From fe7ea0062f2f846bb68447c7b813b9230285dbeb Mon Sep 17 00:00:00 2001 From: Mohan V Date: Fri, 22 Jun 2012 08:40:02 -0600 Subject: [PATCH] ARM: OMAP3: PM: correct enable/disable of daisy io chain Currently the enabling and disabling of IO Daisy chain is not according to the TRM. The below steps are followed to enable/ disable the IO chain, based loosely on the "Sec 3.5.7.2.2 I/O Wake-Up Mechanism" section in OMAP3630 Public TRM[1]. Steps to enable IO chain: [a] Set PM_WKEN_WKUP.EN_IO bit [b] Set the PM_WKEN_WKUP.EN_IO_CHAIN bit [c] Poll for PM_WKST_WKUP.ST_IO_CHAIN. [d] When ST_IO_CHAIN bit set to 1, clear PM_WKEN_WKUP.EN_IO_CHAIN [e] Clear ST_IO_CHAIN bit. Steps to disable IO chain: [a] Clear PM_WKEN_WKUP.EN_IO_CHAIN bit [b] Clear PM_WKEN_WKUP.EN_IO bit [c] Clear PM_WKST_WKUP.ST_IO bit by writing 1 to it. Step [e] & [c] in each case can be skipped, as these are handled by the PRCM interrupt handler later. [1] http://focus.ti.com/pdfs/wtbu/OMAP36xx_ES1.x_PUBLIC_TRM_vV.zip Signed-off-by: Mohan V Signed-off-by: Vishwanath BS [paul@pwsan.com: modified commit message to clarify that these steps are based loosely on the TRM section, rather than documented exactly] Reviewed-by: Rajendra Nayak [paul@pwsan.com: resolved new warnings from checkpatch] Signed-off-by: Paul Walmsley --- arch/arm/mach-omap2/pm34xx.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c index a34023d0ca7c..6d7f0d8a3103 100644 --- a/arch/arm/mach-omap2/pm34xx.c +++ b/arch/arm/mach-omap2/pm34xx.c @@ -81,16 +81,17 @@ static void omap3_enable_io_chain(void) /* Do a readback to assure write has been done */ omap2_prm_read_mod_reg(WKUP_MOD, PM_WKEN); - while (!(omap2_prm_read_mod_reg(WKUP_MOD, PM_WKEN) & + while (!(omap2_prm_read_mod_reg(WKUP_MOD, PM_WKST) & OMAP3430_ST_IO_CHAIN_MASK)) { timeout++; if (timeout > 1000) { pr_err("Wake up daisy chain activation failed.\n"); return; } - omap2_prm_set_mod_reg_bits(OMAP3430_ST_IO_CHAIN_MASK, - WKUP_MOD, PM_WKEN); } + omap2_prm_clear_mod_reg_bits(OMAP3430_EN_IO_CHAIN_MASK, WKUP_MOD, + PM_WKEN); + } static void omap3_disable_io_chain(void) -- 2.39.5