1 /* linux/drivers/spi/spi_s3c24xx.c
3 * Copyright (c) 2006 Ben Dooks
4 * Copyright (c) 2006 Simtec Electronics
5 * Ben Dooks <ben@simtec.co.uk>
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.
13 #include <linux/init.h>
14 #include <linux/spinlock.h>
15 #include <linux/workqueue.h>
16 #include <linux/interrupt.h>
17 #include <linux/delay.h>
18 #include <linux/errno.h>
19 #include <linux/err.h>
20 #include <linux/clk.h>
21 #include <linux/platform_device.h>
22 #include <linux/gpio.h>
24 #include <linux/spi/spi.h>
25 #include <linux/spi/spi_bitbang.h>
29 #include <mach/hardware.h>
31 #include <plat/regs-spi.h>
35 /* bitbang has to be first */
36 struct spi_bitbang bitbang;
37 struct completion done;
44 void (*set_cs)(struct s3c2410_spi_info *spi,
48 const unsigned char *tx;
52 struct resource *ioarea;
53 struct spi_master *master;
54 struct spi_device *curdev;
56 struct s3c2410_spi_info *pdata;
59 #define SPCON_DEFAULT (S3C2410_SPCON_MSTR | S3C2410_SPCON_SMOD_INT)
60 #define SPPIN_DEFAULT (S3C2410_SPPIN_KEEP)
62 static inline struct s3c24xx_spi *to_hw(struct spi_device *sdev)
64 return spi_master_get_devdata(sdev->master);
67 static void s3c24xx_spi_gpiocs(struct s3c2410_spi_info *spi, int cs, int pol)
69 gpio_set_value(spi->pin_cs, pol);
72 static void s3c24xx_spi_chipsel(struct spi_device *spi, int value)
74 struct s3c24xx_spi *hw = to_hw(spi);
75 unsigned int cspol = spi->mode & SPI_CS_HIGH ? 1 : 0;
79 case BITBANG_CS_INACTIVE:
80 hw->set_cs(hw->pdata, spi->chip_select, cspol^1);
83 case BITBANG_CS_ACTIVE:
84 spcon = readb(hw->regs + S3C2410_SPCON);
86 if (spi->mode & SPI_CPHA)
87 spcon |= S3C2410_SPCON_CPHA_FMTB;
89 spcon &= ~S3C2410_SPCON_CPHA_FMTB;
91 if (spi->mode & SPI_CPOL)
92 spcon |= S3C2410_SPCON_CPOL_HIGH;
94 spcon &= ~S3C2410_SPCON_CPOL_HIGH;
96 spcon |= S3C2410_SPCON_ENSCK;
98 /* write new configration */
100 writeb(spcon, hw->regs + S3C2410_SPCON);
101 hw->set_cs(hw->pdata, spi->chip_select, cspol);
107 static int s3c24xx_spi_setupxfer(struct spi_device *spi,
108 struct spi_transfer *t)
110 struct s3c24xx_spi *hw = to_hw(spi);
116 bpw = t ? t->bits_per_word : spi->bits_per_word;
117 hz = t ? t->speed_hz : spi->max_speed_hz;
120 dev_err(&spi->dev, "invalid bits-per-word (%d)\n", bpw);
124 clk = clk_get_rate(hw->clk);
125 div = DIV_ROUND_UP(clk, hz * 2) - 1;
130 dev_dbg(&spi->dev, "setting pre-scaler to %d (wanted %d, got %ld)\n",
131 div, hz, clk / (2 * (div + 1)));
134 writeb(div, hw->regs + S3C2410_SPPRE);
136 spin_lock(&hw->bitbang.lock);
137 if (!hw->bitbang.busy) {
138 hw->bitbang.chipselect(spi, BITBANG_CS_INACTIVE);
139 /* need to ndelay for 0.5 clocktick ? */
141 spin_unlock(&hw->bitbang.lock);
146 static int s3c24xx_spi_setup(struct spi_device *spi)
150 ret = s3c24xx_spi_setupxfer(spi, NULL);
152 dev_err(&spi->dev, "setupxfer returned %d\n", ret);
159 static inline unsigned int hw_txbyte(struct s3c24xx_spi *hw, int count)
