Re: [PATCH] net: ksz8864: Add support for KSZ87xx switches

[Sascha Hauer <sha@pengutronix.de>]

On Mon, Oct 11, 2021 at 11:42:13AM -0700, Trent Piepho wrote:
> This adds support for the ksz8765, ksz8794, and ksz8795 switches.
> 
> IDs for OF bindings are added.  The base chip type is "ksz8795", the
> same as the Linux driver, for the ksz87xx switches added here.
> "ksz8864rmn" is used for the existing switch.
> 
> The registers for these switch chips, as least as far as this simple
> driver is concerned, are the same as the existing ksz8864 support.
> 
> The difference in the ksz87xx chips is the format of the command and
> address bytes:
> 
> C = command
> A = address (used bits)
> a = address (unused bits)
> p = turn around padding bit
> 
> ksz8864: 00000CCC  AAAAAAAA
> ksz8795: CCCaaaaA  AAAAAAAp
> 
> CCC and AAAAAAAA are the same, it's just where they are that changes.
> This is parameterized in the read/write reg functions by using two
> values for the address width and pad width.
> 
> Signed-off-by: Trent Piepho <trent.piepho@igorinstitute.com>
> ---
>  drivers/net/ksz8864rmn.c | 66 ++++++++++++++++++++++++++++++----------
>  1 file changed, 50 insertions(+), 16 deletions(-)

Applied, thanks

Sascha

> 
> diff --git a/drivers/net/ksz8864rmn.c b/drivers/net/ksz8864rmn.c
> index 85063ff0d..72ab86579 100644
> --- a/drivers/net/ksz8864rmn.c
> +++ b/drivers/net/ksz8864rmn.c
> @@ -31,48 +31,55 @@
>  #define CMD_WRITE		0x02
>  #define CMD_READ		0x03
>  
> +enum ksz_type {
> +	unknown,
> +	ksz87,
> +	ksz88
> +};
> +
>  struct micrel_switch_priv {
>  	struct cdev             cdev;
>  	struct spi_device       *spi;
>  	unsigned int		p_enable;
> +	unsigned int		addr_width;
> +	unsigned int		pad;
>  };
>  
> -static int micrel_switch_read_reg(struct spi_device *spi, uint8_t reg)
> +static int micrel_switch_read_reg(const struct micrel_switch_priv *priv, uint8_t reg)
>  {
>  	uint8_t tx[2];
>  	uint8_t rx[1];
>  	int ret;
>  
> -	tx[0] = CMD_READ;
> -	tx[1] = reg;
> +	tx[0] = CMD_READ << (priv->addr_width + priv->pad - 8) | reg >> (8 - priv->pad);
> +	tx[1] = reg << priv->pad;
>  
> -	ret = spi_write_then_read(spi, tx, 2, rx, 1);
> +	ret = spi_write_then_read(priv->spi, tx, 2, rx, 1);
>  	if (ret < 0)
>  		return ret;
>  
>  	return rx[0];
>  }
>  
> -static void micrel_switch_write_reg(struct spi_device *spi, uint8_t reg, uint8_t val)
> +static void micrel_switch_write_reg(const struct micrel_switch_priv *priv, uint8_t reg, uint8_t val)
>  {
>  	uint8_t tx[3];
>  
> -	tx[0] = CMD_WRITE;
> -	tx[1] = reg;
> +	tx[0] = CMD_WRITE << (priv->addr_width + priv->pad - 8) | reg >> (8 - priv->pad);
> +	tx[1] = reg << priv->pad;
>  	tx[2] = val;
>  
> -	spi_write_then_read(spi, tx, 3, NULL, 0);
> +	spi_write_then_read(priv->spi, tx, 3, NULL, 0);
>  }
>  
>  static int micrel_switch_enable_set(struct param_d *param, void *_priv)
>  {
>  	struct micrel_switch_priv *priv = _priv;
> -	struct spi_device *spi = priv->spi;
>  
>  	if (priv->p_enable)
> -		micrel_switch_write_reg(spi, REG_ID1, 1);
> +		micrel_switch_write_reg(priv, REG_ID1, 1);
>  	else
> -		micrel_switch_write_reg(spi, REG_ID1, 0);
> +		micrel_switch_write_reg(priv, REG_ID1, 0);
>  
>  	return 0;
>  }
> @@ -84,7 +91,7 @@ static ssize_t micel_switch_read(struct cdev *cdev, void *_buf, size_t count, lo
>  	struct micrel_switch_priv *priv = cdev->priv;
>  
>  	for (i = 0; i < count; i++) {
> -		ret = micrel_switch_read_reg(priv->spi, offset);
> +		ret = micrel_switch_read_reg(priv, offset);
>  		if (ret < 0)
>  			return ret;
>  		*buf = ret;
> @@ -102,7 +109,7 @@ static ssize_t micel_switch_write(struct cdev *cdev, const void *_buf, size_t co
>  	struct micrel_switch_priv *priv = cdev->priv;
>  
>  	for (i = 0; i < count; i++) {
> -		micrel_switch_write_reg(priv->spi, offset, *buf);
> +		micrel_switch_write_reg(priv, offset, *buf);
>  		buf++;
>  		offset++;
>  	}
> @@ -119,6 +126,11 @@ static int micrel_switch_probe(struct device_d *dev)
>  {
>  	struct micrel_switch_priv *priv;
>  	int ret = 0;
> +	enum ksz_type kind = (enum ksz_type)device_get_match_data(dev);
> +	uint8_t id;
> +
> +	if (kind == unknown)
> +		return -ENODEV;
>  
>  	priv = xzalloc(sizeof(*priv));
>  
> @@ -128,12 +140,27 @@ static int micrel_switch_probe(struct device_d *dev)
>  	priv->spi->mode = SPI_MODE_0;
>  	priv->spi->bits_per_word = 8;
>  
> -	ret = micrel_switch_read_reg(priv->spi, REG_ID0);
> +	switch (kind) {
> +	case ksz87:
> +		priv->addr_width = 12;
> +		priv->pad = 1;
> +		id = 0x87;
> +		break;
> +	case ksz88:
> +		priv->addr_width = 8;
> +		priv->pad = 0;
> +		id = 0x95;
> +		break;
> +	default:
> +		return -ENODEV;
> +	};
> +
> +	ret = micrel_switch_read_reg(priv, REG_ID0);
>  	if (ret < 0) {
>  		dev_err(&priv->spi->dev, "failed to read device id\n");
>  		return ret;
>  	}
> -	if (ret != 0x95) {
> +	if (ret != id) {
>  		dev_err(&priv->spi->dev, "unknown device id: %02x\n", ret);
>  		return -ENODEV;
>  	}
> @@ -149,13 +176,20 @@ static int micrel_switch_probe(struct device_d *dev)
>  			NULL, &priv->p_enable, priv);
>  
>  	priv->p_enable = 1;
> -	micrel_switch_write_reg(priv->spi, REG_ID1, 1);
> +	micrel_switch_write_reg(priv, REG_ID1, 1);
>  
>  	return 0;
>  }
>  
> +static const struct platform_device_id ksz_ids[] = {
> +	{ .name = "ksz8864rmn", .driver_data = ksz88 },
> +	{ .name = "ksz8795", .driver_data = ksz87 },
> +	{ }
> +};
> +
>  static struct driver_d micrel_switch_driver = {
>  	.name  = "ksz8864rmn",
>  	.probe = micrel_switch_probe,
> +	.id_table = ksz_ids,
>  };
>  device_spi_driver(micrel_switch_driver);
> -- 
> 2.31.1
> 
> 
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