[PATCH v2 3/6] net: stmmac: dwmac-sunxi: Implement syscon-based clock handling

From: Priit Laes
Date: Wed Apr 29 2020 - 16:46:29 EST


Convert the sun7i-gmac driver to use a regmap-based driver,
instead of relying on the custom clock implementation.

This allows to get rid of the last custom clock in the sun7i
device tree making the sun7i fully CCU-compatible.

Compatibility with existing devicetrees is retained.

Signed-off-by: Priit Laes <plaes@xxxxxxxxx>
---
.../net/ethernet/stmicro/stmmac/dwmac-sunxi.c | 130 ++++++++++++++++--
1 file changed, 122 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-sunxi.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-sunxi.c
index 0e1ca2cba3c7..206398f7a2af 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-sunxi.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-sunxi.c
@@ -12,8 +12,11 @@
#include <linux/module.h>
#include <linux/phy.h>
#include <linux/platform_device.h>
+#include <linux/of_device.h>
#include <linux/of_net.h>
#include <linux/regulator/consumer.h>
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>

#include "stmmac_platform.h"

@@ -22,11 +25,23 @@ struct sunxi_priv_data {
int clk_enabled;
struct clk *tx_clk;
struct regulator *regulator;
+ struct regmap_field *regmap_field;
+};
+
+/* EMAC clock register @ 0x164 in the CCU address range */
+static const struct reg_field ccu_reg_field = {
+ .reg = 0x164,
+ .lsb = 0,
+ .msb = 31,
};

#define SUN7I_GMAC_GMII_RGMII_RATE 125000000
#define SUN7I_GMAC_MII_RATE 25000000

+#define SUN7I_A20_CLK_MASK GENMASK(2, 0)
+#define SUN7I_A20_RGMII_CLK (BIT(2) | BIT(1))
+#define SUN7I_A20_MII_CLK 0
+
static int sun7i_gmac_init(struct platform_device *pdev, void *priv)
{
struct sunxi_priv_data *gmac = priv;
@@ -38,7 +53,20 @@ static int sun7i_gmac_init(struct platform_device *pdev, void *priv)
return ret;
}

- /* Set GMAC interface port mode
+ if (gmac->regmap_field) {
+ if (phy_interface_mode_is_rgmii(gmac->interface)) {
+ regmap_field_update_bits(gmac->regmap_field,
+ SUN7I_A20_CLK_MASK,
+ SUN7I_A20_RGMII_CLK);
+ return clk_prepare_enable(gmac->tx_clk);
+ }
+ regmap_field_update_bits(gmac->regmap_field,
+ SUN7I_A20_CLK_MASK,
+ SUN7I_A20_MII_CLK);
+ return clk_enable(gmac->tx_clk);
+ }
+
+ /* Legacy devicetree clock (allwinner,sun7i-a20-gmac-clk) support:
*
* The GMAC TX clock lines are configured by setting the clock
* rate, which then uses the auto-reparenting feature of the
@@ -62,9 +90,16 @@ static void sun7i_gmac_exit(struct platform_device *pdev, void *priv)
{
struct sunxi_priv_data *gmac = priv;

- if (gmac->clk_enabled) {
+ if (gmac->regmap_field) {
+ regmap_field_update_bits(gmac->regmap_field,
+ SUN7I_A20_CLK_MASK, 0);
clk_disable(gmac->tx_clk);
- gmac->clk_enabled = 0;
+ } else {
+ /* Handle legacy devicetree clock (sun7i-a20-gmac-clk) */
+ if (gmac->clk_enabled) {
+ clk_disable(gmac->tx_clk);
+ gmac->clk_enabled = 0;
+ }
}
clk_unprepare(gmac->tx_clk);

@@ -72,10 +107,55 @@ static void sun7i_gmac_exit(struct platform_device *pdev, void *priv)
regulator_disable(gmac->regulator);
}

