drivers/gpu/drm/armada/armada_510.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2012 Russell King
   4  *
   5  * Armada 510 (aka Dove) variant support
   6  */
   7 #include <linux/clk.h>
   8 #include <linux/io.h>
   9 #include <drm/drm_probe_helper.h>
  10 #include "armada_crtc.h"
  11 #include "armada_drm.h"
  12 #include "armada_hw.h"
  13
  14 struct armada510_variant_data {
  15         struct clk *clks[4];
  16         struct clk *sel_clk;
  17 };
  18
  19 static int armada510_crtc_init(struct armada_crtc *dcrtc, struct device *dev)
  20 {
  21         struct armada510_variant_data *v;
  22         struct clk *clk;
  23         int idx;
  24
  25         v = devm_kzalloc(dev, sizeof(*v), GFP_KERNEL);
  26         if (!v)
  27                 return -ENOMEM;
  28
  29         dcrtc->variant_data = v;
  30
  31         if (dev->of_node) {
  32                 struct property *prop;
  33                 const char *s;
  34
  35                 of_property_for_each_string(dev->of_node, "clock-names", prop,
  36                                             s) {
  37                         if (!strcmp(s, "ext_ref_clk0"))
  38                                 idx = 0;
  39                         else if (!strcmp(s, "ext_ref_clk1"))
  40                                 idx = 1;
  41                         else if (!strcmp(s, "plldivider"))
  42                                 idx = 2;
  43                         else if (!strcmp(s, "axibus"))
  44                                 idx = 3;
  45                         else
  46                                 continue;
  47
  48                         clk = devm_clk_get(dev, s);
  49                         if (IS_ERR(clk))
  50                                 return PTR_ERR(clk) == -ENOENT ? -EPROBE_DEFER :
  51                                         PTR_ERR(clk);
  52                         v->clks[idx] = clk;
  53                 }
  54         } else {
  55                 clk = devm_clk_get(dev, "ext_ref_clk1");
  56                 if (IS_ERR(clk))
  57                         return PTR_ERR(clk) == -ENOENT ? -EPROBE_DEFER :
  58                                 PTR_ERR(clk);
  59
  60                 v->clks[1] = clk;
  61         }
  62
  63         /*
  64          * Lower the watermark so to eliminate jitter at higher bandwidths.
  65          * Disable SRAM read wait state to avoid system hang with external
  66          * clock.
  67          */
  68         armada_updatel(CFG_DMA_WM(0x20), CFG_SRAM_WAIT | CFG_DMA_WM_MASK,
  69                        dcrtc->base + LCD_CFG_RDREG4F);
  70
  71         /* Initialise SPU register */
  72         writel_relaxed(ADV_HWC32ENABLE | ADV_HWC32ARGB | ADV_HWC32BLEND,
  73                        dcrtc->base + LCD_SPU_ADV_REG);
  74
  75         return 0;
  76 }
  77
  78 static const u32 armada510_clk_sels[] = {
  79         SCLK_510_EXTCLK0,
  80         SCLK_510_EXTCLK1,
  81         SCLK_510_PLL,
  82         SCLK_510_AXI,
  83 };
  84
  85 static const struct armada_clocking_params armada510_clocking = {
  86         /* HDMI requires -0.6%..+0.5% */
  87         .permillage_min = 994,
  88         .permillage_max = 1005,
  89         .settable = BIT(0) | BIT(1),
  90         .div_max = SCLK_510_INT_DIV_MASK,
  91 };
  92
  93 /*
  94  * Armada510 specific SCLK register selection.
  95  * This gets called with sclk = NULL to test whether the mode is
  96  * supportable, and again with sclk != NULL to set the clocks up for
  97  * that.  The former can return an error, but the latter is expected
  98  * not to.
  99  */
 100 static int armada510_crtc_compute_clock(struct armada_crtc *dcrtc,
 101         const struct drm_display_mode *mode, uint32_t *sclk)
 102 {
 103         struct armada510_variant_data *v = dcrtc->variant_data;
 104         unsigned long desired_khz = mode->crtc_clock;
 105         struct armada_clk_result res;
 106         int ret, idx;
 107
 108         idx = armada_crtc_select_clock(dcrtc, &res, &armada510_clocking,
 109                                        v->clks, ARRAY_SIZE(v->clks),
 110                                        desired_khz);
 111         if (idx < 0)
 112                 return idx;
 113
 114         ret = clk_prepare_enable(res.clk);
 115         if (ret)
 116                 return ret;
 117
 118         if (sclk) {
 119                 clk_set_rate(res.clk, res.desired_clk_hz);
 120
 121                 *sclk = res.div | armada510_clk_sels[idx];
 122
 123                 /* We are now using this clock */
 124                 v->sel_clk = res.clk;
 125                 swap(dcrtc->clk, res.clk);
 126         }
 127
 128         clk_disable_unprepare(res.clk);
 129
 130         return 0;
 131 }
 132
 133 static void armada510_crtc_disable(struct armada_crtc *dcrtc)
 134 {
 135         if (dcrtc->clk) {
 136                 clk_disable_unprepare(dcrtc->clk);
 137                 dcrtc->clk = NULL;
 138         }
 139 }
 140
 141 static void armada510_crtc_enable(struct armada_crtc *dcrtc,
 142         const struct drm_display_mode *mode)
 143 {
 144         struct armada510_variant_data *v = dcrtc->variant_data;
 145
 146         if (!dcrtc->clk && v->sel_clk) {
 147                 if (!WARN_ON(clk_prepare_enable(v->sel_clk)))
 148                         dcrtc->clk = v->sel_clk;
 149         }
 150 }
 151
 152 const struct armada_variant armada510_ops = {
 153         .has_spu_adv_reg = true,
 154         .init = armada510_crtc_init,
 155         .compute_clock = armada510_crtc_compute_clock,
 156         .disable = armada510_crtc_disable,
 157         .enable = armada510_crtc_enable,
 158 };