From a6b1e25fc6f9ad3a392526414acb1c3c36eccd0f Mon Sep 17 00:00:00 2001 From: Michael Heimpold Date: Sun, 15 Nov 2015 22:47:12 +0100 Subject: ARM: mxs: fix VDDD brownout setting At the moment, the desired brownout is at 1.0V. However, this setting cannot be realized by hardware since we have only 3 bits to represent the voltage difference from the target value. Target value is 1500 mV, brownout target is 1000 mV, voltage steps are 25 mV. Register content calculation: (1500 [mV] - 1000 [mV]) / 25 [mV] = 20 (decimal) = 0x14 Register takes only 3 bits, that is 0x4. But 0x4 * 25 [mV] = 100 [mV], that means that actual brownout level is 1500 [mV] - 100 [mV] = 1.4 V. Minimum possible BO level is 1500 [mV] - 0x7 * 25 [mV] = 1315 [mV]. So lets use this value as desired BO value (which is also the same as FSL bootlets use). Signed-off-by: Michael Heimpold Cc: Marek Vasut Cc: Otavio Salvador Cc: Fabio Estevam Acked-by: Marek Vasut --- arch/arm/cpu/arm926ejs/mxs/spl_power_init.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/arm/cpu/arm926ejs') diff --git a/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c b/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c index 42f3df2..1972de8 100644 --- a/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c +++ b/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c @@ -1221,8 +1221,8 @@ void mxs_power_init(void) debug("SPL: Setting VDDIO to 3V3 (brownout @ 3v15)\n"); mxs_power_set_vddx(&mxs_vddio_cfg, 3300, 3150); - debug("SPL: Setting VDDD to 1V5 (brownout @ 1v0)\n"); - mxs_power_set_vddx(&mxs_vddd_cfg, 1500, 1000); + debug("SPL: Setting VDDD to 1V5 (brownout @ 1v315)\n"); + mxs_power_set_vddx(&mxs_vddd_cfg, 1500, 1315); #ifdef CONFIG_MX23 debug("SPL: Setting mx23 VDDMEM to 2V5 (brownout @ 1v7)\n"); mxs_power_set_vddx(&mxs_vddmem_cfg, 2500, 1700); -- cgit v1.1