1 /*
2 * Generic PMC MSP71xx GPIO handling. These base gpio are controlled by two
3 * types of registers. The data register sets the output level when in output
4 * mode and when in input mode will contain the value at the input. The config
5 * register sets the various modes for each gpio.
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * @author Patrick Glass <patrickglass@gmail.com>
12 */
13
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/gpio.h>
18 #include <linux/spinlock.h>
19 #include <linux/io.h>
20
21 #define MSP71XX_CFG_OFFSET(gpio) (4 * (gpio))
22 #define CONF_MASK 0x0F
23 #define MSP71XX_GPIO_INPUT 0x01
24 #define MSP71XX_GPIO_OUTPUT 0x08
25
26 #define MSP71XX_GPIO_BASE 0x0B8400000L
27
28 #define to_msp71xx_gpio_chip(c) container_of(c, struct msp71xx_gpio_chip, chip)
29
30 static spinlock_t gpio_lock;
31
32 /*
33 * struct msp71xx_gpio_chip - container for gpio chip and registers
34 * @chip: chip structure for the specified gpio bank
35 * @data_reg: register for reading and writing the gpio pin value
36 * @config_reg: register to set the mode for the gpio pin bank
37 * @out_drive_reg: register to set the output drive mode for the gpio pin bank
38 */
39 struct msp71xx_gpio_chip {
40 struct gpio_chip chip;
41 void __iomem *data_reg;
42 void __iomem *config_reg;
43 void __iomem *out_drive_reg;
44 };
45
46 /*
47 * msp71xx_gpio_get() - return the chip's gpio value
48 * @chip: chip structure which controls the specified gpio
49 * @offset: gpio whose value will be returned
50 *
51 * It will return 0 if gpio value is low and other if high.
52 */
msp71xx_gpio_get(struct gpio_chip * chip,unsigned offset)53 static int msp71xx_gpio_get(struct gpio_chip *chip, unsigned offset)
54 {
55 struct msp71xx_gpio_chip *msp_chip = to_msp71xx_gpio_chip(chip);
56
57 return __raw_readl(msp_chip->data_reg) & (1 << offset);
58 }
59
60 /*
61 * msp71xx_gpio_set() - set the output value for the gpio
62 * @chip: chip structure who controls the specified gpio
63 * @offset: gpio whose value will be assigned
64 * @value: logic level to assign to the gpio initially
65 *
66 * This will set the gpio bit specified to the desired value. It will set the
67 * gpio pin low if value is 0 otherwise it will be high.
68 */
msp71xx_gpio_set(struct gpio_chip * chip,unsigned offset,int value)69 static void msp71xx_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
70 {
71 struct msp71xx_gpio_chip *msp_chip = to_msp71xx_gpio_chip(chip);
72 unsigned long flags;
73 u32 data;
74
75 spin_lock_irqsave(&gpio_lock, flags);
76
77 data = __raw_readl(msp_chip->data_reg);
78 if (value)
79 data |= (1 << offset);
80 else
81 data &= ~(1 << offset);
82 __raw_writel(data, msp_chip->data_reg);
83
84 spin_unlock_irqrestore(&gpio_lock, flags);
85 }
86
87 /*
88 * msp71xx_set_gpio_mode() - declare the mode for a gpio
89 * @chip: chip structure which controls the specified gpio
90 * @offset: gpio whose value will be assigned
91 * @mode: desired configuration for the gpio (see datasheet)
92 *
93 * It will set the gpio pin config to the @mode value passed in.
94 */
msp71xx_set_gpio_mode(struct gpio_chip * chip,unsigned offset,int mode)95 static int msp71xx_set_gpio_mode(struct gpio_chip *chip,
96 unsigned offset, int mode)
97 {
98 struct msp71xx_gpio_chip *msp_chip = to_msp71xx_gpio_chip(chip);
99 const unsigned bit_offset = MSP71XX_CFG_OFFSET(offset);
100 unsigned long flags;
101 u32 cfg;
102
103 spin_lock_irqsave(&gpio_lock, flags);
104
105 cfg = __raw_readl(msp_chip->config_reg);
106 cfg &= ~(CONF_MASK << bit_offset);
107 cfg |= (mode << bit_offset);
108 __raw_writel(cfg, msp_chip->config_reg);
109
110 spin_unlock_irqrestore(&gpio_lock, flags);
111
112 return 0;
113 }
114
115 /*
116 * msp71xx_direction_output() - declare the direction mode for a gpio
117 * @chip: chip structure which controls the specified gpio
118 * @offset: gpio whose value will be assigned
119 * @value: logic level to assign to the gpio initially
120 *
121 * This call will set the mode for the @gpio to output. It will set the
122 * gpio pin low if value is 0 otherwise it will be high.
