1 From 225f36695bb07dad9510f9affd79e63f1a44a195 Mon Sep 17 00:00:00 2001
2 From: John Crispin <blogic@openwrt.org>
3 Date: Sun, 27 Jul 2014 09:52:56 +0100
4 Subject: [PATCH 52/57] i2c: MIPS: adds ralink I2C driver
6 Signed-off-by: John Crispin <blogic@openwrt.org>
8 .../devicetree/bindings/i2c/i2c-ralink.txt | 27 ++
9 drivers/i2c/busses/Kconfig | 4 +
10 drivers/i2c/busses/Makefile | 1 +
11 drivers/i2c/busses/i2c-ralink.c | 274 ++++++++++++++++++++
12 4 files changed, 306 insertions(+)
13 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-ralink.txt
14 create mode 100644 drivers/i2c/busses/i2c-ralink.c
17 +++ b/Documentation/devicetree/bindings/i2c/i2c-ralink.txt
19 +I2C for Ralink platforms
21 +Required properties :
22 +- compatible : Must be "link,rt3052-i2c"
23 +- reg: physical base address of the controller and length of memory mapped
25 +- #address-cells = <1>;
29 +- Child nodes conforming to i2c bus binding
35 + compatible = "link,rt3052-i2c";
36 + reg = <0x900 0x100>;
37 + #address-cells = <1>;
41 + compatible = "national,lm92";
46 --- a/drivers/i2c/busses/Kconfig
47 +++ b/drivers/i2c/busses/Kconfig
48 @@ -711,6 +711,10 @@ config I2C_RK3X
49 This driver can also be built as a module. If so, the module will
53 + tristate "Ralink I2C Controller"
56 config HAVE_S3C2410_I2C
59 --- a/drivers/i2c/busses/Makefile
60 +++ b/drivers/i2c/busses/Makefile
61 @@ -66,6 +66,7 @@ obj-$(CONFIG_I2C_PNX) += i2c-pnx.o
62 obj-$(CONFIG_I2C_PUV3) += i2c-puv3.o
63 obj-$(CONFIG_I2C_PXA) += i2c-pxa.o
64 obj-$(CONFIG_I2C_PXA_PCI) += i2c-pxa-pci.o
65 +obj-$(CONFIG_I2C_RALINK) += i2c-ralink.o
66 obj-$(CONFIG_I2C_QUP) += i2c-qup.o
67 obj-$(CONFIG_I2C_RIIC) += i2c-riic.o
68 obj-$(CONFIG_I2C_RK3X) += i2c-rk3x.o
70 +++ b/drivers/i2c/busses/i2c-ralink.c
73 + * drivers/i2c/busses/i2c-ralink.c
75 + * Copyright (C) 2013 Steven Liu <steven_liu@mediatek.com>
77 + * Improve driver for i2cdetect from i2c-tools to detect i2c devices on the bus.
78 + * (C) 2014 Sittisak <sittisaks@hotmail.com>
80 + * This software is licensed under the terms of the GNU General Public
81 + * License version 2, as published by the Free Software Foundation, and
82 + * may be copied, distributed, and modified under those terms.
84 + * This program is distributed in the hope that it will be useful,
85 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
86 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
87 + * GNU General Public License for more details.
91 +#include <linux/interrupt.h>
92 +#include <linux/kernel.h>
93 +#include <linux/module.h>
94 +#include <linux/reset.h>
95 +#include <linux/delay.h>
96 +#include <linux/slab.h>
97 +#include <linux/init.h>
98 +#include <linux/errno.h>
99 +#include <linux/platform_device.h>
100 +#include <linux/i2c.h>
101 +#include <linux/io.h>
102 +#include <linux/err.h>
104 +#include <asm/mach-ralink/ralink_regs.h>
106 +#define REG_CONFIG_REG 0x00
107 +#define REG_CLKDIV_REG 0x04
108 +#define REG_DEVADDR_REG 0x08
109 +#define REG_ADDR_REG 0x0C
110 +#define REG_DATAOUT_REG 0x10
111 +#define REG_DATAIN_REG 0x14
112 +#define REG_STATUS_REG 0x18
113 +#define REG_STARTXFR_REG 0x1C
114 +#define REG_BYTECNT_REG 0x20
116 +#define I2C_STARTERR BIT(4)
117 +#define I2C_ACKERR BIT(3)
118 +#define I2C_DATARDY BIT(2)
119 +#define I2C_SDOEMPTY BIT(1)
120 +#define I2C_BUSY BIT(0)
122 +#define I2C_DEVADLEN_7 (6 << 2)
123 +#define I2C_ADDRDIS BIT(1)
125 +#define CLKDIV_VALUE 200 // clock rate is 40M, 40M / (200*2) = 100k (standard i2c bus rate).
