netdev - Re: [PATCH v2 3/6] net: phy: spi_ks8995: add support for resetting switch using GPIO

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Date:	Tue, 9 Feb 2016 09:32:14 +0100
From:	Andrew Lunn <andrew@...n.ch>
To:	Helmut Buchsbaum <helmut.buchsbaum@...il.com>
Cc:	"David S. Miller" <davem@...emloft.net>,
	Florian Fainelli <f.fainelli@...il.com>, netdev@...r.kernel.org
Subject: Re: [PATCH v2 3/6] net: phy: spi_ks8995: add support for resetting
 switch using GPIO

On Mon, Feb 08, 2016 at 06:35:34PM +0100, Helmut Buchsbaum wrote:
> When using device tree it is no more possible to reset the PHY at board
> level. Furthermore, doing in the driver allows to power down the switch
> when it is not used any more.
> 
> The patch introduces a new optional property "reset-gpios" denoting an
> appropriate GPIO handle, e.g.:
> 
> reset-gpios = <&gpio0 46 1>

Hi Helmut

Since you are respinning, please change the 1 to GPIO_ACTIVE_LOW.

Reviewed-by: Andrew Lunn <andrew@...n.ch>

Thanks
	Andrew

> 
> Signed-off-by: Helmut Buchsbaum <helmut.buchsbaum@...il.com>
> ---
>  drivers/net/phy/spi_ks8995.c | 71 ++++++++++++++++++++++++++++++++++++++------
>  1 file changed, 62 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/phy/spi_ks8995.c b/drivers/net/phy/spi_ks8995.c
> index 2803c8e..04d468f 100644
> --- a/drivers/net/phy/spi_ks8995.c
> +++ b/drivers/net/phy/spi_ks8995.c
> @@ -18,6 +18,9 @@
>  #include <linux/module.h>
>  #include <linux/delay.h>
>  #include <linux/device.h>
> +#include <linux/of.h>
> +#include <linux/gpio.h>
> +#include <linux/of_gpio.h>
>  
>  #include <linux/spi/spi.h>
>  
> @@ -120,7 +123,8 @@ static const struct ks8995_chip_params ks8995_chip[] = {
>  };
>  
>  struct ks8995_pdata {
> -	/* not yet implemented */
> +	int reset_gpio;
> +	enum of_gpio_flags reset_gpio_flags;
>  };
>  
>  struct ks8995_switch {
> @@ -339,6 +343,24 @@ err_out:
>  	return err;
>  }
>  
> +/* ks8995_parse_dt - setup platform data from devicetree
> + * @ks: pointer to switch instance
> + *
> + * Parses supported DT properties and sets up platform data
> + * accordingly.
> + */
> +static void ks8995_parse_dt(struct ks8995_switch *ks)
> +{
> +	struct device_node *np = ks->spi->dev.of_node;
> +	struct ks8995_pdata *pdata = ks->pdata;
> +
> +	if (!np)
> +		return;
> +
> +	pdata->reset_gpio = of_get_named_gpio_flags(np, "reset-gpios", 0,
> +		&pdata->reset_gpio_flags);
> +}
> +
>  static const struct bin_attribute ks8995_registers_attr = {
>  	.attr = {
>  		.name   = "registers",
> @@ -352,14 +374,10 @@ static const struct bin_attribute ks8995_registers_attr = {
>  /* ------------------------------------------------------------------------ */
>  static int ks8995_probe(struct spi_device *spi)
>  {
> -	struct ks8995_switch    *ks;
> -	struct ks8995_pdata     *pdata;
> -	int     err;
> +	struct ks8995_switch *ks;
> +	int err;
>  	int variant = spi_get_device_id(spi)->driver_data;
>  
> -	/* Chip description */
> -	pdata = spi->dev.platform_data;
> -
>  	if (variant >= max_variant) {
>  		dev_err(&spi->dev, "bad chip variant %d\n", variant);
>  		return -ENODEV;
> @@ -370,10 +388,42 @@ static int ks8995_probe(struct spi_device *spi)
>  		return -ENOMEM;
>  
>  	mutex_init(&ks->lock);
> -	ks->pdata = pdata;
>  	ks->spi = spi_dev_get(spi);
>  	ks->chip = &ks8995_chip[variant];
>  
> +	if (ks->spi->dev.of_node) {
> +		ks->pdata = devm_kzalloc(&spi->dev, sizeof(*ks->pdata),
> +					 GFP_KERNEL);
> +		if (!ks->pdata)
> +			return -ENOMEM;
> +
> +		ks->pdata->reset_gpio = -1;
> +
> +		ks8995_parse_dt(ks);
> +	}
> +
> +	if (!ks->pdata)
> +		ks->pdata = spi->dev.platform_data;
> +
> +	/* de-assert switch reset */
> +	if (ks->pdata && gpio_is_valid(ks->pdata->reset_gpio)) {
> +		unsigned long flags;
> +
> +		flags = (ks->pdata->reset_gpio_flags == OF_GPIO_ACTIVE_LOW ?
> +			 GPIOF_ACTIVE_LOW : 0);
> +
> +		err = devm_gpio_request_one(&spi->dev,
> +					    ks->pdata->reset_gpio,
> +					    flags, "switch-reset");
> +		if (err) {
> +			dev_err(&spi->dev,
> +				"failed to get reset-gpios: %d\n", err);
> +			return -EIO;
> +		}
> +
> +		gpiod_set_value(gpio_to_desc(ks->pdata->reset_gpio), 0);
> +	}
> +
>  	spi_set_drvdata(spi, ks);
>  
>  	spi->mode = SPI_MODE_0;
> @@ -414,11 +464,14 @@ static int ks8995_remove(struct spi_device *spi)
>  
>  	sysfs_remove_bin_file(&spi->dev.kobj, &ks->regs_attr);
>  
> +	/* assert reset */
> +	if (ks->pdata && gpio_is_valid(ks->pdata->reset_gpio))
> +		gpiod_set_value(gpio_to_desc(ks->pdata->reset_gpio), 1);
> +
>  	return 0;
>  }
>  
>  /* ------------------------------------------------------------------------ */
> -
>  static struct spi_driver ks8995_driver = {
>  	.driver = {
>  		.name	    = "spi-ks8995",
> -- 
> 2.1.4
>