linux-kernel - [PATCH v2] clocksource/drivers/sp804: avoid error on multiple instances

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Message-Id: <20220506162522.3675399-1-andre.przywara@arm.com>
Date:   Fri,  6 May 2022 17:25:22 +0100
From:   Andre Przywara <andre.przywara@....com>
To:     Daniel Lezcano <daniel.lezcano@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>
Cc:     Russell King <linux@...linux.org.uk>,
        Kefeng Wang <wangkefeng.wang@...wei.com>,
        Zhen Lei <thunder.leizhen@...wei.com>,
        Robin Murphy <robin.murphy@....com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] clocksource/drivers/sp804: avoid error on multiple instances

When a machine sports more than one SP804 timer instance, we only bring
up the first one, since multiple timers of the same kind are not useful
to Linux. As this is intentional behaviour, we should not return an
error message, as we do today:
===============
[    0.000800] Failed to initialize '/bus@...0000/motherboard-bus@...0000/iofpga-bus@...000000/timer@...000': -22
===============

Replace the -EINVAL return with a debug message and return 0 instead.

Also we do not reach the init function anymore if the DT node is
disabled (as this is now handled by OF_DECLARE), so remove the explicit
check for that case.

This fixes a long standing bogus error when booting ARM's fastmodels.

Signed-off-by: Andre Przywara <andre.przywara@....com>
---
Changelog v1 .. v2:
- demote pr_info() to pr_debug(), to avoid output at all
- use %pOF and reword message

 drivers/clocksource/timer-sp804.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/clocksource/timer-sp804.c b/drivers/clocksource/timer-sp804.c
index 401d592e85f5a..e6a87f4af2b50 100644
--- a/drivers/clocksource/timer-sp804.c
+++ b/drivers/clocksource/timer-sp804.c
@@ -259,6 +259,11 @@ static int __init sp804_of_init(struct device_node *np, struct sp804_timer *time
 	struct clk *clk1, *clk2;
 	const char *name = of_get_property(np, "compatible", NULL);
 
+	if (initialized) {
+		pr_debug("%pOF: skipping further SP804 timer device\n", np);
+		return 0;
+	}
+
 	base = of_iomap(np, 0);
 	if (!base)
 		return -ENXIO;
@@ -270,11 +275,6 @@ static int __init sp804_of_init(struct device_node *np, struct sp804_timer *time
 	writel(0, timer1_base + timer->ctrl);
 	writel(0, timer2_base + timer->ctrl);
 
-	if (initialized || !of_device_is_available(np)) {
-		ret = -EINVAL;
-		goto err;
-	}
-
 	clk1 = of_clk_get(np, 0);
 	if (IS_ERR(clk1))
 		clk1 = NULL;
-- 
2.25.1