inteface. Each connection method has
its own driver which connects to the top level interface-agnostic EC driver.
Other Linux driver (such as cros-ec-keyb for the matrix keyboard) connect to
the top-level driver.
Required properties (I2C):
- compatible: "google,cros-ec-i2c"
- reg: I2C slave address
Required properties (SPI):
- compatible: "google,cros-ec-spi"
- reg: SPI chip select
Required properties (LPC):
- compatible: "google,cros-ec-lpc"
- reg: List of (IO address, size) pairs defining the interface uses
Example for I2C:
i2c@12CA0000 {
cros-ec@1e {
reg = <0x1e>;
compatible = "google,cros-ec-i2c";
interrupts = <14 0>;
interrupt-parent = <&wakeup_eint>;
wakeup-source;
};
Example for SPI:
spi@131b0000 {
ec@0 {
compatible = "google,cros-ec-spi";
reg = <0x0>;
interrupts = <14 0>;
interrupt-parent = <&wakeup_eint>;
wakeup-source;
spi-max-frequency = <5000000>;
controller-data {
cs-gpio = <&gpf0 3 4 3 0>;
samsung,spi-cs;
samsung,spi-feedback-delay = <2>;
};
};
};
Example for LPC is not supplied as it is not yet implemented.
...@@ -21,6 +21,14 @@ config MFD_88PM860X ...@@ -21,6 +21,14 @@ config MFD_88PM860X
select individual components like voltage regulators, RTC and select individual components like voltage regulators, RTC and
battery-charger under the corresponding menus. battery-charger under the corresponding menus.
config MFD_CROS_EC
tristate "Support ChromeOS Embedded Controller"
help
If you say Y here you get support for the ChromeOS Embedded
Controller (EC) providing keyboard, battery and power services.
You also ned to enable the driver for the bus you are using. The
protocol for talking to the EC is defined by the bus driver.
config MFD_88PM800 config MFD_88PM800
tristate "Support Marvell 88PM800" tristate "Support Marvell 88PM800"
depends on I2C=y && GENERIC_HARDIRQS depends on I2C=y && GENERIC_HARDIRQS
......
...@@ -8,6 +8,7 @@ obj-$(CONFIG_MFD_88PM800) += 88pm800.o 88pm80x.o ...@@ -8,6 +8,7 @@ obj-$(CONFIG_MFD_88PM800) += 88pm800.o 88pm80x.o
obj-$(CONFIG_MFD_88PM805) += 88pm805.o 88pm80x.o obj-$(CONFIG_MFD_88PM805) += 88pm805.o 88pm80x.o
obj-$(CONFIG_MFD_SM501) += sm501.o obj-$(CONFIG_MFD_SM501) += sm501.o
obj-$(CONFIG_MFD_ASIC3) += asic3.o tmio_core.o obj-$(CONFIG_MFD_ASIC3) += asic3.o tmio_core.o
obj-$(CONFIG_MFD_CROS_EC) += cros_ec.o
rtsx_pci-objs := rtsx_pcr.o rts5209.o rts5229.o rtl8411.o rts5227.o rtsx_pci-objs := rtsx_pcr.o rts5209.o rts5229.o rtl8411.o rts5227.o
obj-$(CONFIG_MFD_RTSX_PCI) += rtsx_pci.o obj-$(CONFIG_MFD_RTSX_PCI) += rtsx_pci.o
......
/*
* ChromeOS EC multi-function device
*
* Copyright (C) 2012 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.
*
* The ChromeOS EC multi function device is used to mux all the requests
* to the EC device for its multiple features: keyboard controller,
* battery charging and regulator control, firmware update.
