net: ethernet: stmmac: simplify phy modes management for stm32

No new feature, just to simplify stm32 part to be easier to use.
Add by default all Ethernet clocks in DT, and activate or not in function
of phy mode, clock frequency, if property "st,ext-phyclk" is set or not.
Keep backward compatibility
--------------------------------------------------------------------------
|PHY_MODE |    Normal | PHY wo crystal|   PHY wo crystal   |  No 125Mhz  |
|         |	      |      25MHz    |        50MHz       |  from PHY   |
--------------------------------------------------------------------------
|  MII    |	 -    |     eth-ck    |       n/a          |	    n/a  |
|         |	      | st,ext-phyclk |                    |             |
--------------------------------------------------------------------------
|  GMII   |	 -    |     eth-ck    |       n/a          |	    n/a  |
|         |	      | st,ext-phyclk |                    |             |
--------------------------------------------------------------------------
| RGMII   |	 -    |     eth-ck    |       n/a          |     eth-ck  |
|         |	     | st,ext-phyclk |                    |st,eth-clk-sel|
|         |	     |               |                    |       or     |
|         |	     |               |                    | st,ext-phyclk|
----------------==--------------------------------------------------------
| RMII    |	 -   |     eth-ck    |      eth-ck        |       n/a    |
|         | 	     | st,ext-phyclk | st,eth-ref-clk-sel |              |
|         | 	     |               | or st,ext-phyclk   |              |
--------------------------------------------------------------------------
Signed-off-by: Christophe Roullier <christophe.roullier@st.com>
Acked-by: Alexandre TORGUE <alexandre.torgue@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c

@@ -29,6 +29,11 @@
 #define SYSCFG_PMCR_ETH_CLK_SEL		BIT(16)
 #define SYSCFG_PMCR_ETH_REF_CLK_SEL	BIT(17)
 
+/* CLOCK feed to PHY*/
+#define ETH_CK_F_25M	25000000
+#define ETH_CK_F_50M	50000000
+#define ETH_CK_F_125M	125000000
+
 /*  Ethernet PHY interface selection in register SYSCFG Configuration
  *------------------------------------------
  * src	 |BIT(23)| BIT(22)| BIT(21)|BIT(20)|
@@ -58,33 +63,20 @@
  *|         |        |      25MHz    |        50MHz       |                  |
  * ---------------------------------------------------------------------------
  *|  MII    |	 -   |     eth-ck    |	      n/a	  |	  n/a        |
- *|         |        |		     |                    |		     |
+ *|         |        | st,ext-phyclk |                    |		     |
  * ---------------------------------------------------------------------------
  *|  GMII   |	 -   |     eth-ck    |	      n/a	  |	  n/a        |
- *|         |        |               |                    |		     |
+ *|         |        | st,ext-phyclk |                    |		     |
  * ---------------------------------------------------------------------------
- *| RGMII   |	 -   |     eth-ck    |	      n/a	  |  eth-ck (no pin) |
- *|         |        |               |                    |  st,eth-clk-sel  |
+ *| RGMII   |	 -   |     eth-ck    |	      n/a	  |      eth-ck      |
+ *|         |        | st,ext-phyclk |                    | st,eth-clk-sel or|
+ *|         |        |               |                    | st,ext-phyclk    |
  * ---------------------------------------------------------------------------
  *| RMII    |	 -   |     eth-ck    |	    eth-ck        |	  n/a        |
- *|         |        |		     | st,eth-ref-clk-sel |		     |
+ *|         |        | st,ext-phyclk | st,eth-ref-clk-sel |		     |
+ *|         |        |               | or st,ext-phyclk   |		     |
  * ---------------------------------------------------------------------------
  *
- * BIT(17) : set this bit in RMII mode when you have PHY without crystal 50MHz
- * BIT(16) : set this bit in GMII/RGMII PHY when you do not want use 125Mhz
- * from PHY
- *-----------------------------------------------------
- * src	 |         BIT(17)       |       BIT(16)      |
- *-----------------------------------------------------
- * MII   |           n/a	 |         n/a        |
- *-----------------------------------------------------
- * GMII  |           n/a         |   st,eth-clk-sel   |
- *-----------------------------------------------------
- * RGMII |           n/a         |   st,eth-clk-sel   |
- *-----------------------------------------------------
- * RMII  |   st,eth-ref-clk-sel	 |         n/a        |
- *-----------------------------------------------------
- *
  */
 
