drivers/i3c/master/ast2600-i3c-master.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2023 Code Construct
   4  *
   5  * Author: Jeremy Kerr <jk@codeconstruct.com.au>
   6  */
   7
   8 #include <linux/mfd/syscon.h>
   9 #include <linux/module.h>
  10 #include <linux/of.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/regmap.h>
  13
  14 #include "dw-i3c-master.h"
  15
  16 /* AST2600-specific global register set */
  17 #define AST2600_I3CG_REG0(idx)  (((idx) * 4 * 4) + 0x10)
  18 #define AST2600_I3CG_REG1(idx)  (((idx) * 4 * 4) + 0x14)
  19
  20 #define AST2600_I3CG_REG0_SDA_PULLUP_EN_MASK    GENMASK(29, 28)
  21 #define AST2600_I3CG_REG0_SDA_PULLUP_EN_2K      (0x0 << 28)
  22 #define AST2600_I3CG_REG0_SDA_PULLUP_EN_750     (0x2 << 28)
  23 #define AST2600_I3CG_REG0_SDA_PULLUP_EN_545     (0x3 << 28)
  24
  25 #define AST2600_I3CG_REG1_I2C_MODE              BIT(0)
  26 #define AST2600_I3CG_REG1_TEST_MODE             BIT(1)
  27 #define AST2600_I3CG_REG1_ACT_MODE_MASK         GENMASK(3, 2)
  28 #define AST2600_I3CG_REG1_ACT_MODE(x)           (((x) << 2) & AST2600_I3CG_REG1_ACT_MODE_MASK)
  29 #define AST2600_I3CG_REG1_PENDING_INT_MASK      GENMASK(7, 4)
  30 #define AST2600_I3CG_REG1_PENDING_INT(x)        (((x) << 4) & AST2600_I3CG_REG1_PENDING_INT_MASK)
  31 #define AST2600_I3CG_REG1_SA_MASK               GENMASK(14, 8)
  32 #define AST2600_I3CG_REG1_SA(x)                 (((x) << 8) & AST2600_I3CG_REG1_SA_MASK)
  33 #define AST2600_I3CG_REG1_SA_EN                 BIT(15)
  34 #define AST2600_I3CG_REG1_INST_ID_MASK          GENMASK(19, 16)
  35 #define AST2600_I3CG_REG1_INST_ID(x)            (((x) << 16) & AST2600_I3CG_REG1_INST_ID_MASK)
  36
  37 #define AST2600_DEFAULT_SDA_PULLUP_OHMS         2000
  38
  39 #define DEV_ADDR_TABLE_IBI_PEC                  BIT(11)
  40
  41 struct ast2600_i3c {
  42         struct dw_i3c_master dw;
  43         struct regmap *global_regs;
  44         unsigned int global_idx;
  45         unsigned int sda_pullup;
  46 };
  47
  48 static struct ast2600_i3c *to_ast2600_i3c(struct dw_i3c_master *dw)
  49 {
  50         return container_of(dw, struct ast2600_i3c, dw);
  51 }
  52
  53 static int ast2600_i3c_pullup_to_reg(unsigned int ohms, u32 *regp)
  54 {
  55         u32 reg;
  56
  57         switch (ohms) {
  58         case 2000:
  59                 reg = AST2600_I3CG_REG0_SDA_PULLUP_EN_2K;
  60                 break;
  61         case 750:
  62                 reg = AST2600_I3CG_REG0_SDA_PULLUP_EN_750;
  63                 break;
  64         case 545:
  65                 reg = AST2600_I3CG_REG0_SDA_PULLUP_EN_545;
  66                 break;
  67         default:
  68                 return -EINVAL;
  69         }
  70
  71         if (regp)
  72                 *regp = reg;
  73
  74         return 0;
  75 }
  76
  77 static int ast2600_i3c_init(struct dw_i3c_master *dw)
  78 {
  79         struct ast2600_i3c *i3c = to_ast2600_i3c(dw);
  80         u32 reg = 0;
  81         int rc;
  82
  83         /* reg0: set SDA pullup values */
  84         rc = ast2600_i3c_pullup_to_reg(i3c->sda_pullup, &reg);
  85         if (rc)
  86                 return rc;
  87
  88         rc = regmap_write(i3c->global_regs,
  89                           AST2600_I3CG_REG0(i3c->global_idx), reg);
  90         if (rc)
  91                 return rc;
  92
  93         /* reg1: set up the instance id, but leave everything else disabled,
  94          * as it's all for client mode
  95          */
