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jk-ozlabsalexandrebelloni
jk-ozlabs
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alexandrebelloni
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i3c: ast2600: Add AST2600 platform-specific driver
Now that we have platform-specific infrastructure for the dw i3c driver, add platform support for the ASPEED AST2600 SoC. The AST2600 has a small set of "i3c global" registers, providing platform-level i3c configuration outside of the i3c core. For the ast2600, we need a couple of extra setup operations: - on probe: find the i3c global register set and parse the SDA pullup resistor values - on init: set the pullups accordingly, and set the i3c instance IDs Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au> Reviewed-by: Joel Stanley <joel@jms.id.au> Link: https://lore.kernel.org/r/20230331091501.3800299-4-jk@codeconstruct.com.au Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
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‎MAINTAINERS‎

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F: Documentation/devicetree/bindings/i3c/snps,dw-i3c-master.yaml
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F: drivers/i3c/master/dw*
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I3C DRIVER FOR ASPEED AST2600
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M: Jeremy Kerr <jk@codeconstruct.com.au>
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S: Maintained
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F: Documentation/devicetree/bindings/i3c/aspeed,ast2600-i3c.yaml
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F: drivers/i3c/master/ast2600-i3c-master.c
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I3C SUBSYSTEM
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M: Alexandre Belloni <alexandre.belloni@bootlin.com>
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L: linux-i3c@lists.infradead.org (moderated for non-subscribers)

‎drivers/i3c/master/Kconfig‎

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This driver can also be built as a module. If so, the module
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will be called dw-i3c-master.
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config AST2600_I3C_MASTER
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tristate "ASPEED AST2600 I3C master driver"
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depends on DW_I3C_MASTER
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depends on ARCH_ASPEED || COMPILE_TEST
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select MFD_SYSCON
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help
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Support for ASPEED AST2600 I3C Controller.
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This hardware is an instance of the DW I3C controller; this
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driver adds platform- specific support for AST2600 hardware.
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This driver can also be built as a module. If so, the module
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will be called ast2600-i3c-master.
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config SVC_I3C_MASTER
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tristate "Silvaco I3C Dual-Role Master driver"
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depends on I3C

‎drivers/i3c/master/Makefile‎

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# SPDX-License-Identifier: GPL-2.0-only
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obj-$(CONFIG_CDNS_I3C_MASTER) += i3c-master-cdns.o
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obj-$(CONFIG_DW_I3C_MASTER) += dw-i3c-master.o
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obj-$(CONFIG_AST2600_I3C_MASTER) += ast2600-i3c-master.o
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obj-$(CONFIG_SVC_I3C_MASTER) += svc-i3c-master.o
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obj-$(CONFIG_MIPI_I3C_HCI) += mipi-i3c-hci/

