linux-kernel - [PATCH 4.9 50/63] drm/imx: imx-tve: Do not set the regulator voltage

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Message-Id: <20170313083417.490138605@linuxfoundation.org>
Date:   Mon, 13 Mar 2017 16:39:37 +0800
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Lucas Stach <l.stach@...gutronix.de>,
        Fabio Estevam <fabio.estevam@....com>,
        Philipp Zabel <p.zabel@...gutronix.de>
Subject: [PATCH 4.9 50/63] drm/imx: imx-tve: Do not set the regulator voltage

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Fabio Estevam <fabio.estevam@....com>

commit fc12bccda8b6f5c38139eceec9e369ed78091b2b upstream.

Commit deb65870b5d9d ("drm/imx: imx-tve: check the value returned by
regulator_set_voltage()") exposes the following probe issue:

63ff0000.tve supply dac not found, using dummy regulator
imx-drm display-subsystem: failed to bind 63ff0000.tve (ops imx_tve_ops): -22

When the 'dac-supply' is not passed in the device tree a dummy regulator is
used and setting its voltage is not allowed.

To fix this issue, do not set the dac-supply voltage inside the driver
and let its voltage be specified in the device tree.

Print a warning if the the 'dac-supply' voltage has a value different
from 2.75V.

Fixes: deb65870b5d9d ("drm/imx: imx-tve: check the value returned by regulator_set_voltage()")
Suggested-by: Lucas Stach <l.stach@...gutronix.de>
Signed-off-by: Fabio Estevam <fabio.estevam@....com>
Signed-off-by: Philipp Zabel <p.zabel@...gutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/gpu/drm/imx/imx-tve.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/drivers/gpu/drm/imx/imx-tve.c
+++ b/drivers/gpu/drm/imx/imx-tve.c
@@ -98,6 +98,8 @@
 /* TVE_TST_MODE_REG */
 #define TVE_TVDAC_TEST_MODE_MASK	(0x7 << 0)
 
+#define IMX_TVE_DAC_VOLTAGE	2750000
+
 enum {
 	TVE_MODE_TVOUT,
 	TVE_MODE_VGA,
@@ -628,9 +630,8 @@ static int imx_tve_bind(struct device *d
 
 	tve->dac_reg = devm_regulator_get(dev, "dac");
 	if (!IS_ERR(tve->dac_reg)) {
-		ret = regulator_set_voltage(tve->dac_reg, 2750000, 2750000);
-		if (ret)
-			return ret;
+		if (regulator_get_voltage(tve->dac_reg) != IMX_TVE_DAC_VOLTAGE)
+			dev_warn(dev, "dac voltage is not %d uV\n", IMX_TVE_DAC_VOLTAGE);
 		ret = regulator_enable(tve->dac_reg);
 		if (ret)
 			return ret;