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i2c: designware: Do not calculate SCL timing parameters needlessly

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Do SCL timing parameter calculation conditionally depending are custom
parameters provided since calculated values will get instantly overwritten
by provided parameters.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Jarkko Nikula 2015-01-23 11:35:55 +02:00 committed by Wolfram Sang
parent c680eed5cc
commit 42ffd3907c
1 changed files with 22 additions and 23 deletions
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45
drivers/i2c/busses/i2c-designware-core.c
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@ -320,40 +320,39 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
sda_falling_time = dev->sda_falling_time ?: 300; /* ns */
scl_falling_time = dev->scl_falling_time ?: 300; /* ns */
/* Standard-mode */
hcnt = i2c_dw_scl_hcnt(input_clock_khz,
4000, /* tHD;STA = tHIGH = 4.0 us */
sda_falling_time,
0, /* 0: DW default, 1: Ideal */
0); /* No offset */
lcnt = i2c_dw_scl_lcnt(input_clock_khz,
4700, /* tLOW = 4.7 us */
scl_falling_time,
0); /* No offset */
/* Allow platforms to specify the ideal HCNT and LCNT values */
/* Set SCL timing parameters for standard-mode */
if (dev->ss_hcnt && dev->ss_lcnt) {
hcnt = dev->ss_hcnt;
lcnt = dev->ss_lcnt;
} else {
hcnt = i2c_dw_scl_hcnt(input_clock_khz,
4000, /* tHD;STA = tHIGH = 4.0 us */
sda_falling_time,
0, /* 0: DW default, 1: Ideal */
0); /* No offset */
lcnt = i2c_dw_scl_lcnt(input_clock_khz,
4700, /* tLOW = 4.7 us */
scl_falling_time,
0); /* No offset */
}
dw_writel(dev, hcnt, DW_IC_SS_SCL_HCNT);
dw_writel(dev, lcnt, DW_IC_SS_SCL_LCNT);
dev_dbg(dev->dev, "Standard-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
/* Fast-mode */
hcnt = i2c_dw_scl_hcnt(input_clock_khz,
600, /* tHD;STA = tHIGH = 0.6 us */
sda_falling_time,
0, /* 0: DW default, 1: Ideal */
0); /* No offset */
lcnt = i2c_dw_scl_lcnt(input_clock_khz,
1300, /* tLOW = 1.3 us */
scl_falling_time,
0); /* No offset */
/* Set SCL timing parameters for fast-mode */
if (dev->fs_hcnt && dev->fs_lcnt) {
hcnt = dev->fs_hcnt;
lcnt = dev->fs_lcnt;
} else {
hcnt = i2c_dw_scl_hcnt(input_clock_khz,
600, /* tHD;STA = tHIGH = 0.6 us */
sda_falling_time,
0, /* 0: DW default, 1: Ideal */
0); /* No offset */
lcnt = i2c_dw_scl_lcnt(input_clock_khz,
1300, /* tLOW = 1.3 us */
scl_falling_time,
0); /* No offset */
}
dw_writel(dev, hcnt, DW_IC_FS_SCL_HCNT);
dw_writel(dev, lcnt, DW_IC_FS_SCL_LCNT);