Re: [PATCH 1/2] of/phylib: Use device tree properties toinitialize Marvell PHYs.

[Grant Likely]

On Wed, Nov 17, 2010 at 03:54:30PM -0800, David Daney wrote:
> Some aspects of PHY initialization are board dependent, things like
> indicator LED connections and some clocking modes cannot be determined
> by probing.  The dev_flags element of struct phy_device can be used to
> control these things if an appropriate value can be passed from the
> Ethernet driver.  We run into problems however if the PHY connections
> are specified by the device tree.  There is no way for the Ethernet
> driver to know what flags it should pass.
> 
> If we are using the device tree, the struct phy_device will be
> populated with the device tree node corresponding to the PHY, and we
> can extract extra configuration information from there.
> 
> The next question is what should the format of that information be?
> It is highly device specific, and the device tree representation
> should not be tied to any arbitrary kernel defined constants.  A
> straight forward representation is just to specify the exact bits that
> should be set using the "marvell,reg-init" property:
> 
>       phy5: ethernet-phy@5 {
> 	reg = <5>;
> 	device_type = "ethernet-phy";

Some notes:
- device_type is only relevant for real openfirmware platforms.  It
  should not appear in dts files.
- This example phy node needs a compatible property
- This new binding needs to be documented.  You can use devicetree.org.

> 	marvell,reg-init =
> 		<0x00030010 0x5777>, /* Reg 3,16 <- 0x5777 */
> 		<0x00030011 0x00aa>, /* Reg 3,17 <- 0x00aa */
> 		<0x00030012 0x4105>, /* Reg 3,18 <- 0x4105 */
> 		<0x00030013 0x0060>; /* Reg 3,19 <- 0x0060 */
> 		<0x00020015 0x00300000>; /* clear bits 4..5 of Reg 2,21 */
>       };
> 
> The Marvell PHYs have a page select register at register 22 (0x16), we
> can specify any register by its page and register number.  These are
> encoded in the high and low parts of the first word.  The second word
> contains a mask and value to be ORed in its high and low parts.  The
> new marvell_of_reg_init function leaves the page select register
> unchanged, so a call to it can be dropped into the .config_init
> functions without unduly affecting the state of the PHY.

Don't bother trying to pack the values tightly.  Just use one cell per
value. ie: marvell,reg-init = < [page] [register] [mask] [value] >;

> 
> If CONFIG_OF is not set, there is no of_node, or no "marvell,reg-init"
> property, the PHY initialization is unchanged.
> 
> Signed-off-by: David Daney <ddaney@xxxxxxxxxxxxxxxxxx>
> Cc: Grant Likely <grant.likely@xxxxxxxxxxxx>
> Cc: Cyril Chemparathy <cyril@xxxxxx>
> Cc: David Daney <ddaney@xxxxxxxxxxxxxxxxxx>
> Cc: Arnaud Patard <arnaud.patard@xxxxxxxxxxx>
> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> ---
>  drivers/net/phy/marvell.c |   91 +++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 91 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
> index f0bd1a1..33ad654 100644
> --- a/drivers/net/phy/marvell.c
> +++ b/drivers/net/phy/marvell.c
> @@ -30,6 +30,7 @@
>  #include <linux/ethtool.h>
>  #include <linux/phy.h>
>  #include <linux/marvell_phy.h>
> +#include <linux/of.h>
>  
>  #include <asm/io.h>
>  #include <asm/irq.h>
> @@ -186,6 +187,85 @@ static int marvell_config_aneg(struct phy_device *phydev)
>  	return 0;
>  }
>  
> +#ifndef CONFIG_OF

ifndef CONFIG_OF_MDIO

Nit: I usually see these blocks constructed the other way around.  Put
the true case first, and then follow it up with the empty false case.

> +static int marvell_of_reg_init(struct phy_device *phydev)
> +{
> +	return 0;
> +}
> +#else
> +/*
> + * Set and/or override some configuration registers based on the
> + * marvell,reg-init property stored in the of_node for the phydev.
> + *
> + * marvell,reg-init = <reg-spec val-spec>,...;
> + *
> + * There may be one or more  pairs of <reg-spec val-spec>:
> + * reg-spec [16..31]: Page address.
> + * reg-spec [0..15]: Register address.
> + *
> + * val-spec [16..31]: Mask bits.
> + * val-spec [0..15]: Register bits.
> + */
> +static int marvell_of_reg_init(struct phy_device *phydev)
> +{
> +	const __be32 *paddr;
> +	int len, i, saved_page, current_page, page_changed, ret;
> +
> +	if (!phydev->dev.of_node)
> +		return 0;
> +
> +	paddr = of_get_property(phydev->dev.of_node, "marvell,reg-init", &len);
> +	if (!paddr || len < (2 * sizeof(u32)))
> +		return 0;
> +
> +	saved_page = phy_read(phydev, 22);
> +	if (saved_page < 0)
> +		return saved_page;
> +	page_changed = 0;
> +	current_page = saved_page;
> +
> +	ret = 0;
> +	len /= sizeof(u32);
> +	for (i = 0; i < len / 2; i += 2) {
> +		u32 reg_spec =  be32_to_cpup(&paddr[i]);
> +		u32 val_spec =  be32_to_cpup(&paddr[i + 1]);
> +		u16 reg = reg_spec & 0xffff;
> +		u16 reg_page = reg_spec >> 16;
> +		u16 val_bits = val_spec & 0xffff;
> +		u16 mask = val_spec >> 16;
> +		int val;
> +
> +		if (reg_page != current_page) {
> +			ret = phy_write(phydev, 22, reg_page);
> +			if (ret < 0)
> +				goto err;
> +			current_page = reg_page;
> +			page_changed = 1;
> +		}
> +
> +		val = 0;
> +		if (mask) {
> +			val = phy_read(phydev, reg);
> +			if (val < 0) {
> +				ret = val;
> +				goto err;
> +			}
> +			val &= mask;
> +		}
> +		val |= val_bits;
> +
> +		ret = phy_write(phydev, reg, (u16)val);
> +		if (ret < 0)
> +			goto err;
> +
> +	}
> +err:
> +	if (page_changed)
> +		ret = phy_write(phydev, 22, saved_page);

This throws away the previous error code if a single write fails.  It
may return a false success.

> +	return ret;
> +}
> +#endif /* CONFIG_OF */
> +
>  static int m88e1121_config_aneg(struct phy_device *phydev)
>  {
>  	int err, oldpage, mscr;
> @@ -368,6 +448,9 @@ static int m88e1111_config_init(struct phy_device *phydev)
>  			return err;
>  	}
>  
> +	err = marvell_of_reg_init(phydev);
> +	if (err < 0)
> +		return err;
>  
>  	err = phy_write(phydev, MII_BMCR, BMCR_RESET);
>  	if (err < 0)
> @@ -420,6 +503,10 @@ static int m88e1118_config_init(struct phy_device *phydev)
>  	if (err < 0)
>  		return err;
>  
> +	err = marvell_of_reg_init(phydev);
> +	if (err < 0)
> +		return err;
> +
>  	/* Reset address */
>  	err = phy_write(phydev, 0x16, 0x0);
>  	if (err < 0)
> @@ -491,6 +578,10 @@ static int m88e1145_config_init(struct phy_device *phydev)
>  		}
>  	}
>  
> +	err = marvell_of_reg_init(phydev);
> +	if (err < 0)
> +		return err;
> +
>  	return 0;
>  }
>  
> -- 
> 1.7.2.3
> 
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