From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Heimpold Date: Fri, 11 Dec 2015 00:05:36 +0100 Subject: [U-Boot] [PATCH v2] ARM: mxs: allow boards to select DC-DC switching clock source Message-ID: <1449788736-14609-1-git-send-email-mhei@heimpold.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de For some board designs, it might be useful to switch the DC-DC clock source to something else rather the default 24 MHz, e.g. for EMI reasons. For this, override the mxs_power_setup_dcdc_clocksource function in your board support files. Example: void mxs_power_setup_dcdc_clocksource(void) { mxs_power_select_dcdc_clocksource(POWER_MISC_FREQSEL_20MHZ); } Signed-off-by: Michael Heimpold Cc: Marek Vasut Cc: Otavio Salvador Cc: Fabio Estevam --- Changes in v2: - use a weak function approach instead of ifdef'ery as suggested by Marek Vasut arch/arm/cpu/arm926ejs/mxs/spl_power_init.c | 31 +++++++++++++++++++++++++++++ arch/arm/include/asm/arch-mxs/sys_proto.h | 2 ++ 2 files changed, 33 insertions(+) diff --git a/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c b/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c index 1972de8..64e215c 100644 --- a/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c +++ b/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c @@ -248,6 +248,36 @@ static void mxs_power_setup_5v_detect(void) } /** + * mxs_power_switch_dcdc_clocksource() - Switch PLL clock for DC-DC converters + * + * This function configures and then enables an alternative PLL clock source + * for the DC-DC converters. + */ +void mxs_power_select_dcdc_clocksource(uint32_t freqsel) +{ + struct mxs_power_regs *power_regs = + (struct mxs_power_regs *)MXS_POWER_BASE; + + /* Select clocksource for DC-DC converters */ + clrsetbits_le32(&power_regs->hw_power_misc, + POWER_MISC_FREQSEL_MASK, + freqsel); + setbits_le32(&power_regs->hw_power_misc, + POWER_MISC_SEL_PLLCLK); +} + +/** + * mxs_power_setup_dcdc_clocksource() + * + * Normally, there is no need to switch DC-DC clocksource. However, boards + * can implement this function when required. + */ +__weak void mxs_power_setup_dcdc_clocksource(void) +{ + debug("SPL: Using default DC-DC clocksource\n"); +} + +/** * mxs_src_power_init() - Preconfigure the power block * * This function configures reasonable values for the DC-DC control loop @@ -872,6 +902,7 @@ static void mxs_power_configure_power_source(void) debug("SPL: Configuring power source\n"); + mxs_power_setup_dcdc_clocksource(); mxs_src_power_init(); if (readl(&power_regs->hw_power_sts) & POWER_STS_VDD5V_GT_VDDIO) { diff --git a/arch/arm/include/asm/arch-mxs/sys_proto.h b/arch/arm/include/asm/arch-mxs/sys_proto.h index 20ff101..4160e43 100644 --- a/arch/arm/include/asm/arch-mxs/sys_proto.h +++ b/arch/arm/include/asm/arch-mxs/sys_proto.h @@ -25,6 +25,8 @@ int mxsmmc_initialize(bd_t *bis, int id, int (*wp)(int), int (*cd)(int)); void mxs_common_spl_init(const uint32_t arg, const uint32_t *resptr, const iomux_cfg_t *iomux_setup, const unsigned int iomux_size); + +void mxs_power_select_dcdc_clocksource(uint32_t freqsel); #endif struct mxs_pair { -- 2.5.0