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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 #include <linux/property.h>
 23 
 24 #include "spi-dw.h"
 25 
 26 #define DRIVER_NAME "dw_spi_mmio"
 27 
 28 struct dw_spi_mmio {
 29         struct dw_spi  dws;
 30         struct clk     *clk;
 31 };
 32 
 33 static int dw_spi_mmio_probe(struct platform_device *pdev)
 34 {
 35         struct dw_spi_mmio *dwsmmio;
 36         struct dw_spi *dws;
 37         struct resource *mem;
 38         int ret;
 39         int num_cs;
 40 
 41         dwsmmio = devm_kzalloc(&pdev->dev, sizeof(struct dw_spi_mmio),
 42                         GFP_KERNEL);
 43         if (!dwsmmio)
 44                 return -ENOMEM;
 45 
 46         dws = &dwsmmio->dws;
 47 
 48         /* Get basic io resource and map it */
 49         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 50         dws->regs = devm_ioremap_resource(&pdev->dev, mem);
 51         if (IS_ERR(dws->regs)) {
 52                 dev_err(&pdev->dev, "SPI region map failed\n");
 53                 return PTR_ERR(dws->regs);
 54         }
 55 
 56         dws->irq = platform_get_irq(pdev, 0);
 57         if (dws->irq < 0) {
 58                 dev_err(&pdev->dev, "no irq resource?\n");
 59                 return dws->irq; /* -ENXIO */
 60         }
 61 
 62         dwsmmio->clk = devm_clk_get(&pdev->dev, NULL);
 63         if (IS_ERR(dwsmmio->clk))
 64                 return PTR_ERR(dwsmmio->clk);
 65         ret = clk_prepare_enable(dwsmmio->clk);
 66         if (ret)
 67                 return ret;
 68 
 69         dws->bus_num = pdev->id;
 70 
 71         dws->max_freq = clk_get_rate(dwsmmio->clk);
 72 
 73         device_property_read_u32(&pdev->dev, "reg-io-width", &dws->reg_io_width);
 74 
 75         num_cs = 4;
 76 
 77         device_property_read_u32(&pdev->dev, "num-cs", &num_cs);
 78 
 79         dws->num_cs = num_cs;
 80 
 81         if (pdev->dev.of_node) {
 82                 int i;
 83 
 84                 for (i = 0; i < dws->num_cs; i++) {
 85                         int cs_gpio = of_get_named_gpio(pdev->dev.of_node,
 86                                         "cs-gpios", i);
 87 
 88                         if (cs_gpio == -EPROBE_DEFER) {
 89                                 ret = cs_gpio;
 90                                 goto out;
 91                         }
 92 
 93                         if (gpio_is_valid(cs_gpio)) {
 94                                 ret = devm_gpio_request(&pdev->dev, cs_gpio,
 95                                                 dev_name(&pdev->dev));
 96                                 if (ret)
 97                                         goto out;
 98                         }
 99                 }
100         }
101 
102         ret = dw_spi_add_host(&pdev->dev, dws);
103         if (ret)
104                 goto out;
105 
106         platform_set_drvdata(pdev, dwsmmio);
107         return 0;
108 
109 out:
110         clk_disable_unprepare(dwsmmio->clk);
111         return ret;
112 }
113 
114 static int dw_spi_mmio_remove(struct platform_device *pdev)
115 {
116         struct dw_spi_mmio *dwsmmio = platform_get_drvdata(pdev);
117 
118         clk_disable_unprepare(dwsmmio->clk);
119         dw_spi_remove_host(&dwsmmio->dws);
120 
121         return 0;
122 }
123 
124 static const struct of_device_id dw_spi_mmio_of_match[] = {
125         { .compatible = "snps,dw-apb-ssi", },
126         { /* end of table */}
127 };
128 MODULE_DEVICE_TABLE(of, dw_spi_mmio_of_match);
129 
130 static struct platform_driver dw_spi_mmio_driver = {
131         .probe          = dw_spi_mmio_probe,
132         .remove         = dw_spi_mmio_remove,
133         .driver         = {
134                 .name   = DRIVER_NAME,
135                 .of_match_table = dw_spi_mmio_of_match,
136         },
137 };
138 module_platform_driver(dw_spi_mmio_driver);
139 
140 MODULE_AUTHOR("Jean-Hugues Deschenes <jean-hugues.deschenes@octasic.com>");
141 MODULE_DESCRIPTION("Memory-mapped I/O interface driver for DW SPI Core");
142 MODULE_LICENSE("GPL v2");
143 

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