1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2014-2017, The Linux Foundation. All rights reserved.
4 * Copyright (c) 2019, Linaro Ltd.
5 */
6
7 #include <linux/clk-provider.h>
8 #include <linux/clk.h>
9 #include <linux/iopoll.h>
10 #include <linux/module.h>
11 #include <linux/phy/phy.h>
12 #include <linux/platform_device.h>
13 #include <linux/reset.h>
14 #include <linux/slab.h>
15
16 #include <dt-bindings/phy/phy.h>
17
18 #define PCIE20_PARF_PHY_STTS 0x3c
19 #define PCIE2_PHY_RESET_CTRL 0x44
20 #define PCIE20_PARF_PHY_REFCLK_CTRL2 0xa0
21 #define PCIE20_PARF_PHY_REFCLK_CTRL3 0xa4
22 #define PCIE20_PARF_PCS_SWING_CTRL1 0x88
23 #define PCIE20_PARF_PCS_SWING_CTRL2 0x8c
24 #define PCIE20_PARF_PCS_DEEMPH1 0x74
25 #define PCIE20_PARF_PCS_DEEMPH2 0x78
26 #define PCIE20_PARF_PCS_DEEMPH3 0x7c
27 #define PCIE20_PARF_CONFIGBITS 0x84
28 #define PCIE20_PARF_PHY_CTRL3 0x94
29 #define PCIE20_PARF_PCS_CTRL 0x80
30
31 #define TX_AMP_VAL 120
32 #define PHY_RX0_EQ_GEN1_VAL 0
33 #define PHY_RX0_EQ_GEN2_VAL 4
34 #define TX_DEEMPH_GEN1_VAL 24
35 #define TX_DEEMPH_GEN2_3_5DB_VAL 26
36 #define TX_DEEMPH_GEN2_6DB_VAL 36
37 #define PHY_TX0_TERM_OFFST_VAL 0
38
39 struct qcom_phy {
40 struct device *dev;
41 void __iomem *base;
42
43 struct regulator_bulk_data vregs[2];
44
45 struct reset_control *phy_reset;
46 struct reset_control *pipe_reset;
47 struct clk *pipe_clk;
48 };
49
qcom_pcie2_phy_init(struct phy * phy)50 static int qcom_pcie2_phy_init(struct phy *phy)
51 {
52 struct qcom_phy *qphy = phy_get_drvdata(phy);
53 int ret;
54
55 ret = reset_control_deassert(qphy->phy_reset);
56 if (ret) {
57 dev_err(qphy->dev, "cannot deassert pipe reset\n");
58 return ret;
59 }
60
61 ret = regulator_bulk_enable(ARRAY_SIZE(qphy->vregs), qphy->vregs);
62 if (ret)
63 reset_control_assert(qphy->phy_reset);
64
65 return ret;
66 }
67
qcom_pcie2_phy_power_on(struct phy * phy)68 static int qcom_pcie2_phy_power_on(struct phy *phy)
69 {
70 struct qcom_phy *qphy = phy_get_drvdata(phy);
71 int ret;
72 u32 val;
73
74 /* Program REF_CLK source */
75 val = readl(qphy->base + PCIE20_PARF_PHY_REFCLK_CTRL2);
76 val &= ~BIT(1);
77 writel(val, qphy->base + PCIE20_PARF_PHY_REFCLK_CTRL2);
78
79 usleep_range(1000, 2000);
80
81 /* Don't use PAD for refclock */
82 val = readl(qphy->base + PCIE20_PARF_PHY_REFCLK_CTRL2);
83 val &= ~BIT(0);
84 writel(val, qphy->base + PCIE20_PARF_PHY_REFCLK_CTRL2);
85
86 /* Program SSP ENABLE */
87 val = readl(qphy->base + PCIE20_PARF_PHY_REFCLK_CTRL3);
88 val |= BIT(0);
89 writel(val, qphy->base + PCIE20_PARF_PHY_REFCLK_CTRL3);
90
91 usleep_range(1000, 2000);
92
93 /* Assert Phy SW Reset */
94 val = readl(qphy->base + PCIE2_PHY_RESET_CTRL);
95 val |= BIT(0);
96 writel(val, qphy->base + PCIE2_PHY_RESET_CTRL);
97
98 /* Program Tx Amplitude */
99 val = readl(qphy->base + PCIE20_PARF_PCS_SWING_CTRL1);
100 val &= ~0x7f;
101 val |= TX_AMP_VAL;
102 writel(val, qphy->base + PCIE20_PARF_PCS_SWING_CTRL1);
103
104 val = readl(qphy->base + PCIE20_PARF_PCS_SWING_CTRL2);
105 val &= ~0x7f;
106 val |= TX_AMP_VAL;
107 writel(val, qphy->base + PCIE20_PARF_PCS_SWING_CTRL2);
108
109 /* Program De-Emphasis */
