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| author | Tony Lindgren <tony@atomide.com> | 2017-12-15 09:41:14 -0800 |
|---|---|---|
| committer | Tony Lindgren <tony@atomide.com> | 2017-12-21 07:28:54 -0800 |
| commit | a7199e2b91ded41adbb6fd384a85e358d25f48c8 (patch) | |
| tree | 395e5de4d545a5995e16462c9b7378ac6c658216 | |
| parent | 70a65240efb1116f4f580c2f8235ba58000889b0 (diff) | |
| download | lwn-a7199e2b91ded41adbb6fd384a85e358d25f48c8.tar.gz lwn-a7199e2b91ded41adbb6fd384a85e358d25f48c8.zip | |
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>
| -rw-r--r-- | drivers/bus/ti-sysc.c | 17 | ||||
| -rw-r--r-- | include/linux/platform_data/ti-sysc.h | 1 |
2 files changed, 18 insertions, 0 deletions
diff --git a/drivers/bus/ti-sysc.c b/drivers/bus/ti-sysc.c index 0c9b9bcd75b2..4c1e59e53a0c 100644 --- a/drivers/bus/ti-sysc.c +++ b/drivers/bus/ti-sysc.c @@ -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; } diff --git a/include/linux/platform_data/ti-sysc.h b/include/linux/platform_data/ti-sysc.h index b76ace0135b3..059be6f6fa94 100644 --- a/include/linux/platform_data/ti-sysc.h +++ b/include/linux/platform_data/ti-sysc.h @@ -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) |