cpts: specify the input clock frequency via DT

This patch adds a way to configure the CPTS input clock scaling factors
via the device tree.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 22 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/net/cpsw.txt b/Documentation/devicetree/bindings/net/cpsw.txt
index 9f61f2b51681..221460714c56 100644
--- a/Documentation/devicetree/bindings/net/cpsw.txt
+++ b/Documentation/devicetree/bindings/net/cpsw.txt
@@ -24,6 +24,8 @@ Required properties:
                           for the specific platform
 - slaves                : Specifies number for slaves
 - cpts_active_slave     : Specifies the slave to use for time stamping
+- cpts_clock_mult       : Numerator to convert input clock ticks into nanoseconds
+- cpts_clock_shift      : Denominator to convert input clock ticks into nanoseconds
 - slave_reg_ofs         : Specifies slave register offset
 - sliver_reg_ofs        : Specifies slave sliver register offset
 - phy_id                : Specifies slave phy id
@@ -62,6 +64,8 @@ Examples:
                 mac_control = <0x20>;
                 slaves = <2>;
                 cpts_active_slave = <0>;
+                cpts_clock_mult = <0x80000000>;
+                cpts_clock_shift = <29>;
                 cpsw_emac0: slave@0 {
                         slave_reg_ofs = <0x200>;
                         sliver_reg_ofs = <0xd80>;
@@ -98,6 +102,8 @@ Examples:
                 mac_control = <0x20>;
                 slaves = <2>;
                 cpts_active_slave = <0>;
+                cpts_clock_mult = <0x80000000>;
+                cpts_clock_shift = <29>;
                 cpsw_emac0: slave@0 {
                         slave_reg_ofs = <0x200>;
                         sliver_reg_ofs = <0xd80>;
diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
index f16579123c1b..c04627cd60dd 100644
--- a/drivers/net/ethernet/ti/cpsw.c
+++ b/drivers/net/ethernet/ti/cpsw.c
@@ -854,6 +854,20 @@ static int cpsw_probe_dt(struct cpsw_platform_data *data,
         }
         data->cpts_active_slave = prop;
 
+        if (of_property_read_u32(node, "cpts_clock_mult", &prop)) {
+                pr_err("Missing cpts_clock_mult property in the DT.\n");
+                ret = -EINVAL;
+                goto error_ret;
+        }
+        data->cpts_clock_mult = prop;
+
+        if (of_property_read_u32(node, "cpts_clock_shift", &prop)) {
+                pr_err("Missing cpts_clock_shift property in the DT.\n");
+                ret = -EINVAL;
+                goto error_ret;
+        }
+        data->cpts_clock_shift = prop;
+
         data->slave_data = kzalloc(sizeof(struct cpsw_slave_data) *
                                    data->slaves, GFP_KERNEL);
         if (!data->slave_data) {
diff --git a/include/linux/platform_data/cpsw.h b/include/linux/platform_data/cpsw.h
index 15a077eb0689..b5c16c3df458 100644
--- a/include/linux/platform_data/cpsw.h
+++ b/include/linux/platform_data/cpsw.h
@@ -34,6 +34,8 @@ struct cpsw_platform_data {
         u32     slaves;         /* number of slave cpgmac ports */
         struct cpsw_slave_data  *slave_data;
         u32     cpts_active_slave; /* time stamping slave */
+        u32     cpts_clock_mult;  /* convert input clock ticks to nanoseconds */
+        u32     cpts_clock_shift; /* convert input clock ticks to nanoseconds */
 
         u32     ale_reg_ofs;    /* address lookup engine reg offset */
         u32     ale_entries;    /* ale table size */