From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Sanket Goswami <Sanket.Goswami@amd.com>
Cc: jarkko.nikula@linux.intel.com, mika.westerberg@linux.intel.com,
linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
Shyam Sundar S K <Shyam-sundar.S-k@amd.com>,
Nehal Bakulchandra Shah <Nehal-Bakulchandra.shah@amd.com>
Subject: Re: [PATCH] i2c: add i2c bus driver for amd navi gpu
Date: Tue, 9 Mar 2021 16:26:09 +0200 [thread overview]
Message-ID: <YEeFgZSIY5lb2ubP@smile.fi.intel.com> (raw)
In-Reply-To: <20210309133147.1042775-1-Sanket.Goswami@amd.com>
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
next prev parent reply other threads:[~2021-03-09 14:26 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-09 13:31 [PATCH] i2c: add i2c bus driver for amd navi gpu Sanket Goswami
2021-03-09 14:23 ` kernel test robot
2021-03-09 14:26 ` Andy Shevchenko [this message]
2021-03-22 16:56 ` Goswami, Sanket
2021-03-25 17:05 ` Andy Shevchenko
2021-03-26 10:23 ` Goswami, Sanket
2021-03-26 10:40 ` Andy Shevchenko
2021-03-29 5:55 ` Goswami, Sanket
2021-03-29 12:36 ` Andy Shevchenko
2021-03-09 15:35 ` kernel test robot
2021-03-09 15:36 ` kernel test robot
-- strict thread matches above, loose matches on Subject: below --
2020-11-27 19:30 [PATCH] i2c: add i2c bus driver for AMD NAVI GPU Sanjay R Mehta
2020-11-30 11:19 ` Andy Shevchenko
2020-12-02 4:44 ` Sanjay R Mehta
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