Merge branches 'for-4.3/chicony', 'for-4.3/cp2112', 'for-4.3/i2c-hid', 'for-4.3/lenov...
[deliverable/linux.git] / drivers / spi / spi-clps711x.c
1 /*
2 * CLPS711X SPI bus driver
3 *
4 * Copyright (C) 2012-2014 Alexander Shiyan <shc_work@mail.ru>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 */
11
12 #include <linux/io.h>
13 #include <linux/clk.h>
14 #include <linux/gpio.h>
15 #include <linux/delay.h>
16 #include <linux/module.h>
17 #include <linux/interrupt.h>
18 #include <linux/platform_device.h>
19 #include <linux/regmap.h>
20 #include <linux/mfd/syscon.h>
21 #include <linux/mfd/syscon/clps711x.h>
22 #include <linux/spi/spi.h>
23 #include <linux/platform_data/spi-clps711x.h>
24
25 #define DRIVER_NAME "spi-clps711x"
26
27 #define SYNCIO_FRMLEN(x) ((x) << 8)
28 #define SYNCIO_TXFRMEN (1 << 14)
29
30 struct spi_clps711x_data {
31 void __iomem *syncio;
32 struct regmap *syscon;
33 struct clk *spi_clk;
34
35 u8 *tx_buf;
36 u8 *rx_buf;
37 unsigned int bpw;
38 int len;
39 };
40
41 static int spi_clps711x_setup(struct spi_device *spi)
42 {
43 /* We are expect that SPI-device is not selected */
44 gpio_direction_output(spi->cs_gpio, !(spi->mode & SPI_CS_HIGH));
45
46 return 0;
47 }
48
49 static int spi_clps711x_prepare_message(struct spi_master *master,
50 struct spi_message *msg)
51 {
52 struct spi_clps711x_data *hw = spi_master_get_devdata(master);
53 struct spi_device *spi = msg->spi;
54
55 /* Setup mode for transfer */
56 return regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCKNSEN,
57 (spi->mode & SPI_CPHA) ?
58 SYSCON3_ADCCKNSEN : 0);
59 }
60
61 static int spi_clps711x_transfer_one(struct spi_master *master,
62 struct spi_device *spi,
63 struct spi_transfer *xfer)
64 {
65 struct spi_clps711x_data *hw = spi_master_get_devdata(master);
66 u8 data;
67
68 clk_set_rate(hw->spi_clk, xfer->speed_hz ? : spi->max_speed_hz);
69
70 hw->len = xfer->len;
71 hw->bpw = xfer->bits_per_word;
72 hw->tx_buf = (u8 *)xfer->tx_buf;
73 hw->rx_buf = (u8 *)xfer->rx_buf;
74
75 /* Initiate transfer */
76 data = hw->tx_buf ? *hw->tx_buf++ : 0;
77 writel(data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN, hw->syncio);
78
79 return 1;
80 }
81
82 static irqreturn_t spi_clps711x_isr(int irq, void *dev_id)
83 {
84 struct spi_master *master = dev_id;
85 struct spi_clps711x_data *hw = spi_master_get_devdata(master);
86 u8 data;
87
88 /* Handle RX */
89 data = readb(hw->syncio);
90 if (hw->rx_buf)
91 *hw->rx_buf++ = data;
92
93 /* Handle TX */
94 if (--hw->len > 0) {
95 data = hw->tx_buf ? *hw->tx_buf++ : 0;
96 writel(data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN,
97 hw->syncio);
98 } else
99 spi_finalize_current_transfer(master);
100
101 return IRQ_HANDLED;
102 }
103
104 static int spi_clps711x_probe(struct platform_device *pdev)
105 {
106 struct spi_clps711x_data *hw;
107 struct spi_clps711x_pdata *pdata = dev_get_platdata(&pdev->dev);
108 struct spi_master *master;
109 struct resource *res;
110 int i, irq, ret;
111
112 if (!pdata) {
113 dev_err(&pdev->dev, "No platform data supplied\n");
114 return -EINVAL;
115 }
116
117 if (pdata->num_chipselect < 1) {
118 dev_err(&pdev->dev, "At least one CS must be defined\n");
119 return -EINVAL;
120 }
121
122 irq = platform_get_irq(pdev, 0);
123 if (irq < 0)
124 return irq;
125
126 master = spi_alloc_master(&pdev->dev, sizeof(*hw));
127 if (!master)
128 return -ENOMEM;
129
130 master->cs_gpios = devm_kzalloc(&pdev->dev, sizeof(int) *
131 pdata->num_chipselect, GFP_KERNEL);
132 if (!master->cs_gpios) {
133 ret = -ENOMEM;
134 goto err_out;
135 }
136
137 master->bus_num = pdev->id;
138 master->mode_bits = SPI_CPHA | SPI_CS_HIGH;
139 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 8);
140 master->num_chipselect = pdata->num_chipselect;
141 master->setup = spi_clps711x_setup;
142 master->prepare_message = spi_clps711x_prepare_message;
143 master->transfer_one = spi_clps711x_transfer_one;
144
145 hw = spi_master_get_devdata(master);
146
147 for (i = 0; i < master->num_chipselect; i++) {
148 master->cs_gpios[i] = pdata->chipselect[i];
149 ret = devm_gpio_request(&pdev->dev, master->cs_gpios[i],
150 DRIVER_NAME);
151 if (ret) {
152 dev_err(&pdev->dev, "Can't get CS GPIO %i\n", i);
153 goto err_out;
154 }
155 }
156
157 hw->spi_clk = devm_clk_get(&pdev->dev, NULL);
158 if (IS_ERR(hw->spi_clk)) {
159 ret = PTR_ERR(hw->spi_clk);
160 goto err_out;
161 }
162
163 hw->syscon = syscon_regmap_lookup_by_pdevname("syscon.3");
164 if (IS_ERR(hw->syscon)) {
165 ret = PTR_ERR(hw->syscon);
166 goto err_out;
167 }
168
169 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
170 hw->syncio = devm_ioremap_resource(&pdev->dev, res);
171 if (IS_ERR(hw->syncio)) {
172 ret = PTR_ERR(hw->syncio);
173 goto err_out;
174 }
175
176 /* Disable extended mode due hardware problems */
177 regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCON, 0);
178
179 /* Clear possible pending interrupt */
180 readl(hw->syncio);
181
182 ret = devm_request_irq(&pdev->dev, irq, spi_clps711x_isr, 0,
183 dev_name(&pdev->dev), master);
184 if (ret)
185 goto err_out;
186
187 ret = devm_spi_register_master(&pdev->dev, master);
188 if (!ret) {
189 dev_info(&pdev->dev,
190 "SPI bus driver initialized. Master clock %u Hz\n",
191 master->max_speed_hz);
192 return 0;
193 }
194
195 dev_err(&pdev->dev, "Failed to register master\n");
196
197 err_out:
198 spi_master_put(master);
199
200 return ret;
201 }
202
203 static struct platform_driver clps711x_spi_driver = {
204 .driver = {
205 .name = DRIVER_NAME,
206 },
207 .probe = spi_clps711x_probe,
208 };
209 module_platform_driver(clps711x_spi_driver);
210
211 MODULE_LICENSE("GPL");
212 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
213 MODULE_DESCRIPTION("CLPS711X SPI bus driver");
214 MODULE_ALIAS("platform:" DRIVER_NAME);
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