summaryrefslogtreecommitdiffstats
path: root/drivers/spi/spi-clps711x.c
blob: a11cbf02691a88564ea8b8b33331453a7163b72a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
/*
 *  CLPS711X SPI bus driver
 *
 *  Copyright (C) 2012 Alexander Shiyan <shc_work@mail.ru>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/io.h>
#include <linux/clk.h>
#include <linux/init.h>
#include <linux/gpio.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
#include <linux/platform_data/spi-clps711x.h>

#include <mach/hardware.h>

#define DRIVER_NAME	"spi-clps711x"

struct spi_clps711x_data {
	struct completion	done;

	struct clk		*spi_clk;
	u32			max_speed_hz;

	u8			*tx_buf;
	u8			*rx_buf;
	int			count;
	int			len;

	int			chipselect[0];
};

static int spi_clps711x_setup(struct spi_device *spi)
{
	struct spi_clps711x_data *hw = spi_master_get_devdata(spi->master);

	if (spi->bits_per_word != 8) {
		dev_err(&spi->dev, "Unsupported master bus width %i\n",
			spi->bits_per_word);
		return -EINVAL;
	}

	/* We are expect that SPI-device is not selected */
	gpio_direction_output(hw->chipselect[spi->chip_select],
			      !(spi->mode & SPI_CS_HIGH));

	return 0;
}

static void spi_clps711x_setup_mode(struct spi_device *spi)
{
	/* Setup edge for transfer */
	if (spi->mode & SPI_CPHA)
		clps_writew(clps_readw(SYSCON3) | SYSCON3_ADCCKNSEN, SYSCON3);
	else
		clps_writew(clps_readw(SYSCON3) & ~SYSCON3_ADCCKNSEN, SYSCON3);
}

static int spi_clps711x_setup_xfer(struct spi_device *spi,
				   struct spi_transfer *xfer)
{
	u32 speed = xfer->speed_hz ? : spi->max_speed_hz;
	u8 bpw = xfer->bits_per_word;
	struct spi_clps711x_data *hw = spi_master_get_devdata(spi->master);

	if (bpw != 8) {
		dev_err(&spi->dev, "Unsupported master bus width %i\n", bpw);
		return -EINVAL;
	}

	/* Setup SPI frequency divider */
	if (!speed || (speed >= hw->max_speed_hz))
		clps_writel((clps_readl(SYSCON1) & ~SYSCON1_ADCKSEL_MASK) |
			    SYSCON1_ADCKSEL(3), SYSCON1);
	else if (speed >= (hw->max_speed_hz / 2))
		clps_writel((clps_readl(SYSCON1) & ~SYSCON1_ADCKSEL_MASK) |
			    SYSCON1_ADCKSEL(2), SYSCON1);
	else if (speed >= (hw->max_speed_hz / 8))
		clps_writel((clps_readl(SYSCON1) & ~SYSCON1_ADCKSEL_MASK) |
			    SYSCON1_ADCKSEL(1), SYSCON1);
	else
		clps_writel((clps_readl(SYSCON1) & ~SYSCON1_ADCKSEL_MASK) |
			    SYSCON1_ADCKSEL(0), SYSCON1);

	return 0;
}

static int spi_clps711x_transfer_one_message(struct spi_master *master,
					     struct spi_message *msg)
{
	struct spi_clps711x_data *hw = spi_master_get_devdata(master);
	struct spi_transfer *xfer;
	int status = 0, cs = hw->chipselect[msg->spi->chip_select];
	u32 data;

	spi_clps711x_setup_mode(msg->spi);

	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
		if (spi_clps711x_setup_xfer(msg->spi, xfer)) {
			status = -EINVAL;
			goto out_xfr;
		}

		gpio_set_value(cs, !!(msg->spi->mode & SPI_CS_HIGH));

		INIT_COMPLETION(hw->done);

		hw->count = 0;
		hw->len = xfer->len;
		hw->tx_buf = (u8 *)xfer->tx_buf;
		hw->rx_buf = (u8 *)xfer->rx_buf;

		/* Initiate transfer */
		data = hw->tx_buf ? hw->tx_buf[hw->count] : 0;
		clps_writel(data | SYNCIO_FRMLEN(8) | SYNCIO_TXFRMEN, SYNCIO);

		wait_for_completion(&hw->done);

		if (xfer->delay_usecs)
			udelay(xfer->delay_usecs);

		if (xfer->cs_change ||
		    list_is_last(&xfer->transfer_list, &msg->transfers))
			gpio_set_value(cs, !(msg->spi->mode & SPI_CS_HIGH));

		msg->actual_length += xfer->len;
	}

out_xfr:
	msg->status = status;
	spi_finalize_current_message(master);

	return 0;
}

static irqreturn_t spi_clps711x_isr(int irq, void *dev_id)
{
	struct spi_clps711x_data *hw = (struct spi_clps711x_data *)dev_id;
	u32 data;

