[PATCH v3 0/7] Add cros_ec changes for newer boards

[PATCH v3 0/7] Add cros_ec changes for newer boards

[Doug Anderson]

This series adds the most critical cros_ec changes for newer boards
using cros_ec.  Specifically:
* Fixes timing/locking issues with the previously upstreamed (but
  never used upstream) cros_ec_spi driver.
* Updates the cros_ec header file to the latest version which allows
  us to use newer EC features like i2c tunneling.
* Adds an i2c tunnel driver to allow communication to the EC's i2c
  devices.

This _doesn't_ get the EC driver fully up to speed with what's in the
current Chromium OS trees.  There are a whole slew of cleanup patches
there, an addition of an LPC transport mode, and exports of functions
to userspace.  Once these patches land and we have functionality we
can continue to pick more cleanup patches.

Changes in v3:
- Separate out packet sizing from packet stuffing.
- Get rid of useless dev_dbg.
- Check command_sendrecv against NULL.
- Don't check np against NULL.
- Get rid of useless error on memory alloc fail.
- Get rid of useless platform_set_drvdata(dev, NULL);

Changes in v2:
- Update tunnel binding as per swarren
- Removed i2c20 alias for i2c tunnel

Bill Richardson (1):
  mfd: cros_ec: Sync to the latest cros_ec_commands.h from EC sources

David Hendricks (1):
  mfd: cros_ec: spi: calculate delay between transfers correctly

Doug Anderson (5):
  mfd: cros_ec: spi: Add mutex to cros_ec_spi
  mfd: cros_ec: spi: Make the cros_ec_spi timeout more reliable
  mfd: cros_ec: spi: Increase cros_ec_spi deadline from 5ms to 100ms
  i2c: ChromeOS EC tunnel driver
  ARM: tegra: Add the EC i2c tunnel to tegra124-venice2

 .../devicetree/bindings/i2c/i2c-cros-ec-tunnel.txt |   39 +
 arch/arm/boot/dts/tegra124-venice2.dts             |   26 +
 drivers/i2c/busses/Kconfig                         |    9 +
 drivers/i2c/busses/Makefile                        |    1 +
 drivers/i2c/busses/i2c-cros-ec-tunnel.c            |  318 ++++++
 drivers/mfd/cros_ec.c                              |    7 +-
 drivers/mfd/cros_ec_spi.c                          |   67 +-
 include/linux/mfd/cros_ec.h                        |    4 +-
 include/linux/mfd/cros_ec_commands.h               | 1128 ++++++++++++++++++--
 9 files changed, 1507 insertions(+), 92 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-cros-ec-tunnel.txt
 create mode 100644 drivers/i2c/busses/i2c-cros-ec-tunnel.c

-- 
1.9.1.423.g4596e3a

[PATCH v3 6/7] i2c: ChromeOS EC tunnel driver

[Doug Anderson]

On ARM Chromebooks we have a few devices that are accessed by both the
AP (the main "Application Processor") and the EC (the Embedded
Controller).  These are:
* The battery (sbs-battery).
* The power management unit tps65090.

On the original Samsung ARM Chromebook these devices were on an I2C
bus that was shared between the AP and the EC and arbitrated using
some extranal GPIOs (see i2c-arb-gpio-challenge).

The original arbitration scheme worked well enough but had some
downsides:
* It was nonstandard (not using standard I2C multimaster)
* It only worked if the EC-AP communication was I2C
* It was relatively hard to debug problems (hard to tell if i2c issues
  were caused by the EC, the AP, or some device on the bus).

On the HP Chromebook 11 the design was changed to:
* The AP/EC comms were still i2c, but the battery/tps65090 were no
  longer on the bus used for AP/EC communication.  The battery was
  exposed to the AP through a limited i2c tunnel and tps65090 was
  exposed to the AP through a custom Linux driver.

On the Samsung ARM Chromebook 2 the scheme is changed yet again, now:
* The AP/EC comms are now using SPI for faster speeds.
* The EC's i2c bus is exposed to the AP through a full i2c tunnel.

The upstream "tegra124-venice2" uses the same scheme as the Samsung
ARM Chromebook 2, though it has a different set of components on the
other side of the bus.

This driver supports the scheme used by the Samsung ARM Chromebook 2.
Future patches to this driver could add support for the battery tunnel
on the HP Chromebook 11 (and perhaps could even be used to access
tps65090 on the HP Chromebook 11 instead of using a special driver,
but I haven't researched that enough).

Signed-off-by: Vincent Palatin <vpalatin-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Signed-off-by: Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Signed-off-by: Doug Anderson <dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
---
Changes in v3:
- Separate out packet sizing from packet stuffing.
- Get rid of useless dev_dbg.
- Check command_sendrecv against NULL.
- Don't check np against NULL.
- Get rid of useless error on memory alloc fail.
- Get rid of useless platform_set_drvdata(dev, NULL);

Changes in v2:
- Update tunnel binding as per swarren

 .../devicetree/bindings/i2c/i2c-cros-ec-tunnel.txt |  39 +++
 drivers/i2c/busses/Kconfig                         |   9 +
 drivers/i2c/busses/Makefile                        |   1 +
 drivers/i2c/busses/i2c-cros-ec-tunnel.c            | 318 +++++++++++++++++++++
 drivers/mfd/cros_ec.c                              |   5 +
 5 files changed, 372 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-cros-ec-tunnel.txt
 create mode 100644 drivers/i2c/busses/i2c-cros-ec-tunnel.c

diff --git a/Documentation/devicetree/bindings/i2c/i2c-cros-ec-tunnel.txt b/Documentation/devicetree/bindings/i2c/i2c-cros-ec-tunnel.txt
new file mode 100644
index 0000000..898f030
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-cros-ec-tunnel.txt
@@ -0,0 +1,39 @@
+I2C bus that tunnels through the ChromeOS EC (cros-ec)
+======================================================
+On some ChromeOS board designs we've got a connection to the EC (embedded
+controller) but no direct connection to some devices on the other side of
+the EC (like a battery and PMIC).  To get access to those devices we need
+to tunnel our i2c commands through the EC.
+
+The node for this device should be under a cros-ec node like google,cros-ec-spi
+or google,cros-ec-i2c.
+
+
+Required properties:
+- compatible: google,cros-ec-i2c-tunnel
+- google,remote-bus: The EC bus we'd like to talk to.
+
+Optional child nodes:
+- One node per I2C device connected to the tunnelled I2C bus.
+
+
+Example:
+	cros-ec@0 {
+		compatible = "google,cros-ec-spi";
+
+		...
+
+		i2c-tunnel {
+			compatible = "google,cros-ec-i2c-tunnel";
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			google,remote-bus = <0>;
+
+			battery: sbs-battery@b {
+				compatible = "sbs,sbs-battery";
+				reg = <0xb>;
+				sbs,poll-retry-count = <1>;
+			};
+		};
+	}
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index c94db1c..9a0a6cc 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -993,6 +993,15 @@ config I2C_SIBYTE
 	help
 	  Supports the SiByte SOC on-chip I2C interfaces (2 channels).
 
