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

From: [email-masked] (Benoit Cousson)
Date: Mon, 22 Oct 2012 15:05:20 +0200

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.

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...

Benoit