diff options
Diffstat (limited to 'drivers/i3c/master/ast2600-i3c-master.c')
| -rw-r--r-- | drivers/i3c/master/ast2600-i3c-master.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/drivers/i3c/master/ast2600-i3c-master.c b/drivers/i3c/master/ast2600-i3c-master.c new file mode 100644 index 0000000000..01a47d3dd4 --- /dev/null +++ b/drivers/i3c/master/ast2600-i3c-master.c @@ -0,0 +1,188 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2023 Code Construct + * + * Author: Jeremy Kerr <jk@codeconstruct.com.au> + */ + +#include <linux/mfd/syscon.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> + +#include "dw-i3c-master.h" + +/* AST2600-specific global register set */ +#define AST2600_I3CG_REG0(idx) (((idx) * 4 * 4) + 0x10) +#define AST2600_I3CG_REG1(idx) (((idx) * 4 * 4) + 0x14) + +#define AST2600_I3CG_REG0_SDA_PULLUP_EN_MASK GENMASK(29, 28) +#define AST2600_I3CG_REG0_SDA_PULLUP_EN_2K (0x0 << 28) +#define AST2600_I3CG_REG0_SDA_PULLUP_EN_750 (0x2 << 28) +#define AST2600_I3CG_REG0_SDA_PULLUP_EN_545 (0x3 << 28) + +#define AST2600_I3CG_REG1_I2C_MODE BIT(0) +#define AST2600_I3CG_REG1_TEST_MODE BIT(1) +#define AST2600_I3CG_REG1_ACT_MODE_MASK GENMASK(3, 2) +#define AST2600_I3CG_REG1_ACT_MODE(x) (((x) << 2) & AST2600_I3CG_REG1_ACT_MODE_MASK) +#define AST2600_I3CG_REG1_PENDING_INT_MASK GENMASK(7, 4) +#define AST2600_I3CG_REG1_PENDING_INT(x) (((x) << 4) & AST2600_I3CG_REG1_PENDING_INT_MASK) +#define AST2600_I3CG_REG1_SA_MASK GENMASK(14, 8) +#define AST2600_I3CG_REG1_SA(x) (((x) << 8) & AST2600_I3CG_REG1_SA_MASK) +#define AST2600_I3CG_REG1_SA_EN BIT(15) +#define AST2600_I3CG_REG1_INST_ID_MASK GENMASK(19, 16) +#define AST2600_I3CG_REG1_INST_ID(x) (((x) << 16) & AST2600_I3CG_REG1_INST_ID_MASK) + +#define AST2600_DEFAULT_SDA_PULLUP_OHMS 2000 + +#define DEV_ADDR_TABLE_IBI_PEC BIT(11) + +struct ast2600_i3c { + struct dw_i3c_master dw; + struct regmap *global_regs; + unsigned int global_idx; + unsigned int sda_pullup; +}; + +static struct ast2600_i3c *to_ast2600_i3c(struct dw_i3c_master *dw) +{ + return container_of(dw, struct ast2600_i3c, dw); +} + +static int ast2600_i3c_pullup_to_reg(unsigned int ohms, u32 *regp) +{ + u32 reg; + + switch (ohms) { + case 2000: + reg = AST2600_I3CG_REG0_SDA_PULLUP_EN_2K; + break; + case 750: + reg = AST2600_I3CG_REG0_SDA_PULLUP_EN_750; + break; + case 545: + reg = AST2600_I3CG_REG0_SDA_PULLUP_EN_545; + break; + default: + return -EINVAL; + } + + if (regp) + *regp = reg; + + return 0; +} + +static int ast2600_i3c_init(struct dw_i3c_master *dw) +{ + struct ast2600_i3c *i3c = to_ast2600_i3c(dw); + u32 reg = 0; + int rc; + + /* reg0: set SDA pullup values */ + rc = ast2600_i3c_pullup_to_reg(i3c->sda_pullup, ®); + if (rc) + return rc; + + rc = regmap_write(i3c->global_regs, + AST2600_I3CG_REG0(i3c->global_idx), reg); + if (rc) + return rc; + + /* reg1: set up the instance id, but leave everything else disabled, + * as it's all for client mode + */ + reg = AST2600_I3CG_REG1_INST_ID(i3c->global_idx); + rc = regmap_write(i3c->global_regs, + AST2600_I3CG_REG1(i3c->global_idx), reg); + + return rc; +} + +static void ast2600_i3c_set_dat_ibi(struct dw_i3c_master *i3c, + struct i3c_dev_desc *dev, + bool enable, u32 *dat) +{ + /* + * The ast2600 i3c controller will lock up on receiving 4n+1-byte IBIs + * if the PEC is disabled. We have no way to restrict the length of + * IBIs sent to the controller, so we need to unconditionally enable + * PEC checking, which means we drop a byte of payload data + */ + if (enable && dev->info.bcr & I3C_BCR_IBI_PAYLOAD) { + dev_warn_once(&i3c->base.dev, + "Enabling PEC workaround. IBI payloads will be truncated\n"); + *dat |= DEV_ADDR_TABLE_IBI_PEC; + } +} + +static const struct dw_i3c_platform_ops ast2600_i3c_ops = { + .init = ast2600_i3c_init, + .set_dat_ibi = ast2600_i3c_set_dat_ibi, +}; + +static int ast2600_i3c_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct of_phandle_args gspec; + struct ast2600_i3c *i3c; + int rc; + + i3c = devm_kzalloc(&pdev->dev, sizeof(*i3c), GFP_KERNEL); + if (!i3c) + return -ENOMEM; + + rc = of_parse_phandle_with_fixed_args(np, "aspeed,global-regs", 1, 0, + &gspec); + if (rc) + return -ENODEV; + + i3c->global_regs = syscon_node_to_regmap(gspec.np); + of_node_put(gspec.np); + + if (IS_ERR(i3c->global_regs)) + return PTR_ERR(i3c->global_regs); + + i3c->global_idx = gspec.args[0]; + + rc = of_property_read_u32(np, "sda-pullup-ohms", &i3c->sda_pullup); + if (rc) + i3c->sda_pullup = AST2600_DEFAULT_SDA_PULLUP_OHMS; + + rc = ast2600_i3c_pullup_to_reg(i3c->sda_pullup, NULL); + if (rc) + dev_err(&pdev->dev, "invalid sda-pullup value %d\n", + i3c->sda_pullup); + + i3c->dw.platform_ops = &ast2600_i3c_ops; + i3c->dw.ibi_capable = true; + return dw_i3c_common_probe(&i3c->dw, pdev); +} + +static void ast2600_i3c_remove(struct platform_device *pdev) +{ + struct dw_i3c_master *dw_i3c = platform_get_drvdata(pdev); + + dw_i3c_common_remove(dw_i3c); +} + +static const struct of_device_id ast2600_i3c_master_of_match[] = { + { .compatible = "aspeed,ast2600-i3c", }, + {}, +}; +MODULE_DEVICE_TABLE(of, ast2600_i3c_master_of_match); + +static struct platform_driver ast2600_i3c_driver = { + .probe = ast2600_i3c_probe, + .remove_new = ast2600_i3c_remove, + .driver = { + .name = "ast2600-i3c-master", + .of_match_table = ast2600_i3c_master_of_match, + }, +}; +module_platform_driver(ast2600_i3c_driver); + +MODULE_AUTHOR("Jeremy Kerr <jk@codeconstruct.com.au>"); +MODULE_DESCRIPTION("ASPEED AST2600 I3C driver"); +MODULE_LICENSE("GPL"); |