On Sun, Feb 11, 2024 at 9:53 PM Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > > Some MeeGoPad top-set boxes have an ANX7428 Type-C Switch for USB3.1 Gen 1 > and DisplayPort over Type-C alternate mode support. > > The ANX7428 has a microcontroller which takes care of the PD negotiation > and automatically sets the builtin Crosspoint Switch to send the right > signal to the 4 highspeed pairs of the Type-C connector. It also takes > care of HPD and AUX channel routing for DP alternate mode. > > IOW the ANX7428 operates fully autonomous and to the x5-Z8350 SoC > things look like there simple is a USB-3 Type-A connector and a > separate DipslayPort connector. Except that the BIOS does not DisplayPort > power on the ANX7428 at boot (meh). > > Add a driver to power on the ANX7428. This driver is added under > drivers/platform/x86 rather then under drivers/usb/typec for 2 reasons: than > 1. This driver is specificly written to work with how the ANX7428 is specifically > described in the ACPI tables of the MeeGoPad x86 (Cherry Trail) devices. > > 2. This driver only powers on the ANX7428 and does not do anything wrt > its Type-C functionality. It should be possible to tell the controller > which data- and/or power-role to negotiate and to swap the role(s) after > negotiation but the MeeGoPad top-set boxes always draw their power from > a separate power-connector and they only support USB host-mode. So this > functionality is unnecessary and due to lack of documenation this documentation > is tricky to support. ... > +/* > + * meegopad_anx7428.c - Driver to power on the Analogix ANX7428 Keeping a filename inside the file is a burden in case the file gets renamed in the future. > + * USB Type-C crosspoint switch on MeeGoPad top-set boxes. > + * > + * The MeeGoPad T8 and T9 are Cherry Trail top-set boxes which > + * use an ANX7428 to provide a Type-C port with USB3.1 Gen 1 and > + * DisplayPort over Type-C alternate mode support. > + * > + * The ANX7428 has a microcontroller which takes care of the PD > + * negotiation and automatically sets the builtin Crosspoint Switch > + * to send the right signal to the 4 highspeed pairs of the Type-C > + * connector. It also takes care of HPD and AUX channel routing for > + * DP alternate mode. > + * > + * IOW the ANX7428 operates fully autonomous and to the x5-Z8350 SoC > + * things look like there simple is a USB-3 Type-A connector and a > + * separate DipslayPort connector. Except that the BIOS does not DisplayPort > + * power on the ANX7428 at boot. This driver takes care of powering > + * on the ANX7428. > + * > + * It should be possible to tell the micro-controller which data- and/or > + * power-role to negotiate and to swap the role(s) after negotiation > + * but the MeeGoPad top-set boxes always draw their power from a separate > + * power-connector and they only support USB host-mode. So this functionality > + * is unnecessary and due to lack of documenation this is tricky to support. documentation > + * For a more complete ANX7428 driver see drivers/usb/misc/anx7418/ of > + * the LineageOS kernel for the LG G5 (International) aka the LG H850: > + * https://github.com/LineageOS/android_kernel_lge_msm8996/ > + * > + * (C) Copyright 2024 Hans de Goede <hansg@xxxxxxxxxx> > + */ > + > +#include <linux/acpi.h> + bits.h > +#include <linux/delay.h> > +#include <linux/dmi.h> > +#include <linux/gpio/consumer.h> > +#include <linux/i2c.h> > +#include <linux/module.h> ... > +#define VENDOR_ID_L 0x00 > +#define VENDOR_ID_H 0x01 > +#define DEVICE_ID_L 0x02 > +#define DEVICE_ID_H 0x03 You use word (16-bit) access, why do we need to know these? Just define them without suffixes (and if you want add a comment that they are 16-bit LE). ... > + usleep_range(10000, 15000); fsleep() ? ... > + /* Wait for the OCM (On Chip Microcontroller) to start */ > + for (i = 0; i < max_tries; i++) { > + usleep_range(5000, 10000); > + > + ret = i2c_smbus_read_byte_data(client, TX_STATUS); > + if (ret < 0) > + dev_err_probe(dev, ret, "reading status register\n"); > + else if (ret & OCM_STARTUP) > + break; > + } > + if (i == max_tries) > + return dev_err_probe(dev, -EIO, > + "On Chip Microcontroller did not start, status: 0x%02x\n", > + ret); Why not use read_poll_timeout() / readx_poll_timeout() (whichever suits better)? ... > +static struct i2c_driver anx7428_driver = { > + .driver = { > + .name = KBUILD_MODNAME, Strictly speaking this is an ABI and we don't want it to be changed in case of filename change. Personally I _always_ prefer it be open coded. > + .acpi_match_table = anx7428_acpi_match, > + }, > + .probe = anx7428_probe, > +}; -- With Best Regards, Andy Shevchenko