+config I2C_CROS_EC_TUNNEL
+	tristate "ChromeOS EC tunnel I2C bus"
+	depends on MFD_CROS_EC
+	help
+	  If you say yes here you get an I2C bus that will tunnel i2c commands
+	  through to the other side of the ChromeOS EC to the i2c bus
+	  connected there. This will work whatever the interface used to
+	  talk to the EC (SPI, I2C or LPC).
+
 config SCx200_I2C
 	tristate "NatSemi SCx200 I2C using GPIO pins (DEPRECATED)"
 	depends on SCx200_GPIO
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 18d18ff..e110ca9 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -95,6 +95,7 @@ obj-$(CONFIG_I2C_VIPERBOARD)	+= i2c-viperboard.o
 # Other I2C/SMBus bus drivers
 obj-$(CONFIG_I2C_ACORN)		+= i2c-acorn.o
 obj-$(CONFIG_I2C_BCM_KONA)	+= i2c-bcm-kona.o
+obj-$(CONFIG_I2C_CROS_EC_TUNNEL)	+= i2c-cros-ec-tunnel.o
 obj-$(CONFIG_I2C_ELEKTOR)	+= i2c-elektor.o
 obj-$(CONFIG_I2C_PCA_ISA)	+= i2c-pca-isa.o
 obj-$(CONFIG_I2C_SIBYTE)	+= i2c-sibyte.o
diff --git a/drivers/i2c/busses/i2c-cros-ec-tunnel.c b/drivers/i2c/busses/i2c-cros-ec-tunnel.c
new file mode 100644
index 0000000..8e7a714
--- /dev/null
+++ b/drivers/i2c/busses/i2c-cros-ec-tunnel.c
@@ -0,0 +1,318 @@
+/*
+ *  Copyright (C) 2013 Google, Inc
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ * Expose an I2C passthrough to the ChromeOS EC.
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/mfd/cros_ec.h>
+#include <linux/mfd/cros_ec_commands.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+/**
+ * struct ec_i2c_device - Driver data for I2C tunnel
+ *
+ * @dev: Device node
+ * @adap: I2C adapter
+ * @ec: Pointer to EC device
+ * @remote_bus: The EC bus number we tunnel to on the other side.
+ * @request_buf: Buffer for transmitting data; we expect most transfers to fit.
+ * @response_buf: Buffer for receiving data; we expect most transfers to fit.
+ */
+
+struct ec_i2c_device {
+	struct device *dev;
+	struct i2c_adapter adap;
+	struct cros_ec_device *ec;
+
+	u16 remote_bus;
+
+	u8 request_buf[256];
+	u8 response_buf[256];
+};
+
+/**
+ * ec_i2c_count_message - Count bytes needed for ec_i2c_construct_message
+ *
+ * @i2c_msgs: The i2c messages to read
+ * @num: The number of i2c messages.
+ *
+ * Returns the number of bytes the messages will take up.
+ */
+static int ec_i2c_count_message(const struct i2c_msg i2c_msgs[], int num)
+{
+	int i;
+	int size;
+
+	size = sizeof(struct ec_params_i2c_passthru);
+	size += num * sizeof(struct ec_params_i2c_passthru_msg);
+	for (i = 0; i < num; i++)
+		if (!(i2c_msgs[i].flags & I2C_M_RD))
+			size += i2c_msgs[i].len;
+
+	return size;
+}
+
+/**
+ * ec_i2c_construct_message - construct a message to go to the EC
+ *
+ * This function effectively stuffs the standard i2c_msg format of Linux into
+ * a format that the EC understands.
+ *
+ * @buf: The buffer to fill.  We assume that the buffer is big enough.
+ * @i2c_msgs: The i2c messages to read.
+ * @num: The number of i2c messages.
+ * @bus_num: The remote bus number we want to talk to.
+ *
+ * Returns 0 or a negative error number.
+ */
+static int ec_i2c_construct_message(u8 *buf, const struct i2c_msg i2c_msgs[],
+				    int num, u16 bus_num)
+{
+	struct ec_params_i2c_passthru *params;
+	u8 *out_data;
+	int i;
+
+	out_data = buf + sizeof(struct ec_params_i2c_passthru) +
+		   num * sizeof(struct ec_params_i2c_passthru_msg);
+
+	params = (struct ec_params_i2c_passthru *)buf;
+	params->port = bus_num;
+	params->num_msgs = num;
+	for (i = 0; i < num; i++) {
+		const struct i2c_msg *i2c_msg = &i2c_msgs[i];
+		struct ec_params_i2c_passthru_msg *msg = &params->msg[i];
+
+		msg->len = i2c_msg->len;
+		msg->addr_flags = i2c_msg->addr;
+
+		if (i2c_msg->flags & I2C_M_TEN)
+			msg->addr_flags |= EC_I2C_FLAG_10BIT;
+
+		if (i2c_msg->flags & I2C_M_RD) {
+			msg->addr_flags |= EC_I2C_FLAG_READ;
+		} else {
+			memcpy(out_data, i2c_msg->buf, msg->len);
+			out_data += msg->len;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * ec_i2c_count_response - Count bytes needed for ec_i2c_parse_response
+ *
+ * @i2c_msgs: The i2c messages to to fill up.
+ * @num: The number of i2c messages expected.
+ *
+ * Returns the number of response bytes expeced.
+ */
+static int ec_i2c_count_response(struct i2c_msg i2c_msgs[], int num)
+{
+	int size;
+	int i;
+
+	size = sizeof(struct ec_response_i2c_passthru);
+	for (i = 0; i < num; i++)
+		if (i2c_msgs[i].flags & I2C_M_RD)
+			size += i2c_msgs[i].len;
+
+	return size;
+}
+
+/**
+ * ec_i2c_parse_response - Parse a response from the EC
+ *
+ * We'll take the EC's response and copy it back into msgs.
+ *
+ * @buf: The buffer to parse.
+ * @i2c_msgs: The i2c messages to to fill up.
+ * @num: The number of i2c messages; will be modified to include the actual
