Hi Minkyu, On 21 May 2014 00:05, Minkyu Kang <mk7.k...@samsung.com> wrote: > On 20/05/14 20:47, Simon Glass wrote: >> Hi Minkyu, >> >> On 15 May 2014 00:51, Minkyu Kang <mk7.k...@samsung.com> wrote: >>> On 03/04/14 08:24, Simon Glass wrote: >>>> From: Aaron Durbin <adur...@chromium.org> >>>> >>>> The TSP65090 is a PMIC on some exynos5 boards. The init function is >>>> called for the TPS65090 pmic. If that device is not a part of the device >>>> tree (returns -ENODEV) then continue. Otherwise return a failure. >>>> >>>> Signed-off-by: Aaron Durbin <adur...@chromium.org> >>>> Signed-off-by: Simon Glass <s...@chromium.org> >>>> Reviewed-by: Simon Glass <s...@chromium.org> >>>> --- >>>> >>>> Changes in v2: >>>> - Move code to exynos5-dt.c >>>> - Fix comment style >>>> - Add #ifdef around tps65090 code >>>> >>>> board/samsung/smdk5250/exynos5-dt.c | 13 +++++++++++++ >>>> 1 file changed, 13 insertions(+) >>>> >>>> diff --git a/board/samsung/smdk5250/exynos5-dt.c >>>> b/board/samsung/smdk5250/exynos5-dt.c >>>> index 1a64b9b..2c1cf8a 100644 >>>> --- a/board/samsung/smdk5250/exynos5-dt.c >>>> +++ b/board/samsung/smdk5250/exynos5-dt.c >>>> @@ -20,6 +20,7 @@ >>>> #include <asm/arch/sromc.h> >>>> #include <power/pmic.h> >>>> #include <power/max77686_pmic.h> >>>> +#include <power/tps65090_pmic.h> >>>> #include <tmu.h> >>>> >>>> DECLARE_GLOBAL_DATA_PTR; >>>> @@ -164,7 +165,19 @@ int exynos_power_init(void) >>>> >>>> #ifdef CONFIG_POWER_MAX77686 >>>> ret = max77686_init(); >>>> + if (ret) >>>> + return ret; >>>> #endif >>>> +#ifdef CONFIG_POWER_TPS65090 >>>> + /* >>>> + * The TPS65090 may not be in the device tree. If so, it is not >>>> + * an error. >>> >>> Then, how we can initialise the tps65090? >> >> It is initialised if a suitable node is found in the device tree. If >> the device tree does not have it, then the hardware is assumed to not >> have this chip. > > then I think, it's an error. > Why you said, it is not an error?
I may be misunderstanding your question, but I'll try to answer what I think you are asking. The device tree contains nodes for hardware in the machine that you want to initialise, and information about each one. Devices can be enabled or disabled by including or removing this information from the device tree (or marking a device disabled with a status = "disabled" property in the node). The tps65090 chip is not used in all exynos5-dt boards, but is used in some. For example smdk5250 does not have it, but snow does. So we use the device tree to specify the difference, including (on snow) things like the tps65090, the display bridge chip, etc. Regards, Simon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
