net: stmmac: dwmac-qcom-ethqos: Use max frequency for clk_ptp_ref

Qualcomm clocks can set their frequency to a variety of levels
generally. Let's use the max for clk_ptp_ref to ensure the best
timestamping resolution possible.

Without this, the default value of the clock is used. For sa8775p-ride
this is 19.2 MHz, far less than the 230.4 MHz possible.

Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Andrew Halaney <ahalaney@redhat.com>
Link: https://lore.kernel.org/r/20230725211853.895832-4-ahalaney@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c
index 735525b..a855018 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c
@@ -694,6 +694,23 @@ static void ethqos_clks_disable(void *data)
        ethqos_clks_config(data, false);
 }
 
+static void ethqos_ptp_clk_freq_config(struct stmmac_priv *priv)
+{
+       struct plat_stmmacenet_data *plat_dat = priv->plat;
+       int err;
+
+       if (!plat_dat->clk_ptp_ref)
+               return;
+
+       /* Max the PTP ref clock out to get the best resolution possible */
+       err = clk_set_rate(plat_dat->clk_ptp_ref, ULONG_MAX);
+       if (err)
+               netdev_err(priv->dev, "Failed to max out clk_ptp_ref: %d\n", err);
+       plat_dat->clk_ptp_rate = clk_get_rate(plat_dat->clk_ptp_ref);
+
+       netdev_dbg(priv->dev, "PTP rate %d\n", plat_dat->clk_ptp_rate);
+}
+
 static int qcom_ethqos_probe(struct platform_device *pdev)
 {
        struct device_node *np = pdev->dev.of_node;
@@ -779,6 +796,7 @@ static int qcom_ethqos_probe(struct platform_device *pdev)
        plat_dat->bsp_priv = ethqos;
        plat_dat->fix_mac_speed = ethqos_fix_mac_speed;
        plat_dat->dump_debug_regs = rgmii_dump;
+       plat_dat->ptp_clk_freq_config = ethqos_ptp_clk_freq_config;
        plat_dat->has_gmac4 = 1;
        if (ethqos->has_emac_ge_3)
                plat_dat->dwmac4_addrs = &data->dwmac4_addrs;