linux-kernel - Re: [PATCH v3 6/8] ARM: dts: omap36xx: using OPP1G needs to control the abb

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Date:   Mon, 16 Sep 2019 09:25:53 -0700
From:   Tony Lindgren <tony@...mide.com>
To:     "H. Nikolaus Schaller" <hns@...delico.com>
Cc:     Benoît Cousson <bcousson@...libre.com>,
        Rob Herring <robh+dt@...nel.org>,
        Adam Ford <aford173@...il.com>,
        André Roth <neolynx@...il.com>,
        Mark Rutland <mark.rutland@....com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Enric Balletbo i Serra <eballetbo@...il.com>,
        Javier Martinez Canillas <javier@...hile0.org>,
        Roger Quadros <rogerq@...com>,
        Teresa Remmet <t.remmet@...tec.de>, linux-omap@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org, letux-kernel@...nphoenux.org,
        kernel@...a-handheld.com, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v3 6/8] ARM: dts: omap36xx: using OPP1G needs to control
 the abb_ldo

* H. Nikolaus Schaller <hns@...delico.com> [190911 17:48]:
> See DM3730,DM275 data sheet (SPRS685B) footnote (6) in Table 4-19
> which says that ABB must be switched to FBB mode when using the
> OPP1G.
> 
> The LOD definition abb_mpu_iva already exists so that we need
> to add plumbing for vbb-supply = <&abb_mpu_iva>
> and define two voltage vectors for each OPP so that the abb LDO
> is also updated by the ti-cpufreq driver.
> 
> We also must switch the ti_cpufreq_soc_data to multi_regulator.
> 
> Note: reading out the abb reglator voltage to verify that
> it does do transitions can be done by
> 
> cat /sys/devices/platform/68000000.ocp/483072f0.regulator-abb-mpu/regulator/regulator.*/microvolts
> 
> Likewise, read the twl4030 provided VDD voltage by
> 
> cat /sys/devices/platform/68000000.ocp/48070000.i2c/i2c-0/0-0048/48070000.i2c:twl@48:regulator-vdd1/regulator/regulator.*/microvolts
> 
> Note: to check if the ABB FBB is enabled/disabled, check
> registers
> 
> PRM_LDO_ABB_CTRL 0x483072F4 bit 3:0 1=bypass 5=FBB
> PRM_LDO_ABB_SETUP 0x483072F0 0x00=bypass 0x11=FBB
> 
> e.g.
> 
> /dev/mem opened.
> Memory mapped at address 0xb6fe4000.
> Value at address 0x483072F4 (0xb6fe42f4): 0x3205
> /dev/mem opened.
> Memory mapped at address 0xb6f89000.
> Value at address 0x483072F4 (0xb6f892f4): 0x3201
> 
> Note: omap34xx and am3517 have/need no comparable LDO
> or mechanism.

Acked-by: Tony Lindgren <tony@...mide.com>