linux-kernel - [PATCH] mfd: wm8994: Reset device during probe

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Message-Id: <1368793521-30092-1-git-send-email-broonie@opensource.wolfsonmicro.com>
Date:	Fri, 17 May 2013 13:25:21 +0100
From:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
To:	Samuel Ortiz <sameo@...ux.intel.com>
Cc:	linux-kernel@...r.kernel.org, patches@...nsource.wolfsonmicro.com,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>
Subject: [PATCH] mfd: wm8994: Reset device during probe

Ensure that the device is in a known good state. This should have little
practical impact as the runtime PM will reset the device shortly after
probe but it's neater.

Signed-off-by: Mark Brown <broonie@...nsource.wolfsonmicro.com>
---
 drivers/mfd/wm8994-core.c |   11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/mfd/wm8994-core.c b/drivers/mfd/wm8994-core.c
index 00e4fe2..ccdddf9 100644
--- a/drivers/mfd/wm8994-core.c
+++ b/drivers/mfd/wm8994-core.c
@@ -652,6 +652,17 @@ static int wm8994_device_init(struct wm8994 *wm8994, int irq)
 		return ret;
 	}
 
+	/* Explicitly put the device into reset in case regulators
+	 * don't get disabled in order to ensure we know the device
+	 * state.
+	 */
+	ret = wm8994_reg_write(wm8994, WM8994_SOFTWARE_RESET,
+			       wm8994_reg_read(wm8994, WM8994_SOFTWARE_RESET));
+	if (ret != 0) {
+		dev_err(wm8994->dev, "Failed to reset device: %d\n", ret);
+		return ret;
+	}
+
 	if (regmap_patch) {
 		ret = regmap_register_patch(wm8994->regmap, regmap_patch,
 					    patch_regs);
-- 
1.7.10.4

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