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Message-ID: <544d31cc-e840-c91e-f65d-7f7b57ba1337@collabora.corp-partner.google.com>
Date: Thu, 6 Feb 2020 17:19:02 +0100
From: Enric Balletbo i Serra
<enric.balletbo@...labora.corp-partner.google.com>
To: Prashant Malani <pmalani@...omium.org>,
linux-kernel@...r.kernel.org
Cc: heikki.krogerus@...el.com, bleung@...omium.org,
Guenter Roeck <groeck@...omium.org>
Subject: Re: [PATCH 1/3] platform/chrome: Add Type C connector class driver
Hi Prashant,
On 5/2/20 21:59, Prashant Malani wrote:
> Add a driver to implement the Type C connector class for Chrome OS
> devices with ECs (Embedded Controllers).
>
> The driver relies on firmware device specifications for various port
> attributes. On ACPI platforms, this is specified using the logical
> device with HID GOOG0014. On DT platforms, this is specified using the
> DT node with compatible string "google,cros-ec-typec".
>
If that's the case you should document this in a binding file. Will be this
driver a replacement of the cros-ec-extcon driver or is a different thing?
There is a device where I can test this?
> This patch reads the device FW node and uses the port attributes to
> register the typec ports with the Type C connector class framework, but
> doesn't do much else.
>
> Subsequent patches will add more functionality to the driver, including
> obtaining current port information (polarity, vconn role, current power
> role etc.) after querying the EC.
>
> Signed-off-by: Prashant Malani <pmalani@...omium.org>
> ---
> drivers/platform/chrome/Kconfig | 11 ++
> drivers/platform/chrome/Makefile | 1 +
> drivers/platform/chrome/cros_ec_typec.c | 228 ++++++++++++++++++++++++
> 3 files changed, 240 insertions(+)
> create mode 100644 drivers/platform/chrome/cros_ec_typec.c
>
> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
> index 5f57282a28da00..1370dfd1ca1565 100644
> --- a/drivers/platform/chrome/Kconfig
> +++ b/drivers/platform/chrome/Kconfig
> @@ -214,6 +214,17 @@ config CROS_EC_SYSFS
> To compile this driver as a module, choose M here: the
> module will be called cros_ec_sysfs.
>
> +config CROS_EC_TYPEC
> + tristate "ChromeOS EC Type-C Connector Control"
> + depends on MFD_CROS_EC_DEV && TYPEC
> + default n
Default value is already n, so you don't need to put it here. But I'd say that
we might be interested on have default MFD_CROS_EC_DEV like the other drivers.
> + help
> + If you say Y here, you get support for accessing Type C connector
> + information from the Chrome OS EC.
> +
> + To compile this driver as a module, choose M here: the module will be
> + called cros_ec_typec.
> +
> config CROS_USBPD_LOGGER
> tristate "Logging driver for USB PD charger"
> depends on CHARGER_CROS_USBPD
> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
> index aacd5920d8a180..caf2a9cdb5e6d1 100644
> --- a/drivers/platform/chrome/Makefile
> +++ b/drivers/platform/chrome/Makefile
> @@ -12,6 +12,7 @@ obj-$(CONFIG_CROS_EC_ISHTP) += cros_ec_ishtp.o
> obj-$(CONFIG_CROS_EC_RPMSG) += cros_ec_rpmsg.o
> obj-$(CONFIG_CROS_EC_SPI) += cros_ec_spi.o
> cros_ec_lpcs-objs := cros_ec_lpc.o cros_ec_lpc_mec.o
> +obj-$(CONFIG_CROS_EC_TYPEC) += cros_ec_typec.o
> obj-$(CONFIG_CROS_EC_LPC) += cros_ec_lpcs.o
> obj-$(CONFIG_CROS_EC_PROTO) += cros_ec_proto.o cros_ec_trace.o
> obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT) += cros_kbd_led_backlight.o
> diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
> new file mode 100644
> index 00000000000000..fe5659171c2a85
> --- /dev/null
> +++ b/drivers/platform/chrome/cros_ec_typec.c
> @@ -0,0 +1,228 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright 2020 Google LLC
> + *
> + * This driver provides the ability to view and manage Type C ports through the
> + * Chrome OS EC.
