[U-Boot] [PATCH 07/10] ufs: Add glue layer driver for TI J721E devices

[Faiz Abbas]

Vignesh,

On 10/09/19 9:18 AM, Vignesh Raghavendra wrote:
> 
> 
> On 09/09/19 1:49 PM, Faiz Abbas wrote:
>> Add glue layer driver for the controller present on TI's J721E devices.
>>
>> Signed-off-by: Faiz Abbas <faiz_abbas at ti.com>
>> ---
>>  drivers/ufs/Kconfig        |  6 +++
>>  drivers/ufs/Makefile       |  1 +
>>  drivers/ufs/ti-j721e-ufs.c | 75 ++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 82 insertions(+)
>>  create mode 100644 drivers/ufs/ti-j721e-ufs.c
>>
>> diff --git a/drivers/ufs/Kconfig b/drivers/ufs/Kconfig
>> index a320b4561f..4875e9448e 100644
>> --- a/drivers/ufs/Kconfig
>> +++ b/drivers/ufs/Kconfig
>> @@ -14,4 +14,10 @@ config CADENCE_UFS
>>  	  This selects the platform driver for the Cadence UFS host
>>  	  controller present on present TI's J721e devices.
>>  
>> +config TI_J721E_UFS
>> +	bool "Glue Layer driver for UFS on TI J721E devices"
>> +	help
>> +	  This selects the glue layer driver for Cadence controller
>> +	  present on TI's J721E devices.
>> +
>>  endmenu
>> diff --git a/drivers/ufs/Makefile b/drivers/ufs/Makefile
>> index 9262bd6cd0..62ed016608 100644
>> --- a/drivers/ufs/Makefile
>> +++ b/drivers/ufs/Makefile
>> @@ -5,3 +5,4 @@
>>  
>>  obj-$(CONFIG_UFS) += ufs.o ufs-uclass.o
>>  obj-$(CONFIG_CADENCE_UFS) += cdns-platform.o
>> +obj-$(CONFIG_TI_J721E_UFS) += ti-j721e-ufs.o
>> diff --git a/drivers/ufs/ti-j721e-ufs.c b/drivers/ufs/ti-j721e-ufs.c
>> new file mode 100644
>> index 0000000000..249d3796c0
>> --- /dev/null
>> +++ b/drivers/ufs/ti-j721e-ufs.c
>> @@ -0,0 +1,75 @@
>> +// SPDX-License-Identifier: GPL-2.0+
>> +/*
>> + * Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/
>> + */
>> +
>> +#include <clk.h>
>> +#include <common.h>
>> +#include <dm/device.h>
>> +#include <dm/read.h>
> 
> #include <dm.h>
> 
> should be sufficient instead of two includes.

Replaced it.

> 
>> +#include <power-domain.h>
>> +#include <regmap.h>
>> +
>> +#define UFS_SS_CTRL             0x4
>> +#define UFS_SS_RST_N_PCS        BIT(0)
>> +#define UFS_SS_CLK_26MHZ        BIT(4)
>> +
>> +static int ti_j721e_ufs_probe(struct udevice *dev)
>> +{
>> +	struct power_domain ufs_pwrdmn;
>> +	struct regmap *map;
>> +	unsigned int clock;
>> +	struct clk clk;
>> +	u32 reg = 0;
>> +	int ret;
>> +
>> +	ret = power_domain_get(dev, &ufs_pwrdmn);
>> +	if (ret) {
>> +		dev_err(dev, "failed to get power domain %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	ret = power_domain_on(&ufs_pwrdmn);
>> +	if (ret) {
>> +		dev_err(dev, "Power domain on failed\n");
>> +		return ret;
>> +	}
> 
> Core takes care of enabling power domain before calling probe. So this
> can be dropped

Ok.

> 
>> +
>> +	ret = regmap_init_mem(dev_ofnode(dev), &map);
>> +	if (ret)
>> +		return ret;
>> +
> 
> 
> I think regmap is an overkill here.. We are just accessing a single
> register and within dedicated wrapper space. Just use regular IO accessors.

Ok. Going back to writel/readl calls.

> 
> 
> 
>> +	ret = clk_get_by_index(dev, 0, &clk);
>> +	if (ret) {
>> +		dev_err(dev, "failed to get M-PHY clock\n");
>> +		return ret;
>> +	}
>> +
>> +	clock = clk_get_rate(&clk);
>> +	if (IS_ERR_VALUE(clock)) {
>> +		dev_err(dev, "failed to get rate\n");
>> +		return ret;
>> +	}
>> +
>> +	if (clock == 26000000)
>> +		reg |= UFS_SS_CLK_26MHZ;
>> +	/* Take UFS slave device out of reset */
>> +	reg |= UFS_SS_RST_N_PCS;
>> +	regmap_write(map, UFS_SS_CTRL, reg);
>> +
> 
> To be safe, put the slave back to reset before jumping to kernel so that
> card does not see any glitches when kernel is doing any
> re-initialization of clocks etc.
> This can be done in driver remove callback (and needs DM_FLAG_OS_PREPARE
> flag to be set in driver declaration)

Implemented this for v2. Thanks.

Regards,
Faiz