[PATCH 5.11 226/601] drivers: nvmem: Fix voltage settings for QTI qfprom-efuse

Greg Kroah-Hartman
2021-05-12T17:15:51Z

From: Ravi Kumar Bokka <rbokka@codeaurora.org>

[ Upstream commit 9ec4f4b0e9fd3ad4b9a38bddb75b516ea09f4628 ]

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>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Ravi Kumar Bokka <rbokka@codeaurora.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20210330111241.19401-4-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/nvmem/qfprom.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)

diff --git a/drivers/nvmem/qfprom.c b/drivers/nvmem/qfprom.c
index 6cace24dfbf7..100d69d8f2e1 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");
--
2.30.2