2 * CLPS711X SPI bus driver
4 * Copyright (C) 2012 Alexander Shiyan <shc_work@mail.ru>
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.
13 #include <linux/clk.h>
14 #include <linux/init.h>
15 #include <linux/gpio.h>
16 #include <linux/delay.h>
17 #include <linux/module.h>
18 #include <linux/interrupt.h>
19 #include <linux/platform_device.h>
20 #include <linux/spi/spi.h>
21 #include <linux/platform_data/spi-clps711x.h>
23 #include <mach/hardware.h>
25 #define DRIVER_NAME "spi-clps711x"
27 struct spi_clps711x_data {
28 struct completion done;
41 static int spi_clps711x_setup(struct spi_device *spi)
43 struct spi_clps711x_data *hw = spi_master_get_devdata(spi->master);
45 /* We are expect that SPI-device is not selected */
46 gpio_direction_output(hw->chipselect[spi->chip_select],
47 !(spi->mode & SPI_CS_HIGH));
52 static void spi_clps711x_setup_mode(struct spi_device *spi)
54 /* Setup edge for transfer */
55 if (spi->mode & SPI_CPHA)
56 clps_writew(clps_readw(SYSCON3) | SYSCON3_ADCCKNSEN, SYSCON3);
58 clps_writew(clps_readw(SYSCON3) & ~SYSCON3_ADCCKNSEN, SYSCON3);
61 static int spi_clps711x_setup_xfer(struct spi_device *spi,
62 struct spi_transfer *xfer)
64 u32 speed = xfer->speed_hz ? : spi->max_speed_hz;
65 u8 bpw = xfer->bits_per_word;
66 struct spi_clps711x_data *hw = spi_master_get_devdata(spi->master);
69 dev_err(&spi->dev, "Unsupported master bus width %i\n", bpw);
73 /* Setup SPI frequency divider */
74 if (!speed || (speed >= hw->max_speed_hz))
75 clps_writel((clps_readl(SYSCON1) & ~SYSCON1_ADCKSEL_MASK) |
76 SYSCON1_ADCKSEL(3), SYSCON1);
77 else if (speed >= (hw->max_speed_hz / 2))
78 clps_writel((clps_readl(SYSCON1) & ~SYSCON1_ADCKSEL_MASK) |
79 SYSCON1_ADCKSEL(2), SYSCON1);
80 else if (speed >= (hw->max_speed_hz / 8))
81 clps_writel((clps_readl(SYSCON1) & ~SYSCON1_ADCKSEL_MASK) |
82 SYSCON1_ADCKSEL(1), SYSCON1);
84 clps_writel((clps_readl(SYSCON1) & ~SYSCON1_ADCKSEL_MASK) |
85 SYSCON1_ADCKSEL(0), SYSCON1);
90 static int spi_clps711x_transfer_one_message(struct spi_master *master,
91 struct spi_message *msg)
93 struct spi_clps711x_data *hw = spi_master_get_devdata(master);
94 struct spi_transfer *xfer;
95 int status = 0, cs = hw->chipselect[msg->spi->chip_select];
98 spi_clps711x_setup_mode(msg->spi);
100 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
101 if (spi_clps711x_setup_xfer(msg->spi, xfer)) {
106 gpio_set_value(cs, !!(msg->spi->mode & SPI_CS_HIGH));
108 INIT_COMPLETION(hw->done);
112 hw->tx_buf = (u8 *)xfer->tx_buf;
113 hw->rx_buf = (u8 *)xfer->rx_buf;
115 /* Initiate transfer */
116 data = hw->tx_buf ? hw->tx_buf[hw->count] : 0;
117 clps_writel(data | SYNCIO_FRMLEN(8) | SYNCIO_TXFRMEN, SYNCIO);
119 wait_for_completion(&hw->done);
121 if (xfer->delay_usecs)
122 udelay(xfer->delay_usecs);
124 if (xfer->cs_change ||
125 list_is_last(&xfer->transfer_list, &msg->transfers))
126 gpio_set_value(cs, !(msg->spi->mode & SPI_CS_HIGH));
128 msg->actual_length += xfer->len;
132 msg->status = status;
133 spi_finalize_current_message(master);
138 static irqreturn_t spi_clps711x_isr(int irq, void *dev_id)
