drivers/memory/atmel-sdramc.c

   1 /*
   2  * Atmel (Multi-port DDR-)SDRAM Controller driver
   3  *
   4  * Author: Alexandre Belloni <alexandre.belloni@free-electrons.com>
   5  *
   6  * Copyright (C) 2014 Atmel
   7  *
   8  * This program is free software: you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation version 2 of the License.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 #include <linux/clk.h>
  23 #include <linux/err.h>
  24 #include <linux/kernel.h>
  25 #include <linux/init.h>
  26 #include <linux/of_platform.h>
  27 #include <linux/platform_device.h>
  28
  29 struct at91_ramc_caps {
  30         bool has_ddrck;
  31         bool has_mpddr_clk;
  32 };
  33
  34 static const struct at91_ramc_caps at91rm9200_caps = { };
  35
  36 static const struct at91_ramc_caps at91sam9g45_caps = {
  37         .has_ddrck = 1,
  38         .has_mpddr_clk = 0,
  39 };
  40
  41 static const struct at91_ramc_caps sama5d3_caps = {
  42         .has_ddrck = 1,
  43         .has_mpddr_clk = 1,
  44 };
  45
  46 static const struct of_device_id atmel_ramc_of_match[] = {
  47         { .compatible = "atmel,at91rm9200-sdramc", .data = &at91rm9200_caps, },
  48         { .compatible = "atmel,at91sam9260-sdramc", .data = &at91rm9200_caps, },
  49         { .compatible = "atmel,at91sam9g45-ddramc", .data = &at91sam9g45_caps, },
  50         { .compatible = "atmel,sama5d3-ddramc", .data = &sama5d3_caps, },
  51         {},
  52 };
  53
  54 static int atmel_ramc_probe(struct platform_device *pdev)
  55 {
  56         const struct of_device_id *match;
  57         const struct at91_ramc_caps *caps;
  58         struct clk *clk;
  59
  60         match = of_match_device(atmel_ramc_of_match, &pdev->dev);
  61         caps = match->data;
  62
  63         if (caps->has_ddrck) {
  64                 clk = devm_clk_get(&pdev->dev, "ddrck");
  65                 if (IS_ERR(clk))
  66                         return PTR_ERR(clk);
  67                 clk_prepare_enable(clk);
  68         }
  69
  70         if (caps->has_mpddr_clk) {
  71                 clk = devm_clk_get(&pdev->dev, "mpddr");
  72                 if (IS_ERR(clk)) {
  73                         pr_err("AT91 RAMC: couldn't get mpddr clock\n");
  74                         return PTR_ERR(clk);
  75                 }
  76                 clk_prepare_enable(clk);
  77         }
  78
  79         return 0;
  80 }
  81
  82 static struct platform_driver atmel_ramc_driver = {
  83         .probe          = atmel_ramc_probe,
  84         .driver         = {
  85                 .name   = "atmel-ramc",
  86                 .of_match_table = atmel_ramc_of_match,
  87         },
  88 };
  89
  90 static int __init atmel_ramc_init(void)
  91 {
  92         return platform_driver_register(&atmel_ramc_driver);
  93 }
  94 device_initcall(atmel_ramc_init);