On 12/8/2020 6:32 PM, Sanjay R Mehta wrote:
>
>
> On 12/8/2020 6:17 PM, Krzysztof Kozlowski wrote:
>> [CAUTION: External Email]
>>
>> On Tue, Dec 08, 2020 at 06:37:41AM -0600, Sanjay R Mehta wrote:
>>> From: Sanjay R Mehta <Sanju.Mehta@xxxxxxx>
>>>
>>> Latest amdgpu card has USB Type-C interface. There is a Type-C controller
>>> which can be accessed over I2C.
>>>
>>> This driver adds I2C bus driver to communicate with Type-C controller. I2C
>>> client driver will be part of USB Type-C UCSI driver.
>>>
>>> Signed-off-by: Sanjay R Mehta <Sanju.Mehta@xxxxxxx>
>>> Signed-off-by: Nehal Bakulchandra Shah <Nehal-Bakulchandra.Shah@xxxxxxx>
>>> ---
>>>
>>> Changes in v2:
>>>
>>> - converted the code to use regmap, read_poll_timeout and made some cosmetic
>>> changes as suggested by Andy Shevchenko.
>>> ---
>>> MAINTAINERS | 7 +
>>> drivers/i2c/busses/Kconfig | 9 +
>>> drivers/i2c/busses/Makefile | 1 +
>>> drivers/i2c/busses/i2c-amdgpu-navi.c | 345 +++++++++++++++++++++++++++
>>> 4 files changed, 362 insertions(+)
>>> create mode 100644 drivers/i2c/busses/i2c-amdgpu-navi.c
>>>
>>> diff --git a/MAINTAINERS b/MAINTAINERS
>>> index 190c7fa2ea01..93894459a4c8 100644
>>> --- a/MAINTAINERS
>>> +++ b/MAINTAINERS
>>> @@ -8119,6 +8119,13 @@ L: linux-acpi@xxxxxxxxxxxxxxx
>>> S: Maintained
>>> F: drivers/i2c/i2c-core-acpi.c
>>>
>>> +I2C CONTROLLER DRIVER FOR AMD GPU
>>> +M: Nehal Bakulchandra Shah <Nehal-Bakulchandra.Shah@xxxxxxx>
>>> +M: Sanjay R Mehta <sanju.mehta@xxxxxxx>
>>> +L: linux-i2c@xxxxxxxxxxxxxxx
>>> +S: Maintained
>>> +F: drivers/i2c/busses/i2c-amdgpu-navi.*
>>> +
>>> I2C CONTROLLER DRIVER FOR NVIDIA GPU
>>> M: Ajay Gupta <ajayg@xxxxxxxxxx>
>>> L: linux-i2c@xxxxxxxxxxxxxxx
>>> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
>>> index 293e7a0760e7..0ff369c0f41f 100644
>>> --- a/drivers/i2c/busses/Kconfig
>>> +++ b/drivers/i2c/busses/Kconfig
>>> @@ -88,6 +88,15 @@ config I2C_AMD_MP2
>>> This driver can also be built as modules. If so, the modules will
>>> be called i2c-amd-mp2-pci and i2c-amd-mp2-plat.
>>>
>>> +config I2C_AMDGPU_NAVI
>>> + tristate "AMDGPU NAVI I2C controller"
>>> + depends on PCI
>>> + help
>>> + If you say yes to this option, support will be included for the
>>> + NAVI I2C controller which is used to communicate with the GPU's
>>> + Type-C controller. This driver can also be built as a module called
>>> + i2c-amdgpu-navi.
