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 */
 40static 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 */
 49static 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
 55static 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
 61static 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
 67static 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
 73static const struct i2c_algorithm thunderx_i2c_algo = {
 74	.master_xfer = octeon_i2c_xfer,
 75	.functionality = thunderx_i2c_functionality,
 76};
 77
 78static const struct i2c_adapter thunderx_i2c_ops = {
 79	.owner	= THIS_MODULE,
 80	.name	= "ThunderX adapter",
 81	.algo	= &thunderx_i2c_algo,
 82};
 83
 84static 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
105skip:
106	if (!i2c->sys_freq)
107		i2c->sys_freq = SYS_FREQ_DEFAULT;
108}
109
110static 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
118static 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
139static 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
149static void thunder_i2c_smbus_remove(struct octeon_i2c *i2c)
150{
151	i2c_unregister_device(i2c->ara);
152}
153
154static 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
233error:
234	thunder_i2c_clock_disable(dev, i2c->clk);
235	return ret;
236}
237
238static 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
247static 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
252MODULE_DEVICE_TABLE(pci, thunder_i2c_pci_id_table);
253
254static 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
261module_pci_driver(thunder_i2c_pci_driver);
262
263MODULE_LICENSE("GPL");
264MODULE_AUTHOR("Fred Martin <fmartin@caviumnetworks.com>");
265MODULE_DESCRIPTION("I2C-Bus adapter for Cavium ThunderX SOC");