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

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// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2023 Code Construct
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*
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* Author: Jeremy Kerr <jk@codeconstruct.com.au>
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*/
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#include <linux/mfd/syscon.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/regmap.h>
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#include "dw-i3c-master.h"
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/* AST2600-specific global register set */
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#define AST2600_I3CG_REG0(idx) (((idx) * 4 * 4) + 0x10)
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#define AST2600_I3CG_REG1(idx) (((idx) * 4 * 4) + 0x14)
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#define AST2600_I3CG_REG0_SDA_PULLUP_EN_MASK GENMASK(29, 28)
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#define AST2600_I3CG_REG0_SDA_PULLUP_EN_2K (0x0 << 28)
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#define AST2600_I3CG_REG0_SDA_PULLUP_EN_750 (0x2 << 28)
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#define AST2600_I3CG_REG1_I2C_MODE BIT(0)
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#define AST2600_I3CG_REG1_TEST_MODE BIT(1)
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#define AST2600_I3CG_REG1_ACT_MODE_MASK GENMASK(3, 2)
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#define AST2600_I3CG_REG1_ACT_MODE(x) (((x) << 2) & AST2600_I3CG_REG1_ACT_MODE_MASK)
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#define AST2600_I3CG_REG1_PENDING_INT_MASK GENMASK(7, 4)
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#define AST2600_I3CG_REG1_PENDING_INT(x) (((x) << 4) & AST2600_I3CG_REG1_PENDING_INT_MASK)
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#define AST2600_I3CG_REG1_SA_MASK GENMASK(14, 8)
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#define AST2600_I3CG_REG1_SA(x) (((x) << 8) & AST2600_I3CG_REG1_SA_MASK)
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#define AST2600_I3CG_REG1_SA_EN BIT(15)
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#define AST2600_I3CG_REG1_INST_ID_MASK GENMASK(19, 16)
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#define AST2600_I3CG_REG1_INST_ID(x) (((x) << 16) & AST2600_I3CG_REG1_INST_ID_MASK)
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#define AST2600_DEFAULT_SDA_PULLUP_OHMS 2000
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struct ast2600_i3c {
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struct dw_i3c_master dw;
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struct regmap *global_regs;
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unsigned int global_idx;
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unsigned int sda_pullup;
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};
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static struct ast2600_i3c *to_ast2600_i3c(struct dw_i3c_master *dw)
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{
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return container_of(dw, struct ast2600_i3c, dw);
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}
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static int ast2600_i3c_pullup_to_reg(unsigned int ohms, u32 *regp)
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{
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u32 reg;
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switch (ohms) {
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case 2000:
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reg = AST2600_I3CG_REG0_SDA_PULLUP_EN_2K;
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break;
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case 750:
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reg = AST2600_I3CG_REG0_SDA_PULLUP_EN_750;
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break;
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case 545:
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reg = AST2600_I3CG_REG0_SDA_PULLUP_EN_2K |
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AST2600_I3CG_REG0_SDA_PULLUP_EN_750;
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break;
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default:
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return -EINVAL;
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}
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if (regp)
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*regp = reg;
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return 0;
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}
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static int ast2600_i3c_init(struct dw_i3c_master *dw)
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{
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struct ast2600_i3c *i3c = to_ast2600_i3c(dw);
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u32 reg = 0;
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int rc;
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/* reg0: set SDA pullup values */
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rc = ast2600_i3c_pullup_to_reg(i3c->sda_pullup, &reg);
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if (rc)
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return rc;
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rc = regmap_write(i3c->global_regs,
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AST2600_I3CG_REG0(i3c->global_idx), reg);
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if (rc)
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return rc;
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/* reg1: set up the instance id, but leave everything else disabled,
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* as it's all for client mode
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*/
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reg = AST2600_I3CG_REG1_INST_ID(i3c->global_idx);
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rc = regmap_write(i3c->global_regs,
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AST2600_I3CG_REG1(i3c->global_idx), reg);
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return rc;
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}
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const struct dw_i3c_platform_ops ast2600_i3c_ops = {
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.init = ast2600_i3c_init,
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};
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static int ast2600_i3c_probe(struct platform_device *pdev)
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{
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struct device_node *np = pdev->dev.of_node;
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struct of_phandle_args gspec;
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struct ast2600_i3c *i3c;
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int rc;
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i3c = devm_kzalloc(&pdev->dev, sizeof(*i3c), GFP_KERNEL);
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if (!i3c)
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return -ENOMEM;
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rc = of_parse_phandle_with_fixed_args(np, "aspeed,global-regs", 1, 0,
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&gspec);
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if (rc)
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return -ENODEV;
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i3c->global_regs = syscon_node_to_regmap(gspec.np);
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of_node_put(gspec.np);
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if (IS_ERR(i3c->global_regs))
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return PTR_ERR(i3c->global_regs);
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i3c->global_idx = gspec.args[0];
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rc = of_property_read_u32(np, "sda-pullup-ohms", &i3c->sda_pullup);
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if (rc)
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i3c->sda_pullup = AST2600_DEFAULT_SDA_PULLUP_OHMS;
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rc = ast2600_i3c_pullup_to_reg(i3c->sda_pullup, NULL);
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if (rc)
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dev_err(&pdev->dev, "invalid sda-pullup value %d\n",
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i3c->sda_pullup);
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i3c->dw.platform_ops = &ast2600_i3c_ops;
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return dw_i3c_common_probe(&i3c->dw, pdev);
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}
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static void ast2600_i3c_remove(struct platform_device *pdev)
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{
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struct dw_i3c_master *dw_i3c = platform_get_drvdata(pdev);
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dw_i3c_common_remove(dw_i3c);
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}
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static const struct of_device_id ast2600_i3c_master_of_match[] = {
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{ .compatible = "aspeed,ast2600-i3c", },
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{},
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};
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MODULE_DEVICE_TABLE(of, ast2600_i3c_master_of_match);
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static struct platform_driver ast2600_i3c_driver = {
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.probe = ast2600_i3c_probe,
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.remove_new = ast2600_i3c_remove,
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.driver = {
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.name = "ast2600-i3c-master",
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.of_match_table = ast2600_i3c_master_of_match,
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},
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};
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module_platform_driver(ast2600_i3c_driver);
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MODULE_AUTHOR("Jeremy Kerr <jk@codeconstruct.com.au>");
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MODULE_DESCRIPTION("ASPEED AST2600 I3C driver");
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MODULE_LICENSE("GPL");

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