[PATCH v2 1/4] net: stmmac: s32: use a syscon for S32_PHY_INTF_SEL_RGMII

Dan Carpenter
2025-12-15T14:41:54Z

On the s32 chipsets the GMAC_0_CTRL_STS register is in GPR region.
Originally, accessing this register was done in a sort of ad-hoc way,
but we want to use the syscon interface to do it.

This is a little bit ugly because we have to maintain backwards
compatibility to the old device trees so we have to support both ways
to access this register.

Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
---
Fix forward porting bug. s/PHY_INTF_SEL_RGMII/S32_PHY_INTF_SEL_RGMII/

.../net/ethernet/stmicro/stmmac/dwmac-s32.c | 23 +++++++++++++++----
1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-s32.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-s32.c
index 5a485ee98fa7..2e6bb41f49e1 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-s32.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-s32.c
@@ -11,12 +11,14 @@
#include <linux/device.h>
#include <linux/ethtool.h>
#include <linux/io.h>
+#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of_mdio.h>
#include <linux/of_address.h>
#include <linux/phy.h>
#include <linux/phylink.h>
#include <linux/platform_device.h>
+#include <linux/regmap.h>
#include <linux/stmmac.h>

#include "stmmac_platform.h"
@@ -32,6 +34,8 @@
struct s32_priv_data {
void __iomem *ioaddr;
void __iomem *ctrl_sts;
+ struct regmap *sts_regmap;
+ unsigned int sts_offset;
struct device *dev;
phy_interface_t *intf_mode;
struct clk *tx_clk;
@@ -40,7 +44,10 @@ struct s32_priv_data {

static int s32_gmac_write_phy_intf_select(struct s32_priv_data *gmac)
{
- writel(S32_PHY_INTF_SEL_RGMII, gmac->ctrl_sts);
+ if (gmac->ctrl_sts)
+ writel(S32_PHY_INTF_SEL_RGMII, gmac->ctrl_sts);
+ else
+ regmap_write(gmac->sts_regmap, gmac->sts_offset, S32_PHY_INTF_SEL_RGMII);

dev_dbg(gmac->dev, "PHY mode set to %s\n", phy_modes(*gmac->intf_mode));

@@ -125,10 +132,16 @@ static int s32_dwmac_probe(struct platform_device *pdev)
"dt configuration failed\n");

/* PHY interface mode control reg */
- gmac->ctrl_sts = devm_platform_get_and_ioremap_resource(pdev, 1, NULL);
- if (IS_ERR(gmac->ctrl_sts))
- return dev_err_probe(dev, PTR_ERR(gmac->ctrl_sts),
- "S32CC config region is missing\n");
+ gmac->sts_regmap = syscon_regmap_lookup_by_phandle_args(dev->of_node,
+ "nxp,phy-sel", 1, &gmac->sts_offset);
+ if (gmac->sts_regmap == ERR_PTR(-EPROBE_DEFER))
+ return PTR_ERR(gmac->sts_regmap);
+ if (IS_ERR(gmac->sts_regmap)) {
+ gmac->ctrl_sts = devm_platform_get_and_ioremap_resource(pdev, 1, NULL);
+ if (IS_ERR(gmac->ctrl_sts))
+ return dev_err_probe(dev, PTR_ERR(gmac->ctrl_sts),
+ "S32CC config region is missing\n");
+ }

/* tx clock */
gmac->tx_clk = devm_clk_get(&pdev->dev, "tx");
--
2.51.0