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_data/cros_ec_commands.h>
> +#include <linux/platform_data/cros_ec_proto.h>
> +#include <linux/platform_device.h>
> +#include <linux/usb/typec.h>
> +
> +#define DRV_NAME "cros-ec-typec"
> +
> +/* Platform-specific data for the Chrome OS EC Type C controller. */
> +struct cros_typec_data {
> + struct device *dev;
> + struct cros_ec_device *ec;
> + int num_ports;
> + /* Array of ports, indexed by port number. */
> + struct typec_port *ports[EC_USB_PD_MAX_PORTS];
> +};
> +
> +int cros_typec_parse_port_props(struct typec_capability *cap,
static int
> + struct fwnode_handle *fwnode,
> + struct device *dev)
> +{
> + const char *buf;
> + int ret;
> +
> + memset(cap, 0, sizeof(*cap));
> + ret = fwnode_property_read_string(fwnode, "power-role", &buf);
> + if (ret) {
> + dev_err(dev, "power-role not found: %d\n", ret);
> + return ret;
> + }
> +
> + ret = typec_find_port_power_role(buf);
> + if (ret < 0)
> + return ret;
> + cap->type = ret;
> +
> + ret = fwnode_property_read_string(fwnode, "data-role", &buf);
> + if (ret) {
> + dev_err(dev, "data-role not found: %d\n", ret);
> + return ret;
> + }
> +
> + ret = typec_find_port_data_role(buf);
> + if (ret < 0)
> + return ret;
> + cap->data = ret;
> +
> + ret = fwnode_property_read_string(fwnode, "try-power-role", &buf);
> + if (ret) {
> + dev_err(dev, "try-power-role not found: %d\n", ret);
> + return ret;
> + }
> +
> + ret = typec_find_power_role(buf);
> + if (ret < 0)
> + return ret;
> + cap->prefer_role = ret;
> +
> + cap->fwnode = fwnode;
> +
> + return 0;
> +}
> +
> +static int cros_typec_init_ports(struct cros_typec_data *typec)
> +{
> + struct device *dev = typec->dev;
> + struct typec_capability cap;
> + struct fwnode_handle *fwnode;
> + int ret;
> + int i;
> + int nports;
> + u32 port_num;
> +
> + nports = device_get_child_node_count(dev);
> + if (nports == 0) {
> + dev_err(dev, "No port entries found.\n");
> + return -ENODEV;
> + }
> +
> + device_for_each_child_node(dev, fwnode) {
> + if (fwnode_property_read_u32(fwnode, "port-number",
> + &port_num)) {
> + dev_err(dev, "No port-number for port, skipping.\n");
> + ret = -EINVAL;
> + goto unregister_ports;
> + }
> +
> + if (port_num >= typec->num_ports) {
> + dev_err(dev, "Invalid port number.\n");
> + ret = -EINVAL;
> + goto unregister_ports;
> + }
> +
> + dev_dbg(dev, "Registering port %d\n", port_num);
> + ret = cros_typec_parse_port_props(&cap, fwnode, dev);
> + if (ret < 0)
> + goto unregister_ports;
> + typec->ports[port_num] = typec_register_port(dev, &cap);
> + if (IS_ERR(typec->ports[port_num])) {
> + dev_err(dev, "Failed to register port %d\n", port_num);
> + ret = PTR_ERR(typec->ports[port_num]);
> + goto unregister_ports;
> + }
> + }
> +
> + return 0;
> +
> +unregister_ports:
> + for (i = 0; i < typec->num_ports; i++)
> + typec_unregister_port(typec->ports[i]);
> + return ret;
> +}
> +
> +static int cros_typec_ec_command(struct cros_typec_data *typec,
> + unsigned int version,
> + unsigned int command,
> + void *outdata,
> + unsigned int outsize,
> + void *indata,
> + unsigned int insize)
> +{
> + struct cros_ec_command *msg;
> + int ret;
> +
> + msg = kzalloc(sizeof(*msg) + max(outsize, insize), GFP_KERNEL);
> + if (!msg)
> + return -ENOMEM;
> +
> + msg->version = version;
> + msg->command = command;
> + msg->outsize = outsize;
> + msg->insize = insize;
> +
> + if (outsize)
> + memcpy(msg->data, outdata, outsize);
> +
> + ret = cros_ec_cmd_xfer_status(typec->ec, msg);
> + if (ret >= 0 && insize)
> + memcpy(indata, msg->data, insize);
> +
> + kfree(msg);
> + return ret;
> +}
> +
> +
> +static int cros_typec_get_num_ports(struct cros_typec_data *typec)
> +{
This functions is only called once at probe, you can just put the code there. I
had some readibility problems trying to follow de code.
