net: ethernet: ti: cpts: fix ethtool output when no ptp_clock registered

[ Upstream commit 4614792eebcbf81c60ad3604c1aeeb2b0899cea4 ]

The CPTS driver registers PTP PHC clock when first netif is going up and
unregister it when all netif are down. Now ethtool will show:
 - PTP PHC clock index 0 after boot until first netif is up;
 - the last assigned PTP PHC clock index even if PTP PHC clock is not
registered any more after all netifs are down.

This patch ensures that -1 is returned by ethtool when PTP PHC clock is not
registered any more.

Fixes: 8a2c9a5ab4b9 ("net: ethernet: ti: cpts: rework initialization/deinitialization")
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Link: https://lore.kernel.org/r/20201224162405.28032-1-grygorii.strashko@ti.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/ti/cpts.c b/drivers/net/ethernet/ti/cpts.c
index d7543811dfae2dfe528ba6f7f25394cde10b88e7..10b301e7908647d3484b201d4e91fa1140bf0525 100644 (file)
--- a/drivers/net/ethernet/ti/cpts.c
+++ b/drivers/net/ethernet/ti/cpts.c
@@ -476,6 +476,7 @@ void cpts_unregister(struct cpts *cpts)
 
        ptp_clock_unregister(cpts->clock);
        cpts->clock = NULL;
+       cpts->phc_index = -1;
 
        cpts_write32(cpts, 0, int_enable);
        cpts_write32(cpts, 0, control);
@@ -577,6 +578,7 @@ struct cpts *cpts_create(struct device *dev, void __iomem *regs,
        cpts->cc.read = cpts_systim_read;
        cpts->cc.mask = CLOCKSOURCE_MASK(32);
        cpts->info = cpts_info;
+       cpts->phc_index = -1;
 
        cpts_calc_mult_shift(cpts);
        /* save cc.mult original value as it can be modified