/* * Copyright (c) 2014 MediaTek Inc. * Author: Xudong Chen * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define I2C_HS_NACKERR (1 << 2) #define I2C_ACKERR (1 << 1) #define I2C_TRANSAC_COMP (1 << 0) #define I2C_TRANSAC_START (1 << 0) #define I2C_DCM_DISABLE 0x0000 #define I2C_IO_CONFIG_OPEN_DRAIN 0x0003 #define I2C_IO_CONFIG_PUSH_PULL 0x0000 #define I2C_SOFT_RST 0x0001 #define I2C_FIFO_ADDR_CLR 0x0001 #define I2C_DELAY_LEN 0x0002 #define I2C_ST_START_CON 0x8001 #define I2C_FS_START_CON 0x1800 #define I2C_TIME_CLR_VALUE 0x0000 #define I2C_TIME_DEFAULT_VALUE 0x0003 #define I2C_FS_TIME_INIT_VALUE 0x1303 #define I2C_WRRD_TRANAC_VALUE 0x0002 #define I2C_RD_TRANAC_VALUE 0x0001 #define I2C_DMA_CON_TX 0x0000 #define I2C_DMA_CON_RX 0x0001 #define I2C_DMA_START_EN 0x0001 #define I2C_DMA_INT_FLAG_NONE 0x0000 #define I2C_DMA_CLR_FLAG 0x0000 #define I2C_DEFAULT_SPEED 100000 /* hz */ #define MAX_FS_MODE_SPEED 400000 #define MAX_HS_MODE_SPEED 3400000 #define MAX_SAMPLE_CNT_DIV 8 #define MAX_STEP_CNT_DIV 64 #define MAX_HS_STEP_CNT_DIV 8 #define I2C_CONTROL_RS (0x1 << 1) #define I2C_CONTROL_DMA_EN (0x1 << 2) #define I2C_CONTROL_CLK_EXT_EN (0x1 << 3) #define I2C_CONTROL_DIR_CHANGE (0x1 << 4) #define I2C_CONTROL_ACKERR_DET_EN (0x1 << 5) #define I2C_CONTROL_TRANSFER_LEN_CHANGE (0x1 << 6) #define I2C_CONTROL_WRAPPER (0x1 << 0) #define I2C_DRV_NAME "i2c-mt65xx" enum DMA_REGS_OFFSET { OFFSET_INT_FLAG = 0x0, OFFSET_INT_EN = 0x04, OFFSET_EN = 0x08, OFFSET_CON = 0x18, OFFSET_TX_MEM_ADDR = 0x1c, OFFSET_RX_MEM_ADDR = 0x20, OFFSET_TX_LEN = 0x24, OFFSET_RX_LEN = 0x28, }; enum i2c_trans_st_rs { I2C_TRANS_STOP = 0, I2C_TRANS_REPEATED_START, }; enum mtk_trans_op { I2C_MASTER_WR = 1, I2C_MASTER_RD, I2C_MASTER_WRRD, }; enum I2C_REGS_OFFSET { OFFSET_DATA_PORT = 0x0, OFFSET_SLAVE_ADDR = 0x04, OFFSET_INTR_MASK = 0x08, OFFSET_INTR_STAT = 0x0c, OFFSET_CONTROL = 0x10, OFFSET_TRANSFER_LEN = 0x14, OFFSET_TRANSAC_LEN = 0x18, OFFSET_DELAY_LEN = 0x1c, OFFSET_TIMING = 0x20, OFFSET_START = 0x24, OFFSET_EXT_CONF = 0x28, OFFSET_FIFO_STAT = 0x30, OFFSET_FIFO_THRESH = 0x34, OFFSET_FIFO_ADDR_CLR = 0x38, OFFSET_IO_CONFIG = 0x40, OFFSET_RSV_DEBUG = 0x44, OFFSET_HS = 0x48, OFFSET_SOFTRESET = 0x50, OFFSET_DCM_EN = 0x54, OFFSET_PATH_DIR = 0x60, OFFSET_DEBUGSTAT = 0x64, OFFSET_DEBUGCTRL = 0x68, OFFSET_TRANSFER_LEN_AUX = 0x6c, }; struct mtk_i2c_compatible { const struct i2c_adapter_quirks *quirks; unsigned char pmic_i2c: 1; unsigned char dcm: 1; }; struct mtk_i2c { struct i2c_adapter adap; /* i2c host adapter */ struct device *dev; struct completion msg_complete; /* set in i2c probe */ void __iomem *base; /* i2c base addr */ void __iomem *pdmabase; /* dma base address*/ struct clk *clk_main; /* main