+ *	 number received.
+ *
+ * Returns 0 or a negative error number.
+ */
+static int ec_i2c_parse_response(const u8 *buf, struct i2c_msg i2c_msgs[],
+				 int *num)
+{
+	const struct ec_response_i2c_passthru *resp;
+	const u8 *in_data;
+	int i;
+
+	in_data = buf + sizeof(struct ec_response_i2c_passthru);
+
+	resp = (const struct ec_response_i2c_passthru *)buf;
+	if (resp->i2c_status & EC_I2C_STATUS_TIMEOUT)
+		return -ETIMEDOUT;
+	else if (resp->i2c_status & EC_I2C_STATUS_ERROR)
+		return -EREMOTEIO;
+
+	/* Other side could send us back fewer messages, but not more */
+	if (resp->num_msgs > *num)
+		return -EPROTO;
+	*num = resp->num_msgs;
+
+	for (i = 0; i < *num; i++) {
+		struct i2c_msg *i2c_msg = &i2c_msgs[i];
+
+		if (i2c_msgs[i].flags & I2C_M_RD) {
+			memcpy(i2c_msg->buf, in_data, i2c_msg->len);
+			in_data += i2c_msg->len;
+		}
+	}
+
+	return 0;
+}
+
+static int ec_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg i2c_msgs[],
+		       int num)
+{
+	struct ec_i2c_device *bus = adap->algo_data;
+	struct device *dev = bus->dev;
+	const u16 bus_num = bus->remote_bus;
+	int request_len;
+	int response_len;
+	u8 *request = NULL;
+	u8 *response = NULL;
+	int result;
+
+	request_len = ec_i2c_count_message(i2c_msgs, num);
+	if (request_len < 0) {
+		dev_warn(dev, "Error constructing message %d\n", request_len);
+		result = request_len;
+		goto exit;
+	}
+	response_len = ec_i2c_count_response(i2c_msgs, num);
+	if (response_len < 0) {
+		/* Unexpected; no errors should come when NULL response */
+		dev_warn(dev, "Error preparing response %d\n", response_len);
+		result = response_len;
+		goto exit;
+	}
+
+	if (request_len <= ARRAY_SIZE(bus->request_buf)) {
+		request = bus->request_buf;
+	} else {
+		request = kzalloc(request_len, GFP_KERNEL);
+		if (request == NULL) {
+			result = -ENOMEM;
+			goto exit;
+		}
+	}
+	if (response_len <= ARRAY_SIZE(bus->response_buf)) {
+		response = bus->response_buf;
+	} else {
+		response = kzalloc(response_len, GFP_KERNEL);
+		if (response == NULL) {
+			result = -ENOMEM;
+			goto exit;
+		}
+	}
+
+	ec_i2c_construct_message(request, i2c_msgs, num, bus_num);
+	result = bus->ec->command_sendrecv(bus->ec, EC_CMD_I2C_PASSTHRU,
+					   request, request_len,
+					   response, response_len);
+	if (result)
+		goto exit;
+
+	result = ec_i2c_parse_response(response, i2c_msgs, &num);
+	if (result < 0)
+		goto exit;
+
+	/* Indicate success by saying how many messages were sent */
+	result = num;
+exit:
+	if (request != bus->request_buf)
+		kfree(request);
+	if (response != bus->response_buf)
+		kfree(response);
+
+	return result;
+}
+
+static u32 ec_i2c_functionality(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm ec_i2c_algorithm = {
+	.master_xfer	= ec_i2c_xfer,
+	.functionality	= ec_i2c_functionality,
+};
+
+static int ec_i2c_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
+	struct device *dev = &pdev->dev;
+	struct ec_i2c_device *bus = NULL;
+	u32 remote_bus;
+	int err;
+
+	if (!ec->command_sendrecv) {
+		dev_err(dev, "Missing sendrecv\n");
+		return -EINVAL;
+	}
+
+	bus = devm_kzalloc(dev, sizeof(*bus), GFP_KERNEL);
+	if (bus == NULL)
+		return -ENOMEM;
+
+	err = of_property_read_u32(np, "google,remote-bus", &remote_bus);
+	if (err) {
+		dev_err(dev, "Couldn't read remote-bus property\n");
+		return err;
+	}
+	bus->remote_bus = remote_bus;
+
+	bus->ec = ec;
+	bus->dev = dev;
+
+	bus->adap.owner = THIS_MODULE;
+	strlcpy(bus->adap.name, "cros-ec-i2c-tunnel", sizeof(bus->adap.name));
+	bus->adap.algo = &ec_i2c_algorithm;
+	bus->adap.algo_data = bus;
+	bus->adap.dev.parent = &pdev->dev;
+	bus->adap.dev.of_node = np;
+
+	err = i2c_add_adapter(&bus->adap);
+	if (err) {
+		dev_err(dev, "cannot register i2c adapter\n");
+		return err;
+	}
+	platform_set_drvdata(pdev, bus);
+
+	return err;
+}
+
+static int ec_i2c_remove(struct platform_device *dev)
+{
+	struct ec_i2c_device *bus = platform_get_drvdata(dev);
+
+	i2c_del_adapter(&bus->adap);
+
+	return 0;
+}
+
+static struct platform_driver ec_i2c_tunnel_driver = {
+	.probe = ec_i2c_probe,
+	.remove = ec_i2c_remove,
+	.driver = {
+		.name = "cros-ec-i2c-tunnel",
+	},
+};
+
+module_platform_driver(ec_i2c_tunnel_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("EC I2C tunnel driver");
+MODULE_ALIAS("platform:cros-ec-i2c-tunnel");
diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c
index c58ab96..61bc909 100644
--- a/drivers/mfd/cros_ec.c
+++ b/drivers/mfd/cros_ec.c
@@ -90,6 +90,11 @@ static const struct mfd_cell cros_devs[] = {
 		.id = 1,
 		.of_compatible = "google,cros-ec-keyb",
 	},
+	{
+		.name = "cros-ec-i2c-tunnel",
+		.id = 2,
+		.of_compatible = "google,cros-ec-i2c-tunnel",
+	},
 };
 
