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bus: ti-sysc: Detect i2c interconnect target module based on register layout 

We can easily detect i2c based on it's non-standard module registers that
consist of two 32-bit registers accessed in 16-bit mode.

So far we don't have other 16-bit modules, so there's currently no need
to add a custom property for 16-bit register access.

Signed-off-by: Tony Lindgren <tony@atomide.com>
This commit is contained in:
Tony Lindgren 2017-12-15 09:41:14 -08:00
parent 70a65240ef
commit a7199e2b91
2 changed files with 18 additions and 0 deletions
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17
drivers/bus/ti-sysc.c
View File

@ -213,6 +213,21 @@ static int sysc_check_children(struct sysc *ddata)
return 0;
}
/*
* So far only I2C uses 16-bit read access with clockactivity with revision
* in two registers with stride of 4. We can detect this based on the rev
* register size to configure things far enough to be able to properly read
* the revision register.
*/
static void sysc_check_quirk_16bit(struct sysc *ddata, struct resource *res)
{
if (resource_size(res) == 8) {
dev_dbg(ddata->dev,
"enabling 16-bit and clockactivity quirks\n");
ddata->cfg.quirks |= SYSC_QUIRK_16BIT | SYSC_QUIRK_USE_CLOCKACT;
}
}
/**
* sysc_parse_one - parses the interconnect target module registers
* @ddata: device driver data
@ -243,6 +258,8 @@ static int sysc_parse_one(struct sysc *ddata, enum sysc_registers reg)
}
ddata->offsets[reg] = res->start - ddata->module_pa;
if (reg == SYSC_REVISION)
sysc_check_quirk_16bit(ddata, res);
return 0;
}

1
include/linux/platform_data/ti-sysc.h
View File

@ -41,6 +41,7 @@ struct sysc_regbits {
s8 emufree_shift;
};
#define SYSC_QUIRK_16BIT BIT(2)
#define SYSC_QUIRK_UNCACHED BIT(1)
#define SYSC_QUIRK_USE_CLOCKACT BIT(0)