/* * Copyright (C) 2014 Broadcom Corporation * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation version 2. * * This program is distributed "as is" WITHOUT ANY WARRANTY of any * kind, whether express or implied; 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 #define N_DATA_REGS 8 /* * PER_I2C/BSC count register mask depends on 1 byte/4 byte data register * size. Cable modem and DSL SoCs with Peripheral i2c cores use 1 byte per * data register whereas STB SoCs use 4 byte per data register transfer, * account for this difference in total count per transaction and mask to * use. */ #define BSC_CNT_REG1_MASK(nb) (nb == 1 ? GENMASK(3, 0) : GENMASK(5, 0)) #define BSC_CNT_REG1_SHIFT 0 /* BSC CTL register field definitions */ #define BSC_CTL_REG_DTF_MASK 0x00000003 #define BSC_CTL_REG_SCL_SEL_MASK 0x00000030 #define BSC_CTL_REG_SCL_SEL_SHIFT 4 #define BSC_CTL_REG_INT_EN_MASK 0x00000040 #define BSC_CTL_REG_INT_EN_SHIFT 6 #define BSC_CTL_REG_DIV_CLK_MASK 0x00000080 /* BSC_IIC_ENABLE r/w enable and interrupt field definitions */ #define BSC_IIC_EN_RESTART_MASK 0x00000040 #define BSC_IIC_EN_NOSTART_MASK 0x00000020 #define BSC_IIC_EN_NOSTOP_MASK 0x00000010 #define BSC_IIC_EN_NOACK_MASK 0x00000004 #define BSC_IIC_EN_INTRP_MASK 0x00000002 #define BSC_IIC_EN_ENABLE_MASK 0x00000001 /* BSC_CTLHI control register field definitions */ #define BSC_CTLHI_REG_INPUT_SWITCHING_LEVEL_MASK 0x00000080 #define BSC_CTLHI_REG_DATAREG_SIZE_MASK 0x00000040 #define BSC_CTLHI_REG_IGNORE_ACK_MASK 0x00000002 #define BSC_CTLHI_REG_WAIT_DIS_MASK 0x00000001 #define I2C_TIMEOUT 100 /* msecs */ /* Condition mask used for non combined transfer */ #define COND_RESTART BSC_IIC_EN_RESTART_MASK #define COND_NOSTART BSC_IIC_EN_NOSTART_MASK #define COND_NOSTOP BSC_IIC_EN_NOSTOP_MASK #define COND_START_STOP (COND_RESTART | COND_NOSTART | COND_NOSTOP) /* BSC data transfer direction */ #define DTF_WR_MASK 0x00000000 #define DTF_RD_MASK 0x00000001 /* BSC data transfer direction combined format */ #define DTF_RD_WR_MASK 0x00000002 #define DTF_WR_RD_MASK 0x00000003 #define INT_ENABLE true #define INT_DISABLE false /* BSC block register map structure to cache fields to be written */ struct bsc_regs { u32 chip_address; /* slave address */ u32 data_in[N_DATA_REGS]; /* tx data buffer*/ u32 cnt_reg; /* rx/tx data length */ u32 ctl_reg; /* control register */ u32 iic_enable; /* xfer enable and status */ u32 data_out[N_DATA_REGS]; /* rx data buffer */ u32 ctlhi_reg; /* more control fields */ u32 scl_param; /* reserved */ }; struct bsc_clk_param { u32 hz; u32 scl_mask; u32 div_mask; }; enum bsc_xfer_cmd { CMD_WR, CMD_RD, CMD_WR_NOACK, CMD_RD_NOACK, }; static char const *cmd_string[] = { [CMD_WR] = "WR", [CMD_RD] = "RD", [CMD_WR_NOACK] = "WR NOACK", [CMD_RD_NOACK] = "RD NOACK", }; enum bus_speeds { SPD_375K, SPD_390K, SPD_187K, SPD_200K, SPD_93K, SPD_97K, SPD_46K, SPD_50K }; static const struct bsc_clk_param bsc_clk[] = { [SPD_375K] = { .hz = 375000, .scl_mask = SPD_375K << BSC_CTL_REG_SCL_SEL_SHIFT, .div_mask = 0 }, [SPD_390K] = { .hz = 390000, .scl_mask = SPD_390K << BSC_CTL_REG_SCL_SEL_SHIFT, .div_mask = 0 }, [SPD_187K] = { .hz = 187500, .scl_mask = SPD_187K << BSC_CTL_REG_SCL_SEL_SHIFT, .div_mask = 0 }, [SPD_200K] = { .hz = 200000, .scl_mask = SPD_200K << BSC_CTL_REG_SCL_SEL_SHIFT, .div_mask = 0 }, [SPD_93K] = { .hz = 93750, .scl_mask = SPD_375K << BSC_CTL_REG_SCL_SEL_SHIFT, .div_mask = BSC_CTL_REG_DIV_CLK_MASK }, [SPD_97K] = { .hz = 97500, .scl_mask = SPD_390K << BSC_CTL_REG_SCL_SEL_SHIFT, .div_mask = BSC_CTL_REG_DIV_CLK_MASK }, [SPD_46K] = { .hz = 46875, .scl_mask = SPD_187K << BSC_CTL_REG_SCL_SEL_SHIFT, .div_mask = BSC_CTL_REG_DIV_CLK_MASK }, [SPD_50K] = { .hz = 50000, .scl_mask = SPD_200K << BSC_CTL_REG_SCL_SEL_SHIFT, .div_mask = BSC_CTL_REG_DIV_CLK_MASK } }; struct brcmstb_i2c_dev { struct device *device; void __iomem *base; void __iomem *irq_base; int irq; struct bsc_regs *bsc_regmap; struct i2c_adapter adapter; struct completion done; bool is_suspended; u32 clk_freq_hz; int data_regsz; }; /* register accessors for both be and le cpu arch */ #ifdef CONFIG_CPU_BIG_ENDIAN #define __bsc_readl(_reg) ioread32be(_reg) #define __bsc_writel(_val, _reg) iowrite32be(_val, _reg) #else #define __bsc_readl(_reg) ioread32(_reg) #define __bsc_writel(_val, _reg) iowrite32(_val, _reg) #endif #define bsc_readl(_dev, _reg) \ __bsc_readl(_dev->base + offsetof(struct bsc_regs, _reg)) #define bsc_writel(_dev, _val, _reg) \ __bsc_writel(_val, _dev->base + offsetof(struct bsc_regs, _reg)) static inline int brcmstb_i2c_get_xfersz(struct brcmstb_i2c_dev *dev) { return (N_DATA_REGS * dev->data_regsz); } static inline int brcmstb_i2c_get_data_regsz(struct brcmstb_i2c_dev *dev) { return dev->data_regsz; } static void brcmstb_i2c_enable_disable_irq(struct brcmstb_i2c_dev *dev, bool int_en) { if (int_en) /* Enable BSC CTL interrupt line */ dev->bsc_regmap->ctl_reg |= BSC_CTL_REG_INT_EN_MASK; else /* Disable BSC CTL interrupt line */ dev->bsc_regmap->ctl_reg &= ~BSC_CTL_REG_INT_EN_MASK; barrier(); bsc_writel(dev, dev->bsc_regmap->ctl_reg, ctl_reg); } static irqreturn_t brcmstb_i2c_isr(int irq, void *devid) { struct brcmstb_i2c_dev *dev = devid; u32 status_bsc_ctl = bsc_readl(dev, ctl_reg); u32 status_iic_intrp = bsc_readl(dev, iic_enable); dev_dbg(dev->device, "isr CTL_REG %x IIC_EN %x\n", status_bsc_ctl, status_iic_intrp); if (!