]>
Commit | Line | Data |
---|---|---|
a5fd9139 SH |
1 | /* |
2 | * Copyright 2005-2008 Freescale Semiconductor, Inc. All Rights Reserved. | |
3 | * Copyright 2008 Luotao Fu, kernel@pengutronix.de | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or | |
6 | * modify it under the terms of the GNU General Public License | |
7 | * as published by the Free Software Foundation; either version 2 | |
8 | * of the License, or (at your option) any later version. | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, write to the Free Software | |
16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. | |
17 | * | |
18 | */ | |
19 | ||
20 | #include <linux/module.h> | |
21 | #include <linux/interrupt.h> | |
22 | #include <linux/platform_device.h> | |
23 | #include <linux/clk.h> | |
5a0e3ad6 | 24 | #include <linux/slab.h> |
a5fd9139 SH |
25 | #include <linux/delay.h> |
26 | #include <linux/io.h> | |
27 | ||
28 | #include "../w1.h" | |
29 | #include "../w1_int.h" | |
30 | #include "../w1_log.h" | |
31 | ||
32 | /* According to the mx27 Datasheet the reset procedure should take up to about | |
33 | * 1350us. We set the timeout to 500*100us = 50ms for sure */ | |
34 | #define MXC_W1_RESET_TIMEOUT 500 | |
35 | ||
36 | /* | |
37 | * MXC W1 Register offsets | |
38 | */ | |
39 | #define MXC_W1_CONTROL 0x00 | |
40 | #define MXC_W1_TIME_DIVIDER 0x02 | |
41 | #define MXC_W1_RESET 0x04 | |
42 | #define MXC_W1_COMMAND 0x06 | |
43 | #define MXC_W1_TXRX 0x08 | |
44 | #define MXC_W1_INTERRUPT 0x0A | |
45 | #define MXC_W1_INTERRUPT_EN 0x0C | |
46 | ||
47 | struct mxc_w1_device { | |
48 | void __iomem *regs; | |
49 | unsigned int clkdiv; | |
50 | struct clk *clk; | |
51 | struct w1_bus_master bus_master; | |
52 | }; | |
53 | ||
54 | /* | |
55 | * this is the low level routine to | |
56 | * reset the device on the One Wire interface | |
57 | * on the hardware | |
58 | */ | |
59 | static u8 mxc_w1_ds2_reset_bus(void *data) | |
60 | { | |
61 | u8 reg_val; | |
62 | unsigned int timeout_cnt = 0; | |
63 | struct mxc_w1_device *dev = data; | |
64 | ||
65 | __raw_writeb(0x80, (dev->regs + MXC_W1_CONTROL)); | |
66 | ||
67 | while (1) { | |
68 | reg_val = __raw_readb(dev->regs + MXC_W1_CONTROL); | |
69 | ||
70 | if (((reg_val >> 7) & 0x1) == 0 || | |
71 | timeout_cnt > MXC_W1_RESET_TIMEOUT) | |
72 | break; | |
73 | else | |
74 | timeout_cnt++; | |
75 | ||
76 | udelay(100); | |
77 | } | |
78 | return (reg_val >> 7) & 0x1; | |
79 | } | |
80 | ||
81 | /* | |
82 | * this is the low level routine to read/write a bit on the One Wire | |
83 | * interface on the hardware. It does write 0 if parameter bit is set | |
84 | * to 0, otherwise a write 1/read. | |
85 | */ | |
86 | static u8 mxc_w1_ds2_touch_bit(void *data, u8 bit) | |
87 | { | |
88 | struct mxc_w1_device *mdev = data; | |
89 | void __iomem *ctrl_addr = mdev->regs + MXC_W1_CONTROL; | |
90 | unsigned int timeout_cnt = 400; /* Takes max. 120us according to | |
91 | * datasheet. | |
92 | */ | |
93 | ||
94 | __raw_writeb((1 << (5 - bit)), ctrl_addr); | |
95 | ||
96 | while (timeout_cnt--) { | |
97 | if (!((__raw_readb(ctrl_addr) >> (5 - bit)) & 0x1)) | |
98 | break; | |
99 | ||
100 | udelay(1); | |
101 | } | |
102 | ||
103 | return ((__raw_readb(ctrl_addr)) >> 3) & 0x1; | |
