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mtd: gpmi: simplify the DLL setting code 

The setting DLL code is a little mess.
Just simplify the code and the comments.

Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
Huang Shijie 2012-09-13 14:57:57 +08:00 committed by David Woodhouse
parent d37e02d8f3
commit c50d35a9fd
1 changed files with 9 additions and 13 deletions
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22
drivers/mtd/nand/gpmi-nand/gpmi-lib.c
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@ -779,30 +779,26 @@ void gpmi_begin(struct gpmi_nand_data *this)
writel(BM_GPMI_CTRL1_DLL_ENABLE, gpmi_regs + HW_GPMI_CTRL1_CLR); writel(BM_GPMI_CTRL1_DLL_ENABLE, gpmi_regs + HW_GPMI_CTRL1_CLR);
/* Clear out the DLL control fields. */ /* Clear out the DLL control fields. */
writel(BM_GPMI_CTRL1_RDN_DELAY, gpmi_regs + HW_GPMI_CTRL1_CLR); reg = BM_GPMI_CTRL1_RDN_DELAY | BM_GPMI_CTRL1_HALF_PERIOD;
writel(BM_GPMI_CTRL1_HALF_PERIOD, gpmi_regs + HW_GPMI_CTRL1_CLR); writel(reg, gpmi_regs + HW_GPMI_CTRL1_CLR);
/* If no sample delay is called for, return immediately. */ /* If no sample delay is called for, return immediately. */
if (!hw.sample_delay_factor) if (!hw.sample_delay_factor)
return; return;
/* Configure the HALF_PERIOD flag. */ /* Set RDN_DELAY or HALF_PERIOD. */
if (hw.use_half_periods) reg = ((hw.use_half_periods) ? BM_GPMI_CTRL1_HALF_PERIOD : 0)
writel(BM_GPMI_CTRL1_HALF_PERIOD, | BF_GPMI_CTRL1_RDN_DELAY(hw.sample_delay_factor);
gpmi_regs + HW_GPMI_CTRL1_SET);
/* Set the delay factor. */ writel(reg, gpmi_regs + HW_GPMI_CTRL1_SET);
writel(BF_GPMI_CTRL1_RDN_DELAY(hw.sample_delay_factor),
gpmi_regs + HW_GPMI_CTRL1_SET);
/* Enable the DLL. */ /* At last, we enable the DLL. */
writel(BM_GPMI_CTRL1_DLL_ENABLE, gpmi_regs + HW_GPMI_CTRL1_SET); writel(BM_GPMI_CTRL1_DLL_ENABLE, gpmi_regs + HW_GPMI_CTRL1_SET);
/* /*
* After we enable the GPMI DLL, we have to wait 64 clock cycles before * After we enable the GPMI DLL, we have to wait 64 clock cycles before
* we can use the GPMI. * we can use the GPMI. Calculate the amount of time we need to wait,
* * in microseconds.
* Calculate the amount of time we need to wait, in microseconds.
*/ */
clock_period_in_ns = NSEC_PER_SEC / clk_get_rate(r->clock[0]); clock_period_in_ns = NSEC_PER_SEC / clk_get_rate(r->clock[0]);
dll_wait_time_in_us = (clock_period_in_ns * 64) / 1000; dll_wait_time_in_us = (clock_period_in_ns * 64) / 1000;