140 struct spi_clps711x_data *hw = (struct spi_clps711x_data *)dev_id;
144 data = clps_readb(SYNCIO);
146 hw->rx_buf[hw->count] = (u8)data;
151 if (hw->count < hw->len) {
152 data = hw->tx_buf ? hw->tx_buf[hw->count] : 0;
153 clps_writel(data | SYNCIO_FRMLEN(8) | SYNCIO_TXFRMEN, SYNCIO);
160 static int spi_clps711x_probe(struct platform_device *pdev)
163 struct spi_master *master;
164 struct spi_clps711x_data *hw;
165 struct spi_clps711x_pdata *pdata = dev_get_platdata(&pdev->dev);
168 dev_err(&pdev->dev, "No platform data supplied\n");
172 if (pdata->num_chipselect < 1) {
173 dev_err(&pdev->dev, "At least one CS must be defined\n");
177 master = spi_alloc_master(&pdev->dev,
178 sizeof(struct spi_clps711x_data) +
179 sizeof(int) * pdata->num_chipselect);
181 dev_err(&pdev->dev, "SPI allocating memory error\n");
185 master->bus_num = pdev->id;
186 master->mode_bits = SPI_CPHA | SPI_CS_HIGH;
187 master->bits_per_word_mask = SPI_BPW_MASK(8);
188 master->num_chipselect = pdata->num_chipselect;
189 master->setup = spi_clps711x_setup;
190 master->transfer_one_message = spi_clps711x_transfer_one_message;
192 hw = spi_master_get_devdata(master);
194 for (i = 0; i < master->num_chipselect; i++) {
195 hw->chipselect[i] = pdata->chipselect[i];
196 if (!gpio_is_valid(hw->chipselect[i])) {
197 dev_err(&pdev->dev, "Invalid CS GPIO %i\n", i);
201 if (gpio_request(hw->chipselect[i], DRIVER_NAME)) {
202 dev_err(&pdev->dev, "Can't get CS GPIO %i\n", i);
208 hw->spi_clk = devm_clk_get(&pdev->dev, "spi");
209 if (IS_ERR(hw->spi_clk)) {
210 dev_err(&pdev->dev, "Can't get clocks\n");
211 ret = PTR_ERR(hw->spi_clk);
214 hw->max_speed_hz = clk_get_rate(hw->spi_clk);
216 init_completion(&hw->done);
217 platform_set_drvdata(pdev, master);
219 /* Disable extended mode due hardware problems */
220 clps_writew(clps_readw(SYSCON3) & ~SYSCON3_ADCCON, SYSCON3);
222 /* Clear possible pending interrupt */
225 ret = devm_request_irq(&pdev->dev, IRQ_SSEOTI, spi_clps711x_isr, 0,
226 dev_name(&pdev->dev), hw);
228 dev_err(&pdev->dev, "Can't request IRQ\n");
229 clk_put(hw->spi_clk);
233 ret = spi_register_master(master);
236 "SPI bus driver initialized. Master clock %u Hz\n",
241 dev_err(&pdev->dev, "Failed to register master\n");
245 if (gpio_is_valid(hw->chipselect[i]))
246 gpio_free(hw->chipselect[i]);
248 spi_master_put(master);
254 static int spi_clps711x_remove(struct platform_device *pdev)
257 struct spi_master *master = platform_get_drvdata(pdev);
258 struct spi_clps711x_data *hw = spi_master_get_devdata(master);
260 for (i = 0; i < master->num_chipselect; i++)
261 if (gpio_is_valid(hw->chipselect[i]))
262 gpio_free(hw->chipselect[i]);
264 spi_unregister_master(master);
270 static struct platform_driver clps711x_spi_driver = {
273 .owner = THIS_MODULE,
275 .probe = spi_clps711x_probe,
276 .remove = spi_clps711x_remove,
278 module_platform_driver(clps711x_spi_driver);
280 MODULE_LICENSE("GPL");
281 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
282 MODULE_DESCRIPTION("CLPS711X SPI bus driver");