From dea6200ba0a43afb90a277802c3edf0124848eed Mon Sep 17 00:00:00 2001 From: Rajendra Nayak Date: Fri, 22 Jun 2012 08:40:03 -0600 Subject: ARM: OMAP4: PRM: Add IO Daisychain support IO daisychain is a mechanism that allows individual IO pads to generate wakeup events on their own based on a switch of an input signal level. This allows the hardware module behind the pad to be powered down, but still have device level capability to detect IO events, and once this happens the module can be powered back up to resume IO. See section 3.9.4 in OMAP4430 Public TRM for details. Signed-off-by: Rajendra Nayak Signed-off-by: Vishwanath BS Signed-off-by: Tero Kristo [paul@pwsan.com: use the shared MAX_IOPAD_LATCH_TIME declaration; renamed omap4_trigger_io_chain() to conform to other PRM function names; added kerneldoc; resolved checkpatch warnings] Signed-off-by: Paul Walmsley --- arch/arm/mach-omap2/prm44xx.c | 54 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) (limited to 'arch/arm/mach-omap2/prm44xx.c') diff --git a/arch/arm/mach-omap2/prm44xx.c b/arch/arm/mach-omap2/prm44xx.c index f106d21ff581..28ffbc55f8d6 100644 --- a/arch/arm/mach-omap2/prm44xx.c +++ b/arch/arm/mach-omap2/prm44xx.c @@ -233,6 +233,60 @@ void omap44xx_prm_restore_irqen(u32 *saved_mask) OMAP4_PRM_IRQENABLE_MPU_2_OFFSET); } +/** + * omap44xx_prm_reconfigure_io_chain - clear latches and reconfigure I/O chain + * + * Clear any previously-latched I/O wakeup events and ensure that the + * I/O wakeup gates are aligned with the current mux settings. Works + * by asserting WUCLKIN, waiting for WUCLKOUT to be asserted, and then + * deasserting WUCLKIN and waiting for WUCLKOUT to be deasserted. + * No return value. XXX Are the final two steps necessary? + */ +void omap44xx_prm_reconfigure_io_chain(void) +{ + int i = 0; + u32 v; + + v = omap4_prm_read_inst_reg(OMAP4430_PRM_DEVICE_INST, + OMAP4_PRM_IO_PMCTRL_OFFSET); + + /* Enable GLOBAL_WUEN */ + if (!(v & OMAP4430_GLOBAL_WUEN_MASK)) + omap4_prm_rmw_inst_reg_bits(OMAP4430_GLOBAL_WUEN_MASK, + OMAP4430_GLOBAL_WUEN_MASK, + OMAP4430_PRM_DEVICE_INST, + OMAP4_PRM_IO_PMCTRL_OFFSET); + + /* Trigger WUCLKIN enable */ + omap4_prm_rmw_inst_reg_bits(OMAP4430_WUCLK_CTRL_MASK, + OMAP4430_WUCLK_CTRL_MASK, + OMAP4430_PRM_DEVICE_INST, + OMAP4_PRM_IO_PMCTRL_OFFSET); + omap_test_timeout( + (((omap4_prm_read_inst_reg(OMAP4430_PRM_DEVICE_INST, + OMAP4_PRM_IO_PMCTRL_OFFSET) & + OMAP4430_WUCLK_STATUS_MASK) >> + OMAP4430_WUCLK_STATUS_SHIFT) == 1), + MAX_IOPAD_LATCH_TIME, i); + if (i == MAX_IOPAD_LATCH_TIME) + pr_warn("PRM: I/O chain clock line assertion timed out\n"); + + /* Trigger WUCLKIN disable */ + omap4_prm_rmw_inst_reg_bits(OMAP4430_WUCLK_CTRL_MASK, 0x0, + OMAP4430_PRM_DEVICE_INST, + OMAP4_PRM_IO_PMCTRL_OFFSET); + omap_test_timeout( + (((omap4_prm_read_inst_reg(OMAP4430_PRM_DEVICE_INST, + OMAP4_PRM_IO_PMCTRL_OFFSET) & + OMAP4430_WUCLK_STATUS_MASK) >> + OMAP4430_WUCLK_STATUS_SHIFT) == 0), + MAX_IOPAD_LATCH_TIME, i); + if (i == MAX_IOPAD_LATCH_TIME) + pr_warn("PRM: I/O chain clock line deassertion timed out\n"); + + return; +} + static int __init omap4xxx_prcm_init(void) { if (cpu_is_omap44xx()) -- cgit v1.2.3