summaryrefslogtreecommitdiffstats
path: root/arm64-pwm-rockchip-Keep-enabled-PWMs-running-while-probing.patch
blob: 4bdb5cb76fcf21c908b0f92fb36411f9001b1c99 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
From patchwork Sat Sep 19 19:33:06 2020
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
X-Patchwork-Submitter: Simon South <simon@simonsouth.net>
X-Patchwork-Id: 11787259
Return-Path: 
 <SRS0=uBh2=C4=lists.infradead.org=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@kernel.org>
Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org
 [172.30.200.123])
	by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D0780618
	for <patchwork-linux-arm@patchwork.kernel.org>;
 Sat, 19 Sep 2020 19:33:55 +0000 (UTC)
Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134])
	(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
	(No client certificate requested)
	by mail.kernel.org (Postfix) with ESMTPS id 9DF4C21707
	for <patchwork-linux-arm@patchwork.kernel.org>;
 Sat, 19 Sep 2020 19:33:55 +0000 (UTC)
Authentication-Results: mail.kernel.org;
	dkim=pass (2048-bit key) header.d=lists.infradead.org
 header.i=@lists.infradead.org header.b="tXxoe57q"
DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9DF4C21707
Authentication-Results: mail.kernel.org;
 dmarc=none (p=none dis=none) header.from=simonsouth.net
Authentication-Results: mail.kernel.org;
 spf=none
 smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org
DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed;
	d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding:
	Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive:
	List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject:To:From:
	Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender
	:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner;
	bh=rTFhR4wE/kksRMBhCZanM50Dz/U+ohZU+WFgqGfznMQ=; b=tXxoe57qQlrQ18QBvKs3JZ7wYU
	mFyPVtA2yDfFfGESvkL1Xa44HehjqPoeSxNBAyejg6YfozEgeDKKVZsBEex5hw6LE56H8Iofj0pZV
	AFM98+vh4tydKA7vxhGl0cm7jMVq3N68wqcikUkcdCEs3bp+5dHpOowzZaj3sm51gw/g6pD3ut1+V
	IYlRTF/VuDd3IDW4o27pNrgIqWx9f+/eO1gUdxwCa4i0VNLAHXCt5ysGE+CSwVWMEcp5YN5K1iO8b
	sFKtjMiOcg9wrJdEoYpiFbcHETgUGNj5wdbwRvJR2qZ36gSImyUqJobYqSUyVHCJI2JRUch3UDFtt
	yDQgQ99A==;
Received: from localhost ([::1] helo=merlin.infradead.org)
	by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux))
	id 1kJic9-0004AL-NX; Sat, 19 Sep 2020 19:33:41 +0000
Received: from mailout.easymail.ca ([64.68.200.34])
 by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux))
 id 1kJic6-00049d-Ia; Sat, 19 Sep 2020 19:33:39 +0000
Received: from localhost (localhost [127.0.0.1])
 by mailout.easymail.ca (Postfix) with ESMTP id C7C54A05B3;
 Sat, 19 Sep 2020 19:33:37 +0000 (UTC)
X-Virus-Scanned: Debian amavisd-new at emo05-pco.easydns.vpn
Received: from mailout.easymail.ca ([127.0.0.1])
 by localhost (emo05-pco.easydns.vpn [127.0.0.1]) (amavisd-new, port 10024)
 with ESMTP id G6RbiLyf29ms; Sat, 19 Sep 2020 19:33:37 +0000 (UTC)
Received: from jupiter.simonsouth.net (unknown [108.162.141.195])
 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits))
 (No client certificate requested)
 by mailout.easymail.ca (Postfix) with ESMTPSA id 77C83A025D;
 Sat, 19 Sep 2020 19:33:27 +0000 (UTC)
From: Simon South <simon@simonsouth.net>
To: thierry.reding@gmail.com, u.kleine-koenig@pengutronix.de,
 lee.jones@linaro.org, heiko@sntech.de, linux-pwm@vger.kernel.org,
 linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org
Subject: [PATCH v2] pwm: rockchip: Keep enabled PWMs running while probing
Date: Sat, 19 Sep 2020 15:33:06 -0400
Message-Id: <20200919193306.1023-1-simon@simonsouth.net>
X-Mailer: git-send-email 2.28.0
MIME-Version: 1.0
X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 
X-CRM114-CacheID: sfid-20200919_153338_624271_ABEEE8C4 
X-CRM114-Status: GOOD (  16.76  )
X-Spam-Score: -2.3 (--)
X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary:
 Content analysis details:   (-2.3 points)
 pts rule name              description
 ---- ----------------------
 --------------------------------------------------
 -2.3 RCVD_IN_DNSWL_MED      RBL: Sender listed at https://www.dnswl.org/,
 medium trust [64.68.200.34 listed in list.dnswl.org]
 0.0 SPF_HELO_NONE          SPF: HELO does not publish an SPF Record
 -0.0 SPF_PASS               SPF: sender matches SPF record
X-BeenThere: linux-arm-kernel@lists.infradead.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: <linux-arm-kernel.lists.infradead.org>
List-Unsubscribe: 
 <http://lists.infradead.org/mailman/options/linux-arm-kernel>,
 <mailto:linux-arm-kernel-request@lists.infradead.org?subject=unsubscribe>
List-Archive: <http://lists.infradead.org/pipermail/linux-arm-kernel/>
List-Post: <mailto:linux-arm-kernel@lists.infradead.org>
List-Help: <mailto:linux-arm-kernel-request@lists.infradead.org?subject=help>
List-Subscribe: 
 <http://lists.infradead.org/mailman/listinfo/linux-arm-kernel>,
 <mailto:linux-arm-kernel-request@lists.infradead.org?subject=subscribe>
Cc: Simon South <simon@simonsouth.net>
Sender: "linux-arm-kernel" <linux-arm-kernel-bounces@lists.infradead.org>
Errors-To: 
 linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org

