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    Subject[PATCH 4.5 149/200] PM / OPP: Initialize u_volt_min/max to a valid value
    Date
    4.5-stable review patch.  If anyone has any objections, please let me know.

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

    From: Viresh Kumar <viresh.kumar@linaro.org>

    commit c88c395f4a6485f23f81e385c79945d68bcd5c5d upstream.

    We kept u_volt_min/max initialized to 0, when only the target voltage is
    present in DT, instead of the target/min/max triplet.

    This didn't go well with the regulator framework, as on few calls the
    min voltage was set to target and max was set to 0 and so resulted in a
    kernel crash like below:

    kernel BUG at ../drivers/regulator/core.c:216!

    [<c0684af4>] (regulator_check_voltage) from [<c06857ac>] (regulator_set_voltage_unlocked+0x58/0x230)
    [<c06857ac>] (regulator_set_voltage_unlocked) from [<c06859ac>] (regulator_set_voltage+0x28/0x54)
    [<c06859ac>] (regulator_set_voltage) from [<c0775b28>] (_set_opp_voltage+0x30/0x98)
    [<c0775b28>] (_set_opp_voltage) from [<c0776630>] (dev_pm_opp_set_rate+0xf0/0x28c)
    [<c0776630>] (dev_pm_opp_set_rate) from [<c096f784>] (__cpufreq_driver_target+0x184/0x2b4)
    [<c096f784>] (__cpufreq_driver_target) from [<c0973760>] (dbs_check_cpu+0x1b0/0x1f4)
    [<c0973760>] (dbs_check_cpu) from [<c0973f30>] (cpufreq_governor_dbs+0x324/0x5c4)
    [<c0973f30>] (cpufreq_governor_dbs) from [<c0970958>] (__cpufreq_governor+0xe4/0x1ec)
    [<c0970958>] (__cpufreq_governor) from [<c09711e0>] (cpufreq_init_policy+0x64/0x8c)
    [<c09711e0>] (cpufreq_init_policy) from [<c09718cc>] (cpufreq_online+0x2fc/0x708)
    [<c09718cc>] (cpufreq_online) from [<c0765ff0>] (subsys_interface_register+0x94/0xd8)
    [<c0765ff0>] (subsys_interface_register) from [<c0970530>] (cpufreq_register_driver+0x14c/0x19c)
    [<c0970530>] (cpufreq_register_driver) from [<c09746dc>] (dt_cpufreq_probe+0x70/0xec)
    [<c09746dc>] (dt_cpufreq_probe) from [<c076907c>] (platform_drv_probe+0x4c/0xb0)
    [<c076907c>] (platform_drv_probe) from [<c07678e0>] (driver_probe_device+0x214/0x2c0)
    [<c07678e0>] (driver_probe_device) from [<c0767a18>] (__driver_attach+0x8c/0x90)
    [<c0767a18>] (__driver_attach) from [<c0765c2c>] (bus_for_each_dev+0x68/0x9c)
    [<c0765c2c>] (bus_for_each_dev) from [<c0766d78>] (bus_add_driver+0x1a0/0x218)
    [<c0766d78>] (bus_add_driver) from [<c076810c>] (driver_register+0x78/0xf8)
    [<c076810c>] (driver_register) from [<c0301d74>] (do_one_initcall+0x90/0x1d8)
    [<c0301d74>] (do_one_initcall) from [<c1100e14>] (kernel_init_freeable+0x15c/0x1fc)
    [<c1100e14>] (kernel_init_freeable) from [<c0b27a0c>] (kernel_init+0x8/0xf0)
    [<c0b27a0c>] (kernel_init) from [<c0307d78>] (ret_from_fork+0x14/0x3c)
    Code: e1550004 baffffeb e3a00000 e8bd8070 (e7f001f2)

    Fix that by initializing u_volt_min/max to the target voltage in such cases.

    Reported-and-tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
    Fixes: 274659029c9d (PM / OPP: Add support to parse "operating-points-v2" bindings)
    Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
    Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/base/power/opp/core.c | 10 ++++++++--
    1 file changed, 8 insertions(+), 2 deletions(-)

    --- a/drivers/base/power/opp/core.c
    +++ b/drivers/base/power/opp/core.c
    @@ -844,8 +844,14 @@ static int opp_parse_supplies(struct dev
    }

    opp->u_volt = microvolt[0];
    - opp->u_volt_min = microvolt[1];
    - opp->u_volt_max = microvolt[2];
    +
    + if (count == 1) {
    + opp->u_volt_min = opp->u_volt;
    + opp->u_volt_max = opp->u_volt;
    + } else {
    + opp->u_volt_min = microvolt[1];
    + opp->u_volt_max = microvolt[2];
    + }

    /* Search for "opp-microamp-<name>" */
    prop = NULL;

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