 int cros_ec_register(struct cros_ec_device *ec_dev)
-- 
1.9.1.423.g4596e3a

[PATCH v3 7/7] ARM: tegra: Add the EC i2c tunnel to tegra124-venice2

[Doug Anderson]

This adds the EC i2c tunnel (and devices under it) to the
tegra124-venice2 device tree.

Signed-off-by: Doug Anderson <dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Tested-by: Andrew Bresticker <abrestic-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Tested-by: Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
---
Changes in v3: None
Changes in v2:
- Removed i2c20 alias for i2c tunnel

 arch/arm/boot/dts/tegra124-venice2.dts | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/arch/arm/boot/dts/tegra124-venice2.dts b/arch/arm/boot/dts/tegra124-venice2.dts
index c17283c..89cf776 100644
--- a/arch/arm/boot/dts/tegra124-venice2.dts
+++ b/arch/arm/boot/dts/tegra124-venice2.dts
@@ -813,6 +813,32 @@
 
 			google,cros-ec-spi-msg-delay = <2000>;
 
+			i2c-tunnel {
+				compatible = "google,cros-ec-i2c-tunnel";
+				#address-cells = <1>;
+				#size-cells = <0>;
+
+				google,remote-bus = <0>;
+
+				charger: bq24735@9 {
+					compatible = "ti,bq24735";
+					reg = <0x9>;
+					interrupt-parent = <&gpio>;
+					interrupts = <TEGRA_GPIO(J, 0)
+							GPIO_ACTIVE_HIGH>;
+					ti,ac-detect-gpios = <&gpio
+							TEGRA_GPIO(J, 0)
+							GPIO_ACTIVE_HIGH>;
+				};
+
+				battery: sbs-battery@b {
+					compatible = "sbs,sbs-battery";
+					reg = <0xb>;
+					sbs,i2c-retry-count = <2>;
+					sbs,poll-retry-count = <1>;
+				};
+			};
+
 			cros-ec-keyb {
 				compatible = "google,cros-ec-keyb";
 				keypad,num-rows = <8>;
-- 
1.9.1.423.g4596e3a

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Re: [PATCH v3 6/7] i2c: ChromeOS EC tunnel driver

[Stephen Warren]

On 04/30/2014 11:44 AM, Doug Anderson wrote:
> On ARM Chromebooks we have a few devices that are accessed by both the
> AP (the main "Application Processor") and the EC (the Embedded
> Controller).  These are:
> * The battery (sbs-battery).
> * The power management unit tps65090.
...
> On the Samsung ARM Chromebook 2 the scheme is changed yet again, now:
> * The AP/EC comms are now using SPI for faster speeds.
> * The EC's i2c bus is exposed to the AP through a full i2c tunnel.
> 
> The upstream "tegra124-venice2" uses the same scheme as the Samsung
> ARM Chromebook 2, though it has a different set of components on the
> other side of the bus.
> 
> This driver supports the scheme used by the Samsung ARM Chromebook 2.
> Future patches to this driver could add support for the battery tunnel
> on the HP Chromebook 11 (and perhaps could even be used to access
> tps65090 on the HP Chromebook 11 instead of using a special driver,
> but I haven't researched that enough).

The binding looks reasonable to me, so that part,
Acked-by: Stephen Warren <swarren@nvidia.com>

Re: [PATCH v3 7/7] ARM: tegra: Add the EC i2c tunnel to tegra124-venice2

[Stephen Warren]

On 04/30/2014 11:44 AM, Doug Anderson wrote:
> This adds the EC i2c tunnel (and devices under it) to the
> tegra124-venice2 device tree.

I'll happily take this into the Tegra tree once the patch containing the
binding it uses is applied.

Re: [PATCH v3 6/7] i2c: ChromeOS EC tunnel driver

[Rahul Sharma]

Hi Doug,

On 30 April 2014 23:14, Doug Anderson <dianders@chromium.org> wrote:
> On ARM Chromebooks we have a few devices that are accessed by both the
> AP (the main "Application Processor") and the EC (the Embedded
> Controller).  These are:
[snip]

> +       .remove = ec_i2c_remove,
> +       .driver = {
> +               .name = "cros-ec-i2c-tunnel",
> +       },
> +};
> +
> +module_platform_driver(ec_i2c_tunnel_driver);

In peach-pit, tps65090 is connected to i2c tunnel which provides
regulators for lcd, led and hdmi. We need to make all regulators
available before platform devices get probed. Shall it be changed to
subsys_initcall like other i2c controllers ?

Regards,
Rahul Sharma

> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("EC I2C tunnel driver");
> +MODULE_ALIAS("platform:cros-ec-i2c-tunnel");
> diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c
> index c58ab96..61bc909 100644
> --- a/drivers/mfd/cros_ec.c
> +++ b/drivers/mfd/cros_ec.c
> @@ -90,6 +90,11 @@ static const struct mfd_cell cros_devs[] = {
>                 .id = 1,
>                 .of_compatible = "google,cros-ec-keyb",
>         },
> +       {
> +               .name = "cros-ec-i2c-tunnel",
> +               .id = 2,
> +               .of_compatible = "google,cros-ec-i2c-tunnel",
> +       },
>  };
>
>  int cros_ec_register(struct cros_ec_device *ec_dev)
> --
> 1.9.1.423.g4596e3a
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH v3 6/7] i2c: ChromeOS EC tunnel driver

[Doug Anderson]

Rahul,

On Tue, May 6, 2014 at 3:55 AM, Rahul Sharma <rahul.sharma@samsung.com> wrote:
>> +module_platform_driver(ec_i2c_tunnel_driver);
>
> In peach-pit, tps65090 is connected to i2c tunnel which provides
> regulators for lcd, led and hdmi. We need to make all regulators
> available before platform devices get probed. Shall it be changed to
> subsys_initcall like other i2c controllers ?

I wouldn't object it it being subsys_initcall, but I'd rather do it in
a separate patch series so we can have discussion about it and not
block this basic support from landing.  Specifically when I originally
submitted the "i2c arbitrator" for exynos5250-snow I had
subsys_initcall and was asked to change away from that.  See
<http://comments.gmane.org/gmane.linux.drivers.devicetree/30172>

The answer I got was that the rest of the system should handle the
regulator showing up late by using deferred probing.  That's not my
favorite mechanism since in this case it means that the LCD turns on
much later in the boot process, but it still can be workable.  Last I
checked DRM had a whole lot of work to do to handle deferred probing
well, though.  :(

Note also that there are other dependencies if we actually want to
make this work properly as a subsys_initcall.  Specifically:

* Last I checked you'd also need to move the pl330 driver to be
subsys_initcall.  That's actually a latent upstream bug since the SPI
driver uses subsys_initcall, has a dependency on pl330, and doesn't
check / defer probe if pl330 isn't ready.  I'd need to check if that
still happens and also whether upstream would accept a change to the
init ordering or would rather see the spi driver somehow detect this
and defer.

* You'll also need to adjust cros_ec_spi to init earlier to make
things actually work properly.


See <https://code.google.com/p/chromium/issues/detail?id=239659> for
the patches that changed initcall ordering locally in the Chromium OS
tree.


Since I'm really not interested in fighting a fight about the benefits
and alternatives to deferred probing, I'd be inclined to let someone
else drive this (especially if you can point to a use case where
deferred probing is causing a problem and can justify why fixing that
is too big of a burden).