>>> +
>>> config I2C_HIX5HD2
>>> tristate "Hix5hd2 high-speed I2C driver"
>>> depends on ARCH_HISI || ARCH_HIX5HD2 || COMPILE_TEST
>>> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
>>> index 19aff0e45cb5..f599473a8ad9 100644
>>> --- a/drivers/i2c/busses/Makefile
>>> +++ b/drivers/i2c/busses/Makefile
>>> @@ -13,6 +13,7 @@ obj-$(CONFIG_I2C_ALI15X3) += i2c-ali15x3.o
>>> obj-$(CONFIG_I2C_AMD756) += i2c-amd756.o
>>> obj-$(CONFIG_I2C_AMD756_S4882) += i2c-amd756-s4882.o
>>> obj-$(CONFIG_I2C_AMD8111) += i2c-amd8111.o
>>> +obj-$(CONFIG_I2C_AMDGPU_NAVI) += i2c-amdgpu-navi.o
>>> obj-$(CONFIG_I2C_CHT_WC) += i2c-cht-wc.o
>>> obj-$(CONFIG_I2C_I801) += i2c-i801.o
>>> obj-$(CONFIG_I2C_ISCH) += i2c-isch.o
>>> diff --git a/drivers/i2c/busses/i2c-amdgpu-navi.c b/drivers/i2c/busses/i2c-amdgpu-navi.c
>>> new file mode 100644
>>> index 000000000000..3922b8aebc26
>>> --- /dev/null
>>> +++ b/drivers/i2c/busses/i2c-amdgpu-navi.c
>>> @@ -0,0 +1,345 @@
>>> +// SPDX-License-Identifier: GPL-2.0+
>>> +//
>>> +// AMD I2C Controller Driver for Navi GPU's
>>> +//
>>> +// Copyright (c) 2020, Advanced Micro Devices, Inc.
>>> +//
>>> +// Authors:
>>> +// Nehal Bakulchandra Shah <Nehal-Bakulchandra.Shah@xxxxxxx>
>>> +// Sanjay R Mehta <Sanju.Mehta@xxxxxxx>
>>> +
>>> +#include <linux/bits.h>
>>> +#include <linux/delay.h>
>>> +#include <linux/i2c.h>
>>> +#include <linux/interrupt.h>
>>> +#include <linux/module.h>
>>> +#include <linux/pci.h>
>>> +#include <linux/platform_device.h>
>>> +#include <linux/pm.h>
>>> +#include <linux/regmap.h>
>>> +#include <asm/unaligned.h>
>>> +#include "i2c-designware-core.h"
>>> +
>>> +#define AMD_UCSI_INTR_EN 0xD
>>> +#define AMD_UCSI_INTR_REG 0x474
>>> +#define AMD_MASTERCFG_MASK GENMASK(15, 0)
>>> +
>>> +struct amdgpu_i2c_dev {
>>> + void __iomem *regs;
>>> + struct regmap *map;
>>> + struct device *dev;
>>> + u32 master_cfg;
>>> + u32 slave_adr;
>>> + u32 tx_fifo_depth;
>>> + u32 rx_fifo_depth;
>>> + u16 ss_hcnt;
>>> + u16 ss_lcnt;
>>> + struct i2c_adapter adapter;
>>> + struct i2c_board_info *gpu_ccgx_ucsi;
>>> + struct i2c_client *ccgx_client;
>>> +};
>>> +
>>> +static int amdgpu_i2c_read(void *context, unsigned int reg, unsigned int *val)
>>> +{
>>> + struct amdgpu_i2c_dev *i2cd = context;
>>> +
>>> + *val = readl_relaxed(i2cd->regs + reg);
>>
>> It's quite confusing calling it "i2c_read" function. What is more
>> important - why do you need it? It's a simple MMIO on PCI, so why regmap
>> MMIO cannot be used?
>>
Hi Krzysztof,
As suggested have made the changes in the code to use regmap MMIO and it works fine :).
will send v3 patch with this change.
Thanks,
Sanjay
> Thanks Krzysztof.
>
> I am new to using regmap based API's and had referred to designware code for this.
> (https://elixir.bootlin.com/linux/latest/source/drivers/i2c/busses/i2c-designware-common.c#L61)
>
> Any specific API you recommend me to use or any driver you want me to refer will be helpful.
>
> Thanks & Regards,
> Sanjay
>
>> Best regards,
>> Krzysztof
>>
