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>
25 #include <linux/spi/spi.h>
26 #include <linux/spi/spi_bitbang.h>
28 #include <plat/regs-spi.h>
32 /* bitbang has to be first */
33 struct spi_bitbang bitbang;
34 struct completion done;
41 void (*set_cs)(struct s3c2410_spi_info *spi,
45 const unsigned char *tx;
49 struct resource *ioarea;
50 struct spi_master *master;
51 struct spi_device *curdev;
53 struct s3c2410_spi_info *pdata;
56 #define SPCON_DEFAULT (S3C2410_SPCON_MSTR | S3C2410_SPCON_SMOD_INT)
57 #define SPPIN_DEFAULT (S3C2410_SPPIN_KEEP)
59 static inline struct s3c24xx_spi *to_hw(struct spi_device *sdev)
61 return spi_master_get_devdata(sdev->master);
64 static void s3c24xx_spi_gpiocs(struct s3c2410_spi_info *spi, int cs, int pol)
66 gpio_set_value(spi->pin_cs, pol);
69 static void s3c24xx_spi_chipsel(struct spi_device *spi, int value)
71 struct s3c24xx_spi *hw = to_hw(spi);
72 unsigned int cspol = spi->mode & SPI_CS_HIGH ? 1 : 0;
76 case BITBANG_CS_INACTIVE:
77 hw->set_cs(hw->pdata, spi->chip_select, cspol^1);
80 case BITBANG_CS_ACTIVE:
81 spcon = readb(hw->regs + S3C2410_SPCON);
83 if (spi->mode & SPI_CPHA)
84 spcon |= S3C2410_SPCON_CPHA_FMTB;
86 spcon &= ~S3C2410_SPCON_CPHA_FMTB;
88 if (spi->mode & SPI_CPOL)
89 spcon |= S3C2410_SPCON_CPOL_HIGH;
91 spcon &= ~S3C2410_SPCON_CPOL_HIGH;
93 spcon |= S3C2410_SPCON_ENSCK;
95 /* write new configration */
97 writeb(spcon, hw->regs + S3C2410_SPCON);
98 hw->set_cs(hw->pdata, spi->chip_select, cspol);
104 static int s3c24xx_spi_setupxfer(struct spi_device *spi,
105 struct spi_transfer *t)
107 struct s3c24xx_spi *hw = to_hw(spi);
113 bpw = t ? t->bits_per_word : spi->bits_per_word;
114 hz = t ? t->speed_hz : spi->max_speed_hz;
120 hz = spi->max_speed_hz;
123 dev_err(&spi->dev, "invalid bits-per-word (%d)\n", bpw);
127 clk = clk_get_rate(hw->clk);
128 div = DIV_ROUND_UP(clk, hz * 2) - 1;
133 dev_dbg(&spi->dev, "setting pre-scaler to %d (wanted %d, got %ld)\n",
134 div, hz, clk / (2 * (div + 1)));
137 writeb(div, hw->regs + S3C2410_SPPRE);
139 spin_lock(&hw->bitbang.lock);
140 if (!hw->bitbang.busy) {
141 hw->bitbang.chipselect(spi, BITBANG_CS_INACTIVE);
142 /* need to ndelay for 0.5 clocktick ? */
144 spin_unlock(&hw->bitbang.lock);
149 static int s3c24xx_spi_setup(struct spi_device *spi)
153 ret = s3c24xx_spi_setupxfer(spi, NULL);
155 dev_err(&spi->dev, "setupxfer returned %d\n", ret);
162 static inline unsigned int hw_txbyte(struct s3c24xx_spi *hw, int count)
164 return hw->tx ? hw->tx[count] : 0;
167 static int s3c24xx_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
169 struct s3c24xx_spi *hw = to_hw(spi);
171 dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n",
172 t->tx_buf, t->rx_buf, t->len);
179 init_completion(&hw->done);
181 /* send the first byte */
182 writeb(hw_txbyte(hw, 0), hw->regs + S3C2410_SPTDAT);
184 wait_for_completion(&hw->done);
189 static irqreturn_t s3c24xx_spi_irq(int irq, void *dev)
191 struct s3c24xx_spi *hw = dev;
192 unsigned int spsta = readb(hw->regs + S3C2410_SPSTA);
193 unsigned int count = hw->count;
195 if (spsta & S3C2410_SPSTA_DCOL) {
196 dev_dbg(hw->dev, "data-collision\n");
201 if (!(spsta & S3C2410_SPSTA_READY)) {
202 dev_dbg(hw->dev, "spi not ready for tx?\n");
210 hw->rx[count] = readb(hw->regs + S3C2410_SPRDAT);
215 writeb(hw_txbyte(hw, count), hw->regs + S3C2410_SPTDAT);
223 static void s3c24xx_spi_initialsetup(struct s3c24xx_spi *hw)
225 /* for the moment, permanently enable the clock */
229 /* program defaults into the registers */
231 writeb(0xff, hw->regs + S3C2410_SPPRE);
232 writeb(SPPIN_DEFAULT, hw->regs + S3C2410_SPPIN);
233 writeb(SPCON_DEFAULT, hw->regs + S3C2410_SPCON);
236 if (hw->set_cs == s3c24xx_spi_gpiocs)
237 gpio_direction_output(hw->pdata->pin_cs, 1);
239 if (hw->pdata->gpio_setup)
240 hw->pdata->gpio_setup(hw->pdata, 1);
244 static int __init s3c24xx_spi_probe(struct platform_device *pdev)
246 struct s3c2410_spi_info *pdata;
247 struct s3c24xx_spi *hw;
248 struct spi_master *master;
249 struct resource *res;
252 master = spi_alloc_master(&pdev->dev, sizeof(struct s3c24xx_spi));
