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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 | // SPDX-License-Identifier: GPL-2.0-or-later /* * Wondermedia I2C Master Mode Driver * * Copyright (C) 2012 Tony Prisk <linux@prisktech.co.nz> * * Derived from GPLv2+ licensed source: * - Copyright (C) 2008 WonderMedia Technologies, Inc. */ #include <linux/clk.h> #include <linux/of.h> #include <linux/of_address.h> #include "i2c-viai2c-common.h" #define REG_SLAVE_CR 0x10 #define REG_SLAVE_SR 0x12 #define REG_SLAVE_ISR 0x14 #define REG_SLAVE_IMR 0x16 #define REG_SLAVE_DR 0x18 #define REG_SLAVE_TR 0x1A /* REG_TR */ #define SCL_TIMEOUT(x) (((x) & 0xFF) << 8) #define TR_STD 0x0064 #define TR_HS 0x0019 /* REG_MCR */ #define MCR_APB_96M 7 #define MCR_APB_166M 12 static u32 wmt_i2c_func(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_NOSTART; } static const struct i2c_algorithm wmt_i2c_algo = { .master_xfer = viai2c_xfer, .functionality = wmt_i2c_func, }; static int wmt_i2c_reset_hardware(struct viai2c *i2c) { int err; err = clk_prepare_enable(i2c->clk); if (err) { dev_err(i2c->dev, "failed to enable clock\n"); return err; } err = clk_set_rate(i2c->clk, 20000000); if (err) { dev_err(i2c->dev, "failed to set clock = 20Mhz\n"); clk_disable_unprepare(i2c->clk); return err; } writew(0, i2c->base + VIAI2C_REG_CR); writew(MCR_APB_166M, i2c->base + VIAI2C_REG_MCR); writew(VIAI2C_ISR_MASK_ALL, i2c->base + VIAI2C_REG_ISR); writew(VIAI2C_IMR_ENABLE_ALL, i2c->base + VIAI2C_REG_IMR); writew(VIAI2C_CR_ENABLE, i2c->base + VIAI2C_REG_CR); readw(i2c->base + VIAI2C_REG_CSR); /* read clear */ writew(VIAI2C_ISR_MASK_ALL, i2c->base + VIAI2C_REG_ISR); if (i2c->tcr == VIAI2C_TCR_FAST) writew(SCL_TIMEOUT(128) | TR_HS, i2c->base + VIAI2C_REG_TR); else writew(SCL_TIMEOUT(128) | TR_STD, i2c->base + VIAI2C_REG_TR); return 0; } static irqreturn_t wmt_i2c_isr(int irq, void *data) { struct viai2c *i2c = data; u8 status; /* save the status and write-clear it */ status = readw(i2c->base + VIAI2C_REG_ISR); writew(status, i2c->base + VIAI2C_REG_ISR); i2c->ret = 0; if (status & VIAI2C_ISR_NACK_ADDR) i2c->ret = -EIO; if (status & VIAI2C_ISR_SCL_TIMEOUT) i2c->ret = -ETIMEDOUT; if (!i2c->ret) i2c->ret = viai2c_irq_xfer(i2c); /* All the data has been successfully transferred or error occurred */ if (i2c->ret) complete(&i2c->complete); return IRQ_HANDLED; } static int wmt_i2c_probe(struct platform_device *pdev) { struct device_node *np = pdev->dev.of_node; struct viai2c *i2c; struct i2c_adapter *adap; int err; u32 clk_rate; err = viai2c_init(pdev, &i2c, VIAI2C_PLAT_WMT); if (err) return err; i2c->irq = platform_get_irq(pdev, 0); if (i2c->irq < 0) return i2c->irq; err = devm_request_irq(&pdev->dev, i2c->irq, wmt_i2c_isr, 0, pdev->name, i2c); if (err) return dev_err_probe(&pdev->dev, err, "failed to request irq %i\n", i2c->irq); i2c->clk = of_clk_get(np, 0); if (IS_ERR(i2c->clk)) { dev_err(&pdev->dev, "unable to request clock\n"); return PTR_ERR(i2c->clk); } err = of_property_read_u32(np, "clock-frequency", &clk_rate); if (!err && clk_rate == I2C_MAX_FAST_MODE_FREQ) i2c->tcr = VIAI2C_TCR_FAST; adap = &i2c->adapter; i2c_set_adapdata(adap, i2c); strscpy(adap->name, "WMT I2C adapter", sizeof(adap->name)); adap->owner = THIS_MODULE; adap->algo = &wmt_i2c_algo; adap->dev.parent = &pdev->dev; adap->dev.of_node = pdev->dev.of_node; err = wmt_i2c_reset_hardware(i2c); if (err) { dev_err(&pdev->dev, "error initializing hardware\n"); return err; } err = i2c_add_adapter(adap); if (err) /* wmt_i2c_reset_hardware() enables i2c_dev->clk */ clk_disable_unprepare(i2c->clk); return err; } static void wmt_i2c_remove(struct platform_device *pdev) { struct viai2c *i2c = platform_get_drvdata(pdev); /* Disable interrupts, clock and delete adapter */ writew(0, i2c->base + VIAI2C_REG_IMR); clk_disable_unprepare(i2c->clk); i2c_del_adapter(&i2c->adapter); } static const struct of_device_id wmt_i2c_dt_ids[] = { { .compatible = "wm,wm8505-i2c" }, { /* Sentinel */ }, }; static struct platform_driver wmt_i2c_driver = { .probe = wmt_i2c_probe, .remove_new = wmt_i2c_remove, .driver = { .name = "wmt-i2c", .of_match_table = wmt_i2c_dt_ids, }, }; module_platform_driver(wmt_i2c_driver); MODULE_DESCRIPTION("Wondermedia I2C master-mode bus adapter"); MODULE_AUTHOR("Tony Prisk <linux@prisktech.co.nz>"); MODULE_LICENSE("GPL"); MODULE_DEVICE_TABLE(of, wmt_i2c_dt_ids); |