1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * MDIO bus driver for the Xilinx TEMAC device
4 *
5 * Copyright (c) 2009 Secret Lab Technologies, Ltd.
6 */
7
8 #include <linux/io.h>
9 #include <linux/netdevice.h>
10 #include <linux/mutex.h>
11 #include <linux/phy.h>
12 #include <linux/of.h>
13 #include <linux/of_device.h>
14 #include <linux/of_address.h>
15 #include <linux/slab.h>
16 #include <linux/of_mdio.h>
17 #include <linux/platform_data/xilinx-ll-temac.h>
18
19 #include "ll_temac.h"
20
21 /* ---------------------------------------------------------------------
22 * MDIO Bus functions
23 */
temac_mdio_read(struct mii_bus * bus,int phy_id,int reg)24 static int temac_mdio_read(struct mii_bus *bus, int phy_id, int reg)
25 {
26 struct temac_local *lp = bus->priv;
27 u32 rc;
28 unsigned long flags;
29
30 /* Write the PHY address to the MIIM Access Initiator register.
31 * When the transfer completes, the PHY register value will appear
32 * in the LSW0 register */
33 spin_lock_irqsave(lp->indirect_lock, flags);
34 temac_iow(lp, XTE_LSW0_OFFSET, (phy_id << 5) | reg);
35 rc = temac_indirect_in32_locked(lp, XTE_MIIMAI_OFFSET);
36 spin_unlock_irqrestore(lp->indirect_lock, flags);
37
38 dev_dbg(lp->dev, "temac_mdio_read(phy_id=%i, reg=%x) == %x\n",
39 phy_id, reg, rc);
40
41 return rc;
42 }
43
temac_mdio_write(struct mii_bus * bus,int phy_id,int reg,u16 val)44 static int temac_mdio_write(struct mii_bus *bus, int phy_id, int reg, u16 val)
45 {
46 struct temac_local *lp = bus->priv;
47 unsigned long flags;
48
49 dev_dbg(lp->dev, "temac_mdio_write(phy_id=%i, reg=%x, val=%x)\n",
50 phy_id, reg, val);
51
52 /* First write the desired value into the write data register
53 * and then write the address into the access initiator register
54 */
55 spin_lock_irqsave(lp->indirect_lock, flags);
56 temac_indirect_out32_locked(lp, XTE_MGTDR_OFFSET, val);
57 temac_indirect_out32_locked(lp, XTE_MIIMAI_OFFSET, (phy_id << 5) | reg);
58 spin_unlock_irqrestore(lp->indirect_lock, flags);
59
60 return 0;
61 }
62
temac_mdio_setup(struct temac_local * lp,struct platform_device * pdev)63 int temac_mdio_setup(struct temac_local *lp, struct platform_device *pdev)
64 {
65 struct ll_temac_platform_data *pdata = dev_get_platdata(&pdev->dev);
66 struct device_node *np = dev_of_node(&pdev->dev);
67 struct mii_bus *bus;
68 u32 bus_hz;
69 int clk_div;
70 int rc;
71 struct resource res;
72
73 /* Get MDIO bus frequency (if specified) */
74 bus_hz = 0;
75 if (np)
76 of_property_read_u32(np, "clock-frequency", &bus_hz);
77 else if (pdata)
78 bus_hz = pdata->mdio_clk_freq;
79
80 /* Calculate a reasonable divisor for the clock rate */
81 clk_div = 0x3f; /* worst-case default setting */
82 if (bus_hz != 0) {
83 clk_div = bus_hz / (2500 * 1000 * 2) - 1;
84 if (clk_div < 1)
85 clk_div = 1;
86 if (clk_div > 0x3f)
87 clk_div = 0x3f;
88 }
89
90 /* Enable the MDIO bus by asserting the enable bit and writing
91 * in the clock config */
92 temac_indirect_out32(lp, XTE_MC_OFFSET, 1 << 6 | clk_div);
93
94 bus = devm_mdiobus_alloc(&pdev->dev);
95 if (!bus)
96 return -ENOMEM;
97
98 if (np) {
99 of_address_to_resource(np, 0, &res);
100 snprintf(bus->id, MII_BUS_ID_SIZE, "%.8llx",
101 (unsigned long long)res.start);
102 } else if (pdata) {
103 snprintf(bus->id, MII_BUS_ID_SIZE, "%.8llx",
104 pdata->mdio_bus_id);
105 }
106
107 bus->priv = lp;
108 bus->name = "Xilinx TEMAC MDIO";
109 bus->read = temac_mdio_read;
110 bus->write = temac_mdio_write;
111 bus->parent = lp->dev;
112
113 lp->mii_bus = bus;
114
115 rc = of_mdiobus_register(bus, np);
116 if (rc)
117 return rc;
118
119 dev_dbg(lp->dev, "MDIO bus registered; MC:%x\n",
120 temac_indirect_in32(lp, XTE_MC_OFFSET));
121 return 0;
122 }
123
temac_mdio_teardown(struct temac_local * lp)124 void temac_mdio_teardown(struct temac_local *lp)
125 {
126 mdiobus_unregister(lp->mii_bus);
127 }
128