*/
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/mfd/core.h>
#include <linux/mfd/cros_ec.h>
#include <linux/mfd/cros_ec_commands.h>
int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
struct cros_ec_msg *msg)
{
uint8_t *out;
int csum, i;
BUG_ON(msg->out_len > EC_HOST_PARAM_SIZE);
out = ec_dev->dout;
out[0] = EC_CMD_VERSION0 + msg->version;
out[1] = msg->cmd;
out[2] = msg->out_len;
csum = out[0] + out[1] + out[2];
for (i = 0; i < msg->out_len; i++)
csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->out_buf[i];
out[EC_MSG_TX_HEADER_BYTES + msg->out_len] = (uint8_t)(csum & 0xff);
return EC_MSG_TX_PROTO_BYTES + msg->out_len;
}
static int cros_ec_command_sendrecv(struct cros_ec_device *ec_dev,
uint16_t cmd, void *out_buf, int out_len,
void *in_buf, int in_len)
{
struct cros_ec_msg msg;
msg.version = cmd >> 8;
msg.cmd = cmd & 0xff;
msg.out_buf = out_buf;
msg.out_len = out_len;
msg.in_buf = in_buf;
msg.in_len = in_len;
return ec_dev->command_xfer(ec_dev, &msg);
}
static int cros_ec_command_recv(struct cros_ec_device *ec_dev,
uint16_t cmd, void *buf, int buf_len)
{
return cros_ec_command_sendrecv(ec_dev, cmd, NULL, 0, buf, buf_len);
}
static int cros_ec_command_send(struct cros_ec_device *ec_dev,
uint16_t cmd, void *buf, int buf_len)
{
return cros_ec_command_sendrecv(ec_dev, cmd, buf, buf_len, NULL, 0);
}
static irqreturn_t ec_irq_thread(int irq, void *data)
{
struct cros_ec_device *ec_dev = data;
if (device_may_wakeup(ec_dev->dev))
pm_wakeup_event(ec_dev->dev, 0);
blocking_notifier_call_chain(&ec_dev->event_notifier, 1, ec_dev);
return IRQ_HANDLED;
}
static struct mfd_cell cros_devs[] = {
{
.name = "cros-ec-keyb",
.id = 1,
.of_compatible = "google,cros-ec-keyb",
},
};
int cros_ec_register(struct cros_ec_device *ec_dev)
{
struct device *dev = ec_dev->dev;
int err = 0;
BLOCKING_INIT_NOTIFIER_HEAD(&ec_dev->event_notifier);
ec_dev->command_send = cros_ec_command_send;
ec_dev->command_recv = cros_ec_command_recv;
ec_dev->command_sendrecv = cros_ec_command_sendrecv;
if (ec_dev->din_size) {
ec_dev->din = kmalloc(ec_dev->din_size, GFP_KERNEL);
if (!ec_dev->din) {
err = -ENOMEM;
goto fail_din;
}
}
if (ec_dev->dout_size) {
ec_dev->dout = kmalloc(ec_dev->dout_size, GFP_KERNEL);
if (!ec_dev->dout) {
err = -ENOMEM;
goto fail_dout;
}
}
if (!ec_dev->irq) {
dev_dbg(dev, "no valid IRQ: %d\n", ec_dev->irq);
goto fail_irq;
}
err = request_threaded_irq(ec_dev->irq, NULL, ec_irq_thread,
IRQF_TRIGGER_LOW | IRQF_ONESHOT,
"chromeos-ec", ec_dev);
if (err) {
dev_err(dev, "request irq %d: error %d\n", ec_dev->irq, err);
goto fail_irq;
}
err = mfd_add_devices(dev, 0, cros_devs,
ARRAY_SIZE(cros_devs),
NULL, ec_dev->irq, NULL);
if (err) {
dev_err(dev, "failed to add mfd devices\n");
goto fail_mfd;
}
dev_info(dev, "Chrome EC (%s)\n", ec_dev->name);
return 0;
fail_mfd:
free_irq(ec_dev->irq, ec_dev);
fail_irq:
kfree(ec_dev->dout);
fail_dout:
kfree(ec_dev->din);
fail_din:
return err;
}
int cros_ec_remove(struct cros_ec_device *ec_dev)
{
mfd_remove_devices(ec_dev->dev);
free_irq(ec_dev->irq, ec_dev);
kfree(ec_dev->dout);
kfree(ec_dev->din);
return 0;
}
#ifdef CONFIG_PM_SLEEP
int cros_ec_suspend(struct cros_ec_device *ec_dev)
{
struct device *dev = ec_dev->dev;
if (device_may_wakeup(dev))
ec_dev->wake_enabled = !enable_irq_wake(ec_dev->irq);
disable_irq(ec_dev->irq);
ec_dev->was_wake_device = ec_dev->wake_enabled;
return 0;
}
int cros_ec_resume(struct cros_ec_device *ec_dev)
{
enable_irq(ec_dev->irq);
if (ec_dev->wake_enabled) {
disable_irq_wake(ec_dev->irq);
ec_dev->wake_enabled = 0;
}
return 0;
}
#endif
/*
* ChromeOS EC multi-function device
*
* Copyright (C) 2012 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.
*/
#ifndef __LINUX_MFD_CROS_EC_H
#define __LINUX_MFD_CROS_EC_H
#include <linux/mfd/cros_ec_commands.h>
/*
* Command interface between EC and AP, for LPC, I2C and SPI interfaces.
