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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Wondermedia I2C Controller Driver4 *5 * Copyright (C) 2012 Tony Prisk <linux@prisktech.co.nz>6 *7 * Derived from GPLv2+ licensed source:8 * - Copyright (C) 2008 WonderMedia Technologies, Inc.9 */10 11#include <linux/clk.h>12#include <linux/of.h>13#include <linux/of_address.h>14#include "i2c-viai2c-common.h"15 16#define REG_SLAVE_CR 0x1017#define REG_SLAVE_SR 0x1218#define REG_SLAVE_ISR 0x1419#define REG_SLAVE_IMR 0x1620#define REG_SLAVE_DR 0x1821#define REG_SLAVE_TR 0x1A22 23/* REG_TR */24#define SCL_TIMEOUT(x) (((x) & 0xFF) << 8)25#define TR_STD 0x006426#define TR_HS 0x001927 28/* REG_MCR */29#define MCR_APB_96M 730#define MCR_APB_166M 1231 32static u32 wmt_i2c_func(struct i2c_adapter *adap)33{34 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_NOSTART;35}36 37static const struct i2c_algorithm wmt_i2c_algo = {38 .xfer = viai2c_xfer,39 .functionality = wmt_i2c_func,40};41 42static int wmt_i2c_reset_hardware(struct viai2c *i2c)43{44 int err;45 46 err = clk_prepare_enable(i2c->clk);47 if (err) {48 dev_err(i2c->dev, "failed to enable clock\n");49 return err;50 }51 52 err = clk_set_rate(i2c->clk, 20000000);53 if (err) {54 dev_err(i2c->dev, "failed to set clock = 20Mhz\n");55 clk_disable_unprepare(i2c->clk);56 return err;57 }58 59 writew(0, i2c->base + VIAI2C_REG_CR);60 writew(MCR_APB_166M, i2c->base + VIAI2C_REG_MCR);61 writew(VIAI2C_ISR_MASK_ALL, i2c->base + VIAI2C_REG_ISR);62 writew(VIAI2C_IMR_ENABLE_ALL, i2c->base + VIAI2C_REG_IMR);63 writew(VIAI2C_CR_ENABLE, i2c->base + VIAI2C_REG_CR);64 readw(i2c->base + VIAI2C_REG_CSR); /* read clear */65 writew(VIAI2C_ISR_MASK_ALL, i2c->base + VIAI2C_REG_ISR);66 67 if (i2c->tcr == VIAI2C_TCR_FAST)68 writew(SCL_TIMEOUT(128) | TR_HS, i2c->base + VIAI2C_REG_TR);69 else70 writew(SCL_TIMEOUT(128) | TR_STD, i2c->base + VIAI2C_REG_TR);71 72 return 0;73}74 75static irqreturn_t wmt_i2c_isr(int irq, void *data)76{77 struct viai2c *i2c = data;78 u8 status;79 80 /* save the status and write-clear it */81 status = readw(i2c->base + VIAI2C_REG_ISR);82 writew(status, i2c->base + VIAI2C_REG_ISR);83 84 i2c->ret = 0;85 if (status & VIAI2C_ISR_NACK_ADDR)86 i2c->ret = -EIO;87 88 if (status & VIAI2C_ISR_SCL_TIMEOUT)89 i2c->ret = -ETIMEDOUT;90 91 if (!i2c->ret)92 i2c->ret = viai2c_irq_xfer(i2c);93 94 /* All the data has been successfully transferred or error occurred */95 if (i2c->ret)96 complete(&i2c->complete);97 98 return IRQ_HANDLED;99}100 101static int wmt_i2c_probe(struct platform_device *pdev)102{103 struct device_node *np = pdev->dev.of_node;104 struct viai2c *i2c;105 struct i2c_adapter *adap;106 int err;107 u32 clk_rate;108 109 err = viai2c_init(pdev, &i2c, VIAI2C_PLAT_WMT);110 if (err)111 return err;112 113 i2c->irq = platform_get_irq(pdev, 0);114 if (i2c->irq < 0)115 return i2c->irq;116 117 err = devm_request_irq(&pdev->dev, i2c->irq, wmt_i2c_isr,118 0, pdev->name, i2c);119 if (err)120 return dev_err_probe(&pdev->dev, err,121 "failed to request irq %i\n", i2c->irq);122 123 i2c->clk = of_clk_get(np, 0);124 if (IS_ERR(i2c->clk)) {125 dev_err(&pdev->dev, "unable to request clock\n");126 return PTR_ERR(i2c->clk);127 }128 129 err = of_property_read_u32(np, "clock-frequency", &clk_rate);130 if (!err && clk_rate == I2C_MAX_FAST_MODE_FREQ)131 i2c->tcr = VIAI2C_TCR_FAST;132 133 adap = &i2c->adapter;134 i2c_set_adapdata(adap, i2c);135 strscpy(adap->name, "WMT I2C adapter", sizeof(adap->name));136 adap->owner = THIS_MODULE;137 adap->algo = &wmt_i2c_algo;138 adap->dev.parent = &pdev->dev;139 adap->dev.of_node = pdev->dev.of_node;140 141 err = wmt_i2c_reset_hardware(i2c);142 if (err) {143 dev_err(&pdev->dev, "error initializing hardware\n");144 return err;145 }146 147 err = i2c_add_adapter(adap);148 if (err)149 /* wmt_i2c_reset_hardware() enables i2c_dev->clk */150 clk_disable_unprepare(i2c->clk);151 152 return err;153}154 155static void wmt_i2c_remove(struct platform_device *pdev)156{157 struct viai2c *i2c = platform_get_drvdata(pdev);158 159 /* Disable interrupts, clock and delete adapter */160 writew(0, i2c->base + VIAI2C_REG_IMR);161 clk_disable_unprepare(i2c->clk);162 i2c_del_adapter(&i2c->adapter);163}164 165static const struct of_device_id wmt_i2c_dt_ids[] = {166 { .compatible = "wm,wm8505-i2c" },167 { /* Sentinel */ },168};169 170static struct platform_driver wmt_i2c_driver = {171 .probe = wmt_i2c_probe,172 .remove_new = wmt_i2c_remove,173 .driver = {174 .name = "wmt-i2c",175 .of_match_table = wmt_i2c_dt_ids,176 },177};178 179module_platform_driver(wmt_i2c_driver);180 181MODULE_DESCRIPTION("Wondermedia I2C controller driver");182MODULE_AUTHOR("Tony Prisk <linux@prisktech.co.nz>");183MODULE_LICENSE("GPL");184MODULE_DEVICE_TABLE(of, wmt_i2c_dt_ids);185