Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18

Linux/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                 .owner  = THIS_MODULE,
207         },
208         .probe  = spi_clps711x_probe,
209 };
210 module_platform_driver(clps711x_spi_driver);
211 
212 MODULE_LICENSE("GPL");
213 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
214 MODULE_DESCRIPTION("CLPS711X SPI bus driver");
215 MODULE_ALIAS("platform:" DRIVER_NAME);
216 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us