On Tue, Feb 10, 2015 at 3:23 AM, Stefano Babic sbabic@denx.de wrote:
Ok - with this explanation, I would try to understand how the changes can be split. If the feature/change works for several boards, it makes sense to have it common and general. If it is only for one board, must flow into the board directory.
It should be common as there are several boards which use PMIC's and can use it.
It looks like that ldo-bypass is strictly dependent on the board. Firstly, it must have PMIC, and not all boards have it. Your last sentence:
Any board that has a PMIC capable of regulating VDD_ARM_IN and VDD_SOC_IN to the setpoints from the IMX6 datasheet can operate in LDO bypass mode, unless operating at 1.2GHz in which case the datasheet states that the LDO must be used (not bypassed) to avoid ripple sensitivity issues.
In ldo-bypass mode, we need trigger WDOG_B pin to reset pmic in ldo-bypass mode. So add set_wdog_reset to do this work.
This looks to me as an item very bound to the board. Could it be possible to use another pin (I do not know the schematics, I remember that such as reset pin was fix on previous i.MX) ? If answer is yes, can these changes be used by other board or are they only for sabresd ?
agreed - this is a board-specific pinmux
Signed-off-by: Peng Fan Peng.Fan@freescale.com Signed-off-by: Robin Gong b38343@freescale.com Signed-off-by: Nitin Garg nitin.garg@freescale.com
arch/arm/cpu/armv7/mx6/soc.c | 141 ++++++++++++++++++++++++++++++ arch/arm/include/asm/arch-mx6/sys_proto.h | 9 ++ 2 files changed, 150 insertions(+)
diff --git a/arch/arm/cpu/armv7/mx6/soc.c b/arch/arm/cpu/armv7/mx6/soc.c index 5f5f497..5d02755 100644 --- a/arch/arm/cpu/armv7/mx6/soc.c +++ b/arch/arm/cpu/armv7/mx6/soc.c @@ -18,6 +18,7 @@ #include <asm/arch/sys_proto.h> #include <asm/imx-common/boot_mode.h> #include <asm/imx-common/dma.h> +#include <libfdt.h> #include <stdbool.h> #include <asm/arch/mxc_hdmi.h> #include <asm/arch/crm_regs.h> @@ -429,6 +430,146 @@ void s_init(void) writel(mask528, &anatop->pfd_528_clr); }
+#ifdef CONFIG_LDO_BYPASS_CHECK +DECLARE_GLOBAL_DATA_PTR; +static int ldo_bypass;
mmmhh....global to the module ?
+int check_ldo_bypass(void) +{
const int *ldo_mode;int node;/* get the right fdt_blob from the global working_fdt */gd->fdt_blob = working_fdt;/* Get the node from FDT for anatop ldo-bypass */node = fdt_node_offset_by_compatible(gd->fdt_blob, -1,"fsl,imx6q-gpc");if (node < 0) {printf("No gpc device node %d, force to ldo-enable.\n", node);return 0;}ldo_mode = fdt_getprop(gd->fdt_blob, node, "fsl,ldo-bypass", NULL);I am quite lost. I have searched in kernel (current TOT), and I have not found such property. Can you help me to understand ?
Right - you won't find it because its a Freescale vendor kernel implementation only. A hack if you ask me to avoid having to doing ldo-byapss the right way.
Here are the threads that I know of regarding ldo-bypass in the kernel, where it needs to be:
https://lkml.org/lkml/2014/12/18/255 https://lkml.org/lkml/2014/10/31/3
Peng,
I think what you are trying to do here is to put the anatop regulators in bypass mode so that the Freescale vendor kernel leaves them bypassed (which is what the 3.10.x based vendor kernels supporting device-tree at http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git do). This is what the Freescale vendor U-Boot does and so they have created a horrible dependence between kernel and bootloader.
Instead you may be interested in what I did for our BSP's that use the Freescale vendor kernel. Instead of touching U-Boot, I look for the fsl,ldo-bypass node in the kernel and enable it just like their bootloader would have: https://github.com/Gateworks/linux-imx6/commit/a1af6ac6f00b4da7c8a5656e8ff09...
That said, I would love to see some help getting IMX6 ldo-bypass support upstream. All of our boards have an external PMIC and are capable of bypass mode. Bypassing the LDO on such boards really helps reduce overall board power consumption as well as move heat from the CPU to the PMIC.
Tim