104 | } | |
105 | ||
582ef52a | 106 | static int __devinit mxc_w1_probe(struct platform_device *pdev) |
a5fd9139 SH |
107 | { |
108 | struct mxc_w1_device *mdev; | |
109 | struct resource *res; | |
110 | int err = 0; | |
111 | ||
112 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
113 | if (!res) | |
114 | return -ENODEV; | |
115 | ||
116 | mdev = kzalloc(sizeof(struct mxc_w1_device), GFP_KERNEL); | |
117 | if (!mdev) | |
118 | return -ENOMEM; | |
119 | ||
e65fb009 | 120 | mdev->clk = clk_get(&pdev->dev, "owire"); |
a5fd9139 SH |
121 | if (!mdev->clk) { |
122 | err = -ENODEV; | |
123 | goto failed_clk; | |
124 | } | |
125 | ||
126 | mdev->clkdiv = (clk_get_rate(mdev->clk) / 1000000) - 1; | |
127 | ||
128 | res = request_mem_region(res->start, resource_size(res), | |
129 | "mxc_w1"); | |
130 | if (!res) { | |
131 | err = -EBUSY; | |
132 | goto failed_req; | |
133 | } | |
134 | ||
135 | mdev->regs = ioremap(res->start, resource_size(res)); | |
136 | if (!mdev->regs) { | |
137 | printk(KERN_ERR "Cannot map frame buffer registers\n"); | |
138 | goto failed_ioremap; | |
139 | } | |
140 | ||
141 | clk_enable(mdev->clk); | |
142 | __raw_writeb(mdev->clkdiv, mdev->regs + MXC_W1_TIME_DIVIDER); | |
143 | ||
144 | mdev->bus_master.data = mdev; | |
145 | mdev->bus_master.reset_bus = mxc_w1_ds2_reset_bus; | |
146 | mdev->bus_master.touch_bit = mxc_w1_ds2_touch_bit; | |
147 | ||
148 | err = w1_add_master_device(&mdev->bus_master); | |
149 | ||
150 | if (err) | |
151 | goto failed_add; | |
152 | ||
153 | platform_set_drvdata(pdev, mdev); | |
154 | return 0; | |
155 | ||
156 | failed_add: | |
157 | iounmap(mdev->regs); | |
158 | failed_ioremap: | |
159 | release_mem_region(res->start, resource_size(res)); | |
160 | failed_req: | |
161 | clk_put(mdev->clk); | |
162 | failed_clk: | |
163 | kfree(mdev); | |
164 | return err; | |
165 | } | |
166 | ||
167 | /* | |
168 | * disassociate the w1 device from the driver | |
169 | */ | |
582ef52a | 170 | static int __devexit mxc_w1_remove(struct platform_device *pdev) |
a5fd9139 SH |
171 | { |
172 | struct mxc_w1_device *mdev = platform_get_drvdata(pdev); | |
173 | struct resource *res; | |
174 | ||
175 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
176 | ||
177 | w1_remove_master_device(&mdev->bus_master); | |
178 | ||
179 | iounmap(mdev->regs); | |
180 | release_mem_region(res->start, resource_size(res)); | |
181 | clk_disable(mdev->clk); | |
182 | clk_put(mdev->clk); | |
183 | ||
184 | platform_set_drvdata(pdev, NULL); | |
185 | ||
186 | return 0; | |
187 | } | |
188 | ||
189 | static struct platform_driver mxc_w1_driver = { | |
190 | .driver = { | |
191 | .name = "mxc_w1", | |
192 | }, | |
193 | .probe = mxc_w1_probe, | |
194 | .remove = mxc_w1_remove, | |
195 | }; | |
196 | ||
197 | static int __init mxc_w1_init(void) | |
198 | { | |
199 | return platform_driver_register(&mxc_w1_driver); | |
200 | } | |
201 | ||
202 | static void mxc_w1_exit(void) | |
203 | { | |
204 | platform_driver_unregister(&mxc_w1_driver); | |
205 | } | |
206 | ||
207 | module_init(mxc_w1_init); | |
208 | module_exit(mxc_w1_exit); | |
209 | ||
210 | MODULE_LICENSE("GPL"); | |
211 | MODULE_AUTHOR("Freescale Semiconductors Inc"); | |
212 | MODULE_DESCRIPTION("Driver for One-Wire on MXC"); |