linux-kernel - [PATCH v16 28/40] soc/tegra: fuse: Reset hardware

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Message-Id: <20211130232347.950-29-digetx@gmail.com>
Date:   Wed,  1 Dec 2021 02:23:35 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Viresh Kumar <vireshk@...nel.org>,
        Stephen Boyd <sboyd@...nel.org>,
        Peter De Schrijver <pdeschrijver@...dia.com>,
        Mikko Perttunen <mperttunen@...dia.com>,
        Lee Jones <lee.jones@...aro.org>,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>, Nishanth Menon <nm@...com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Michael Turquette <mturquette@...libre.com>
Cc:     linux-kernel@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-pm@...r.kernel.org, linux-pwm@...r.kernel.org,
        linux-mmc@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-clk@...r.kernel.org, David Heidelberg <david@...t.cz>
Subject: [PATCH v16 28/40] soc/tegra: fuse: Reset hardware

The FUSE controller is enabled at a boot time. Reset it in order to put
hardware and clock into clean and disabled state.

Reviewed-by: Ulf Hansson <ulf.hansson@...aro.org>
Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
 drivers/soc/tegra/fuse/fuse-tegra.c | 25 +++++++++++++++++++++++++
 drivers/soc/tegra/fuse/fuse.h       |  1 +
 2 files changed, 26 insertions(+)

diff --git a/drivers/soc/tegra/fuse/fuse-tegra.c b/drivers/soc/tegra/fuse/fuse-tegra.c
index f2151815db58..cc032729a143 100644
--- a/drivers/soc/tegra/fuse/fuse-tegra.c
+++ b/drivers/soc/tegra/fuse/fuse-tegra.c
@@ -14,6 +14,7 @@
 #include <linux/of_address.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/reset.h>
 #include <linux/slab.h>
 #include <linux/sys_soc.h>
 
@@ -243,6 +244,30 @@ static int tegra_fuse_probe(struct platform_device *pdev)
 		goto restore;
 	}
 
+	fuse->rst = devm_reset_control_get_optional(&pdev->dev, "fuse");
+	if (IS_ERR(fuse->rst)) {
+		err = PTR_ERR(fuse->rst);
+		dev_err(&pdev->dev, "failed to get FUSE reset: %pe\n",
+			fuse->rst);
+		goto restore;
+	}
+
+	/*
+	 * FUSE clock is enabled at a boot time, hence this resume/suspend
+	 * disables the clock besides the h/w resetting.
+	 */
+	err = pm_runtime_resume_and_get(&pdev->dev);
+	if (err)
+		goto restore;
+
+	err = reset_control_reset(fuse->rst);
+	pm_runtime_put(&pdev->dev);
+
+	if (err < 0) {
+		dev_err(&pdev->dev, "failed to reset FUSE: %d\n", err);
+		goto restore;
+	}
+
 	/* release the early I/O memory mapping */
 	iounmap(base);
 
diff --git a/drivers/soc/tegra/fuse/fuse.h b/drivers/soc/tegra/fuse/fuse.h
index de58feba0435..1b719d85bd04 100644
--- a/drivers/soc/tegra/fuse/fuse.h
+++ b/drivers/soc/tegra/fuse/fuse.h
@@ -43,6 +43,7 @@ struct tegra_fuse {
 	void __iomem *base;
 	phys_addr_t phys;
 	struct clk *clk;
+	struct reset_control *rst;
 
 	u32 (*read_early)(struct tegra_fuse *fuse, unsigned int offset);
 	u32 (*read)(struct tegra_fuse *fuse, unsigned int offset);
-- 
2.33.1