1 /*
2  * Cavium ThunderX i2c driver.
3  *
4  * Copyright (C) 2015,2016 Cavium Inc.
5  * Authors: Fred Martin <fmartin@caviumnetworks.com>
6  *	    Jan Glauber <jglauber@cavium.com>
7  *
8  * This file is licensed under the terms of the GNU General Public
9  * License version 2. This program is licensed "as is" without any
10  * warranty of any kind, whether express or implied.
11  */
12 
13 #include <linux/acpi.h>
14 #include <linux/clk.h>
15 #include <linux/delay.h>
16 #include <linux/i2c.h>
17 #include <linux/i2c-smbus.h>
18 #include <linux/interrupt.h>
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/of_irq.h>
22 #include <linux/pci.h>
23 
24 #include "i2c-octeon-core.h"
25 
26 #define DRV_NAME "i2c-thunderx"
27 
28 #define PCI_DEVICE_ID_THUNDER_TWSI	0xa012
29 
30 #define SYS_FREQ_DEFAULT		700000000
31 
32 #define TWSI_INT_ENA_W1C		0x1028
33 #define TWSI_INT_ENA_W1S		0x1030
34 
35 /*
36  * Enable the CORE interrupt.
37  * The interrupt will be asserted when there is non-STAT_IDLE state in the
38  * SW_TWSI_EOP_TWSI_STAT register.
39  */
thunder_i2c_int_enable(struct octeon_i2c * i2c)40 static void thunder_i2c_int_enable(struct octeon_i2c *i2c)
41 {
42 	octeon_i2c_writeq_flush(TWSI_INT_CORE_INT,
43 				i2c->twsi_base + TWSI_INT_ENA_W1S);
44 }
45 
46 /*
47  * Disable the CORE interrupt.
48  */
thunder_i2c_int_disable(struct octeon_i2c * i2c)49 static void thunder_i2c_int_disable(struct octeon_i2c *i2c)
50 {
51 	octeon_i2c_writeq_flush(TWSI_INT_CORE_INT,
52 				i2c->twsi_base + TWSI_INT_ENA_W1C);
53 }
54 
thunder_i2c_hlc_int_enable(struct octeon_i2c * i2c)55 static void thunder_i2c_hlc_int_enable(struct octeon_i2c *i2c)
56 {
57 	octeon_i2c_writeq_flush(TWSI_INT_ST_INT | TWSI_INT_TS_INT,
58 				i2c->twsi_base + TWSI_INT_ENA_W1S);
59 }
60 
thunder_i2c_hlc_int_disable(struct octeon_i2c * i2c)61 static void thunder_i2c_hlc_int_disable(struct octeon_i2c *i2c)
62 {
63 	octeon_i2c_writeq_flush(TWSI_INT_ST_INT | TWSI_INT_TS_INT,
64 				i2c->twsi_base + TWSI_INT_ENA_W1C);
65 }
66 
thunderx_i2c_functionality(struct i2c_adapter * adap)67 static u32 thunderx_i2c_functionality(struct i2c_adapter *adap)
68 {
69 	return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK) |
70 	       I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_SMBUS_BLOCK_PROC_CALL;
71 }
72 
73 static const struct i2c_algorithm thunderx_i2c_algo = {
74 	.master_xfer = octeon_i2c_xfer,
75 	.functionality = thunderx_i2c_functionality,
76 };
77 
78 static const struct i2c_adapter thunderx_i2c_ops = {
79 	.owner	= THIS_MODULE,
80 	.name	= "ThunderX adapter",
81 	.algo	= &thunderx_i2c_algo,
82 };
83 
thunder_i2c_clock_enable(struct device * dev,struct octeon_i2c * i2c)84 static void thunder_i2c_clock_enable(struct device *dev, struct octeon_i2c *i2c)
85 {
86 	int ret;
87 
88 	if (acpi_disabled) {
89 		/* DT */
90 		i2c->clk = clk_get(dev, NULL);
91 		if (IS_ERR(i2c->clk)) {
92 			i2c->clk = NULL;
93 			goto skip;
94 		}
95 
96 		ret = clk_prepare_enable(i2c->clk);
97 		if (ret)
98 			goto skip;
99 		i2c->sys_freq = clk_get_rate(i2c->clk);
100 	} else {
101 		/* ACPI */
102 		device_property_read_u32(dev, "sclk", &i2c->sys_freq);
103 	}
104 
105 skip:
106 	if (!i2c->sys_freq)
107 		i2c->sys_freq = SYS_FREQ_DEFAULT;
108 }
109 
thunder_i2c_clock_disable(struct device * dev,struct clk * clk)110 static void thunder_i2c_clock_disable(struct device *dev, struct clk *clk)
111 {
112 	if (!clk)
113 		return;
114 	clk_disable_unprepare(clk);
115 	clk_put(clk);
116 }
117 
thunder_i2c_smbus_setup_of(struct octeon_i2c * i2c,struct device_node * node)118 static int thunder_i2c_smbus_setup_of(struct octeon_i2c *i2c,
119 				      struct device_node *node)
120 {
121 	struct i2c_client *ara;
122 
123 	if (!node)
124 		return -EINVAL;
125 
126 	i2c->alert_data.irq = irq_of_parse_and_map(node, 0);
127 	if (!i2c->alert_data.irq)
128 		return -EINVAL;
129 
130 	ara = i2c_new_smbus_alert_device(&i2c->adap, &i2c->alert_data);
131 	if (IS_ERR(ara))
132 		return PTR_ERR(ara);
133 
