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

[Vignesh Raghavendra]

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.

> +#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

> +
> +	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.



> +	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)

> +	return dm_scan_fdt_dev(dev);
> +}
> +
> +static const struct udevice_id ti_j721e_ufs_ids[] = {
> +	{
> +		.compatible = "ti,j721e-ufs",
> +	},
> +	{},
> +};
> +
> +U_BOOT_DRIVER(ti_j721e_ufs) = {
> +	.name			= "ti-j721e-ufs",
> +	.id			= UCLASS_UFS,
> +	.of_match		= ti_j721e_ufs_ids,
> +	.probe			= ti_j721e_ufs_probe,
> +};
> 

-- 
Regards
Vignesh