126 +//#define CLKDIV_VALUE 50 // clock rate is 40M, 40M / (50*2) = 400k (fast i2c bus rate).
128 +#define READ_CMD 0x01
129 +#define WRITE_CMD 0x00
130 +#define READ_BLOCK 64
132 +/* timeout waiting for I2C devices to respond (clock streching) */
133 +#define RT_I2C_TIMEOUT (msecs_to_jiffies(1000))
135 +static void __iomem *membase;
136 +static struct i2c_adapter *adapter;
138 +static void rt_i2c_w32(u32 val, unsigned reg)
140 + iowrite32(val, membase + reg);
143 +static u32 rt_i2c_r32(unsigned reg)
145 + return ioread32(membase + reg);
148 +static inline int rt_i2c_get_ack(void)
150 + return (rt_i2c_r32(REG_STATUS_REG) & I2C_ACKERR) ? -EIO : 0;
153 +static inline int rt_i2c_wait_rx_done(void)
155 + unsigned long timeout;
157 + timeout = jiffies + RT_I2C_TIMEOUT;
160 + if (time_after(jiffies, timeout))
161 + return (-ETIMEDOUT);
163 + } while (!(rt_i2c_r32(REG_STATUS_REG) & I2C_DATARDY));
168 +static inline int rt_i2c_wait_idle(void)
170 + unsigned long timeout;
172 + timeout = jiffies + RT_I2C_TIMEOUT;
175 + if (time_after(jiffies, timeout)) {
176 + printk("i2c-read line busy\n");
179 + } while (rt_i2c_r32(REG_STATUS_REG) & I2C_BUSY);
184 +static inline int rt_i2c_wait_tx_done(void)
186 + unsigned long timeout;
188 + timeout = jiffies + RT_I2C_TIMEOUT;
191 + if (time_after(jiffies, timeout))
192 + return (-ETIMEDOUT);
194 + } while (!(rt_i2c_r32(REG_STATUS_REG) & I2C_SDOEMPTY));
199 +static int rt_i2c_handle_msg(struct i2c_adapter *a, struct i2c_msg* msg)
201 + int i = 0, j = 0, pos = 0;
202 + int nblock = msg->len / READ_BLOCK;
203 + int rem = msg->len % READ_BLOCK;
206 + if (msg->flags & I2C_M_TEN) {
207 + printk("10 bits addr not supported\n");
211 + if (msg->flags & I2C_M_RD) {
212 + for (i = 0; i < nblock; i++) {
213 + if (rt_i2c_wait_idle())
215 + rt_i2c_w32(READ_BLOCK - 1, REG_BYTECNT_REG);
216 + rt_i2c_w32(READ_CMD, REG_STARTXFR_REG);
217 + for (j = 0; j < READ_BLOCK; j++) {
218 + if (rt_i2c_wait_rx_done() < 0)
219 + ret = rt_i2c_wait_rx_done();
220 + if (rt_i2c_get_ack() < 0)
221 + ret = rt_i2c_get_ack();
222 + msg->buf[pos++] = rt_i2c_r32(REG_DATAIN_REG);
226 + if (rt_i2c_wait_idle())
229 + rt_i2c_w32(rem - 1, REG_BYTECNT_REG);
230 + rt_i2c_w32(READ_CMD, REG_STARTXFR_REG);
232 + for (i = 0; i < rem; i++) {
233 + if (rt_i2c_wait_rx_done() < 0)
234 + ret = rt_i2c_wait_rx_done();
235 + if (rt_i2c_get_ack() < 0)
236 + ret = rt_i2c_get_ack();
238 + msg->buf[pos++] = rt_i2c_r32(REG_DATAIN_REG);
241 + if (rt_i2c_wait_idle())
243 + rt_i2c_w32(msg->len - 1, REG_BYTECNT_REG);
244 + for (i = 0; i < msg->len; i++) {
245 + rt_i2c_w32(msg->buf[i], REG_DATAOUT_REG);
