On Tue, Mar 09, 2021 at 07:01:47PM +0530, Sanket Goswami wrote: i2c: -> i2c: designware: add i2c bus driver -> add a driver amd -> AMD gpu -> GPU in the subject > Latest AMDGPU NAVI cards have USB Type-C interface which can be accessed > over I2C. I didn't get this. You mean that USB traffic over I²C? This sounds insane for a least. Maybe something else is there and description is not fully correct? > The Type-C controller has integrated designware i2c which is DesignWare > exposed as a PCI device to the AMD platform. > > Also there exists couple of notable IP problems that are dealt as a > workaround: > - I2C transactions work on a polling mode as IP does not generate > interrupt. > > - I2C reads commands are sent twice to address the IP issues. Please, read this article: https://chris.beams.io/posts/git-commit/ ... > +#define AMD_UCSI_INTR_EN 0xD Why it's capitalized? ... > #include "i2c-designware-core.h" + Blank line > +#define AMD_TIMEOUT_MSEC_MIN 10000 > +#define AMD_TIMEOUT_MSEC_MAX 11000 Use unit suffix in the definitions. ... > +static void i2c_dw_configure_bus(struct dw_i2c_dev *i2cd) Why all this is customized? Why FIFO can't be autodetected? ... > +/* Initiate and continue master read/write transaction with polling > + * based transfer routine and write messages into the tx buffer. > + */ Wrong multi-line comment style. ... > +static int amd_i2c_dw_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num_msgs) Why do you need a custom function for that? Can it be generic and not AMD specific? ... > + /* Enable ucsi interrupt */ > + if (dev->flags & AMD_NON_INTR_MODE) > + regmap_write(dev->map, AMD_UCSI_INTR_REG, AMD_UCSI_INTR_EN); This is looks like a hack. Why is it here? ... > + if (dev->flags & AMD_NON_INTR_MODE) > + return amd_i2c_dw_master_xfer(adap, msgs, num); Ditto. ... > +int amd_i2c_adap_quirk(struct dw_i2c_dev *amdev) > +{ > + struct i2c_adapter *amdap = &amdev->adapter; > + int ret; See below. > + if (!(amdev->flags & AMD_NON_INTR_MODE)) > + return -ENODEV; > + return i2c_add_numbered_adapter(amdap); > + > + return ret; What the second one does? > +} ... > + ret = amd_i2c_adap_quirk(dev); > + if (ret != -ENODEV) This is ugly. Can we run quirk if and only if we have an AMD chip? > + return ret; ... > #define DRIVER_NAME "i2c-designware-pci" > +#define AMD_CLK_RATE 100000 Add units. ... > +/* NAVI-AMD HCNT/LCNT/SDA hold time */ > +static struct dw_scl_sda_cfg navi_amd_config = { > + .ss_hcnt = 0x1ae, > + .ss_lcnt = 0x23a, > + .sda_hold = 0x9, > +}; (1) ... > +static int i2c_dw_populate_client(struct dw_i2c_dev *i2cd) > +{ > + struct i2c_board_info *i2c_dw_ccgx_ucsi; > + struct i2c_client *ccgx_client; > + > + i2c_dw_ccgx_ucsi = devm_kzalloc(i2cd->dev, sizeof(*i2c_dw_ccgx_ucsi), GFP_KERNEL); > + if (!i2c_dw_ccgx_ucsi) > + return -ENOMEM; > + > + strscpy(i2c_dw_ccgx_ucsi->type, "ccgx-ucsi", sizeof(i2c_dw_ccgx_ucsi->type)); > + i2c_dw_ccgx_ucsi->addr = 0x08; > + i2c_dw_ccgx_ucsi->irq = i2cd->irq; > + > + ccgx_client = i2c_new_client_device(&i2cd->adapter, i2c_dw_ccgx_ucsi); > + if (!ccgx_client) > + return -ENODEV; > + > + return 0; > +} This is the same as in nVidia GPU I²C driver. Can you do a preparatory changes to deduplicate this? Also why (1) and this can't be instantiated from ACPI / DT? -- With Best Regards, Andy Shevchenko
