[RFT net-next v2 1/3] net: stmmac: dwmac-meson8b: only configure the clocks in RGMII mode

[Martin Blumenstingl]

Neither the m25_div_clk nor the m250_div_clk or m250_mux_clk are used in
RMII mode. The m25_div_clk output is routed to the RGMII PHY's "RGMII
clock".
This means that we don't need to configure the clocks in RMII mode. The
driver however did this - with no effect since the clocks are not routed
to the PHY in RMII mode.

While here also rename meson8b_init_clk to meson8b_init_rgmii_clk to
make it easier to understand the code.

Fixes: 566e8251625304 ("net: stmmac: add a glue driver for the Amlogic Meson 8b 
/ GXBB DWMAC")
Signed-off-by: Martin Blumenstingl <martin.blumensti...@googlemail.com>
---
 .../net/ethernet/stmicro/stmmac/dwmac-meson8b.c    | 46 ++++++++++------------
 1 file changed, 21 insertions(+), 25 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c 
b/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
index 4404650b32c5..e1d5907e481c 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
@@ -81,7 +81,7 @@ static void meson8b_dwmac_mask_bits(struct meson8b_dwmac 
*dwmac, u32 reg,
        writel(data, dwmac->regs + reg);
 }
 
-static int meson8b_init_clk(struct meson8b_dwmac *dwmac)
+static int meson8b_init_rgmii_clk(struct meson8b_dwmac *dwmac)
 {
        struct clk_init_data init;
        int i, ret;
@@ -176,7 +176,6 @@ static int meson8b_init_clk(struct meson8b_dwmac *dwmac)
 static int meson8b_init_prg_eth(struct meson8b_dwmac *dwmac)
 {
        int ret;
-       unsigned long clk_rate;
        u8 tx_dly_val = 0;
 
        switch (dwmac->phy_mode) {
@@ -191,9 +190,6 @@ static int meson8b_init_prg_eth(struct meson8b_dwmac *dwmac)
 
        case PHY_INTERFACE_MODE_RGMII_ID:
        case PHY_INTERFACE_MODE_RGMII_TXID:
-               /* Generate a 25MHz clock for the PHY */
-               clk_rate = 25 * 1000 * 1000;
-
                /* enable RGMII mode */
                meson8b_dwmac_mask_bits(dwmac, PRG_ETH0, PRG_ETH0_RGMII_MODE,
                                        PRG_ETH0_RGMII_MODE);
@@ -204,12 +200,24 @@ static int meson8b_init_prg_eth(struct meson8b_dwmac 
*dwmac)
 
                meson8b_dwmac_mask_bits(dwmac, PRG_ETH0, PRG_ETH0_TXDLY_MASK,
                                        tx_dly_val << PRG_ETH0_TXDLY_SHIFT);
+
+               ret = clk_prepare_enable(dwmac->m25_div_clk);
+               if (ret) {
+                       dev_err(&dwmac->pdev->dev, "failed to enable the PHY 
clock\n");
+                       return ret;
+               }
+
+               /* Generate the 25MHz RGMII clock for the PHY */
+               ret = clk_set_rate(dwmac->m25_div_clk, 25 * 1000 * 1000);
+               if (ret) {
+                       clk_disable_unprepare(dwmac->m25_div_clk);
+
+                       dev_err(&dwmac->pdev->dev, "failed to set PHY clock\n");
+                       return ret;
+               }
                break;
 
        case PHY_INTERFACE_MODE_RMII:
-               /* Use the rate of the mux clock for the internal RMII PHY */
-               clk_rate = clk_get_rate(dwmac->m250_mux_clk);
-
                /* disable RGMII mode -> enables RMII mode */
                meson8b_dwmac_mask_bits(dwmac, PRG_ETH0, PRG_ETH0_RGMII_MODE,
                                        0);
@@ -231,20 +239,6 @@ static int meson8b_init_prg_eth(struct meson8b_dwmac 
*dwmac)
                return -EINVAL;
        }
 
-       ret = clk_prepare_enable(dwmac->m25_div_clk);
-       if (ret) {
-               dev_err(&dwmac->pdev->dev, "failed to enable the PHY clock\n");
-               return ret;
-       }
-
-       ret = clk_set_rate(dwmac->m25_div_clk, clk_rate);
-       if (ret) {
-               clk_disable_unprepare(dwmac->m25_div_clk);
-
-               dev_err(&dwmac->pdev->dev, "failed to set PHY clock\n");
-               return ret;
-       }
-
        /* enable TX_CLK and PHY_REF_CLK generator */
        meson8b_dwmac_mask_bits(dwmac, PRG_ETH0, PRG_ETH0_TX_AND_PHY_REF_CLK,
                                PRG_ETH0_TX_AND_PHY_REF_CLK);
@@ -294,7 +288,7 @@ static int meson8b_dwmac_probe(struct platform_device *pdev)
                                 &dwmac->tx_delay_ns))
                dwmac->tx_delay_ns = 2;
 
-       ret = meson8b_init_clk(dwmac);
+       ret = meson8b_init_rgmii_clk(dwmac);
        if (ret)
                goto err_remove_config_dt;
 
@@ -311,7 +305,8 @@ static int meson8b_dwmac_probe(struct platform_device *pdev)
        return 0;
 
 err_clk_disable:
-       clk_disable_unprepare(dwmac->m25_div_clk);
+       if (phy_interface_mode_is_rgmii(dwmac->phy_mode))
+               clk_disable_unprepare(dwmac->m25_div_clk);
 err_remove_config_dt:
        stmmac_remove_config_dt(pdev, plat_dat);
 
@@ -322,7 +317,8 @@ static int meson8b_dwmac_remove(struct platform_device 
*pdev)
 {
        struct meson8b_dwmac *dwmac = get_stmmac_bsp_priv(&pdev->dev);
 
-       clk_disable_unprepare(dwmac->m25_div_clk);
+       if (phy_interface_mode_is_rgmii(dwmac->phy_mode))
+               clk_disable_unprepare(dwmac->m25_div_clk);
 
        return stmmac_pltfr_remove(pdev);
 }
-- 
2.15.1