Hi, On 19 August 2018 at 17:33, Tom Rini <tr...@konsulko.com> wrote: > On Sun, Aug 19, 2018 at 01:37:29PM -0500, Adam Ford wrote: >> On Sun, Aug 19, 2018 at 11:53 AM Tom Rini <tr...@konsulko.com> wrote: >> > >> > On Sun, Aug 19, 2018 at 09:45:30AM -0500, Adam Ford wrote: >> > > On Fri, Aug 17, 2018 at 10:21 PM Adam Ford <aford...@gmail.com> wrote: >> > > > >> > > > I am working to disable CONFIG_DM_I2C_COMPAT for the omap3 boards. >> > > > Some of these boards use the TWL4030 PMIC which is still using the >> > > > older i2c_write and i2c_read functions. >> > > > >> > > > I wonder if someone can point me to a good patch that I can use a >> > > > model one how to appropriately port I2C drivers forward? I'd like to >> > > > disable this feature so the notice goes away since it seems like >> > > > DM_I2C should be do-able by now. >> > > > >> > > >> > > More specifically, the TWL4030 has multiple I2C addresses, but it's >> > > primary address is 0x48 and is assigned in the device tree as such. I >> > > have been able to create the primary PMIC on address 0x48, but there >> > > are multiple i2c addresses through which it can be addressed. The >> > > device tree for the twl4030 lists multuple sub-regulators, but they >> > > are not contained within 'regulators' node, and the bind function >> > > cannot locate the children because there are no regulator-names >> > > associated. The individual regulators are sub-nodes, but their >> > > control registers are not necessarily on the same i2c address of the >> > > primary. The additional i2c addresses are 0x49, 0x4a, and 0x4b, but >> > > none are listed in the device tree. >> > > >> > > What I'd like to do is replace the stock initialization sequence with >> > > a more generic one that not only initializes the PMIC and all >> > > corresponding registers, I'd also like to have it set all the >> > > sub-regulators based on the voltage ratings listed by the device tree, >> > > I was hoping someone might teach me the 'proper' way to create these >> > > 3 additional i2c devices (not shown on the device tree) on the same >> > > I2C bus as the original, have them list all sub-regulators of the >> > > original PMIC, and be able to address them individually. >> > >> > So, when you refer to the device tree I assume you're talking about one >> > that's relatively in sync with the Linux kernel and all of these devices >> > Just Work there. So, in that case, how does Linux go from "the device >> > tree describes $this" to "we need to bind drivers x/y/z" ? >> >> From what I can tell, each regulator in the PMIC is independant to >> each other. They're using .compatible = "xxx" for each regulator, and >> they have a bunch of macros to connect either twl4030 or 6030 to the >> table. >> They also have a helper function that associates the various i2c >> addresses to each regulator. >> >> Currently, we're using CONFIG_DM_I2C_COMPAT to allow the i2c_read and >> i2c_write funtions to exist where part of the parameter is the pass >> the i2c address which is then abstracted by the twl driver. >> >> If I create the PMIC type, the address of the PMIC is contained so all >> read/write functions go to 0x48 instead of 0x4b, where I want it. >> >> I can certainly try to create completely separate regulators using the >> .compatible flag, but it's not clear to me how to assign the I2C >> address to a manually generated regulator because each regulator is a >> sub-node of the PMIC. It's also not clear to how to continue to >> associate the reulators to the PMIC. >> >> Would it be better to just create a bunch of individual regulators? >> They would all share the same I2C address, and I am not sure if that's >> a conflict or not. > > Simon, Jaehoon, any ideas on how to make this setup that works under > Linux work here? Thanks!
I was not aware that we could support multiple I2C addresses with a single device. How does Linux handle that? It is particularly strange to me that the DT does not specify the addresses. Regards, Simon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
