linux-kernel - [PATCH v5 5/5] power: supply: cros_charge-control: don't load if Framework control is present

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Message-Id: <20240630-cros_ec-charge-control-v5-5-8f649d018c52@weissschuh.net>
Date: Sun, 30 Jun 2024 22:54:12 +0200
From: Thomas Weißschuh <linux@...ssschuh.net>
To: Benson Leung <bleung@...omium.org>, Guenter Roeck <groeck@...omium.org>, 
 Sebastian Reichel <sre@...nel.org>, 
 Thomas Weißschuh <thomas@...ssschuh.net>, 
 "Rafael J. Wysocki" <rafael@...nel.org>, Len Brown <lenb@...nel.org>, 
 Robert Moore <robert.moore@...el.com>, Tzung-Bi Shih <tzungbi@...nel.org>
Cc: chrome-platform@...ts.linux.dev, linux-kernel@...r.kernel.org, 
 linux-pm@...r.kernel.org, Mario Limonciello <mario.limonciello@....com>, 
 Dustin Howett <dustin@...ett.net>, 
 Stephen Horvath <s.horvath@...look.com.au>, 
 Rajas Paranjpe <paranjperajas@...il.com>, linux-acpi@...r.kernel.org, 
 acpica-devel@...ts.linux.dev, Matt Hartley <matt.hartley@...il.com>, 
 Kieran Levin <ktl@...mework.net>, 
 Thomas Weißschuh <linux@...ssschuh.net>
Subject: [PATCH v5 5/5] power: supply: cros_charge-control: don't load if
 Framework control is present

Framework laptops implement a custom charge control EC command.
The upstream CrOS EC command is also present and functional but can get
overridden by the custom one.

Until Framework make both commands compatible or remove their custom
one, don't load the driver on those machines.

If the user knows they are not going to use the custom command they can
use a module parameter to load cros_charge-control anyways.

Note that the UEFI setup configuration for battery control also uses
their custom command.

Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>
---
 drivers/power/supply/cros_charge-control.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/power/supply/cros_charge-control.c b/drivers/power/supply/cros_charge-control.c
index 521b0eb4ff3b..73d7f2dc0fa3 100644
--- a/drivers/power/supply/cros_charge-control.c
+++ b/drivers/power/supply/cros_charge-control.c
@@ -6,6 +6,7 @@
  */
 #include <acpi/battery.h>
 #include <linux/container_of.h>
+#include <linux/dmi.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/platform_data/cros_ec_commands.h>
@@ -256,6 +257,19 @@ static int cros_chctl_remove_battery(struct power_supply *battery, struct acpi_b
 	return 0;
 }

+static bool probe_with_fwk_charge_control;
+module_param(probe_with_fwk_charge_control, bool, 0644);
+MODULE_PARM_DESC(probe_with_fwk_charge_control,
+		 "Probe the driver in the presence of the custom Framework EC charge control");
+
+static int cros_chctl_fwk_charge_control_versions(struct cros_ec_device *cros_ec)
+{
+	if (!dmi_match(DMI_SYS_VENDOR, "Framework"))
+		return 0;
+
+	return cros_ec_get_cmd_versions(cros_ec, 0x3E03 /* FW_EC_CMD_CHARGE_LIMIT */);
+}
+
 static int cros_chctl_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -265,6 +279,14 @@ static int cros_chctl_probe(struct platform_device *pdev)
 	size_t i;
 	int ret;

+	ret = cros_chctl_fwk_charge_control_versions(cros_ec);
+	if (ret < 0)
+		return ret;
+	if (ret > 0 && !probe_with_fwk_charge_control) {
+		dev_info(dev, "Framework charge control detected, preventing load\n");
+		return -ENODEV;
+	}
+
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;

-- 
2.45.2