(status_bsc_ctl & BSC_CTL_REG_INT_EN_MASK)) return IRQ_NONE; brcmstb_i2c_enable_disable_irq(dev, INT_DISABLE); complete(&dev->done); dev_dbg(dev->device, "isr handled"); return IRQ_HANDLED; } /* Wait for device to be ready */ static int brcmstb_i2c_wait_if_busy(struct brcmstb_i2c_dev *dev) { unsigned long timeout = jiffies + msecs_to_jiffies(I2C_TIMEOUT); while ((bsc_readl(dev, iic_enable) & BSC_IIC_EN_INTRP_MASK)) { if (time_after(jiffies, timeout)) return -ETIMEDOUT; cpu_relax(); } return 0; } /* i2c xfer completion function, handles both irq and polling mode */ static int brcmstb_i2c_wait_for_completion(struct brcmstb_i2c_dev *dev) { int ret = 0; unsigned long timeout = msecs_to_jiffies(I2C_TIMEOUT); if (dev->irq >= 0) { if (!wait_for_completion_timeout(&dev->done, timeout)) ret = -ETIMEDOUT; } else { /* we are in polling mode */ u32 bsc_intrp; unsigned long time_left = jiffies + timeout; do { bsc_intrp = bsc_readl(dev, iic_enable) & BSC_IIC_EN_INTRP_MASK; if (time_after(jiffies, time_left)) { ret = -ETIMEDOUT; break; } cpu_relax(); } while (!bsc_intrp); } if (dev->irq < 0 || ret == -ETIMEDOUT) brcmstb_i2c_enable_disable_irq(dev, INT_DISABLE); return ret; } /* Set xfer START/STOP conditions for subsequent transfer */ static void brcmstb_set_i2c_start_stop(struct brcmstb_i2c_dev *dev, u32 cond_flag) { u32 regval = dev->bsc_regmap->iic_enable; dev->bsc_regmap->iic_enable = (regval & ~COND_START_STOP) | cond_flag; } /* Send I2C request check completion */ static int brcmstb_send_i2c_cmd(struct brcmstb_i2c_dev *dev, enum bsc_xfer_cmd cmd) { int rc = 0; struct bsc_regs *pi2creg = dev->bsc_regmap; /* Make sure the hardware is ready */ rc = brcmstb_i2c_wait_if_busy(dev); if (rc < 0) return rc; /* only if we are in interrupt mode */ if (dev->irq >= 0) reinit_completion(&dev->done); /* enable BSC CTL interrupt line */ brcmstb_i2c_enable_disable_irq(dev, INT_ENABLE); /* initiate transfer by setting iic_enable */ pi2creg->iic_enable |= BSC_IIC_EN_ENABLE_MASK; bsc_writel(dev, pi2creg->iic_enable, iic_enable); /* Wait for transaction to finish or timeout */ rc = brcmstb_i2c_wait_for_completion(dev); if (rc) { dev_dbg(dev->device, "intr timeout for cmd %s\n", cmd_string[cmd]); goto cmd_out; } if ((cmd == CMD_RD || cmd == CMD_WR) && bsc_readl(dev, iic_enable) & BSC_IIC_EN_NOACK_MASK) { rc = -EREMOTEIO; dev_dbg(dev->device, "controller received NOACK intr for %s\n", cmd_string[cmd]); } cmd_out: bsc_writel(dev, 0, cnt_reg); bsc_writel(dev, 0, iic_enable); return rc; } /* Actual data transfer through the BSC master */ static int brcmstb_i2c_xfer_bsc_data(struct brcmstb_i2c_dev *dev, u8 *buf, unsigned int len, struct i2c_msg *pmsg) { int cnt, byte, i, rc; enum bsc_xfer_cmd cmd; u32 ctl_reg; struct bsc_regs *pi2creg = dev->bsc_regmap; int no_ack = pmsg->flags & I2C_M_IGNORE_NAK; int data_regsz = brcmstb_i2c_get_data_regsz(dev); /* see if the transaction needs to check NACK conditions */ if (no_ack) { cmd = (pmsg->flags & I2C_M_RD) ? CMD_RD_NOACK : CMD_WR_NOACK; pi2creg->ctlhi_reg |= BSC_CTLHI_REG_IGNORE_ACK_MASK; } else { cmd = (pmsg->flags & I2C_M_RD) ? CMD_RD : CMD_WR; pi2creg->ctlhi_reg &= ~BSC_CTLHI_REG_IGNORE_ACK_MASK; } bsc_writel(dev, pi2creg->ctlhi_reg, ctlhi_reg); /* set data