[U-Boot] [PATCH 0/3] Bring in new I2C framework

Tom Rini trini at ti.com
Wed Oct 31 06:20:01 CET 2012


On Tue, Oct 30, 2012 at 10:22:54AM -0700, Simon Glass wrote:
> Hi,
> 
> On Tue, Oct 30, 2012 at 9:50 AM, Stephen Warren <swarren at wwwdotorg.org> wrote:
> > On 10/29/2012 11:57 PM, Heiko Schocher wrote:
> >> Hello Stephen,
> >>
> >> On 29.10.2012 16:34, Stephen Warren wrote:
> > ...
> >>> If there are e.g. 4 I2C controllers in an SoC, the driver needs to know
> >>> which one is in use. Passing that information directly to the driver
> >>> functions is much simple than requiring the SoC I2C driver to go grovel
> >>> in some I2C core global variables to find out the same information.
> >>
> >> Ah, do you mean we should change the i2c adapter struct from:
> >>
> >> struct i2c_adapter {
> >>        void            (*init)(int speed, int slaveaddr);
> >>        int             (*probe)(uint8_t chip);
> >>        int             (*read)(uint8_t chip, uint addr, int alen,
> >>                                uint8_t *buffer, int len);
> >>        int             (*write)(uint8_t chip, uint addr, int alen,
> >>                                uint8_t *buffer, int len);
> >>        uint            (*set_bus_speed)(uint speed);
> >> [...]
> >>
> >> to
> >>
> >> struct i2c_adapter {
> >>        void            (*init)(struct i2c_adapter *adap, int speed, int
> >> slaveaddr);
> >>        int             (*probe)(struct i2c_adapter *adap, uint8_t chip);
> >>        int             (*read)(struct i2c_adapter *adap, uint8_t chip,
> >> uint addr, int alen,
> >>                                uint8_t *buffer, int len);
> >>        int             (*write)(struct i2c_adapter *adap, uint8_t chip,
> >> uint addr, int alen,
> >>                                uint8_t *buffer, int len);
> >>        uint            (*set_bus_speed)(struct i2c_adapter *adap, uint
> >> speed);
> >> [...]
> >> ?
> >>
> >> We can do this. Simon suggested this too ...
> >
> > Yes, exactly. (the functions will need some way to get information out
> > of the struct i2c_adapter; I assume there's some kind of driver_private
> > field in there too).
> 
> Yes.
> 
> I will post a few patches to move Tegra over to the new framework as
> it is, so that people can see the impact. Given that every driver has
> to change, it would be my preference to set the i2c API once. But I
> suppose within a short while everything will move to the device model,
> so perhaps the job of this series is just to move things in the right
> direction?

Funny enough I don't see a UDM-i2c.txt file, so I guess the community
gets to think about that one :)

-- 
Tom
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