drivers/scsi/ufs/ti-j721e-ufs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 //
   3 // Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/
   4 //
   5
   6 #include <linux/clk.h>
   7 #include <linux/io.h>
   8 #include <linux/kernel.h>
   9 #include <linux/module.h>
  10 #include <linux/of_platform.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/pm_runtime.h>
  13
  14 #define TI_UFS_SS_CTRL          0x4
  15 #define TI_UFS_SS_RST_N_PCS     BIT(0)
  16 #define TI_UFS_SS_CLK_26MHZ     BIT(4)
  17
  18 static int ti_j721e_ufs_probe(struct platform_device *pdev)
  19 {
  20         struct device *dev = &pdev->dev;
  21         unsigned long clk_rate;
  22         void __iomem *regbase;
  23         struct clk *clk;
  24         u32 reg = 0;
  25         int ret;
  26
  27         regbase = devm_platform_ioremap_resource(pdev, 0);
  28         if (IS_ERR(regbase))
  29                 return PTR_ERR(regbase);
  30
  31         pm_runtime_enable(dev);
  32         ret = pm_runtime_get_sync(dev);
  33         if (ret < 0) {
  34                 pm_runtime_put_noidle(dev);
  35                 return ret;
  36         }
  37
  38         /* Select MPHY refclk frequency */
  39         clk = devm_clk_get(dev, NULL);
  40         if (IS_ERR(clk)) {
  41                 dev_err(dev, "Cannot claim MPHY clock.\n");
  42                 return PTR_ERR(clk);
  43         }
  44         clk_rate = clk_get_rate(clk);
  45         if (clk_rate == 26000000)
  46                 reg |= TI_UFS_SS_CLK_26MHZ;
  47         devm_clk_put(dev, clk);
  48
  49         /*  Take UFS slave device out of reset */
  50         reg |= TI_UFS_SS_RST_N_PCS;
  51         writel(reg, regbase + TI_UFS_SS_CTRL);
  52
  53         ret = of_platform_populate(pdev->dev.of_node, NULL, NULL,
  54                                    dev);
  55         if (ret) {
  56                 dev_err(dev, "failed to populate child nodes %d\n", ret);
  57                 pm_runtime_put_sync(dev);
  58         }
  59
  60         return ret;
  61 }
  62
  63 static int ti_j721e_ufs_remove(struct platform_device *pdev)
  64 {
  65         of_platform_depopulate(&pdev->dev);
  66         pm_runtime_put_sync(&pdev->dev);
  67
  68         return 0;
  69 }
  70
  71 static const struct of_device_id ti_j721e_ufs_of_match[] = {
  72         {
  73                 .compatible = "ti,j721e-ufs",
  74         },
  75         { },
  76 };
  77
  78 static struct platform_driver ti_j721e_ufs_driver = {
  79         .probe  = ti_j721e_ufs_probe,
  80         .remove = ti_j721e_ufs_remove,
  81         .driver = {
  82                 .name   = "ti-j721e-ufs",
  83                 .of_match_table = ti_j721e_ufs_of_match,
  84         },
  85 };
  86 module_platform_driver(ti_j721e_ufs_driver);
  87
  88 MODULE_AUTHOR("Vignesh Raghavendra <vigneshr@ti.com>");
  89 MODULE_DESCRIPTION("TI UFS host controller glue driver");
  90 MODULE_LICENSE("GPL v2");