123 */
msp71xx_direction_output(struct gpio_chip * chip,unsigned offset,int value)124 static int msp71xx_direction_output(struct gpio_chip *chip,
125 unsigned offset, int value)
126 {
127 msp71xx_gpio_set(chip, offset, value);
128
129 return msp71xx_set_gpio_mode(chip, offset, MSP71XX_GPIO_OUTPUT);
130 }
131
132 /*
133 * msp71xx_direction_input() - declare the direction mode for a gpio
134 * @chip: chip structure which controls the specified gpio
135 * @offset: gpio whose to which the value will be assigned
136 *
137 * This call will set the mode for the @gpio to input.
138 */
msp71xx_direction_input(struct gpio_chip * chip,unsigned offset)139 static int msp71xx_direction_input(struct gpio_chip *chip, unsigned offset)
140 {
141 return msp71xx_set_gpio_mode(chip, offset, MSP71XX_GPIO_INPUT);
142 }
143
144 /*
145 * msp71xx_set_output_drive() - declare the output drive for the gpio line
146 * @gpio: gpio pin whose output drive you wish to modify
147 * @value: zero for active drain 1 for open drain drive
148 *
149 * This call will set the output drive mode for the @gpio to output.
150 */
msp71xx_set_output_drive(unsigned gpio,int value)151 int msp71xx_set_output_drive(unsigned gpio, int value)
152 {
153 unsigned long flags;
154 u32 data;
155
156 if (gpio > 15 || gpio < 0)
157 return -EINVAL;
158
159 spin_lock_irqsave(&gpio_lock, flags);
160
161 data = __raw_readl((void __iomem *)(MSP71XX_GPIO_BASE + 0x190));
162 if (value)
163 data |= (1 << gpio);
164 else
165 data &= ~(1 << gpio);
166 __raw_writel(data, (void __iomem *)(MSP71XX_GPIO_BASE + 0x190));
167
168 spin_unlock_irqrestore(&gpio_lock, flags);
169
170 return 0;
171 }
172 EXPORT_SYMBOL(msp71xx_set_output_drive);
173
174 #define MSP71XX_GPIO_BANK(name, dr, cr, base_gpio, num_gpio) \
175 { \
176 .chip = { \
177 .label = name, \
178 .direction_input = msp71xx_direction_input, \
179 .direction_output = msp71xx_direction_output, \
180 .get = msp71xx_gpio_get, \
181 .set = msp71xx_gpio_set, \
182 .base = base_gpio, \
183 .ngpio = num_gpio \
184 }, \
185 .data_reg = (void __iomem *)(MSP71XX_GPIO_BASE + dr), \
186 .config_reg = (void __iomem *)(MSP71XX_GPIO_BASE + cr), \
187 .out_drive_reg = (void __iomem *)(MSP71XX_GPIO_BASE + 0x190), \
188 }
189
190 /*
191 * struct msp71xx_gpio_banks[] - container array of gpio banks
192 * @chip: chip structure for the specified gpio bank
193 * @data_reg: register for reading and writing the gpio pin value
194 * @config_reg: register to set the mode for the gpio pin bank
195 *
196 * This array structure defines the gpio banks for the PMC MIPS Processor.
197 * We specify the bank name, the data register, the config register, base
198 * starting gpio number, and the number of gpios exposed by the bank.
199 */
200 static struct msp71xx_gpio_chip msp71xx_gpio_banks[] = {
201
202 MSP71XX_GPIO_BANK("GPIO_1_0", 0x170, 0x180, 0, 2),
203 MSP71XX_GPIO_BANK("GPIO_5_2", 0x174, 0x184, 2, 4),
204 MSP71XX_GPIO_BANK("GPIO_9_6", 0x178, 0x188, 6, 4),
205 MSP71XX_GPIO_BANK("GPIO_15_10", 0x17C, 0x18C, 10, 6),
206 };
207
msp71xx_init_gpio(void)208 void __init msp71xx_init_gpio(void)
209 {
210 int i;
211
212 spin_lock_init(&gpio_lock);
213
214 for (i = 0; i < ARRAY_SIZE(msp71xx_gpio_banks); i++)
215 gpiochip_add(&msp71xx_gpio_banks[i].chip);
216 }
217