Hi Andy, Thank you for the review. I agree with all your review comments below and I have fixed them all for v2 of the patch which I'm about to post. Regards, Hans On 2/11/24 9:50 PM, Andy Shevchenko wrote: > 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, >> +}; >
