[U-Boot] [PATCH 4/4] i2c: muxes: Add support for TI PCA954X mux

[Simon Glass]

Hi Michal,

On 14 April 2016 at 06:15, Michal Simek <michal.simek at xilinx.com> wrote:
> Add support for common TI i2c mux which is available on ZynqMP zcu102
> board.
> DM i2c mux core code is selecting/deselecting bus before/after
> every command is performed that's why only one channel is active at a
> time. That's also the reason why deselect is just disable all available
> channels.
>
> Signed-off-by: Michal Simek <michal.simek at xilinx.com>
> ---
>
>  drivers/i2c/muxes/Kconfig   |  7 ++++
>  drivers/i2c/muxes/Makefile  |  1 +
>  drivers/i2c/muxes/pca954x.c | 79 +++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 87 insertions(+)
>  create mode 100644 drivers/i2c/muxes/pca954x.c

nits below, but otherwise:


Reviewed-by: Simon Glass <sjg at chromium.org>
>
> diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
> index f959d9de9e8b..e16b902f9611 100644
> --- a/drivers/i2c/muxes/Kconfig
> +++ b/drivers/i2c/muxes/Kconfig
> @@ -24,3 +24,10 @@ config I2C_ARB_GPIO_CHALLENGE
>           I2C multimaster arbitration scheme using GPIOs and a challenge &
>           response mechanism where masters have to claim the bus by asserting
>           a GPIO.
> +
> +config I2C_MUX_PCA954X
> +        tristate "TI PCA954x I2C Mux/switches"
> +        depends on I2C_MUX
> +        help
> +          If you say yes here you get support for the TI PCA954x
> +          I2C mux/switch devices.

Can you add a few lines about what this device is? What does it allow?

> diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile
> index 47c1240d7e9e..fb2d67ec9a97 100644
> --- a/drivers/i2c/muxes/Makefile
> +++ b/drivers/i2c/muxes/Makefile
> @@ -5,3 +5,4 @@
>  #
>  obj-$(CONFIG_I2C_ARB_GPIO_CHALLENGE) += i2c-arb-gpio-challenge.o
>  obj-$(CONFIG_$(SPL_)I2C_MUX) += i2c-mux-uclass.o
> +obj-$(CONFIG_I2C_MUX_PCA954X) += pca954x.o
> diff --git a/drivers/i2c/muxes/pca954x.c b/drivers/i2c/muxes/pca954x.c
> new file mode 100644
> index 000000000000..206581d3d908
> --- /dev/null
> +++ b/drivers/i2c/muxes/pca954x.c
> @@ -0,0 +1,79 @@
> +/*
> + * Copyright (C) 2015 - 2016 Xilinx, Inc.
> + * Written by Michal Simek
> + *
> + * SPDX-License-Identifier:    GPL-2.0+
> + */
> +
> +#include <common.h>
> +#include <dm.h>
> +#include <errno.h>
> +#include <i2c.h>
> +#include <asm/gpio.h>
> +
> +DECLARE_GLOBAL_DATA_PTR;
> +
> +struct pca95xx_priv {
> +       u32 addr;

ulong?

> +       u32 width;

Comments?

> +};
> +
> +static int pca95xx_deselect(struct udevice *mux, struct udevice *bus,
> +                           uint channel)
> +{
> +       struct pca95xx_priv *priv = dev_get_priv(mux);
> +       uchar byte = 0;
> +
> +       return dm_i2c_write(mux, priv->addr, &byte, 1);
> +}
> +
> +static int pca95xx_select(struct udevice *mux, struct udevice *bus,
> +                         uint channel)
> +{
> +       struct pca95xx_priv *priv = dev_get_priv(mux);
> +       uchar byte = 1 << channel;
> +
> +       return dm_i2c_write(mux, priv->addr, &byte, 1);
> +}
> +
> +static const struct i2c_mux_ops pca95xx_ops = {
> +       .select = pca95xx_select,
> +       .deselect = pca95xx_deselect,
> +};
> +
> +static const struct udevice_id pca95xx_ids[] = {
> +       { .compatible = "nxp,pca9548", .data = (ulong)8 },
> +       { .compatible = "nxp,pca9544", .data = (ulong)4 },
> +       { }
> +};
> +
> +static int pca95xx_ofdata_to_platdata(struct udevice *dev)
> +{
> +       struct pca95xx_priv *priv = dev_get_priv(dev);
> +
> +       priv->addr = dev_get_addr(dev);
> +       if (!priv->addr) {
> +               debug("MUX not found\n");
> +               return -ENOSYS;

-EINVAL

> +       }
> +       priv->width = dev_get_driver_data(dev);
> +
> +       if (!priv->width) {
> +               debug("No I2C MUX width specified\n");
> +               return -ENOSYS;

-EINVAL

> +       }
> +
> +       debug("Device %s at 0x%x with width %d\n",
> +             dev->name, priv->addr, priv->width);
> +
> +       return 0;
> +}
> +
> +U_BOOT_DRIVER(pca95xx) = {
> +       .name = "pca95xx",
> +       .id = UCLASS_I2C_MUX,
> +       .of_match = pca95xx_ids,
> +       .ops = &pca95xx_ops,
> +       .ofdata_to_platdata = pca95xx_ofdata_to_platdata,
> +       .priv_auto_alloc_size = sizeof(struct pca95xx_priv),
> +};
> --
> 1.9.1
>

Regards,
Simon