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Subject[PATCH] drivers: nvmem: Fix voltage settings for QTI qfprom-efuse
Date
QFPROM controller hardware requires 1.8V min for fuse blowing.
So, this change sets the voltage to 1.8V, required to blow the fuse
for qfprom-efuse controller.

To disable fuse blowing, we set the voltage to 0V since this may
be a shared rail and may be able to run at a lower rate when we're
not blowing fuses.

Fixes: 93b4e49f8c86 ("nvmem: qfprom: Add fuse blowing support")
Reported-by: Douglas Anderson <dianders@chromium.org>
Suggested-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Ravi Kumar Bokka <rbokka@codeaurora.org>
---
drivers/nvmem/qfprom.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)

diff --git a/drivers/nvmem/qfprom.c b/drivers/nvmem/qfprom.c
index 6cace24..100d69d 100644
--- a/drivers/nvmem/qfprom.c
+++ b/drivers/nvmem/qfprom.c
@@ -127,6 +127,16 @@ static void qfprom_disable_fuse_blowing(const struct qfprom_priv *priv,
{
int ret;

+ /*
+ * This may be a shared rail and may be able to run at a lower rate
+ * when we're not blowing fuses. At the moment, the regulator framework
+ * applies voltage constraints even on disabled rails, so remove our
+ * constraints and allow the rail to be adjusted by other users.
+ */
+ ret = regulator_set_voltage(priv->vcc, 0, INT_MAX);
+ if (ret)
+ dev_warn(priv->dev, "Failed to set 0 voltage (ignoring)\n");
+
ret = regulator_disable(priv->vcc);
if (ret)
dev_warn(priv->dev, "Failed to disable regulator (ignoring)\n");
@@ -172,6 +182,17 @@ static int qfprom_enable_fuse_blowing(const struct qfprom_priv *priv,
goto err_clk_prepared;
}

+ /*
+ * Hardware requires 1.8V min for fuse blowing; this may be
+ * a rail shared do don't specify a max--regulator constraints
+ * will handle.
+ */
+ ret = regulator_set_voltage(priv->vcc, 1800000, INT_MAX);
+ if (ret) {
+ dev_err(priv->dev, "Failed to set 1.8 voltage\n");
+ goto err_clk_rate_set;
+ }
+
ret = regulator_enable(priv->vcc);
if (ret) {
dev_err(priv->dev, "Failed to enable regulator\n");
--
Qualcomm INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by the Linux Foundation.
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