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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.h>
 20 #include <linux/of_gpio.h>
 21 #include <linux/of_platform.h>
 22 
 23 #include "spi-dw.h"
 24 
 25 #define DRIVER_NAME "dw_spi_mmio"
 26 
 27 struct dw_spi_mmio {
 28         struct dw_spi  dws;
 29         struct clk     *clk;
 30 };
 31 
 32 static int dw_spi_mmio_probe(struct platform_device *pdev)
 33 {
 34         struct dw_spi_mmio *dwsmmio;
 35         struct dw_spi *dws;
 36         struct resource *mem;
 37         int ret;
 38         int num_cs;
 39 
 40         dwsmmio = devm_kzalloc(&pdev->dev, sizeof(struct dw_spi_mmio),
 41                         GFP_KERNEL);
 42         if (!dwsmmio)
 43                 return -ENOMEM;
 44 
 45         dws = &dwsmmio->dws;
 46 
 47         /* Get basic io resource and map it */
 48         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 49         if (!mem) {
 50                 dev_err(&pdev->dev, "no mem resource?\n");
 51                 return -EINVAL;
 52         }
 53 
 54         dws->regs = devm_ioremap_resource(&pdev->dev, mem);
 55         if (IS_ERR(dws->regs)) {
 56                 dev_err(&pdev->dev, "SPI region map failed\n");
 57                 return PTR_ERR(dws->regs);
 58         }
 59 
 60         dws->irq = platform_get_irq(pdev, 0);
 61         if (dws->irq < 0) {
 62                 dev_err(&pdev->dev, "no irq resource?\n");
 63                 return dws->irq; /* -ENXIO */
 64         }
 65 
 66         dwsmmio->clk = devm_clk_get(&pdev->dev, NULL);
 67         if (IS_ERR(dwsmmio->clk))
 68                 return PTR_ERR(dwsmmio->clk);
 69         ret = clk_prepare_enable(dwsmmio->clk);
 70         if (ret)
 71                 return ret;
 72 
 73         dws->bus_num = pdev->id;
 74 
 75         dws->max_freq = clk_get_rate(dwsmmio->clk);
 76 
 77         num_cs = 4;
 78 
 79         if (pdev->dev.of_node)
 80                 of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs);
 81 
 82         dws->num_cs = num_cs;
 83 
 84         if (pdev->dev.of_node) {
 85                 int i;
 86 
 87                 for (i = 0; i < dws->num_cs; i++) {
 88                         int cs_gpio = of_get_named_gpio(pdev->dev.of_node,
 89                                         "cs-gpios", i);
 90 
 91                         if (cs_gpio == -EPROBE_DEFER) {
 92                                 ret = cs_gpio;
 93                                 goto out;
 94                         }
 95 
 96                         if (gpio_is_valid(cs_gpio)) {
 97                                 ret = devm_gpio_request(&pdev->dev, cs_gpio,
 98                                                 dev_name(&pdev->dev));
 99                                 if (ret)
100                                         goto out;
101                         }
102                 }
103         }
104 
105         ret = dw_spi_add_host(&pdev->dev, dws);
106         if (ret)
107                 goto out;
108 
109         platform_set_drvdata(pdev, dwsmmio);
110         return 0;
111 
112 out:
113         clk_disable_unprepare(dwsmmio->clk);
114         return ret;
115 }
116 
117 static int dw_spi_mmio_remove(struct platform_device *pdev)
118 {
119         struct dw_spi_mmio *dwsmmio = platform_get_drvdata(pdev);
120 
121         clk_disable_unprepare(dwsmmio->clk);
122         dw_spi_remove_host(&dwsmmio->dws);
123 
124         return 0;
125 }
126 
127 static const struct of_device_id dw_spi_mmio_of_match[] = {
128         { .compatible = "snps,dw-apb-ssi", },
129         { /* end of table */}
130 };
131 MODULE_DEVICE_TABLE(of, dw_spi_mmio_of_match);
132 
133 static struct platform_driver dw_spi_mmio_driver = {
134         .probe          = dw_spi_mmio_probe,
135         .remove         = dw_spi_mmio_remove,
136         .driver         = {
137                 .name   = DRIVER_NAME,
138                 .owner  = THIS_MODULE,
139                 .of_match_table = dw_spi_mmio_of_match,
140         },
141 };
142 module_platform_driver(dw_spi_mmio_driver);
143 
144 MODULE_AUTHOR("Jean-Hugues Deschenes <jean-hugues.deschenes@octasic.com>");
145 MODULE_DESCRIPTION("Memory-mapped I/O interface driver for DW SPI Core");
146 MODULE_LICENSE("GPL v2");
147 

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