linux-kernel - [PATCH 2/3] mfd: cros_ec_dev: Only register PCHG device if present

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Date:   Thu, 14 Apr 2022 17:32:52 -0700
From:   Stephen Boyd <swboyd@...omium.org>
To:     Benson Leung <bleung@...omium.org>
Cc:     linux-kernel@...r.kernel.org, patches@...ts.linux.dev,
        Lee Jones <lee.jones@...aro.org>,
        Daisuke Nojiri <dnojiri@...omium.org>,
        Guenter Roeck <groeck@...omium.org>,
        chrome-platform@...ts.linux.dev
Subject: [PATCH 2/3] mfd: cros_ec_dev: Only register PCHG device if present

Don't create a device for the peripheral charger (PCHG) if there aren't
any peripheral charger ports. This removes a device on most ChromeOS
systems, because the peripheral charger functionality isn't always
present.

Cc: Lee Jones <lee.jones@...aro.org>
Cc: Daisuke Nojiri <dnojiri@...omium.org>
Cc: Benson Leung <bleung@...omium.org>
Cc: Guenter Roeck <groeck@...omium.org>
Cc: <chrome-platform@...ts.linux.dev>
Signed-off-by: Stephen Boyd <swboyd@...omium.org>
---
 drivers/mfd/cros_ec_dev.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index 546feef851ab..d2ba6a1fbc1d 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -114,6 +114,9 @@ static const struct mfd_cell cros_ec_platform_cells[] = {
 	{ .name = "cros-ec-chardev", },
 	{ .name = "cros-ec-debugfs", },
 	{ .name = "cros-ec-sysfs", },
+};
+
+static const struct mfd_cell cros_ec_pchg_cells[] = {
 	{ .name = "cros-ec-pchg", },
 };
 
@@ -242,6 +245,19 @@ static int ec_device_probe(struct platform_device *pdev)
 		}
 	}
 
+	/*
+	 * The PCHG device cannot be detected by sending EC_FEATURE_GET_CMD, but
+	 * it can be detected by querying the number of peripheral chargers.
+	 */
+	if (cros_ec_pchg_port_count(ec)) {
+		retval = mfd_add_hotplug_devices(ec->dev,
+					cros_ec_pchg_cells,
+					ARRAY_SIZE(cros_ec_pchg_cells));
+		if (retval)
+			dev_warn(ec->dev, "failed to add pchg: %d\n",
+				 retval);
+	}
+
 	/*
 	 * The following subdevices cannot be detected by sending the
 	 * EC_FEATURE_GET_CMD to the Embedded Controller device.
-- 
https://chromeos.dev