drivers/gpu/drm/fsl-dcu/fsl_tcon.c

   1 /*
   2  * Copyright 2015 Toradex AG
   3  *
   4  * Stefan Agner <stefan@agner.ch>
   5  *
   6  * Freescale TCON device driver
   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; either version 2 of the License, or
  11  * (at your option) any later version.
  12  */
  13
  14 #include <linux/clk.h>
  15 #include <linux/io.h>
  16 #include <linux/mm.h>
  17 #include <linux/of_address.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/regmap.h>
  20
  21 #include "fsl_tcon.h"
  22
  23 void fsl_tcon_bypass_disable(struct fsl_tcon *tcon)
  24 {
  25         regmap_update_bits(tcon->regs, FSL_TCON_CTRL1,
  26                            FSL_TCON_CTRL1_TCON_BYPASS, 0);
  27 }
  28
  29 void fsl_tcon_bypass_enable(struct fsl_tcon *tcon)
  30 {
  31         regmap_update_bits(tcon->regs, FSL_TCON_CTRL1,
  32                            FSL_TCON_CTRL1_TCON_BYPASS,
  33                            FSL_TCON_CTRL1_TCON_BYPASS);
  34 }
  35
  36 static struct regmap_config fsl_tcon_regmap_config = {
  37         .reg_bits = 32,
  38         .reg_stride = 4,
  39         .val_bits = 32,
  40
  41         .name = "tcon",
  42 };
  43
  44 static int fsl_tcon_init_regmap(struct device *dev,
  45                                 struct fsl_tcon *tcon,
  46                                 struct device_node *np)
  47 {
  48         struct resource res;
  49         void __iomem *regs;
  50
  51         if (of_address_to_resource(np, 0, &res))
  52                 return -EINVAL;
  53
  54         regs = devm_ioremap_resource(dev, &res);
  55         if (IS_ERR(regs))
  56                 return PTR_ERR(regs);
  57
  58         tcon->regs = devm_regmap_init_mmio(dev, regs,
  59                                            &fsl_tcon_regmap_config);
  60         return PTR_ERR_OR_ZERO(tcon->regs);
  61 }
  62
  63 struct fsl_tcon *fsl_tcon_init(struct device *dev)
  64 {
  65         struct fsl_tcon *tcon;
  66         struct device_node *np;
  67         int ret;
  68
  69         /* TCON node is not mandatory, some devices do not provide TCON */
  70         np = of_parse_phandle(dev->of_node, "fsl,tcon", 0);
  71         if (!np)
  72                 return NULL;
  73
  74         tcon = devm_kzalloc(dev, sizeof(*tcon), GFP_KERNEL);
  75         if (!tcon) {
  76                 ret = -ENOMEM;
  77                 goto err_node_put;
  78         }
  79
  80         ret = fsl_tcon_init_regmap(dev, tcon, np);
  81         if (ret) {
  82                 dev_err(dev, "Couldn't create the TCON regmap\n");
  83                 goto err_node_put;
  84         }
  85
  86         tcon->ipg_clk = of_clk_get_by_name(np, "ipg");
  87         if (IS_ERR(tcon->ipg_clk)) {
  88                 dev_err(dev, "Couldn't get the TCON bus clock\n");
  89                 goto err_node_put;
  90         }
  91
  92         of_node_put(np);
  93         clk_prepare_enable(tcon->ipg_clk);
  94
  95         dev_info(dev, "Using TCON in bypass mode\n");
  96
  97         return tcon;
  98
  99 err_node_put:
 100         of_node_put(np);
 101         return NULL;
 102 }
 103
 104 void fsl_tcon_free(struct fsl_tcon *tcon)
 105 {
 106         clk_disable_unprepare(tcon->ipg_clk);
 107         clk_put(tcon->ipg_clk);
 108 }
 109