linux-kernel - [PATCH 4.19 027/110] opp: ti-opp-supply: Dynamically update u_volt

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Date:   Thu, 29 Nov 2018 15:11:58 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Keerthy <j-keerthy@...com>,
        Dave Gerlach <d-gerlach@...com>,
        Viresh Kumar <viresh.kumar@...aro.org>
Subject: [PATCH 4.19 027/110] opp: ti-opp-supply: Dynamically update u_volt_min

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

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

From: Keerthy <j-keerthy@...com>

commit ba038546ff9e15d54d1134b5c5d2355648c00dec upstream.

The voltage range (min, max) provided in the device tree is from
the data manual and is pretty big, catering to a wide range of devices.
On a i2c read/write failure the regulator_set_voltage_triplet function
falls back to set voltage between min and max. The min value from Device
Tree can be lesser than the optimal value and in that case that can lead
to a hang or crash. Hence set the u_volt_min dynamically to the optimal
voltage value.

Cc: 4.16+ <stable@...r.kernel.org> # v4.16+
Fixes: 9a835fa6e47 ("PM / OPP: Add ti-opp-supply driver")
Signed-off-by: Keerthy <j-keerthy@...com>
Acked-by: Dave Gerlach <d-gerlach@...com>
Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/opp/ti-opp-supply.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/opp/ti-opp-supply.c
+++ b/drivers/opp/ti-opp-supply.c
@@ -290,6 +290,9 @@ static int ti_opp_supply_set_opp(struct
 	vdd_uv = _get_optimal_vdd_voltage(dev, &opp_data,
 					  new_supply_vbb->u_volt);
 
+	if (new_supply_vdd->u_volt_min < vdd_uv)
+		new_supply_vdd->u_volt_min = vdd_uv;
+
 	/* Scaling up? Scale voltage before frequency */
 	if (freq > old_freq) {
 		ret = _opp_set_voltage(dev, new_supply_vdd, vdd_uv, vdd_reg,