110 val = readl(qphy->base + PCIE20_PARF_PCS_DEEMPH1);
111 val &= ~0x3f;
112 val |= TX_DEEMPH_GEN2_6DB_VAL;
113 writel(val, qphy->base + PCIE20_PARF_PCS_DEEMPH1);
114
115 val = readl(qphy->base + PCIE20_PARF_PCS_DEEMPH2);
116 val &= ~0x3f;
117 val |= TX_DEEMPH_GEN2_3_5DB_VAL;
118 writel(val, qphy->base + PCIE20_PARF_PCS_DEEMPH2);
119
120 val = readl(qphy->base + PCIE20_PARF_PCS_DEEMPH3);
121 val &= ~0x3f;
122 val |= TX_DEEMPH_GEN1_VAL;
123 writel(val, qphy->base + PCIE20_PARF_PCS_DEEMPH3);
124
125 /* Program Rx_Eq */
126 val = readl(qphy->base + PCIE20_PARF_CONFIGBITS);
127 val &= ~0x7;
128 val |= PHY_RX0_EQ_GEN2_VAL;
129 writel(val, qphy->base + PCIE20_PARF_CONFIGBITS);
130
131 /* Program Tx0_term_offset */
132 val = readl(qphy->base + PCIE20_PARF_PHY_CTRL3);
133 val &= ~0x1f;
134 val |= PHY_TX0_TERM_OFFST_VAL;
135 writel(val, qphy->base + PCIE20_PARF_PHY_CTRL3);
136
137 /* disable Tx2Rx Loopback */
138 val = readl(qphy->base + PCIE20_PARF_PCS_CTRL);
139 val &= ~BIT(1);
140 writel(val, qphy->base + PCIE20_PARF_PCS_CTRL);
141
142 /* De-assert Phy SW Reset */
143 val = readl(qphy->base + PCIE2_PHY_RESET_CTRL);
144 val &= ~BIT(0);
145 writel(val, qphy->base + PCIE2_PHY_RESET_CTRL);
146
147 usleep_range(1000, 2000);
148
149 ret = reset_control_deassert(qphy->pipe_reset);
150 if (ret) {
151 dev_err(qphy->dev, "cannot deassert pipe reset\n");
152 goto out;
153 }
154
155 clk_set_rate(qphy->pipe_clk, 250000000);
156
157 ret = clk_prepare_enable(qphy->pipe_clk);
158 if (ret) {
159 dev_err(qphy->dev, "failed to enable pipe clock\n");
160 goto out;
161 }
162
163 ret = readl_poll_timeout(qphy->base + PCIE20_PARF_PHY_STTS, val,
164 !(val & BIT(0)), 1000, 10);
165 if (ret)
166 dev_err(qphy->dev, "phy initialization failed\n");
167
168 out:
169 return ret;
170 }
171
qcom_pcie2_phy_power_off(struct phy * phy)172 static int qcom_pcie2_phy_power_off(struct phy *phy)
173 {
174 struct qcom_phy *qphy = phy_get_drvdata(phy);
175 u32 val;
176
177 val = readl(qphy->base + PCIE2_PHY_RESET_CTRL);
178 val |= BIT(0);
179 writel(val, qphy->base + PCIE2_PHY_RESET_CTRL);
180
181 clk_disable_unprepare(qphy->pipe_clk);
182 reset_control_assert(qphy->pipe_reset);
183
184 return 0;
185 }
186
qcom_pcie2_phy_exit(struct phy * phy)187 static int qcom_pcie2_phy_exit(struct phy *phy)
188 {
189 struct qcom_phy *qphy = phy_get_drvdata(phy);
190
191 regulator_bulk_disable(ARRAY_SIZE(qphy->vregs), qphy->vregs);
192 reset_control_assert(qphy->phy_reset);
193
194 return 0;
195 }
196
197 static const struct phy_ops qcom_pcie2_ops = {
198 .init = qcom_pcie2_phy_init,
199 .power_on = qcom_pcie2_phy_power_on,
200 .power_off = qcom_pcie2_phy_power_off,
201 .exit = qcom_pcie2_phy_exit,
202 .owner = THIS_MODULE,
203 };
204
205 /*
206 * Register a fixed rate pipe clock.
207 *
208 * The <s>_pipe_clksrc generated by PHY goes to the GCC that gate
209 * controls it. The <s>_pipe_clk coming out of the GCC is requested
210 * by the PHY driver for its operations.
211 * We register the <s>_pipe_clksrc here. The gcc driver takes care
212 * of assigning this <s>_pipe_clksrc as parent to <s>_pipe_clk.