clock for i2c bus */ struct clk *clk_dma; /* DMA clock for i2c via DMA */ struct clk *clk_pmic; /* PMIC clock for i2c from PMIC */ bool have_pmic; /* can use i2c pins from PMIC */ bool use_push_pull; /* IO config push-pull mode */ u16 irq_stat; /* interrupt status */ unsigned int speed_hz; /* The speed in transfer */ enum mtk_trans_op op; u16 timing_reg; u16 high_speed_reg; const struct mtk_i2c_compatible *dev_comp; }; static const struct i2c_adapter_quirks mt6577_i2c_quirks = { .flags = I2C_AQ_COMB_WRITE_THEN_READ, .max_num_msgs = 1, .max_write_len = 255, .max_read_len = 255, .max_comb_1st_msg_len = 255, .max_comb_2nd_msg_len = 31, }; static const struct mtk_i2c_compatible mt6577_compat = { .quirks = &mt6577_i2c_quirks, .pmic_i2c = 0, .dcm = 1, }; static const struct mtk_i2c_compatible mt6589_compat = { .quirks = &mt6577_i2c_quirks, .pmic_i2c = 1, .dcm = 0, }; static const struct of_device_id mtk_i2c_of_match[] = { { .compatible = "mediatek,mt6577-i2c", .data = &mt6577_compat }, { .compatible = "mediatek,mt6589-i2c", .data = &mt6589_compat }, {} }; MODULE_DEVICE_TABLE(of, mtk_i2c_of_match); static int mtk_i2c_clock_enable(struct mtk_i2c *i2c) { int ret; ret = clk_prepare_enable(i2c->clk_dma); if (ret) return ret; ret = clk_prepare_enable(i2c->clk_main); if (ret) goto err_main; if (i2c->have_pmic) { ret = clk_prepare_enable(i2c->clk_pmic); if (ret) goto err_pmic; } return 0; err_pmic: clk_disable_unprepare(i2c->clk_main); err_main: clk_disable_unprepare(i2c->clk_dma); return ret; } static void mtk_i2c_clock_disable(struct mtk_i2c *i2c) { if (i2c->have_pmic) clk_disable_unprepare(i2c->clk_pmic); clk_disable_unprepare(i2c->clk_main); clk_disable_unprepare(i2c->clk_dma); } static void mtk_i2c_init_hw(struct mtk_i2c *i2c) { u16 control_reg; writew(I2C_SOFT_RST, i2c->base + OFFSET_SOFTRESET); /* Set ioconfig */ if (i2c->use_push_pull) writew(I2C_IO_CONFIG_PUSH_PULL, i2c->base + OFFSET_IO_CONFIG); else writew(I2C_IO_CONFIG_OPEN_DRAIN, i2c->base + OFFSET_IO_CONFIG); if (i2c->dev_comp->dcm) writew(I2C_DCM_DISABLE, i2c->base + OFFSET_DCM_EN); writew(i2c->timing_reg, i2c->base + OFFSET_TIMING); writew(i2c->high_speed_reg, i2c->base + OFFSET_HS); /* If use i2c pin from PMIC mt6397 side, need set PATH_DIR first */ if (i2c->have_pmic) writew(I2C_CONTROL_WRAPPER, i2c->base + OFFSET_PATH_DIR); control_reg = I2C_CONTROL_ACKERR_DET_EN | I2C_CONTROL_CLK_EXT_EN | I2C_CONTROL_DMA_EN; writew(control_reg, i2c->base + OFFSET_CONTROL); writew(I2C_DELAY_LEN, i2c->base + OFFSET_DELAY_LEN); } /* * Calculate i2c port speed * * Hardware design: * i2c_bus_freq = parent_clk / (clock_div * 2 * sample_cnt * step_cnt) * clock_div: fixed in hardware, but may be various