From: Dave Gerlach <d-gerlach@ti.com> To: "J, KEERTHY" <j-keerthy@ti.com>, Viresh Kumar <viresh.kumar@linaro.org> Cc: <vireshk@kernel.org>, <nm@ti.com>, <sboyd@kernel.org>, <linux-pm@vger.kernel.org>, <linux-kernel@vger.kernel.org>, <t-kristo@ti.com> Subject: Re: [PATCH 1/2] opp: ti-opp-supply: Dynamically update u_volt_min Date: Mon, 12 Nov 2018 16:05:47 -0600 [thread overview] Message-ID: <d86733f4-fb87-c7ce-88ff-bc2150a8acb2@ti.com> (raw) In-Reply-To: <e383feb1-ba04-7f56-0cd8-257660a95bd3@ti.com> On 11/11/2018 09:15 PM, J, KEERTHY wrote: > > > On 11/8/2018 11:24 AM, Viresh Kumar wrote: >> On 07-11-18, 10:04, Keerthy wrote: >>> 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. >> >> And why shouldn't we fix the DT for this ? > > The DT voltages do not cater to the broad range of devices. In some > particular cases the DT min voltage is slightly lower the voltage at > which the device cannot sustain a particular frequency in which case the > device just silently hangs. So best thing to do is to actually read the > device specific voltages dynamically which will guarantee a particular > device sustaining a particular frequency at the optimal voltage. > Acked-by: Dave Gerlach <d-gerlach@ti.com> >>
WARNING: multiple messages have this Message-ID (diff)
From: Dave Gerlach <d-gerlach@ti.com> To: "J, KEERTHY" <j-keerthy@ti.com>, Viresh Kumar <viresh.kumar@linaro.org> Cc: vireshk@kernel.org, nm@ti.com, sboyd@kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, t-kristo@ti.com Subject: Re: [PATCH 1/2] opp: ti-opp-supply: Dynamically update u_volt_min Date: Mon, 12 Nov 2018 16:05:47 -0600 [thread overview] Message-ID: <d86733f4-fb87-c7ce-88ff-bc2150a8acb2@ti.com> (raw) In-Reply-To: <e383feb1-ba04-7f56-0cd8-257660a95bd3@ti.com> On 11/11/2018 09:15 PM, J, KEERTHY wrote: > > > On 11/8/2018 11:24 AM, Viresh Kumar wrote: >> On 07-11-18, 10:04, Keerthy wrote: >>> 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. >> >> And why shouldn't we fix the DT for this ? > > The DT voltages do not cater to the broad range of devices. In some > particular cases the DT min voltage is slightly lower the voltage at > which the device cannot sustain a particular frequency in which case the > device just silently hangs. So best thing to do is to actually read the > device specific voltages dynamically which will guarantee a particular > device sustaining a particular frequency at the optimal voltage. > Acked-by: Dave Gerlach <d-gerlach@ti.com> >>
next prev parent reply other threads:[~2018-11-12 22:05 UTC|newest] Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-11-07 4:34 [PATCH 0/2] opp: ti-opp-supply: Fixes Keerthy 2018-11-07 4:34 ` Keerthy 2018-11-07 4:34 ` [PATCH 1/2] opp: ti-opp-supply: Dynamically update u_volt_min Keerthy 2018-11-07 4:34 ` Keerthy 2018-11-08 5:54 ` Viresh Kumar 2018-11-12 3:15 ` J, KEERTHY 2018-11-12 3:15 ` J, KEERTHY 2018-11-12 22:05 ` Dave Gerlach [this message] 2018-11-12 22:05 ` Dave Gerlach 2018-11-07 4:34 ` [PATCH 2/2] opp: ti-opp-supply: Correct the supply in _get_optimal_vdd_voltage call Keerthy 2018-11-07 4:34 ` Keerthy 2018-11-12 21:49 ` Dave Gerlach 2018-11-12 21:49 ` Dave Gerlach 2018-11-08 5:53 ` [PATCH 0/2] opp: ti-opp-supply: Fixes Viresh Kumar 2018-11-13 4:12 ` Viresh Kumar
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