> + struct ec_response_usb_pd_ports resp;
> + int ret;
> +
> + ret = cros_typec_ec_command(typec, 0, EC_CMD_USB_PD_PORTS, NULL, 0,
> + &resp, sizeof(resp));
> + if (ret < 0)
> + return ret;
> +
> + typec->num_ports = resp.num_ports;
> + if (typec->num_ports > EC_USB_PD_MAX_PORTS) {
> + dev_warn(typec->dev,
> + "Too many ports reported: %d, limiting to max: %d\n",
> + typec->num_ports, EC_USB_PD_MAX_PORTS);
You say that you are limiting the number of ports to max but typec->num_ports is
still resp.num_ports, is that correct?
> + }
> +
> + return 0;
> +}
> +
> +#ifdef CONFIG_ACPI
> +static const struct acpi_device_id cros_typec_acpi_id[] = {
> + { "GOOG0014", 0 },
> + { /* sentinel */ }
No need to add /* sentinel */ here, is obvious.
> +};
> +MODULE_DEVICE_TABLE(acpi, cros_typec_acpi_id);
> +#endif
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id cros_typec_of_match[] = {
> + { .compatible = "google,cros-ec-typec", },
> + { /* sentinel */ },
No need to add /* sentinel */ here, is obvious. And no need for the colon at the
end.
> +};
> +MODULE_DEVICE_TABLE(of, cros_typec_of_match);
> +#endif
> +
> +static int cros_typec_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct cros_typec_data *typec;
> + int ret;
> +
> + typec = devm_kzalloc(dev, sizeof(*typec), GFP_KERNEL);
> + if (!typec)
> + return -ENOMEM;
> + typec->dev = dev;
> + typec->ec = dev_get_drvdata(pdev->dev.parent);
> + platform_set_drvdata(pdev, typec);
> +
> + ret = cros_typec_get_num_ports(typec);
> + if (ret < 0)
> + return ret;
> +
> + ret = cros_typec_init_ports(typec);
both, cros_typec_get_num_ports and cros_typec_init_ports are only called once,
as I said I had some problems of readibility because typec->num_ports is set in
one function and unregister in another function when fails.
I'd just remove those two functions and put the code directly here.
> + if (!ret)
> + return ret;
> +
> + return 0;
> +}
> +
> +static struct platform_driver cros_typec_driver = {
> + .driver = {
> + .name = DRV_NAME,
no tab, just space after .-name
> + .acpi_match_table = ACPI_PTR(cros_typec_acpi_id),
> + .of_match_table = of_match_ptr(cros_typec_of_match),
> + },
> + .probe = cros_typec_probe,
no tab, just space after .probe
> +};
> +
> +module_platform_driver(cros_typec_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Chrome OS EC Type C control");
>
You probably want to add the MODULE_AUTHOR here
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