in different SoCs * * The calculation want to pick the highest bus frequency that is still * less than or equal to i2c->speed_hz. The calculation try to get * sample_cnt and step_cn */ static int mtk_i2c_set_speed(struct mtk_i2c *i2c, unsigned int parent_clk, unsigned int clock_div) { unsigned int clk_src; unsigned int step_cnt; unsigned int sample_cnt; unsigned int max_step_cnt; unsigned int target_speed; unsigned int base_sample_cnt = MAX_SAMPLE_CNT_DIV; unsigned int base_step_cnt; unsigned int opt_div; unsigned int best_mul; unsigned int cnt_mul; clk_src = parent_clk / clock_div; target_speed = i2c->speed_hz; if (target_speed > MAX_HS_MODE_SPEED) target_speed = MAX_HS_MODE_SPEED; if (target_speed > MAX_FS_MODE_SPEED) max_step_cnt = MAX_HS_STEP_CNT_DIV; else max_step_cnt = MAX_STEP_CNT_DIV; base_step_cnt = max_step_cnt; /* Find the best combination */ opt_div = DIV_ROUND_UP(clk_src >> 1, target_speed); best_mul = MAX_SAMPLE_CNT_DIV * max_step_cnt; /* Search for the best pair (sample_cnt, step_cnt) with * 0 < sample_cnt < MAX_SAMPLE_CNT_DIV * 0 < step_cnt < max_step_cnt * sample_cnt * step_cnt >= opt_div * optimizing for sample_cnt * step_cnt being minimal */ for (sample_cnt = 1; sample_cnt <= MAX_SAMPLE_CNT_DIV; sample_cnt++) { step_cnt = DIV_ROUND_UP(opt_div, sample_cnt); cnt_mul = step_cnt * sample_cnt; if (step_cnt > max_step_cnt) continue; if (cnt_mul < best_mul) { best_mul = cnt_mul; base_sample_cnt = sample_cnt; base_step_cnt = step_cnt; if (best_mul == opt_div) break; } } sample_cnt = base_sample_cnt; step_cnt = base_step_cnt; if ((clk_src / (2 * sample_cnt * step_cnt)) > target_speed) { /* In this case, hardware can't support such * low i2c_bus_freq */ dev_dbg(i2c->dev, "Unsupported speed (%uhz)\n", target_speed); return -EINVAL; } step_cnt--; sample_cnt--; if (target_speed > MAX_FS_MODE_SPEED) { /* Set the high speed mode register */ i2c->timing_reg = I2C_FS_TIME_INIT_VALUE; i2c->high_speed_reg = I2C_TIME_DEFAULT_VALUE | (sample_cnt << 12) | (step_cnt << 8); } else { i2c->timing_reg = (sample_cnt << 8) | (step_cnt << 0); /* Disable the high speed transaction */ i2c->high_speed_reg = I2C_TIME_CLR_VALUE; } return 0; } static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs) { u16 addr_reg; u16 control_reg; dma_addr_t rpaddr = 0; dma_addr_t wpaddr = 0; int ret; i2c->irq_stat = 0; reinit_completion(&i2c->msg_complete); control_reg = readw(i2c->base + OFFSET_CONTROL) & ~(I2C_CONTROL_DIR_CHANGE | I2C_CONTROL_RS); if (i2c->speed_hz > 400000) control_reg |= I2C_CONTROL_RS; if (i2c->op == I2C_MASTER_WRRD) control_reg |= I2C_CONTROL_DIR_CHANGE | I2C_CONTROL_RS; writew(control_reg, i2c->base + OFFSET_CONTROL); /* set start condition */ if (i2c->speed_hz <= 100000) writew(I2C_ST_START_CON, i2c->base + OFFSET_EXT_CONF); else writew(I2C_FS_START_CON, i2c->base + OFFSET_EXT_CONF); addr_reg = msgs->addr << 1; if (i2c->op == I2C_MASTER_RD) addr_reg |= 0x1; writew(addr_reg, i2c->base + OFFSET_SLAVE_ADDR); /* Clear interrupt status */ writew(I2C_HS_NACKERR | I2C_ACKERR | I2C_TRANSAC_COMP, i2c->base + OFFSET_INTR_STAT); writew(I2C_FIFO_ADDR_CLR, i2c->base + OFFSET_FIFO_ADDR_CLR); /* Enable interrupt */ writew(I2C_HS_NACKERR | I2C_ACKERR | I2C_TRANSAC_COMP, i2c->base + OFFSET_INTR_MASK); /* Set transfer and transaction len */ if (i2c->op == I2C_MASTER_WRRD) { writew(msgs->len | ((msgs + 1)->len) << 8, i2c->base + OFFSET_TRANSFER_LEN); writew(I2C_WRRD_TRANAC_VALUE, i2c->base + OFFSET_TRANSAC_LEN); } else { writew(msgs->len, i2c->base + OFFSET_TRANSFER_LEN); writew(I2C_RD_TRANAC_VALUE, i2c->base + OFFSET_TRANSAC_LEN); } /* Prepare buffer data to start transfer */ if (i2c->op == I2C_MASTER_RD) { writel(I2C_DMA_INT_FLAG_NONE, i2c->pdmabase + OFFSET_INT_FLAG); writel(I2C_DMA_CON_RX, i2c->pdmabase + OFFSET_CON); rpaddr = dma_map_single(i2c->dev, msgs->buf, msgs->len, DMA_FROM_DEVICE); if (dma_mapping_error(i2c->dev, rpaddr)) return -ENOMEM; writel((u32)rpaddr, i2c->pdmabase + OFFSET_RX_MEM_ADDR); writel(msgs->len, i2c->pdmabase + OFFSET_RX_LEN); } else if (i2c->op == I2C_MASTER_WR) { writel(I2C_DMA_INT_FLAG_NONE, i2c->pdmabase + OFFSET_INT_FLAG); writel(I2C_DMA_CON_TX, i2c->pdmabase + OFFSET_CON); wpaddr = dma_map_single(i2c->dev, msgs->buf, msgs->len, DMA_TO_DEVICE); if (dma_mapping_error(i2c->dev, wpaddr)) return -ENOMEM; writel((u32)wpaddr, i2c->pdmabase + OFFSET_TX_MEM_ADDR); writel(msgs->len, i2c->pdmabase + OFFSET_TX_LEN); } else { writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_INT_FLAG); writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_CON); wpaddr = dma_map_single(i2c->dev, msgs->buf, msgs->len, DMA_TO_DEVICE); if (dma_mapping_error(i2c->dev, wpaddr)) return -ENOMEM; rpaddr = dma_map_single(i2c->dev, (msgs + 1)->buf, (msgs + 1)->len, DMA_FROM_DEVICE); if (dma_mapping_error(i2c->dev, rpaddr)) { dma_unmap_single(i2c->dev, wpaddr, msgs->len, DMA_TO_DEVICE); return -ENOMEM; } writel((u32)wpaddr, i2c->pdmabase + OFFSET_TX_MEM_ADDR); writel((u32)rpaddr, i2c->pdmabase + OFFSET_RX_MEM_ADDR); writel(msgs->len, i2c->pdmabase + OFFSET_TX_LEN); writel((msgs + 1)->len, i2c->pdmabase + OFFSET_RX_LEN); } writel(I2C_DMA_START_EN, i2c->pdmabase + OFFSET_EN); writew(I2C_TRANSAC_START, i2c->base + OFFSET_START); ret = wait_for_completion_timeout(&i2c->msg_complete, i2c->adap.timeout); /* Clear interrupt mask */ writew(~(I2C_HS_NACKERR | I2C_ACKERR | I2C_TRANSAC_COMP), i2c->base + OFFSET_INTR_MASK); if (i2c->op == I2C_MASTER_WR) { dma_unmap_single(i2c->dev, wpaddr, msgs->len, DMA_TO_DEVICE); } else if (i2c->op == I2C_MASTER_RD) { dma_unmap_single(i2c->dev, rpaddr, msgs->len, DMA_FROM_DEVICE); } else { dma_unmap_single(i2c->dev, wpaddr, msgs->len, DMA_TO_DEVICE); dma_unmap_single(i2c->dev, rpaddr, (msgs + 1)->len, DMA_FROM_DEVICE); } if (ret == 0) { dev_dbg(i2c->dev, "addr: %x, transfer timeout\n", msgs->addr); mtk_i2c_init_hw(i2c); return -ETIMEDOUT; } completion_done(&i2c->msg_complete); if (i2c->irq_stat & (I2C_HS_NACKERR | I2C_ACKERR)) { dev_dbg(i2c->dev, "addr: %x, transfer ACK error\n", msgs->addr); mtk_i2c_init_hw(i2c); return -ENXIO; } return 0; } static int mtk_i2c_transfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) { int ret; int left_num = num; struct mtk_i2c *i2c = i2c_get_adapdata(adap); ret = mtk_i2c_clock_enable(i2c); if (ret) return ret; if (!msgs->buf) { dev_dbg(i2c->dev, "data buffer is NULL.\n"); ret = -EINVAL; goto err_exit; } if (msgs->flags & I2C_M_RD) i2c->op = I2C_MASTER_RD; else i2c->op = I2C_MASTER_WR; if (num > 1) { /* combined two messages into one transaction */ i2c->op = I2C_MASTER_WRRD; left_num--; } /* always use DMA mode. */ ret = mtk_i2c_do_transfer(i2c, msgs); if (ret < 0) goto err_exit; /* the return value is number of executed messages */ ret = num; err_exit: mtk_i2c_clock_disable(i2c); return ret; } static irqreturn_t mtk_i2c_irq(int irqno, void *dev_id) { struct mtk_i2c *i2c = dev_id; i2c->irq_stat = readw(i2c->base + OFFSET_INTR_STAT); writew(I2C_HS_NACKERR | I2C_ACKERR | I2C_TRANSAC_COMP, i2c->base + OFFSET_INTR_STAT); complete(&i2c->msg_complete); return IRQ_HANDLED; } static u32 mtk_i2c_functionality(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; } static const struct i2c_algorithm mtk_i2c_algorithm = { .master_xfer = mtk_i2c_transfer, .functionality = mtk_i2c_functionality, }; static int mtk_i2c_parse_dt(struct device_node *np, struct mtk_i2c *i2c, unsigned int *clk_src_div) { int ret; ret = of_property_read_u32(np, "clock-frequency", &i2c->speed_hz); if (ret < 0) i2c->speed_hz = I2C_DEFAULT_SPEED; ret = of_property_read_u32(np, "clock-div", clk_src_div); if (ret < 0) return ret; if (*clk_src_div == 0) return -EINVAL; i2c->have_pmic = of_property_read_bool(np, "mediatek,have-pmic"); i2c->use_push_pull = of_property_read_bool(np, "mediatek,use-push-pull"); return 0; } static int mtk_i2c_probe(struct platform_device *pdev) { const struct of_device_id *of_id; int ret = 0; struct mtk_i2c *i2c; struct clk *clk; unsigned int clk_src_div; struct resource *res; int irq; i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL); if (!i2c) return -ENOMEM; ret = mtk_i2c_parse_dt(pdev->dev.of_node, i2c, &clk_src_div); if (ret) return -EINVAL; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); i2c->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(i2c->base)) return PTR_ERR(i2c->base); res = platform_get_resource(pdev, IORESOURCE_MEM, 1); i2c->pdmabase = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(i2c->pdmabase)) return PTR_ERR(i2c->pdmabase); irq = platform_get_irq(pdev, 0); if (irq <= 0) return irq; init_completion(&i2c->msg_complete); of_id = of_match_node(mtk_i2c_of_match, pdev->dev.of_node); if (!of_id) return -EINVAL; i2c->dev_comp = of_id->data; i2c->adap.dev.of_node = pdev->dev.of_node; i2c->dev = &pdev->dev; i2c->adap.dev.parent = &pdev->dev; i2c->adap.owner = THIS_MODULE; i2c->adap.algo = &mtk_i2c_algorithm; i2c->adap.quirks = i2c->dev_comp->quirks; i2c->adap.timeout = 2 * HZ; i2c->adap.retries = 1; if (i2c->have_pmic && !i2c->dev_comp->pmic_i2c) return -EINVAL; i2c->clk_main = devm_clk_get(&pdev->dev, "main"); if (IS_ERR(i2c->clk_main)) { dev_err(&pdev->dev, "cannot get main clock\n"); return PTR_ERR(i2c->clk_main); } i2c->clk_dma = devm_clk_get(&pdev->dev, "dma"); if (IS_ERR(i2c->clk_dma)) { dev_err(&pdev->dev, "cannot get dma clock\n"); return PTR_ERR(i2c->clk_dma); } clk = i2c->clk_main; if (i2c->have_pmic) { i2c->clk_pmic = devm_clk_get(&pdev->dev, "pmic"); if (IS_ERR(i2c->clk_pmic)) { dev_err(&pdev->dev, "cannot get pmic clock\n"); return PTR_ERR(i2c->clk_pmic); } clk = i2c->clk_pmic; } strlcpy(i2c->adap.name, I2C_DRV_NAME, sizeof(i2c->adap.name)); ret = mtk_i2c_set_speed(i2c, clk_get_rate(clk), clk_src_div); if (ret) { dev_err(&pdev->dev, "Failed to set the speed.\n"); return -EINVAL; } ret = mtk_i2c_clock_enable(i2c); if (ret) { dev_err(&pdev->dev, "clock enable failed!\n"); return ret; } mtk_i2c_init_hw(i2c); mtk_i2c_clock_disable(i2c); ret = devm_request_irq(&pdev->dev, irq, mtk_i2c_irq, IRQF_TRIGGER_NONE, I2C_DRV_NAME, i2c); if (ret < 0) { dev_err(&pdev->dev, "Request I2C IRQ %d fail\n", irq); return ret; } i2c_set_adapdata(&i2c->adap, i2c); ret = i2c_add_adapter(&i2c->adap); if (ret) { dev_err(&pdev->dev, "Failed to add i2c bus to i2c core\n"); return ret; } platform_set_drvdata(pdev, i2c); return 0; } static int mtk_i2c_remove(struct platform_device *pdev) { struct mtk_i2c *i2c = platform_get_drvdata(pdev); i2c_del_adapter(&i2c->adap); return 0; } static struct platform_driver mtk_i2c_driver = { .probe = mtk_i2c_probe, .remove = mtk_i2c_remove, .driver = { .name = I2C_DRV_NAME, .of_match_table = of_match_ptr(mtk_i2c_of_match), }, }; module_platform_driver(mtk_i2c_driver); MODULE_LICENSE("GPL v2"); MODULE_DESCRIPTION("MediaTek I2C Bus Driver"); MODULE_AUTHOR("Xudong Chen ");