-Doug

Re: [PATCH v3 6/7] i2c: ChromeOS EC tunnel driver

[Doug Anderson]

Wolfram,

On Wed, Apr 30, 2014 at 10:44 AM, Doug Anderson <dianders@chromium.org> wrote:
> On ARM Chromebooks we have a few devices that are accessed by both the
> AP (the main "Application Processor") and the EC (the Embedded
> Controller).  These are:
> * The battery (sbs-battery).
> * The power management unit tps65090.
>
> On the original Samsung ARM Chromebook these devices were on an I2C
> bus that was shared between the AP and the EC and arbitrated using
> some extranal GPIOs (see i2c-arb-gpio-challenge).
>
> The original arbitration scheme worked well enough but had some
> downsides:
> * It was nonstandard (not using standard I2C multimaster)
> * It only worked if the EC-AP communication was I2C
> * It was relatively hard to debug problems (hard to tell if i2c issues
>   were caused by the EC, the AP, or some device on the bus).
>
> On the HP Chromebook 11 the design was changed to:
> * The AP/EC comms were still i2c, but the battery/tps65090 were no
>   longer on the bus used for AP/EC communication.  The battery was
>   exposed to the AP through a limited i2c tunnel and tps65090 was
>   exposed to the AP through a custom Linux driver.
>
> On the Samsung ARM Chromebook 2 the scheme is changed yet again, now:
> * The AP/EC comms are now using SPI for faster speeds.
> * The EC's i2c bus is exposed to the AP through a full i2c tunnel.
>
> The upstream "tegra124-venice2" uses the same scheme as the Samsung
> ARM Chromebook 2, though it has a different set of components on the
> other side of the bus.
>
> This driver supports the scheme used by the Samsung ARM Chromebook 2.
> Future patches to this driver could add support for the battery tunnel
> on the HP Chromebook 11 (and perhaps could even be used to access
> tps65090 on the HP Chromebook 11 instead of using a special driver,
> but I haven't researched that enough).
>
> Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
> Signed-off-by: Simon Glass <sjg@chromium.org>
> Signed-off-by: Doug Anderson <dianders@chromium.org>
> ---
> Changes in v3:
> - Separate out packet sizing from packet stuffing.
> - Get rid of useless dev_dbg.
> - Check command_sendrecv against NULL.
> - Don't check np against NULL.
> - Get rid of useless error on memory alloc fail.
> - Get rid of useless platform_set_drvdata(dev, NULL);
>
> Changes in v2:
> - Update tunnel binding as per swarren
>
>  .../devicetree/bindings/i2c/i2c-cros-ec-tunnel.txt |  39 +++
>  drivers/i2c/busses/Kconfig                         |   9 +
>  drivers/i2c/busses/Makefile                        |   1 +
>  drivers/i2c/busses/i2c-cros-ec-tunnel.c            | 318 +++++++++++++++++++++
>  drivers/mfd/cros_ec.c                              |   5 +
>  5 files changed, 372 insertions(+)

Please let me know if there are any other changes you'd like me to
make to this driver.  I'm happy to resend this with Stephen's binding
Ack if you'd like.


Thanks!

-Doug

Re: [PATCH v3 6/7] i2c: ChromeOS EC tunnel driver

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 1645 bytes --]


> +I2C bus that tunnels through the ChromeOS EC (cros-ec)
> +======================================================
> +On some ChromeOS board designs we've got a connection to the EC (embedded
> +controller) but no direct connection to some devices on the other side of
> +the EC (like a battery and PMIC).  To get access to those devices we need
> +to tunnel our i2c commands through the EC.
> +
> +The node for this device should be under a cros-ec node like google,cros-ec-spi
> +or google,cros-ec-i2c.
> +
> +
> +Required properties:
> +- compatible: google,cros-ec-i2c-tunnel
> +- google,remote-bus: The EC bus we'd like to talk to.
> +
> +Optional child nodes:
> +- One node per I2C device connected to the tunnelled I2C bus.
> +
> +
> +Example:
> +	cros-ec@0 {
> +		compatible = "google,cros-ec-spi";

Ooookay, now I get it. From the compatible name of this snipplet, I
assumed this node describes only an SPI IP core inside the EC. This is
why I complained about the location of the I2C busses, since placing it
as subnodes of the EC based SPI didn't make sense to me, even though the
connection of the tunnel was SPI. Now I understand that this is the core
driver for the EC, talking to it via SPI. Since this driver is an SPI
child node I would not have expected the "-spi" suffix. Sorry, for this
confusion :/ Now, the bindings make much more sense to me.

> +			google,remote-bus = <0>;

I am still not too happy about this one, but it is good enough for now,
I suppose.

Code looks good, so

Reviewed-by: Wolfram Sang <wsa@the-dreams.de>

I don't mind how it gets upstream. I can take it, but you can also keep
it in this series.


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Re: [PATCH v3 6/7] i2c: ChromeOS EC tunnel driver

[Doug Anderson]

Wolfram and Lee,

On Mon, May 19, 2014 at 3:50 AM, Wolfram Sang <wsa@the-dreams.de> wrote:
>
>> +I2C bus that tunnels through the ChromeOS EC (cros-ec)
>> +======================================================
>> +On some ChromeOS board designs we've got a connection to the EC (embedded
>> +controller) but no direct connection to some devices on the other side of
>> +the EC (like a battery and PMIC).  To get access to those devices we need
>> +to tunnel our i2c commands through the EC.
>> +
>> +The node for this device should be under a cros-ec node like google,cros-ec-spi
>> +or google,cros-ec-i2c.
>> +
>> +
>> +Required properties:
>> +- compatible: google,cros-ec-i2c-tunnel
>> +- google,remote-bus: The EC bus we'd like to talk to.
>> +
>> +Optional child nodes:
>> +- One node per I2C device connected to the tunnelled I2C bus.
>> +
>> +
>> +Example:
>> +     cros-ec@0 {
>> +             compatible = "google,cros-ec-spi";
>
> Ooookay, now I get it. From the compatible name of this snipplet, I
> assumed this node describes only an SPI IP core inside the EC. This is
> why I complained about the location of the I2C busses, since placing it
> as subnodes of the EC based SPI didn't make sense to me, even though the
> connection of the tunnel was SPI. Now I understand that this is the core
> driver for the EC, talking to it via SPI. Since this driver is an SPI
> child node I would not have expected the "-spi" suffix. Sorry, for this
> confusion :/ Now, the bindings make much more sense to me.
>
>> +                     google,remote-bus = <0>;
>
> I am still not too happy about this one, but it is good enough for now,
> I suppose.
>
> Code looks good, so
>
> Reviewed-by: Wolfram Sang <wsa@the-dreams.de>
>
> I don't mind how it gets upstream. I can take it, but you can also keep
> it in this series.

Thanks for the review.  I think the easiest would be for Lee to take
the whole series for the next merge window.