213 * Below picture shows this relationship.
214 *
215 * +---------------+
216 * | PHY block |<<---------------------------------------+
217 * | | |
218 * | +-------+ | +-----+ |
219 * I/P---^-->| PLL |---^--->pipe_clksrc--->| GCC |--->pipe_clk---+
220 * clk | +-------+ | +-----+
221 * +---------------+
222 */
phy_pipe_clksrc_register(struct qcom_phy * qphy)223 static int phy_pipe_clksrc_register(struct qcom_phy *qphy)
224 {
225 struct device_node *np = qphy->dev->of_node;
226 struct clk_fixed_rate *fixed;
227 struct clk_init_data init = { };
228 int ret;
229
230 ret = of_property_read_string(np, "clock-output-names", &init.name);
231 if (ret) {
232 dev_err(qphy->dev, "%s: No clock-output-names\n", np->name);
233 return ret;
234 }
235
236 fixed = devm_kzalloc(qphy->dev, sizeof(*fixed), GFP_KERNEL);
237 if (!fixed)
238 return -ENOMEM;
239
240 init.ops = &clk_fixed_rate_ops;
241
242 /* controllers using QMP phys use 250MHz pipe clock interface */
243 fixed->fixed_rate = 250000000;
244 fixed->hw.init = &init;
245
246 ret = devm_clk_hw_register(qphy->dev, &fixed->hw);
247 if (ret < 0)
248 return ret;
249
250 return devm_of_clk_add_hw_provider(qphy->dev, of_clk_hw_simple_get, &fixed->hw);
251 }
252
qcom_pcie2_phy_probe(struct platform_device * pdev)253 static int qcom_pcie2_phy_probe(struct platform_device *pdev)
254 {
255 struct phy_provider *phy_provider;
256 struct qcom_phy *qphy;
257 struct device *dev = &pdev->dev;
258 struct phy *phy;
259 int ret;
260
261 qphy = devm_kzalloc(dev, sizeof(*qphy), GFP_KERNEL);
262 if (!qphy)
263 return -ENOMEM;
264
265 qphy->dev = dev;
266 qphy->base = devm_platform_ioremap_resource(pdev, 0);
267 if (IS_ERR(qphy->base))
268 return PTR_ERR(qphy->base);
269
270 ret = phy_pipe_clksrc_register(qphy);
271 if (ret) {
272 dev_err(dev, "failed to register pipe_clk\n");
273 return ret;
274 }
275
276 qphy->vregs[0].supply = "vdda-vp";
277 qphy->vregs[1].supply = "vdda-vph";
278 ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(qphy->vregs), qphy->vregs);
279 if (ret < 0)
280 return ret;
281
282 qphy->pipe_clk = devm_clk_get(dev, NULL);
283 if (IS_ERR(qphy->pipe_clk)) {
284 dev_err(dev, "failed to acquire pipe clock\n");
285 return PTR_ERR(qphy->pipe_clk);
286 }
287
288 qphy->phy_reset = devm_reset_control_get_exclusive(dev, "phy");
289 if (IS_ERR(qphy->phy_reset)) {
290 dev_err(dev, "failed to acquire phy reset\n");
291 return PTR_ERR(qphy->phy_reset);
292 }
293
294 qphy->pipe_reset = devm_reset_control_get_exclusive(dev, "pipe");
295 if (IS_ERR(qphy->pipe_reset)) {
296 dev_err(dev, "failed to acquire pipe reset\n");
297 return PTR_ERR(qphy->pipe_reset);
298 }
299
300 phy = devm_phy_create(dev, dev->of_node, &qcom_pcie2_ops);
301 if (IS_ERR(phy)) {
302 dev_err(dev, "failed to create phy\n");
303 return PTR_ERR(phy);
304 }
305
306 phy_set_drvdata(phy, qphy);
307
308 phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
309 if (IS_ERR(phy_provider))
310 dev_err(dev, "failed to register phy provider\n");
311
312 return PTR_ERR_OR_ZERO(phy_provider);
313 }
314
315 static const struct of_device_id qcom_pcie2_phy_match_table[] = {
316 { .compatible = "qcom,pcie2-phy" },
317 {}
318 };
319 MODULE_DEVICE_TABLE(of, qcom_pcie2_phy_match_table);
320
321 static struct platform_driver qcom_pcie2_phy_driver = {
322 .probe = qcom_pcie2_phy_probe,
323 .driver = {
324 .name = "phy-qcom-pcie2",
325 .of_match_table = qcom_pcie2_phy_match_table,
326 },
327 };
328
329 module_platform_driver(qcom_pcie2_phy_driver);
330
331 MODULE_DESCRIPTION("Qualcomm PCIe PHY driver");
332 MODULE_LICENSE("GPL v2");
333