+static struct regmap *sun7i_gmac_get_syscon_from_dev(struct device_node *node)
+{
+ struct device_node *syscon_node;
+ struct platform_device *syscon_pdev;
+ struct regmap *regmap = NULL;
+
+ syscon_node = of_parse_phandle(node, "syscon", 0);
+ if (!syscon_node)
+ return ERR_PTR(-ENODEV);
+
+ syscon_pdev = of_find_device_by_node(syscon_node);
+ if (!syscon_pdev) {
+ /* platform device might not be probed yet */
+ regmap = ERR_PTR(-EPROBE_DEFER);
+ goto out_put_node;
+ }
+
+ /* If no regmap is found then the other device driver is at fault */
+ regmap = dev_get_regmap(&syscon_pdev->dev, NULL);
+ if (!regmap)
+ regmap = ERR_PTR(-EINVAL);
+
+ platform_device_put(syscon_pdev);
+out_put_node:
+ of_node_put(syscon_node);
+ return regmap;
+}
+
static void sun7i_fix_speed(void *priv, unsigned int speed)
{
struct sunxi_priv_data *gmac = priv;

+ if (gmac->regmap_field) {
+ clk_disable(gmac->tx_clk);
+ clk_unprepare(gmac->tx_clk);
+ if (speed == 1000)
+ regmap_field_update_bits(gmac->regmap_field,
+ SUN7I_A20_CLK_MASK,
+ SUN7I_A20_RGMII_CLK);
+ else
+ regmap_field_update_bits(gmac->regmap_field,
+ SUN7I_A20_CLK_MASK,
+ SUN7I_A20_MII_CLK);
+ clk_prepare_enable(gmac->tx_clk);
+ return;
+ }
+
+ /* Handle legacy devicetree clock (sun7i-a20-gmac-clk) */
+
/* only GMII mode requires us to reconfigure the clock lines */
if (gmac->interface != PHY_INTERFACE_MODE_GMII)
return;
@@ -102,6 +182,8 @@ static int sun7i_gmac_probe(struct platform_device *pdev)
struct stmmac_resources stmmac_res;
struct sunxi_priv_data *gmac;
struct device *dev = &pdev->dev;
+ struct device_node *syscon_node;
+ struct regmap *regmap = NULL;
int ret;

ret = stmmac_get_platform_resources(pdev, &stmmac_res);
@@ -124,11 +206,43 @@ static int sun7i_gmac_probe(struct platform_device *pdev)
goto err_remove_config_dt;
}

- gmac->tx_clk = devm_clk_get(dev, "allwinner_gmac_tx");
- if (IS_ERR(gmac->tx_clk)) {
- dev_err(dev, "could not get tx clock\n");
- ret = PTR_ERR(gmac->tx_clk);
- goto err_remove_config_dt;
+ /* Attempt to fetch syscon node... */
+ syscon_node = of_parse_phandle(dev->of_node, "syscon", 0);
+ if (syscon_node) {
+ gmac->tx_clk = devm_clk_get(dev, "stmmaceth");
+ if (IS_ERR(gmac->tx_clk)) {
+ dev_err(dev, "Could not get TX clock\n");
+ ret = PTR_ERR(gmac->tx_clk);
+ goto err_remove_config_dt;
+ }
+
+ regmap = sun7i_gmac_get_syscon_from_dev(pdev->dev.of_node);
+ if (IS_ERR(regmap))
+ regmap = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
+ "syscon");
+ if (IS_ERR(regmap)) {
+ ret = PTR_ERR(regmap);
+ dev_err(&pdev->dev, "Unable to map syscon: %d\n", ret);
+ goto err_remove_config_dt;
+ }
+
+ gmac->regmap_field = devm_regmap_field_alloc(dev, regmap,
+ ccu_reg_field);
+
+ if (IS_ERR(gmac->regmap_field)) {
+ ret = PTR_ERR(gmac->regmap_field);
+ dev_err(dev, "Unable to map syscon register: %d\n", ret);
+ goto err_remove_config_dt;
+ }
+ /* ...or fall back to legacy clock setup */
+ } else {
+ gmac->tx_clk = devm_clk_get(dev, "allwinner_gmac_tx");
+ if (IS_ERR(gmac->tx_clk)) {
+ dev_err(dev, "could not get tx clock\n");
+ ret = PTR_ERR(gmac->tx_clk);
+ goto err_remove_config_dt;
+ }
+ dev_info(dev, "allwinner_gmac_tx support is deprecated!\n");
}

/* Optional regulator for PHY */
--
2.26.2