-Doug

Re: [PATCH v3 6/7] i2c: ChromeOS EC tunnel driver

[Lee Jones]

> Code looks good, so
> 
> Reviewed-by: Wolfram Sang <wsa@the-dreams.de>
> 
> I don't mind how it gets upstream. I can take it, but you can also keep
> it in this series.

Let's keep the series together.  Are you happy with me just merging it
through MFD, or would you like a pull-request, so you can take it in
too?

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v3 6/7] i2c: ChromeOS EC tunnel driver

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 455 bytes --]

On Mon, May 19, 2014 at 06:22:58PM +0100, Lee Jones wrote:
> > Code looks good, so
> > 
> > Reviewed-by: Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
> > 
> > I don't mind how it gets upstream. I can take it, but you can also keep
> > it in this series.
> 
> Let's keep the series together.  Are you happy with me just merging it
> through MFD, or would you like a pull-request, so you can take it in
> too?

Just merge it...


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Re: [PATCH v3 6/7] i2c: ChromeOS EC tunnel driver

[Lee Jones]

> > > Code looks good, so
> > > 
> > > Reviewed-by: Wolfram Sang <wsa@the-dreams.de>
> > > 
> > > I don't mind how it gets upstream. I can take it, but you can also keep
> > > it in this series.
> > 
> > Let's keep the series together.  Are you happy with me just merging it
> > through MFD, or would you like a pull-request, so you can take it in
> > too?
> 
> Just merge it...

Thanks dude.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v3 6/7] i2c: ChromeOS EC tunnel driver

[Lee Jones]

On Wed, 30 Apr 2014, Doug Anderson wrote:

> On ARM Chromebooks we have a few devices that are accessed by both the
> AP (the main "Application Processor") and the EC (the Embedded
> Controller).  These are:
> * The battery (sbs-battery).
> * The power management unit tps65090.
> 
> On the original Samsung ARM Chromebook these devices were on an I2C
> bus that was shared between the AP and the EC and arbitrated using
> some extranal GPIOs (see i2c-arb-gpio-challenge).
> 
> The original arbitration scheme worked well enough but had some
> downsides:
> * It was nonstandard (not using standard I2C multimaster)
> * It only worked if the EC-AP communication was I2C
> * It was relatively hard to debug problems (hard to tell if i2c issues
>   were caused by the EC, the AP, or some device on the bus).
> 
> On the HP Chromebook 11 the design was changed to:
> * The AP/EC comms were still i2c, but the battery/tps65090 were no
>   longer on the bus used for AP/EC communication.  The battery was
>   exposed to the AP through a limited i2c tunnel and tps65090 was
>   exposed to the AP through a custom Linux driver.
> 
> On the Samsung ARM Chromebook 2 the scheme is changed yet again, now:
> * The AP/EC comms are now using SPI for faster speeds.
> * The EC's i2c bus is exposed to the AP through a full i2c tunnel.
> 
> The upstream "tegra124-venice2" uses the same scheme as the Samsung
> ARM Chromebook 2, though it has a different set of components on the
> other side of the bus.
> 
> This driver supports the scheme used by the Samsung ARM Chromebook 2.
> Future patches to this driver could add support for the battery tunnel
> on the HP Chromebook 11 (and perhaps could even be used to access
> tps65090 on the HP Chromebook 11 instead of using a special driver,
> but I haven't researched that enough).
> 
> Signed-off-by: Vincent Palatin <vpalatin-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
> Signed-off-by: Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
> Signed-off-by: Doug Anderson <dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
> ---
> Changes in v3:
> - Separate out packet sizing from packet stuffing.
> - Get rid of useless dev_dbg.
> - Check command_sendrecv against NULL.
> - Don't check np against NULL.
> - Get rid of useless error on memory alloc fail.
> - Get rid of useless platform_set_drvdata(dev, NULL);
> 
> Changes in v2:
> - Update tunnel binding as per swarren
> 
>  .../devicetree/bindings/i2c/i2c-cros-ec-tunnel.txt |  39 +++
>  drivers/i2c/busses/Kconfig                         |   9 +
>  drivers/i2c/busses/Makefile                        |   1 +
>  drivers/i2c/busses/i2c-cros-ec-tunnel.c            | 318 +++++++++++++++++++++
>  drivers/mfd/cros_ec.c                              |   5 +
>  5 files changed, 372 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/i2c/i2c-cros-ec-tunnel.txt
>  create mode 100644 drivers/i2c/busses/i2c-cros-ec-tunnel.c

Applied, thanks.