134 	i2c->ara = ara;
135 
136 	return 0;
137 }
138 
thunder_i2c_smbus_setup(struct octeon_i2c * i2c,struct device_node * node)139 static int thunder_i2c_smbus_setup(struct octeon_i2c *i2c,
140 				   struct device_node *node)
141 {
142 	/* TODO: ACPI support */
143 	if (!acpi_disabled)
144 		return -EOPNOTSUPP;
145 
146 	return thunder_i2c_smbus_setup_of(i2c, node);
147 }
148 
thunder_i2c_smbus_remove(struct octeon_i2c * i2c)149 static void thunder_i2c_smbus_remove(struct octeon_i2c *i2c)
150 {
151 	i2c_unregister_device(i2c->ara);
152 }
153 
thunder_i2c_probe_pci(struct pci_dev * pdev,const struct pci_device_id * ent)154 static int thunder_i2c_probe_pci(struct pci_dev *pdev,
155 				 const struct pci_device_id *ent)
156 {
157 	struct device *dev = &pdev->dev;
158 	struct octeon_i2c *i2c;
159 	int ret;
160 
161 	i2c = devm_kzalloc(dev, sizeof(*i2c), GFP_KERNEL);
162 	if (!i2c)
163 		return -ENOMEM;
164 
165 	i2c->roff.sw_twsi = 0x1000;
166 	i2c->roff.twsi_int = 0x1010;
167 	i2c->roff.sw_twsi_ext = 0x1018;
168 
169 	i2c->dev = dev;
170 	pci_set_drvdata(pdev, i2c);
171 	ret = pcim_enable_device(pdev);
172 	if (ret)
173 		return ret;
174 
175 	ret = pci_request_regions(pdev, DRV_NAME);
176 	if (ret)
177 		return ret;
178 
179 	i2c->twsi_base = pcim_iomap(pdev, 0, pci_resource_len(pdev, 0));
180 	if (!i2c->twsi_base)
181 		return -EINVAL;
182 
183 	thunder_i2c_clock_enable(dev, i2c);
184 	ret = device_property_read_u32(dev, "clock-frequency", &i2c->twsi_freq);
185 	if (ret)
186 		i2c->twsi_freq = I2C_MAX_STANDARD_MODE_FREQ;
187 
188 	init_waitqueue_head(&i2c->queue);
189 
190 	i2c->int_enable = thunder_i2c_int_enable;
191 	i2c->int_disable = thunder_i2c_int_disable;
192 	i2c->hlc_int_enable = thunder_i2c_hlc_int_enable;
193 	i2c->hlc_int_disable = thunder_i2c_hlc_int_disable;
194 
195 	ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSIX);
196 	if (ret < 0)
197 		goto error;
198 
199 	ret = devm_request_irq(dev, pci_irq_vector(pdev, 0), octeon_i2c_isr, 0,
200 			       DRV_NAME, i2c);
201 	if (ret)
202 		goto error;
203 
204 	ret = octeon_i2c_init_lowlevel(i2c);
205 	if (ret)
206 		goto error;
207 
208 	octeon_i2c_set_clock(i2c);
209 
210 	i2c->adap = thunderx_i2c_ops;
211 	i2c->adap.retries = 5;
212 	i2c->adap.class = I2C_CLASS_HWMON;
213 	i2c->adap.bus_recovery_info = &octeon_i2c_recovery_info;
214 	i2c->adap.dev.parent = dev;
215 	i2c->adap.dev.of_node = pdev->dev.of_node;
216 	i2c->adap.dev.fwnode = dev->fwnode;
217 	snprintf(i2c->adap.name, sizeof(i2c->adap.name),
218 		 "Cavium ThunderX i2c adapter at %s", dev_name(dev));
219 	i2c_set_adapdata(&i2c->adap, i2c);
220 
221 	ret = i2c_add_adapter(&i2c->adap);
222 	if (ret)
223 		goto error;
224 
225 	dev_info(i2c->dev, "Probed. Set system clock to %u\n", i2c->sys_freq);
226 
227 	ret = thunder_i2c_smbus_setup(i2c, pdev->dev.of_node);
228 	if (ret)
229 		dev_info(dev, "SMBUS alert not active on this bus\n");
230 
231 	return 0;
232 
233 error:
234 	thunder_i2c_clock_disable(dev, i2c->clk);
235 	return ret;
236 }
237 
thunder_i2c_remove_pci(struct pci_dev * pdev)238 static void thunder_i2c_remove_pci(struct pci_dev *pdev)
239 {
240 	struct octeon_i2c *i2c = pci_get_drvdata(pdev);
241 
242 	thunder_i2c_smbus_remove(i2c);
243 	thunder_i2c_clock_disable(&pdev->dev, i2c->clk);
244 	i2c_del_adapter(&i2c->adap);
245 }
246 
247 static const struct pci_device_id thunder_i2c_pci_id_table[] = {
248 	{ PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, PCI_DEVICE_ID_THUNDER_TWSI) },
249 	{ 0, }
250 };
251 
252 MODULE_DEVICE_TABLE(pci, thunder_i2c_pci_id_table);
253 
254 static struct pci_driver thunder_i2c_pci_driver = {
255 	.name		= DRV_NAME,
256 	.id_table	= thunder_i2c_pci_id_table,
257 	.probe		= thunder_i2c_probe_pci,
258 	.remove		= thunder_i2c_remove_pci,
259 };
260 
261 module_pci_driver(thunder_i2c_pci_driver);
262 
263 MODULE_LICENSE("GPL");
264 MODULE_AUTHOR("Fred Martin <fmartin@caviumnetworks.com>");
265 MODULE_DESCRIPTION("I2C-Bus adapter for Cavium ThunderX SOC");
266