Messages in this thread | | | Date | Tue, 9 Mar 2021 16:26:09 +0200 | From | Andy Shevchenko <> | Subject | Re: [PATCH] i2c: add i2c bus driver for amd navi gpu |
| |
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
| |