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[PATCH 3.12 10/72] regulator: tps65910: Work around silicon erratum SWCZ010

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From: Jan Remmet <j.remmet@phytec.de>

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

===============

commit 8f9165c981fed187bb483de84caf9adf835aefda upstream.

http://www.ti.com/lit/pdf/SWCZ010:
  DCDC o/p voltage can go higher than programmed value

Impact:
VDDI, VDD2, and VIO output programmed voltage level can go higher than
expected or crash, when coming out of PFM to PWM mode or using DVFS.

Description:
When DCDC CLK SYNC bits are 11/01:
* VIO 3-MHz oscillator is the source clock of the digital core and input
  clock of VDD1 and VDD2
* Turn-on of VDD1 and VDD2 HSD PFETis synchronized or at a constant
  phase shift
* Current pulled though VCC1+VCC2 is Iload(VDD1) + Iload(VDD2)
* The 3 HSD PFET will be turned-on at the same time, causing the highest
  possible switching noise on the application. This noise level depends
  on the layout, the VBAT level, and the load current. The noise level
  increases with improper layout.

When DCDC CLK SYNC bits are 00:
* VIO 3-MHz oscillator is the source clock of digital core
* VDD1 and VDD2 are running on their own 3-MHz oscillator
* Current pulled though VCC1+VCC2 average of Iload(VDD1) + Iload(VDD2)
* The switching noise of the 3 SMPS will be randomly spread over time,
  causing lower overall switching noise.

Workaround:
Set DCDCCTRL_REG[1:0]= 00.

Signed-off-by: Jan Remmet <j.remmet@phytec.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/regulator/tps65910-regulator.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/regulator/tps65910-regulator.c b/drivers/regulator/tps65910-regulator.c
index 45c16447744b..1ed4145164d6 100644
--- a/drivers/regulator/tps65910-regulator.c
+++ b/drivers/regulator/tps65910-regulator.c
@@ -1080,6 +1080,12 @@ static int tps65910_probe(struct platform_device *pdev)
 		pmic->num_regulators = ARRAY_SIZE(tps65910_regs);
 		pmic->ext_sleep_control = tps65910_ext_sleep_control;
 		info = tps65910_regs;
+		/* Work around silicon erratum SWCZ010: output programmed
+		 * voltage level can go higher than expected or crash
+		 * Workaround: use no synchronization of DCDC clocks
+		 */
+		tps65910_reg_clear_bits(pmic->mfd, TPS65910_DCDCCTRL,
+					DCDCCTRL_DCDCCKSYNC_MASK);
 		break;
 	case TPS65911:
 		pmic->get_ctrl_reg = &tps65911_get_ctrl_register;
-- 
2.10.2

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[PATCH 3.12 00/72] 3.12.67-stable review Jiri Slaby <jslaby@suse.cz> - 2016-11-07 14:10 +0100
  [PATCH 3.12 01/72] i40e: avoid NULL pointer dereference and recursive errors on early PCI error Jiri Slaby <jslaby@suse.cz> - 2016-11-07 14:30 +0100
    [PATCH 3.12 03/72] scsi: ibmvfc: Fix I/O hang when port is not mapped Jiri Slaby <jslaby@suse.cz> - 2016-11-07 14:30 +0100
    [PATCH 3.12 19/72] powerpc/pseries: Fix stack corruption in htpe code Jiri Slaby <jslaby@suse.cz> - 2016-11-07 14:30 +0100
    [PATCH 3.12 10/72] regulator: tps65910: Work around silicon erratum SWCZ010 Jiri Slaby <jslaby@suse.cz> - 2016-11-07 14:30 +0100
    [PATCH 3.12 15/72] dm: mark request_queue dead before destroying the DM device Jiri Slaby <jslaby@suse.cz> - 2016-11-07 14:30 +0100
    [PATCH 3.12 16/72] powerpc/vdso64: Use double word compare on pointers Jiri Slaby <jslaby@suse.cz> - 2016-11-07 14:30 +0100
    [PATCH 3.12 22/72] zfcp: close window with unblocked rport during rport gone Jiri Slaby <jslaby@suse.cz> - 2016-11-07 14:30 +0100
    [PATCH 3.12 09/72] gpio: mpc8xxx: Correct irq handler function Jiri Slaby <jslaby@suse.cz> - 2016-11-07 14:30 +0100
    [PATCH 3.12 23/72] zfcp: retain trace level for SCSI and HBA FSF response records Jiri Slaby <jslaby@suse.cz> - 2016-11-07 14:30 +0100
    [PATCH 3.12 07/72] pstore: Fix buffer overflow while write offset equal to buffer size Jiri Slaby <jslaby@suse.cz> - 2016-11-07 14:30 +0100
    [PATCH 3.12 06/72] cfq: fix starvation of asynchronous writes Jiri Slaby <jslaby@suse.cz> - 2016-11-07 14:30 +0100
    [PATCH 3.12 08/72] ipc: remove use of seq_printf return value Jiri Slaby <jslaby@suse.cz> - 2016-11-07 14:30 +0100
    [PATCH 3.12 17/72] powerpc/powernv: Use CPU-endian PEST in pnv_pci_dump_p7ioc_diag_data() Jiri Slaby <jslaby@suse.cz> - 2016-11-07 14:30 +0100
    [PATCH 3.12 20/72] zfcp: fix fc_host port_type with NPIV Jiri Slaby <jslaby@suse.cz> - 2016-11-07 14:30 +0100
  [PATCH 3.12 62/72] powerpc/eeh: Null check uses of eeh_pe_bus_get Jiri Slaby <jslaby@suse.cz> - 2016-11-07 14:40 +0100
  Re: [PATCH 3.12 00/72] 3.12.67-stable review Guenter Roeck <linux@roeck-us.net> - 2016-11-07 18:20 +0100
    Re: [PATCH 3.12 00/72] 3.12.67-stable review Jiri Slaby <jslaby@suse.cz> - 2016-11-08 16:50 +0100
      Re: [PATCH 3.12 00/72] 3.12.67-stable review Guenter Roeck <linux@roeck-us.net> - 2016-11-09 05:20 +0100
        Re: [PATCH 3.12 00/72] 3.12.67-stable review Jiri Slaby <jslaby@suse.cz> - 2016-11-10 20:00 +0100
  Re: [PATCH 3.12 00/72] 3.12.67-stable review Shuah Khan <shuah.kh@samsung.com> - 2016-11-07 19:40 +0100
    Re: [PATCH 3.12 00/72] 3.12.67-stable review Jiri Slaby <jslaby@suse.cz> - 2016-11-10 20:00 +0100

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