161 return hw->tx ? hw->tx[count] : 0;
164 static int s3c24xx_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
166 struct s3c24xx_spi *hw = to_hw(spi);
168 dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n",
169 t->tx_buf, t->rx_buf, t->len);
176 init_completion(&hw->done);
178 /* send the first byte */
179 writeb(hw_txbyte(hw, 0), hw->regs + S3C2410_SPTDAT);
181 wait_for_completion(&hw->done);
186 static irqreturn_t s3c24xx_spi_irq(int irq, void *dev)
188 struct s3c24xx_spi *hw = dev;
189 unsigned int spsta = readb(hw->regs + S3C2410_SPSTA);
190 unsigned int count = hw->count;
192 if (spsta & S3C2410_SPSTA_DCOL) {
193 dev_dbg(hw->dev, "data-collision\n");
198 if (!(spsta & S3C2410_SPSTA_READY)) {
199 dev_dbg(hw->dev, "spi not ready for tx?\n");
207 hw->rx[count] = readb(hw->regs + S3C2410_SPRDAT);
212 writeb(hw_txbyte(hw, count), hw->regs + S3C2410_SPTDAT);
220 static void s3c24xx_spi_initialsetup(struct s3c24xx_spi *hw)
222 /* for the moment, permanently enable the clock */
226 /* program defaults into the registers */
228 writeb(0xff, hw->regs + S3C2410_SPPRE);
229 writeb(SPPIN_DEFAULT, hw->regs + S3C2410_SPPIN);
230 writeb(SPCON_DEFAULT, hw->regs + S3C2410_SPCON);
233 if (hw->set_cs == s3c24xx_spi_gpiocs)
234 gpio_direction_output(hw->pdata->pin_cs, 1);
236 if (hw->pdata->gpio_setup)
237 hw->pdata->gpio_setup(hw->pdata, 1);
241 static int __init s3c24xx_spi_probe(struct platform_device *pdev)
243 struct s3c2410_spi_info *pdata;
244 struct s3c24xx_spi *hw;
245 struct spi_master *master;
246 struct resource *res;
249 master = spi_alloc_master(&pdev->dev, sizeof(struct s3c24xx_spi));
250 if (master == NULL) {
251 dev_err(&pdev->dev, "No memory for spi_master\n");
256 hw = spi_master_get_devdata(master);
257 memset(hw, 0, sizeof(struct s3c24xx_spi));
259 hw->master = spi_master_get(master);
260 hw->pdata = pdata = pdev->dev.platform_data;
261 hw->dev = &pdev->dev;
264 dev_err(&pdev->dev, "No platform data supplied\n");
269 platform_set_drvdata(pdev, hw);
270 init_completion(&hw->done);
272 /* setup the master state. */
274 /* the spi->mode bits understood by this driver: */
275 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
277 master->num_chipselect = hw->pdata->num_cs;
278 master->bus_num = pdata->bus_num;
280 /* setup the state for the bitbang driver */
282 hw->bitbang.master = hw->master;
283 hw->bitbang.setup_transfer = s3c24xx_spi_setupxfer;
284 hw->bitbang.chipselect = s3c24xx_spi_chipsel;
285 hw->bitbang.txrx_bufs = s3c24xx_spi_txrx;
286 hw->bitbang.master->setup = s3c24xx_spi_setup;
288 dev_dbg(hw->dev, "bitbang at %p\n", &hw->bitbang);
290 /* find and map our resources */
292 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
294 dev_err(&pdev->dev, "Cannot get IORESOURCE_MEM\n");
299 hw->ioarea = request_mem_region(res->start, (res->end - res->start)+1,
