Re: [PATCH 5/8] i2c: omap: introduce and use OMAP_I2C_IP_VERSION_3

Felipe Balbi
2012-10-22T13:09:08Z

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Hi,

On Mon, Oct 22, 2012 at 03:05:20PM +0200, Benoit Cousson wrote:
> On 10/22/2012 02:28 PM, Felipe Balbi wrote:
> > Hi,
> >
> > On Mon, Oct 22, 2012 at 02:27:20PM +0200, Benoit Cousson wrote:
> >> Hi Felipe,
> >>
> >> On 10/22/2012 11:46 AM, Felipe Balbi wrote:
> >>> on OMAP4+ we want to read IRQSTATUS_RAW register,
> >>> instead of IRQSTATUS. The reason being that IRQSTATUS
> >>> will only contain the bits which were enabled on
> >>> IRQENABLE_SET and that will break when we need to
> >>> poll for a certain bit which wasn't enabled as an
> >>> IRQ source.
> >>>
> >>> One such case is after we finish converting to
> >>> deferred stop bit, we will have to poll for ARDY
> >>> bit before returning control for the client driver
> >>> in order to prevent us from trying to start a
> >>> transfer on a bus which is already busy.
> >>>
> >>> Note, however, that omap-i2c.c needs a big rework
> >>> on register definition and register access. Such
> >>> work will be done in a separate series of patches.
> >>
> >> Do you need OMAP_I2C_IP_VERSION_3 for OMAP4?
> >>
> >> OMAP_I2C_IP_VERSION_2 was already introduced to detect OMAP3630 vs
> >> omap4430 because they were sharing the same IP version..
> >>
> >> /* I2C controller revisions present on specific hardware */
> >> #define OMAP_I2C_REV_ON_2430 0x36
> >> #define OMAP_I2C_REV_ON_3430_3530 0x3C
> >> #define OMAP_I2C_REV_ON_3630_4430 0x40
> >>
> >> So in theory you should not need an extra version.
> >
> > are you sure that's how they're used ? Looking at the code where we
> > choose reg_map_ip_v1 and reg_map_ip_v2:
> >
> > 1120 if (dev->dtrev == OMAP_I2C_IP_VERSION_2)
> > 1121 dev->regs = (u8 *)reg_map_ip_v2;
> > 1122 else
> > 1123 dev->regs = (u8 *)reg_map_ip_v1;
> >
> > And looking at reg_map_ip_v1:
> >
> > 218 static const u8 reg_map_ip_v1[] = {
> > 219 [OMAP_I2C_REV_REG] = 0x00,
> > 220 [OMAP_I2C_IE_REG] = 0x01,
> > 221 [OMAP_I2C_STAT_REG] = 0x02,
> > 222 [OMAP_I2C_IV_REG] = 0x03,
> > 223 [OMAP_I2C_WE_REG] = 0x03,
> > 224 [OMAP_I2C_SYSS_REG] = 0x04,
> > 225 [OMAP_I2C_BUF_REG] = 0x05,
> > 226 [OMAP_I2C_CNT_REG] = 0x06,
> > 227 [OMAP_I2C_DATA_REG] = 0x07,
> > 228 [OMAP_I2C_SYSC_REG] = 0x08,
> > 229 [OMAP_I2C_CON_REG] = 0x09,
> > 230 [OMAP_I2C_OA_REG] = 0x0a,
> > 231 [OMAP_I2C_SA_REG] = 0x0b,
> > 232 [OMAP_I2C_PSC_REG] = 0x0c,
> > 233 [OMAP_I2C_SCLL_REG] = 0x0d,
> > 234 [OMAP_I2C_SCLH_REG] = 0x0e,
> > 235 [OMAP_I2C_SYSTEST_REG] = 0x0f,
> > 236 [OMAP_I2C_BUFSTAT_REG] = 0x10,
> > 237 };
> >
> > that's really not the register map on OMAP3. That only looks valid for
> > OMAP1.
>
> No that should be valid as well for OMAP2&3 thanks to the
> OMAP_I2C_FLAG_BUS_SHIFT_2.

aha.. I see. What a hack!

> It was introduced during DT adaptation:
>
> #ifdef CONFIG_OF
> static struct omap_i2c_bus_platform_data omap3_pdata = {
> .rev = OMAP_I2C_IP_VERSION_1,
> .flags = OMAP_I2C_FLAG_APPLY_ERRATA_I207 |
> OMAP_I2C_FLAG_RESET_REGS_POSTIDLE |
> OMAP_I2C_FLAG_BUS_SHIFT_2,
> };
>
> static struct omap_i2c_bus_platform_data omap4_pdata = {
> .rev = OMAP_I2C_IP_VERSION_2,
> };
>
> static const struct of_device_id omap_i2c_of_match[] = {
> {
> .compatible = "ti,omap4-i2c",
> .data = &omap4_pdata,
> },
> {
> .compatible = "ti,omap3-i2c",
> .data = &omap3_pdata,
> },
> { },
> };
> MODULE_DEVICE_TABLE(of, omap_i2c_of_match);
> #endif
>
>
> > -ECONFUSED
>
> Well, it is confusing...

Tell me about it... in that case, $SUBJECT can be dropped silently, I
will respin next patch so that it checks for VERSION_2 instead of
VERSION_3.

cheers.

--
balbi

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