  96         reg = AST2600_I3CG_REG1_INST_ID(i3c->global_idx);
  97         rc = regmap_write(i3c->global_regs,
  98                           AST2600_I3CG_REG1(i3c->global_idx), reg);
  99
 100         return rc;
 101 }
 102
 103 static void ast2600_i3c_set_dat_ibi(struct dw_i3c_master *i3c,
 104                                     struct i3c_dev_desc *dev,
 105                                     bool enable, u32 *dat)
 106 {
 107         /*
 108          * The ast2600 i3c controller will lock up on receiving 4n+1-byte IBIs
 109          * if the PEC is disabled. We have no way to restrict the length of
 110          * IBIs sent to the controller, so we need to unconditionally enable
 111          * PEC checking, which means we drop a byte of payload data
 112          */
 113         if (enable && dev->info.bcr & I3C_BCR_IBI_PAYLOAD) {
 114                 dev_warn_once(&i3c->base.dev,
 115                       "Enabling PEC workaround. IBI payloads will be truncated\n");
 116                 *dat |= DEV_ADDR_TABLE_IBI_PEC;
 117         }
 118 }
 119
 120 static const struct dw_i3c_platform_ops ast2600_i3c_ops = {
 121         .init = ast2600_i3c_init,
 122         .set_dat_ibi = ast2600_i3c_set_dat_ibi,
 123 };
 124
 125 static int ast2600_i3c_probe(struct platform_device *pdev)
 126 {
 127         struct device_node *np = pdev->dev.of_node;
 128         struct of_phandle_args gspec;
 129         struct ast2600_i3c *i3c;
 130         int rc;
 131
 132         i3c = devm_kzalloc(&pdev->dev, sizeof(*i3c), GFP_KERNEL);
 133         if (!i3c)
 134                 return -ENOMEM;
 135
 136         rc = of_parse_phandle_with_fixed_args(np, "aspeed,global-regs", 1, 0,
 137                                               &gspec);
 138         if (rc)
 139                 return -ENODEV;
 140
 141         i3c->global_regs = syscon_node_to_regmap(gspec.np);
 142         of_node_put(gspec.np);
 143
 144         if (IS_ERR(i3c->global_regs))
 145                 return PTR_ERR(i3c->global_regs);
 146
 147         i3c->global_idx = gspec.args[0];
 148
 149         rc = of_property_read_u32(np, "sda-pullup-ohms", &i3c->sda_pullup);
 150         if (rc)
 151                 i3c->sda_pullup = AST2600_DEFAULT_SDA_PULLUP_OHMS;
 152
 153         rc = ast2600_i3c_pullup_to_reg(i3c->sda_pullup, NULL);
 154         if (rc)
 155                 dev_err(&pdev->dev, "invalid sda-pullup value %d\n",
 156                         i3c->sda_pullup);
 157
 158         i3c->dw.platform_ops = &ast2600_i3c_ops;
 159         return dw_i3c_common_probe(&i3c->dw, pdev);
 160 }
 161
 162 static void ast2600_i3c_remove(struct platform_device *pdev)
 163 {
 164         struct dw_i3c_master *dw_i3c = platform_get_drvdata(pdev);
 165
 166         dw_i3c_common_remove(dw_i3c);
 167 }
 168
 169 static const struct of_device_id ast2600_i3c_master_of_match[] = {
 170         { .compatible = "aspeed,ast2600-i3c", },
 171         {},
 172 };
 173 MODULE_DEVICE_TABLE(of, ast2600_i3c_master_of_match);
 174
 175 static struct platform_driver ast2600_i3c_driver = {
 176         .probe = ast2600_i3c_probe,
 177         .remove = ast2600_i3c_remove,
 178         .driver = {
 179                 .name = "ast2600-i3c-master",
 180                 .of_match_table = ast2600_i3c_master_of_match,
 181         },
 182 };
 183 module_platform_driver(ast2600_i3c_driver);
 184
 185 MODULE_AUTHOR("Jeremy Kerr <jk@codeconstruct.com.au>");
 186 MODULE_DESCRIPTION("ASPEED AST2600 I3C driver");
 187 MODULE_LICENSE("GPL");