Following commit cfc4c189bc70 ("pwm: Read initial hardware state at
request time") the Rockchip PWM driver can no longer assume a device's
pwm_state structure has been populated after a call to pwmchip_add().
Consequently, the test in rockchip_pwm_probe() intended to prevent the
driver from stopping PWM devices already enabled by the bootloader no
longer functions reliably and this can lead to the kernel hanging
during startup, particularly on devices like the Pinebook Pro that use
a PWM-controlled backlight for their display.

Avoid this by querying the device directly at probe time to determine
whether or not it is enabled.

Fixes: cfc4c189bc70 ("pwm: Read initial hardware state at request time")
Signed-off-by: Simon South <simon@simonsouth.net>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
---
 drivers/pwm/pwm-rockchip.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c
index eb8c9cb645a6..098e94335cb5 100644
--- a/drivers/pwm/pwm-rockchip.c
+++ b/drivers/pwm/pwm-rockchip.c
@@ -288,6 +288,7 @@ static int rockchip_pwm_probe(struct platform_device *pdev)
 	const struct of_device_id *id;
 	struct rockchip_pwm_chip *pc;
 	struct resource *r;
+	u32 enable_conf, ctrl;
 	int ret, count;
 
 	id = of_match_device(rockchip_pwm_dt_ids, &pdev->dev);
@@ -362,7 +363,9 @@ static int rockchip_pwm_probe(struct platform_device *pdev)
 	}
 
 	/* Keep the PWM clk enabled if the PWM appears to be up and running. */
-	if (!pwm_is_enabled(pc->chip.pwms))
+	enable_conf = pc->data->enable_conf;
+	ctrl = readl_relaxed(pc->base + pc->data->regs.ctrl);
+	if ((ctrl & enable_conf) != enable_conf)
 		clk_disable(pc->clk);
 
 	return 0;