253 if (master == NULL) {
254 dev_err(&pdev->dev, "No memory for spi_master\n");
259 hw = spi_master_get_devdata(master);
260 memset(hw, 0, sizeof(struct s3c24xx_spi));
262 hw->master = spi_master_get(master);
263 hw->pdata = pdata = pdev->dev.platform_data;
264 hw->dev = &pdev->dev;
267 dev_err(&pdev->dev, "No platform data supplied\n");
272 platform_set_drvdata(pdev, hw);
273 init_completion(&hw->done);
275 /* setup the master state. */
277 /* the spi->mode bits understood by this driver: */
278 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
280 master->num_chipselect = hw->pdata->num_cs;
281 master->bus_num = pdata->bus_num;
283 /* setup the state for the bitbang driver */
285 hw->bitbang.master = hw->master;
286 hw->bitbang.setup_transfer = s3c24xx_spi_setupxfer;
287 hw->bitbang.chipselect = s3c24xx_spi_chipsel;
288 hw->bitbang.txrx_bufs = s3c24xx_spi_txrx;
289 hw->bitbang.master->setup = s3c24xx_spi_setup;
291 dev_dbg(hw->dev, "bitbang at %p\n", &hw->bitbang);
293 /* find and map our resources */
295 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
297 dev_err(&pdev->dev, "Cannot get IORESOURCE_MEM\n");
302 hw->ioarea = request_mem_region(res->start, (res->end - res->start)+1,
305 if (hw->ioarea == NULL) {
306 dev_err(&pdev->dev, "Cannot reserve region\n");
311 hw->regs = ioremap(res->start, (res->end - res->start)+1);
312 if (hw->regs == NULL) {
313 dev_err(&pdev->dev, "Cannot map IO\n");
318 hw->irq = platform_get_irq(pdev, 0);
320 dev_err(&pdev->dev, "No IRQ specified\n");
325 err = request_irq(hw->irq, s3c24xx_spi_irq, 0, pdev->name, hw);
327 dev_err(&pdev->dev, "Cannot claim IRQ\n");
331 hw->clk = clk_get(&pdev->dev, "spi");
332 if (IS_ERR(hw->clk)) {
333 dev_err(&pdev->dev, "No clock for device\n");
334 err = PTR_ERR(hw->clk);
338 /* setup any gpio we can */
340 if (!pdata->set_cs) {
341 if (pdata->pin_cs < 0) {
342 dev_err(&pdev->dev, "No chipselect pin\n");
346 err = gpio_request(pdata->pin_cs, dev_name(&pdev->dev));
348 dev_err(&pdev->dev, "Failed to get gpio for cs\n");
352 hw->set_cs = s3c24xx_spi_gpiocs;
353 gpio_direction_output(pdata->pin_cs, 1);
355 hw->set_cs = pdata->set_cs;
357 s3c24xx_spi_initialsetup(hw);
359 /* register our spi controller */
361 err = spi_bitbang_start(&hw->bitbang);
363 dev_err(&pdev->dev, "Failed to register SPI master\n");
370 if (hw->set_cs == s3c24xx_spi_gpiocs)
371 gpio_free(pdata->pin_cs);
373 clk_disable(hw->clk);
377 free_irq(hw->irq, hw);
383 release_resource(hw->ioarea);
388 spi_master_put(hw->master);
394 static int __exit s3c24xx_spi_remove(struct platform_device *dev)
396 struct s3c24xx_spi *hw = platform_get_drvdata(dev);
398 platform_set_drvdata(dev, NULL);
400 spi_unregister_master(hw->master);
402 clk_disable(hw->clk);
405 free_irq(hw->irq, hw);
408 if (hw->set_cs == s3c24xx_spi_gpiocs)
409 gpio_free(hw->pdata->pin_cs);
411 release_resource(hw->ioarea);
414 spi_master_put(hw->master);
421 static int s3c24xx_spi_suspend(struct platform_device *pdev, pm_message_t msg)
423 struct s3c24xx_spi *hw = platform_get_drvdata(pdev);
425 if (hw->pdata && hw->pdata->gpio_setup)
426 hw->pdata->gpio_setup(hw->pdata, 0);
428 clk_disable(hw->clk);
432 static int s3c24xx_spi_resume(struct platform_device *pdev)
434 struct s3c24xx_spi *hw = platform_get_drvdata(pdev);
436 s3c24xx_spi_initialsetup(hw);
441 #define s3c24xx_spi_suspend NULL
442 #define s3c24xx_spi_resume NULL
445 MODULE_ALIAS("platform:s3c2410-spi");
446 static struct platform_driver s3c24xx_spi_driver = {
447 .remove = __exit_p(s3c24xx_spi_remove),
448 .suspend = s3c24xx_spi_suspend,
449 .resume = s3c24xx_spi_resume,
451 .name = "s3c2410-spi",
452 .owner = THIS_MODULE,
456 static int __init s3c24xx_spi_init(void)
458 return platform_driver_probe(&s3c24xx_spi_driver, s3c24xx_spi_probe);
461 static void __exit s3c24xx_spi_exit(void)
463 platform_driver_unregister(&s3c24xx_spi_driver);
466 module_init(s3c24xx_spi_init);
467 module_exit(s3c24xx_spi_exit);
469 MODULE_DESCRIPTION("S3C24XX SPI Driver");
470 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
471 MODULE_LICENSE("GPL");