> diff --git a/Documentation/devicetree/bindings/i2c/i2c-cros-ec-tunnel.txt b/Documentation/devicetree/bindings/i2c/i2c-cros-ec-tunnel.txt
> new file mode 100644
> index 0000000..898f030
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i2c/i2c-cros-ec-tunnel.txt
> @@ -0,0 +1,39 @@
> +I2C bus that tunnels through the ChromeOS EC (cros-ec)
> +======================================================
> +On some ChromeOS board designs we've got a connection to the EC (embedded
> +controller) but no direct connection to some devices on the other side of
> +the EC (like a battery and PMIC).  To get access to those devices we need
> +to tunnel our i2c commands through the EC.
> +
> +The node for this device should be under a cros-ec node like google,cros-ec-spi
> +or google,cros-ec-i2c.
> +
> +
> +Required properties:
> +- compatible: google,cros-ec-i2c-tunnel
> +- google,remote-bus: The EC bus we'd like to talk to.
> +
> +Optional child nodes:
> +- One node per I2C device connected to the tunnelled I2C bus.
> +
> +
> +Example:
> +	cros-ec@0 {
> +		compatible = "google,cros-ec-spi";
> +
> +		...
> +
> +		i2c-tunnel {
> +			compatible = "google,cros-ec-i2c-tunnel";
> +			#address-cells = <1>;
> +			#size-cells = <0>;
> +
> +			google,remote-bus = <0>;
> +
> +			battery: sbs-battery@b {
> +				compatible = "sbs,sbs-battery";
> +				reg = <0xb>;
> +				sbs,poll-retry-count = <1>;
> +			};
> +		};
> +	}
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index c94db1c..9a0a6cc 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -993,6 +993,15 @@ config I2C_SIBYTE
>  	help
>  	  Supports the SiByte SOC on-chip I2C interfaces (2 channels).
>  
> +config I2C_CROS_EC_TUNNEL
> +	tristate "ChromeOS EC tunnel I2C bus"
> +	depends on MFD_CROS_EC
> +	help
> +	  If you say yes here you get an I2C bus that will tunnel i2c commands
> +	  through to the other side of the ChromeOS EC to the i2c bus
> +	  connected there. This will work whatever the interface used to
> +	  talk to the EC (SPI, I2C or LPC).
> +
>  config SCx200_I2C
>  	tristate "NatSemi SCx200 I2C using GPIO pins (DEPRECATED)"
>  	depends on SCx200_GPIO
> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> index 18d18ff..e110ca9 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -95,6 +95,7 @@ obj-$(CONFIG_I2C_VIPERBOARD)	+= i2c-viperboard.o
>  # Other I2C/SMBus bus drivers
>  obj-$(CONFIG_I2C_ACORN)		+= i2c-acorn.o
>  obj-$(CONFIG_I2C_BCM_KONA)	+= i2c-bcm-kona.o
> +obj-$(CONFIG_I2C_CROS_EC_TUNNEL)	+= i2c-cros-ec-tunnel.o
>  obj-$(CONFIG_I2C_ELEKTOR)	+= i2c-elektor.o
>  obj-$(CONFIG_I2C_PCA_ISA)	+= i2c-pca-isa.o
>  obj-$(CONFIG_I2C_SIBYTE)	+= i2c-sibyte.o
> diff --git a/drivers/i2c/busses/i2c-cros-ec-tunnel.c b/drivers/i2c/busses/i2c-cros-ec-tunnel.c
> new file mode 100644
> index 0000000..8e7a714
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-cros-ec-tunnel.c
> @@ -0,0 +1,318 @@
> +/*
> + *  Copyright (C) 2013 Google, Inc
> + *
> + *  This program is free software; you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation; either version 2 of the License, or
> + *  (at your option) any later version.
> + *
> + * Expose an I2C passthrough to the ChromeOS EC.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/i2c.h>
> +#include <linux/mfd/cros_ec.h>
> +#include <linux/mfd/cros_ec_commands.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +/**
> + * struct ec_i2c_device - Driver data for I2C tunnel
> + *
> + * @dev: Device node
> + * @adap: I2C adapter
> + * @ec: Pointer to EC device
> + * @remote_bus: The EC bus number we tunnel to on the other side.
> + * @request_buf: Buffer for transmitting data; we expect most transfers to fit.
> + * @response_buf: Buffer for receiving data; we expect most transfers to fit.
> + */
> +
> +struct ec_i2c_device {
> +	struct device *dev;
> +	struct i2c_adapter adap;
> +	struct cros_ec_device *ec;
> +
> +	u16 remote_bus;
> +
> +	u8 request_buf[256];
> +	u8 response_buf[256];
> +};
> +
> +/**
> + * ec_i2c_count_message - Count bytes needed for ec_i2c_construct_message
> + *
> + * @i2c_msgs: The i2c messages to read
> + * @num: The number of i2c messages.
> + *
> + * Returns the number of bytes the messages will take up.
> + */
> +static int ec_i2c_count_message(const struct i2c_msg i2c_msgs[], int num)
> +{
> +	int i;
> +	int size;
> +
> +	size = sizeof(struct ec_params_i2c_passthru);
> +	size += num * sizeof(struct ec_params_i2c_passthru_msg);
> +	for (i = 0; i < num; i++)
> +		if (!(i2c_msgs[i].flags & I2C_M_RD))
> +			size += i2c_msgs[i].len;
> +
> +	return size;
> +}
> +
> +/**
> + * ec_i2c_construct_message - construct a message to go to the EC
> + *
> + * This function effectively stuffs the standard i2c_msg format of Linux into
> + * a format that the EC understands.
> + *
> + * @buf: The buffer to fill.  We assume that the buffer is big enough.
> + * @i2c_msgs: The i2c messages to read.
> + * @num: The number of i2c messages.
> + * @bus_num: The remote bus number we want to talk to.
> + *
> + * Returns 0 or a negative error number.
> + */
> +static int ec_i2c_construct_message(u8 *buf, const struct i2c_msg i2c_msgs[],
> +				    int num, u16 bus_num)
> +{
> +	struct ec_params_i2c_passthru *params;
> +	u8 *out_data;
> +	int i;
> +
> +	out_data = buf + sizeof(struct ec_params_i2c_passthru) +
> +		   num * sizeof(struct ec_params_i2c_passthru_msg);
> +
> +	params = (struct ec_params_i2c_passthru *)buf;
> +	params->port = bus_num;
> +	params->num_msgs = num;
> +	for (i = 0; i < num; i++) {
> +		const struct i2c_msg *i2c_msg = &i2c_msgs[i];
> +		struct ec_params_i2c_passthru_msg *msg = &params->msg[i];
> +
> +		msg->len = i2c_msg->len;
> +		msg->addr_flags = i2c_msg->addr;
> +
> +		if (i2c_msg->flags & I2C_M_TEN)
> +			msg->addr_flags |= EC_I2C_FLAG_10BIT;
> +
> +		if (i2c_msg->flags & I2C_M_RD) {
> +			msg->addr_flags |= EC_I2C_FLAG_READ;
> +		} else {
> +			memcpy(out_data, i2c_msg->buf, msg->len);
> +			out_data += msg->len;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +/**
> + * ec_i2c_count_response - Count bytes needed for ec_i2c_parse_response
> + *
> + * @i2c_msgs: The i2c messages to to fill up.
> + * @num: The number of i2c messages expected.
> + *
> + * Returns the number of response bytes expeced.
> + */
> +static int ec_i2c_count_response(struct i2c_msg i2c_msgs[], int num)
> +{
> +	int size;
> +	int i;
> +
> +	size = sizeof(struct ec_response_i2c_passthru);