	/* Handle RX */
	data = clps_readb(SYNCIO);
	if (hw->rx_buf)
		hw->rx_buf[hw->count] = (u8)data;

	hw->count++;

	/* Handle TX */
	if (hw->count < hw->len) {
		data = hw->tx_buf ? hw->tx_buf[hw->count] : 0;
		clps_writel(data | SYNCIO_FRMLEN(8) | SYNCIO_TXFRMEN, SYNCIO);
	} else
		complete(&hw->done);

	return IRQ_HANDLED;
}

static int spi_clps711x_probe(struct platform_device *pdev)
{
	int i, ret;
	struct spi_master *master;
	struct spi_clps711x_data *hw;
	struct spi_clps711x_pdata *pdata = dev_get_platdata(&pdev->dev);

	if (!pdata) {
		dev_err(&pdev->dev, "No platform data supplied\n");
		return -EINVAL;
	}

	if (pdata->num_chipselect < 1) {
		dev_err(&pdev->dev, "At least one CS must be defined\n");
		return -EINVAL;
	}

	master = spi_alloc_master(&pdev->dev,
				  sizeof(struct spi_clps711x_data) +
				  sizeof(int) * pdata->num_chipselect);
	if (!master) {
		dev_err(&pdev->dev, "SPI allocating memory error\n");
		return -ENOMEM;
	}

	master->bus_num = pdev->id;
	master->mode_bits = SPI_CPHA | SPI_CS_HIGH;
	master->num_chipselect = pdata->num_chipselect;
	master->setup = spi_clps711x_setup;
	master->transfer_one_message = spi_clps711x_transfer_one_message;

	hw = spi_master_get_devdata(master);

	for (i = 0; i < master->num_chipselect; i++) {
		hw->chipselect[i] = pdata->chipselect[i];
		if (!gpio_is_valid(hw->chipselect[i])) {
			dev_err(&pdev->dev, "Invalid CS GPIO %i\n", i);
			ret = -EINVAL;
			goto err_out;
		}
		if (gpio_request(hw->chipselect[i], DRIVER_NAME)) {
			dev_err(&pdev->dev, "Can't get CS GPIO %i\n", i);
			ret = -EINVAL;
			goto err_out;
		}
	}

	hw->spi_clk = devm_clk_get(&pdev->dev, "spi");
	if (IS_ERR(hw->spi_clk)) {
		dev_err(&pdev->dev, "Can't get clocks\n");
		ret = PTR_ERR(hw->spi_clk);
		goto err_out;
	}
	hw->max_speed_hz = clk_get_rate(hw->spi_clk);

	init_completion(&hw->done);
	platform_set_drvdata(pdev, master);

	/* Disable extended mode due hardware problems */
	clps_writew(clps_readw(SYSCON3) & ~SYSCON3_ADCCON, SYSCON3);

	/* Clear possible pending interrupt */
	clps_readl(SYNCIO);

	ret = devm_request_irq(&pdev->dev, IRQ_SSEOTI, spi_clps711x_isr, 0,
			       dev_name(&pdev->dev), hw);
	if (ret) {
		dev_err(&pdev->dev, "Can't request IRQ\n");
		clk_put(hw->spi_clk);
		goto clk_out;
	}

	ret = spi_register_master(master);
	if (!ret) {
		dev_info(&pdev->dev,
			 "SPI bus driver initialized. Master clock %u Hz\n",
			 hw->max_speed_hz);
		return 0;
	}

	dev_err(&pdev->dev, "Failed to register master\n");
	devm_free_irq(&pdev->dev, IRQ_SSEOTI, hw);

clk_out:
	devm_clk_put(&pdev->dev, hw->spi_clk);

err_out:
	while (--i >= 0)
		if (gpio_is_valid(hw->chipselect[i]))
			gpio_free(hw->chipselect[i]);

	platform_set_drvdata(pdev, NULL);
	spi_master_put(master);
	kfree(master);

	return ret;
}

static int spi_clps711x_remove(struct platform_device *pdev)
{
	int i;
	struct spi_master *master = platform_get_drvdata(pdev);
	struct spi_clps711x_data *hw = spi_master_get_devdata(master);

	devm_free_irq(&pdev->dev, IRQ_SSEOTI, hw);

	for (i = 0; i < master->num_chipselect; i++)
		if (gpio_is_valid(hw->chipselect[i]))
			gpio_free(hw->chipselect[i]);

	devm_clk_put(&pdev->dev, hw->spi_clk);
	platform_set_drvdata(pdev, NULL);
	spi_unregister_master(master);
	kfree(master);

	return 0;
}

static struct platform_driver clps711x_spi_driver = {
	.driver	= {
		.name	= DRIVER_NAME,
		.owner	= THIS_MODULE,
	},
	.probe	= spi_clps711x_probe,
	.remove	= spi_clps711x_remove,
};
module_platform_driver(clps711x_spi_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
MODULE_DESCRIPTION("CLPS711X SPI bus driver");