 struct stm32_dwmac {
@@ -93,6 +85,8 @@ struct stm32_dwmac {
 	struct clk *clk_eth_ck;
 	struct clk *clk_ethstp;
 	struct clk *syscfg_clk;
+	int ext_phyclk;
+	int enable_eth_ck;
 	int eth_clk_sel_reg;
 	int eth_ref_clk_sel_reg;
 	int irq_pwr_wakeup;
@@ -155,14 +149,17 @@ static int stm32mp1_clk_prepare(struct stm32_dwmac *dwmac, bool prepare)
 		ret = clk_prepare_enable(dwmac->syscfg_clk);
 		if (ret)
 			return ret;
-		ret = clk_prepare_enable(dwmac->clk_eth_ck);
-		if (ret) {
-			clk_disable_unprepare(dwmac->syscfg_clk);
-			return ret;
+		if (dwmac->enable_eth_ck) {
+			ret = clk_prepare_enable(dwmac->clk_eth_ck);
+			if (ret) {
+				clk_disable_unprepare(dwmac->syscfg_clk);
+				return ret;
+			}
 		}
 	} else {
 		clk_disable_unprepare(dwmac->syscfg_clk);
-		clk_disable_unprepare(dwmac->clk_eth_ck);
+		if (dwmac->enable_eth_ck)
+			clk_disable_unprepare(dwmac->clk_eth_ck);
 	}
 	return ret;
 }
@@ -170,24 +167,34 @@ static int stm32mp1_clk_prepare(struct stm32_dwmac *dwmac, bool prepare)
 static int stm32mp1_set_mode(struct plat_stmmacenet_data *plat_dat)
 {
 	struct stm32_dwmac *dwmac = plat_dat->bsp_priv;
-	u32 reg = dwmac->mode_reg;
+	u32 reg = dwmac->mode_reg, clk_rate;
 	int val;
 
+	clk_rate = clk_get_rate(dwmac->clk_eth_ck);
+	dwmac->enable_eth_ck = false;
 	switch (plat_dat->interface) {
 	case PHY_INTERFACE_MODE_MII:
+		if (clk_rate == ETH_CK_F_25M && dwmac->ext_phyclk)
+			dwmac->enable_eth_ck = true;
 		val = SYSCFG_PMCR_ETH_SEL_MII;
 		pr_debug("SYSCFG init : PHY_INTERFACE_MODE_MII\n");
 		break;
 	case PHY_INTERFACE_MODE_GMII:
 		val = SYSCFG_PMCR_ETH_SEL_GMII;
-		if (dwmac->eth_clk_sel_reg)
+		if (clk_rate == ETH_CK_F_25M &&
+		    (dwmac->eth_clk_sel_reg || dwmac->ext_phyclk)) {
+			dwmac->enable_eth_ck = true;
 			val |= SYSCFG_PMCR_ETH_CLK_SEL;
+		}
 		pr_debug("SYSCFG init : PHY_INTERFACE_MODE_GMII\n");
 		break;
 	case PHY_INTERFACE_MODE_RMII:
 		val = SYSCFG_PMCR_ETH_SEL_RMII;
-		if (dwmac->eth_ref_clk_sel_reg)
+		if ((clk_rate == ETH_CK_F_25M || clk_rate == ETH_CK_F_50M) &&
+		    (dwmac->eth_ref_clk_sel_reg || dwmac->ext_phyclk)) {
+			dwmac->enable_eth_ck = true;
 			val |= SYSCFG_PMCR_ETH_REF_CLK_SEL;
+		}
 		pr_debug("SYSCFG init : PHY_INTERFACE_MODE_RMII\n");
 		break;
 	case PHY_INTERFACE_MODE_RGMII:
@@ -195,8 +202,11 @@ static int stm32mp1_set_mode(struct plat_stmmacenet_data *plat_dat)
 	case PHY_INTERFACE_MODE_RGMII_RXID:
 	case PHY_INTERFACE_MODE_RGMII_TXID:
 		val = SYSCFG_PMCR_ETH_SEL_RGMII;
-		if (dwmac->eth_clk_sel_reg)
+		if ((clk_rate == ETH_CK_F_25M || clk_rate == ETH_CK_F_125M) &&
+		    (dwmac->eth_clk_sel_reg || dwmac->ext_phyclk)) {
+			dwmac->enable_eth_ck = true;
 			val |= SYSCFG_PMCR_ETH_CLK_SEL;
+		}
 		pr_debug("SYSCFG init : PHY_INTERFACE_MODE_RGMII\n");
 		break;
 	default:
@@ -294,6 +304,9 @@ static int stm32mp1_parse_data(struct stm32_dwmac *dwmac,
 	struct device_node *np = dev->of_node;
 	int err = 0;
 
+	/* Ethernet PHY have no crystal */
+	dwmac->ext_phyclk = of_property_read_bool(np, "st,ext-phyclk");
+
 	/* Gigabit Ethernet 125MHz clock selection. */
 	dwmac->eth_clk_sel_reg = of_property_read_bool(np, "st,eth-clk-sel");
 
@@ -431,7 +444,8 @@ static int stm32mp1_suspend(struct stm32_dwmac *dwmac)
 
 	clk_disable_unprepare(dwmac->clk_tx);
 	clk_disable_unprepare(dwmac->syscfg_clk);
-	clk_disable_unprepare(dwmac->clk_eth_ck);
+	if (dwmac->enable_eth_ck)
+		clk_disable_unprepare(dwmac->clk_eth_ck);
 
 	return ret;
 }