> +	for (i = 0; i < num; i++)
> +		if (i2c_msgs[i].flags & I2C_M_RD)
> +			size += i2c_msgs[i].len;
> +
> +	return size;
> +}
> +
> +/**
> + * ec_i2c_parse_response - Parse a response from the EC
> + *
> + * We'll take the EC's response and copy it back into msgs.
> + *
> + * @buf: The buffer to parse.
> + * @i2c_msgs: The i2c messages to to fill up.
> + * @num: The number of i2c messages; will be modified to include the actual
> + *	 number received.
> + *
> + * Returns 0 or a negative error number.
> + */
> +static int ec_i2c_parse_response(const u8 *buf, struct i2c_msg i2c_msgs[],
> +				 int *num)
> +{
> +	const struct ec_response_i2c_passthru *resp;
> +	const u8 *in_data;
> +	int i;
> +
> +	in_data = buf + sizeof(struct ec_response_i2c_passthru);
> +
> +	resp = (const struct ec_response_i2c_passthru *)buf;
> +	if (resp->i2c_status & EC_I2C_STATUS_TIMEOUT)
> +		return -ETIMEDOUT;
> +	else if (resp->i2c_status & EC_I2C_STATUS_ERROR)
> +		return -EREMOTEIO;
> +
> +	/* Other side could send us back fewer messages, but not more */
> +	if (resp->num_msgs > *num)
> +		return -EPROTO;
> +	*num = resp->num_msgs;
> +
> +	for (i = 0; i < *num; i++) {
> +		struct i2c_msg *i2c_msg = &i2c_msgs[i];
> +
> +		if (i2c_msgs[i].flags & I2C_M_RD) {
> +			memcpy(i2c_msg->buf, in_data, i2c_msg->len);
> +			in_data += i2c_msg->len;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int ec_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg i2c_msgs[],
> +		       int num)
> +{
> +	struct ec_i2c_device *bus = adap->algo_data;
> +	struct device *dev = bus->dev;
> +	const u16 bus_num = bus->remote_bus;
> +	int request_len;
> +	int response_len;
> +	u8 *request = NULL;
> +	u8 *response = NULL;
> +	int result;
> +
> +	request_len = ec_i2c_count_message(i2c_msgs, num);
> +	if (request_len < 0) {
> +		dev_warn(dev, "Error constructing message %d\n", request_len);
> +		result = request_len;
> +		goto exit;
> +	}
> +	response_len = ec_i2c_count_response(i2c_msgs, num);
> +	if (response_len < 0) {
> +		/* Unexpected; no errors should come when NULL response */
> +		dev_warn(dev, "Error preparing response %d\n", response_len);
> +		result = response_len;
> +		goto exit;
> +	}
> +
> +	if (request_len <= ARRAY_SIZE(bus->request_buf)) {
> +		request = bus->request_buf;
> +	} else {
> +		request = kzalloc(request_len, GFP_KERNEL);
> +		if (request == NULL) {
> +			result = -ENOMEM;
> +			goto exit;
> +		}
> +	}
> +	if (response_len <= ARRAY_SIZE(bus->response_buf)) {
> +		response = bus->response_buf;
> +	} else {
> +		response = kzalloc(response_len, GFP_KERNEL);
> +		if (response == NULL) {
> +			result = -ENOMEM;
> +			goto exit;
> +		}
> +	}
> +
> +	ec_i2c_construct_message(request, i2c_msgs, num, bus_num);
> +	result = bus->ec->command_sendrecv(bus->ec, EC_CMD_I2C_PASSTHRU,
> +					   request, request_len,
> +					   response, response_len);
> +	if (result)
> +		goto exit;
> +
> +	result = ec_i2c_parse_response(response, i2c_msgs, &num);
> +	if (result < 0)
> +		goto exit;
> +
> +	/* Indicate success by saying how many messages were sent */
> +	result = num;
> +exit:
> +	if (request != bus->request_buf)
> +		kfree(request);
> +	if (response != bus->response_buf)
> +		kfree(response);
> +
> +	return result;
> +}
> +
> +static u32 ec_i2c_functionality(struct i2c_adapter *adap)
> +{
> +	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
> +}
> +
> +static const struct i2c_algorithm ec_i2c_algorithm = {
> +	.master_xfer	= ec_i2c_xfer,
> +	.functionality	= ec_i2c_functionality,
> +};
> +
> +static int ec_i2c_probe(struct platform_device *pdev)
> +{
> +	struct device_node *np = pdev->dev.of_node;
> +	struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
> +	struct device *dev = &pdev->dev;
> +	struct ec_i2c_device *bus = NULL;
> +	u32 remote_bus;
> +	int err;
> +
> +	if (!ec->command_sendrecv) {
> +		dev_err(dev, "Missing sendrecv\n");
> +		return -EINVAL;
> +	}
> +
> +	bus = devm_kzalloc(dev, sizeof(*bus), GFP_KERNEL);
> +	if (bus == NULL)
> +		return -ENOMEM;
> +
> +	err = of_property_read_u32(np, "google,remote-bus", &remote_bus);
> +	if (err) {
> +		dev_err(dev, "Couldn't read remote-bus property\n");
> +		return err;
> +	}
> +	bus->remote_bus = remote_bus;
> +
> +	bus->ec = ec;
> +	bus->dev = dev;
> +
> +	bus->adap.owner = THIS_MODULE;
> +	strlcpy(bus->adap.name, "cros-ec-i2c-tunnel", sizeof(bus->adap.name));
> +	bus->adap.algo = &ec_i2c_algorithm;
> +	bus->adap.algo_data = bus;
> +	bus->adap.dev.parent = &pdev->dev;
> +	bus->adap.dev.of_node = np;
> +
> +	err = i2c_add_adapter(&bus->adap);
> +	if (err) {
> +		dev_err(dev, "cannot register i2c adapter\n");
> +		return err;
> +	}
> +	platform_set_drvdata(pdev, bus);
> +
> +	return err;
> +}
> +
> +static int ec_i2c_remove(struct platform_device *dev)
> +{
> +	struct ec_i2c_device *bus = platform_get_drvdata(dev);
> +
> +	i2c_del_adapter(&bus->adap);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver ec_i2c_tunnel_driver = {
> +	.probe = ec_i2c_probe,
> +	.remove = ec_i2c_remove,
> +	.driver = {
> +		.name = "cros-ec-i2c-tunnel",
> +	},
> +};
> +
> +module_platform_driver(ec_i2c_tunnel_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("EC I2C tunnel driver");
> +MODULE_ALIAS("platform:cros-ec-i2c-tunnel");
> diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c
> index c58ab96..61bc909 100644
> --- a/drivers/mfd/cros_ec.c
> +++ b/drivers/mfd/cros_ec.c
> @@ -90,6 +90,11 @@ static const struct mfd_cell cros_devs[] = {
>  		.id = 1,
>  		.of_compatible = "google,cros-ec-keyb",
>  	},
> +	{
> +		.name = "cros-ec-i2c-tunnel",
> +		.id = 2,
> +		.of_compatible = "google,cros-ec-i2c-tunnel",
> +	},
>  };
>  
>  int cros_ec_register(struct cros_ec_device *ec_dev)

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v3 7/7] ARM: tegra: Add the EC i2c tunnel to tegra124-venice2

[Lee Jones]

> > This adds the EC i2c tunnel (and devices under it) to the
> > tegra124-venice2 device tree.
> 
> I'll happily take this into the Tegra tree once the patch containing the
> binding it uses is applied.

All other patches applied.  Take this when ready.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v3 7/7] ARM: tegra: Add the EC i2c tunnel to tegra124-venice2

[Stephen Warren]

On 04/30/2014 11:44 AM, Doug Anderson wrote:
> This adds the EC i2c tunnel (and devices under it) to the
> tegra124-venice2 device tree.

I've applied this to Tegra's for-3.17/dt branch.