Hi Mika,
On 12/18/2015 4:13 AM, Mika Westerberg wrote:
[....]
So instead of this, what if we do not assign dev->get_clk_rate_khz at
all and then do something like below in the core driver?
I like the changes below since it is clear to see within the core file
how things are handled when get_clk_rate_khz is not assigned (i.e.
input_clock_hz = 0), and not necessary relying on the platform driver to
return 0 in this case.
So, at this point, I can re-submit the V3 and combine these changes, and
we both can sign-off. How does that sound?
Thanks,
Suravee
Of course we still need the other changes you did in this patch to cope
with the missing clock.
diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
index 8c48b27ba059..25dccd8df772 100644
--- a/drivers/i2c/busses/i2c-designware-core.c
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -271,6 +271,17 @@ static void __i2c_dw_enable(struct dw_i2c_dev *dev, bool enable)
enable ? "en" : "dis");
}
+static unsigned long i2c_dw_clk_rate(struct dw_i2c_dev *dev)
+{
+ /*
+ * Clock is not necessary if we got LCNT/HCNT values directly from
+ * the platform code.
+ */
+ if (WARN_ON_ONCE(!dev->get_clk_rate_khz))
+ return 0;
+ return dev->get_clk_rate_khz(dev);
+}
+
/**
* i2c_dw_init() - initialize the designware i2c master hardware
* @dev: device private data
@@ -281,7 +292,6 @@ static void __i2c_dw_enable(struct dw_i2c_dev *dev, bool enable)
*/
int i2c_dw_init(struct dw_i2c_dev *dev)
{
- u32 input_clock_khz;
u32 hcnt, lcnt;
u32 reg;
u32 sda_falling_time, scl_falling_time;
@@ -295,8 +305,6 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
}
}
- input_clock_khz = dev->get_clk_rate_khz(dev);
-
reg = dw_readl(dev, DW_IC_COMP_TYPE);
if (reg == ___constant_swab32(DW_IC_COMP_TYPE_VALUE)) {
/* Configure register endianess access */
@@ -325,12 +333,12 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
hcnt = dev->ss_hcnt;
lcnt = dev->ss_lcnt;
} else {
- hcnt = i2c_dw_scl_hcnt(input_clock_khz,
+ hcnt = i2c_dw_scl_hcnt(i2c_dw_clk_rate(dev),
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,
+ lcnt = i2c_dw_scl_lcnt(i2c_dw_clk_rate(dev),
4700, /* tLOW = 4.7 us */
scl_falling_time,
0); /* No offset */
@@ -344,12 +352,12 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
hcnt = dev->fs_hcnt;
lcnt = dev->fs_lcnt;
} else {
- hcnt = i2c_dw_scl_hcnt(input_clock_khz,
+ hcnt = i2c_dw_scl_hcnt(i2c_dw_clk_rate(dev),
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,
+ lcnt = i2c_dw_scl_lcnt(i2c_dw_clk_rate(dev),
1300, /* tLOW = 1.3 us */
scl_falling_time,
0); /* No offset */
--
To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