302 if (hw->ioarea == NULL) {
303 dev_err(&pdev->dev, "Cannot reserve region\n");
308 hw->regs = ioremap(res->start, (res->end - res->start)+1);
309 if (hw->regs == NULL) {
310 dev_err(&pdev->dev, "Cannot map IO\n");
315 hw->irq = platform_get_irq(pdev, 0);
317 dev_err(&pdev->dev, "No IRQ specified\n");
322 err = request_irq(hw->irq, s3c24xx_spi_irq, 0, pdev->name, hw);
324 dev_err(&pdev->dev, "Cannot claim IRQ\n");
328 hw->clk = clk_get(&pdev->dev, "spi");
329 if (IS_ERR(hw->clk)) {
330 dev_err(&pdev->dev, "No clock for device\n");
331 err = PTR_ERR(hw->clk);
335 /* setup any gpio we can */
337 if (!pdata->set_cs) {
338 if (pdata->pin_cs < 0) {
339 dev_err(&pdev->dev, "No chipselect pin\n");
343 err = gpio_request(pdata->pin_cs, dev_name(&pdev->dev));
345 dev_err(&pdev->dev, "Failed to get gpio for cs\n");
349 hw->set_cs = s3c24xx_spi_gpiocs;
350 gpio_direction_output(pdata->pin_cs, 1);
352 hw->set_cs = pdata->set_cs;
354 s3c24xx_spi_initialsetup(hw);
356 /* register our spi controller */
358 err = spi_bitbang_start(&hw->bitbang);
360 dev_err(&pdev->dev, "Failed to register SPI master\n");
367 if (hw->set_cs == s3c24xx_spi_gpiocs)
368 gpio_free(pdata->pin_cs);
370 clk_disable(hw->clk);
374 free_irq(hw->irq, hw);
380 release_resource(hw->ioarea);
385 spi_master_put(hw->master);;
391 static int __exit s3c24xx_spi_remove(struct platform_device *dev)
393 struct s3c24xx_spi *hw = platform_get_drvdata(dev);
395 platform_set_drvdata(dev, NULL);
397 spi_unregister_master(hw->master);
399 clk_disable(hw->clk);
402 free_irq(hw->irq, hw);
405 if (hw->set_cs == s3c24xx_spi_gpiocs)
406 gpio_free(hw->pdata->pin_cs);
408 release_resource(hw->ioarea);
411 spi_master_put(hw->master);
418 static int s3c24xx_spi_suspend(struct platform_device *pdev, pm_message_t msg)
420 struct s3c24xx_spi *hw = platform_get_drvdata(pdev);
422 if (hw->pdata && hw->pdata->gpio_setup)
423 hw->pdata->gpio_setup(hw->pdata, 0);
425 clk_disable(hw->clk);
429 static int s3c24xx_spi_resume(struct platform_device *pdev)
431 struct s3c24xx_spi *hw = platform_get_drvdata(pdev);
433 s3c24xx_spi_initialsetup(hw);
438 #define s3c24xx_spi_suspend NULL
439 #define s3c24xx_spi_resume NULL
442 MODULE_ALIAS("platform:s3c2410-spi");
443 static struct platform_driver s3c24xx_spi_driver = {
444 .remove = __exit_p(s3c24xx_spi_remove),
445 .suspend = s3c24xx_spi_suspend,
446 .resume = s3c24xx_spi_resume,
448 .name = "s3c2410-spi",
449 .owner = THIS_MODULE,
453 static int __init s3c24xx_spi_init(void)
455 return platform_driver_probe(&s3c24xx_spi_driver, s3c24xx_spi_probe);
458 static void __exit s3c24xx_spi_exit(void)
460 platform_driver_unregister(&s3c24xx_spi_driver);
463 module_init(s3c24xx_spi_init);
464 module_exit(s3c24xx_spi_exit);
466 MODULE_DESCRIPTION("S3C24XX SPI Driver");
467 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
468 MODULE_LICENSE("GPL");