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Linux/drivers/spi/spi-dw-mmio.c

  1 /*
  2  * Memory-mapped interface driver for DW SPI Core
  3  *
  4  * Copyright (c) 2010, Octasic semiconductor.
  5  *
  6  * This program is free software; you can redistribute it and/or modify it
  7  * under the terms and conditions of the GNU General Public License,
  8  * version 2, as published by the Free Software Foundation.
  9  */
 10 
 11 #include <linux/clk.h>
 12 #include <linux/err.h>
 13 #include <linux/interrupt.h>
 14 #include <linux/platform_device.h>
 15 #include <linux/slab.h>
 16 #include <linux/spi/spi.h>
 17 #include <linux/scatterlist.h>
 18 #include <linux/module.h>
 19 #include <linux/of_gpio.h>
 20 
 21 #include "spi-dw.h"
 22 
 23 #define DRIVER_NAME "dw_spi_mmio"
 24 
 25 struct dw_spi_mmio {
 26         struct dw_spi  dws;
 27         struct clk     *clk;
 28 };
 29 
 30 static int dw_spi_mmio_probe(struct platform_device *pdev)
 31 {
 32         struct dw_spi_mmio *dwsmmio;
 33         struct dw_spi *dws;
 34         struct resource *mem;
 35         int ret;
 36 
 37         dwsmmio = devm_kzalloc(&pdev->dev, sizeof(struct dw_spi_mmio),
 38                         GFP_KERNEL);
 39         if (!dwsmmio)
 40                 return -ENOMEM;
 41 
 42         dws = &dwsmmio->dws;
 43 
 44         /* Get basic io resource and map it */
 45         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 46         if (!mem) {
 47                 dev_err(&pdev->dev, "no mem resource?\n");
 48                 return -EINVAL;
 49         }
 50 
 51         dws->regs = devm_ioremap_resource(&pdev->dev, mem);
 52         if (IS_ERR(dws->regs)) {
 53                 dev_err(&pdev->dev, "SPI region map failed\n");
 54                 return PTR_ERR(dws->regs);
 55         }
 56 
 57         dws->irq = platform_get_irq(pdev, 0);
 58         if (dws->irq < 0) {
 59                 dev_err(&pdev->dev, "no irq resource?\n");
 60                 return dws->irq; /* -ENXIO */
 61         }
 62 
 63         dwsmmio->clk = devm_clk_get(&pdev->dev, NULL);
 64         if (IS_ERR(dwsmmio->clk))
 65                 return PTR_ERR(dwsmmio->clk);
 66         ret = clk_prepare_enable(dwsmmio->clk);
 67         if (ret)
 68                 return ret;
 69 
 70         dws->bus_num = pdev->id;
 71         dws->num_cs = 4;
 72         dws->max_freq = clk_get_rate(dwsmmio->clk);
 73 
 74         if (pdev->dev.of_node) {
 75                 int i;
 76 
 77                 for (i = 0; i < dws->num_cs; i++) {
 78                         int cs_gpio = of_get_named_gpio(pdev->dev.of_node,
 79                                         "cs-gpios", i);
 80 
 81                         if (cs_gpio == -EPROBE_DEFER) {
 82                                 ret = cs_gpio;
 83                                 goto out;
 84                         }
 85 
 86                         if (gpio_is_valid(cs_gpio)) {
 87                                 ret = devm_gpio_request(&pdev->dev, cs_gpio,
 88                                                 dev_name(&pdev->dev));
 89                                 if (ret)
 90                                         goto out;
 91                         }
 92                 }
 93         }
 94 
 95         ret = dw_spi_add_host(&pdev->dev, dws);
 96         if (ret)
 97                 goto out;
 98 
 99         platform_set_drvdata(pdev, dwsmmio);
100         return 0;
101 
102 out:
103         clk_disable_unprepare(dwsmmio->clk);
104         return ret;
105 }
106 
107 static int dw_spi_mmio_remove(struct platform_device *pdev)
108 {
109         struct dw_spi_mmio *dwsmmio = platform_get_drvdata(pdev);
110 
111         clk_disable_unprepare(dwsmmio->clk);
112         dw_spi_remove_host(&dwsmmio->dws);
113 
114         return 0;
115 }
116 
117 static struct platform_driver dw_spi_mmio_driver = {
118         .probe          = dw_spi_mmio_probe,
119         .remove         = dw_spi_mmio_remove,
120         .driver         = {
121                 .name   = DRIVER_NAME,
122                 .owner  = THIS_MODULE,
123         },
124 };
125 module_platform_driver(dw_spi_mmio_driver);
126 
127 MODULE_AUTHOR("Jean-Hugues Deschenes <jean-hugues.deschenes@octasic.com>");
128 MODULE_DESCRIPTION("Memory-mapped I/O interface driver for DW SPI Core");
129 MODULE_LICENSE("GPL v2");
130 

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