stmmac: ptp: fix the reference clock
The PTP reference clock, used for setting the addend in the Timestamp Addend
Register, was erroneously hard-coded (as reported in the databook just as
example).
The patch removes the macro named: STMMAC_SYSCLOCK and allows to use a
reference clock (clk_ptp_ref_i) that can be passed from the platform.
If not passed, the main driver clock will be used as default; note that
this can be fine on some platforms.
Note that, prior this patch, using the old STMMAC_SYSCLOCK on some platforms,
as side effect, the ptp clock can move faster/slower than the system clock.
Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 51a89d4..0365289 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -603,16 +603,16 @@
/* calculate default added value:
* formula is :
* addend = (2^32)/freq_div_ratio;
- * where, freq_div_ratio = STMMAC_SYSCLOCK/50MHz
- * hence, addend = ((2^32) * 50MHz)/STMMAC_SYSCLOCK;
- * NOTE: STMMAC_SYSCLOCK should be >= 50MHz to
+ * where, freq_div_ratio = clk_ptp_ref_i/50MHz
+ * hence, addend = ((2^32) * 50MHz)/clk_ptp_ref_i;
+ * NOTE: clk_ptp_ref_i should be >= 50MHz to
* achive 20ns accuracy.
*
* 2^x * y == (y << x), hence
* 2^32 * 50000000 ==> (50000000 << 32)
*/
temp = (u64) (50000000ULL << 32);
- priv->default_addend = div_u64(temp, STMMAC_SYSCLOCK);
+ priv->default_addend = div_u64(temp, priv->clk_ptp_rate);
priv->hw->ptp->config_addend(priv->ioaddr,
priv->default_addend);
@@ -638,6 +638,16 @@
if (!(priv->dma_cap.time_stamp || priv->dma_cap.atime_stamp))
return -EOPNOTSUPP;
+ /* Fall-back to main clock in case of no PTP ref is passed */
+ priv->clk_ptp_ref = devm_clk_get(priv->device, "clk_ptp_ref");
+ if (IS_ERR(priv->clk_ptp_ref)) {
+ priv->clk_ptp_rate = clk_get_rate(priv->stmmac_clk);
+ priv->clk_ptp_ref = NULL;
+ } else {
+ clk_prepare_enable(priv->clk_ptp_ref);
+ priv->clk_ptp_rate = clk_get_rate(priv->clk_ptp_ref);
+ }
+
priv->adv_ts = 0;
if (priv->dma_cap.atime_stamp && priv->extend_desc)
priv->adv_ts = 1;
@@ -657,6 +667,8 @@
static void stmmac_release_ptp(struct stmmac_priv *priv)
{
+ if (priv->clk_ptp_ref)
+ clk_disable_unprepare(priv->clk_ptp_ref);
stmmac_ptp_unregister(priv);
}