*/
enum {
EC_MSG_TX_HEADER_BYTES = 3,
EC_MSG_TX_TRAILER_BYTES = 1,
EC_MSG_TX_PROTO_BYTES = EC_MSG_TX_HEADER_BYTES +
EC_MSG_TX_TRAILER_BYTES,
EC_MSG_RX_PROTO_BYTES = 3,
/* Max length of messages */
EC_MSG_BYTES = EC_HOST_PARAM_SIZE + EC_MSG_TX_PROTO_BYTES,
};
/**
* struct cros_ec_msg - A message sent to the EC, and its reply
*
* @version: Command version number (often 0)
* @cmd: Command to send (EC_CMD_...)
* @out_buf: Outgoing payload (to EC)
* @outlen: Outgoing length
* @in_buf: Incoming payload (from EC)
* @in_len: Incoming length
*/
struct cros_ec_msg {
u8 version;
u8 cmd;
uint8_t *out_buf;
int out_len;
uint8_t *in_buf;
int in_len;
};
/**
* struct cros_ec_device - Information about a ChromeOS EC device
*
* @name: Name of this EC interface
* @priv: Private data
* @irq: Interrupt to use
* @din: input buffer (from EC)
* @dout: output buffer (to EC)
* \note
* These two buffers will always be dword-aligned and include enough
* space for up to 7 word-alignment bytes also, so we can ensure that
* the body of the message is always dword-aligned (64-bit).
*
* We use this alignment to keep ARM and x86 happy. Probably word
* alignment would be OK, there might be a small performance advantage
* to using dword.
* @din_size: size of din buffer
* @dout_size: size of dout buffer
* @command_send: send a command
* @command_recv: receive a command
* @ec_name: name of EC device (e.g. 'chromeos-ec')
* @phys_name: name of physical comms layer (e.g. 'i2c-4')
* @parent: pointer to parent device (e.g. i2c or spi device)
* @dev: Device pointer
* dev_lock: Lock to prevent concurrent access
* @wake_enabled: true if this device can wake the system from sleep
* @was_wake_device: true if this device was set to wake the system from
* sleep at the last suspend
* @event_notifier: interrupt event notifier for transport devices
*/
struct cros_ec_device {
const char *name;
void *priv;
int irq;
uint8_t *din;
uint8_t *dout;
int din_size;
int dout_size;
int (*command_send)(struct cros_ec_device *ec,
uint16_t cmd, void *out_buf, int out_len);
int (*command_recv)(struct cros_ec_device *ec,
uint16_t cmd, void *in_buf, int in_len);
int (*command_sendrecv)(struct cros_ec_device *ec,
uint16_t cmd, void *out_buf, int out_len,
void *in_buf, int in_len);
int (*command_xfer)(struct cros_ec_device *ec,
struct cros_ec_msg *msg);
const char *ec_name;
const char *phys_name;
struct device *parent;
/* These are --private-- fields - do not assign */
struct device *dev;
struct mutex dev_lock;
bool wake_enabled;
bool was_wake_device;
struct blocking_notifier_head event_notifier;
};
/**
* cros_ec_suspend - Handle a suspend operation for the ChromeOS EC device
*
* This can be called by drivers to handle a suspend event.
*
* ec_dev: Device to suspend
* @return 0 if ok, -ve on error
*/
int cros_ec_suspend(struct cros_ec_device *ec_dev);
/**
* cros_ec_resume - Handle a resume operation for the ChromeOS EC device
*
* This can be called by drivers to handle a resume event.
*
* @ec_dev: Device to resume
* @return 0 if ok, -ve on error
*/
int cros_ec_resume(struct cros_ec_device *ec_dev);
/**
* cros_ec_prepare_tx - Prepare an outgoing message in the output buffer
*
* This is intended to be used by all ChromeOS EC drivers, but at present
* only SPI uses it. Once LPC uses the same protocol it can start using it.
* I2C could use it now, with a refactor of the existing code.
*
* @ec_dev: Device to register
* @msg: Message to write
*/
int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
struct cros_ec_msg *msg);
/**
* cros_ec_remove - Remove a ChromeOS EC
*
* Call this to deregister a ChromeOS EC. After this you should call
* cros_ec_free().
*
* @ec_dev: Device to register
* @return 0 if ok, -ve on error
*/
int cros_ec_remove(struct cros_ec_device *ec_dev);
/**
* cros_ec_register - Register a new ChromeOS EC, using the provided info
*
* Before calling this, allocate a pointer to a new device and then fill
* in all the fields up to the --private-- marker.
*
* @ec_dev: Device to register
* @return 0 if ok, -ve on error
*/
int cros_ec_register(struct cros_ec_device *ec_dev);
#endif /* __LINUX_MFD_CROS_EC_H */
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