246 + rt_i2c_w32(WRITE_CMD, REG_STARTXFR_REG);
248 + if (rt_i2c_wait_tx_done() < 0)
249 + ret = rt_i2c_wait_tx_done();
250 + if (rt_i2c_get_ack() < 0)
251 + ret = rt_i2c_get_ack();
258 +static int rt_i2c_master_xfer(struct i2c_adapter *a, struct i2c_msg *m, int n)
263 + if (rt_i2c_wait_idle())
266 + device_reset(a->dev.parent);
268 + rt_i2c_w32(m->addr, REG_DEVADDR_REG);
269 + rt_i2c_w32(I2C_DEVADLEN_7 | I2C_ADDRDIS, REG_CONFIG_REG);
270 + rt_i2c_w32(CLKDIV_VALUE, REG_CLKDIV_REG);
272 + for (i = 0; i < n && !ret; i++) {
273 + ret = rt_i2c_handle_msg(a, &m[i]);
283 +static u32 rt_i2c_func(struct i2c_adapter *a)
285 + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
288 +static const struct i2c_algorithm rt_i2c_algo = {
289 + .master_xfer = rt_i2c_master_xfer,
290 + .functionality = rt_i2c_func,
293 +static int rt_i2c_probe(struct platform_device *pdev)
295 + struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
299 + dev_err(&pdev->dev, "no memory resource found\n");
303 + adapter = devm_kzalloc(&pdev->dev, sizeof(struct i2c_adapter), GFP_KERNEL);
305 + dev_err(&pdev->dev, "failed to allocate i2c_adapter\n");
309 + membase = devm_ioremap_resource(&pdev->dev, res);
310 + if (IS_ERR(membase))
311 + return PTR_ERR(membase);
313 + strlcpy(adapter->name, dev_name(&pdev->dev), sizeof(adapter->name));
314 + adapter->owner = THIS_MODULE;
315 + adapter->nr = pdev->id;
316 + adapter->timeout = HZ;
317 + adapter->algo = &rt_i2c_algo;
318 + adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
319 + adapter->dev.parent = &pdev->dev;
320 + adapter->dev.of_node = pdev->dev.of_node;
322 + ret = i2c_add_numbered_adapter(adapter);
326 + platform_set_drvdata(pdev, adapter);
328 + dev_info(&pdev->dev, "loaded\n");
333 +static int rt_i2c_remove(struct platform_device *pdev)
335 + platform_set_drvdata(pdev, NULL);
340 +static const struct of_device_id i2c_rt_dt_ids[] = {
341 + { .compatible = "ralink,rt2880-i2c", },
345 +MODULE_DEVICE_TABLE(of, i2c_rt_dt_ids);
347 +static struct platform_driver rt_i2c_driver = {
348 + .probe = rt_i2c_probe,
349 + .remove = rt_i2c_remove,
351 + .owner = THIS_MODULE,
352 + .name = "i2c-ralink",
353 + .of_match_table = i2c_rt_dt_ids,
357 +static int __init i2c_rt_init (void)
359 + return platform_driver_register(&rt_i2c_driver);
361 +subsys_initcall(i2c_rt_init);
363 +static void __exit i2c_rt_exit (void)
365 + platform_driver_unregister(&rt_i2c_driver);
368 +module_exit (i2c_rt_exit);
370 +MODULE_AUTHOR("Steven Liu <steven_liu@mediatek.com>");
371 +MODULE_DESCRIPTION("Ralink I2c host driver");
372 +MODULE_LICENSE("GPL");
373 +MODULE_ALIAS("platform:Ralink-I2C");