transfer direction */ ctl_reg = pi2creg->ctl_reg & ~BSC_CTL_REG_DTF_MASK; if (cmd == CMD_WR || cmd == CMD_WR_NOACK) pi2creg->ctl_reg = ctl_reg | DTF_WR_MASK; else pi2creg->ctl_reg = ctl_reg | DTF_RD_MASK; /* set the read/write length */ bsc_writel(dev, BSC_CNT_REG1_MASK(data_regsz) & (len << BSC_CNT_REG1_SHIFT), cnt_reg); /* Write data into data_in register */ if (cmd == CMD_WR || cmd == CMD_WR_NOACK) { for (cnt = 0, i = 0; cnt < len; cnt += data_regsz, i++) { u32 word = 0; for (byte = 0; byte < data_regsz; byte++) { word >>= BITS_PER_BYTE; if ((cnt + byte) < len) word |= buf[cnt + byte] << (BITS_PER_BYTE * (data_regsz - 1)); } bsc_writel(dev, word, data_in[i]); } } /* Initiate xfer, the function will return on completion */ rc = brcmstb_send_i2c_cmd(dev, cmd); if (rc != 0) { dev_dbg(dev->device, "%s failure", cmd_string[cmd]); return rc; } /* Read data from data_out register */ if (cmd == CMD_RD || cmd == CMD_RD_NOACK) { for (cnt = 0, i = 0; cnt < len; cnt += data_regsz, i++) { u32 data = bsc_readl(dev, data_out[i]); for (byte = 0; byte < data_regsz && (byte + cnt) < len; byte++) { buf[cnt + byte] = data & 0xff; data >>= BITS_PER_BYTE; } } } return 0; } /* Write a single byte of data to the i2c bus */ static int brcmstb_i2c_write_data_byte(struct brcmstb_i2c_dev *dev, u8 *buf, unsigned int nak_expected) { enum bsc_xfer_cmd cmd = nak_expected ? CMD_WR : CMD_WR_NOACK; bsc_writel(dev, 1, cnt_reg); bsc_writel(dev, *buf, data_in); return brcmstb_send_i2c_cmd(dev, cmd); } /* Send i2c address */ static int brcmstb_i2c_do_addr(struct brcmstb_i2c_dev *dev, struct i2c_msg *msg) { unsigned char addr; if (msg->flags & I2C_M_TEN) { /* First byte is 11110XX0 where XX is upper 2 bits */ addr = 0xF0 | ((msg->addr & 0x300) >> 7); bsc_writel(dev, addr, chip_address); /* Second byte is the remaining 8 bits */ addr = msg->addr & 0xFF; if (brcmstb_i2c_write_data_byte(dev, &addr, 0) < 0) return -EREMOTEIO; if (msg->flags & I2C_M_RD) { /* For read, send restart without stop condition */ brcmstb_set_i2c_start_stop(dev, COND_RESTART | COND_NOSTOP); /* Then re-send the first byte with the read bit set */ addr = 0xF0 | ((msg->addr & 0x300) >> 7) | 0x01; if (brcmstb_i2c_write_data_byte(dev, &addr, 0) < 0) return -EREMOTEIO; } } else { addr = i2c_8bit_addr_from_msg(msg); bsc_writel(dev, addr, chip_address); } return 0; } /* Master transfer function */ static int brcmstb_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg msgs[], int num) { struct brcmstb_i2c_dev *dev = i2c_get_adapdata(adapter); struct i2c_msg *pmsg; int rc = 0; int i; int bytes_to_xfer; u8 *tmp_buf; int len = 0; int xfersz = brcmstb_i2c_get_xfersz(dev); u32 cond, cond_per_msg; if (dev->is_suspended) return -EBUSY; /* Loop through all messages */ for (i = 0; i < num; i++) { pmsg = &msgs[i]; len = pmsg->len; tmp_buf = pmsg->buf; dev_dbg(dev->device, "msg# %d/%d flg %x buf %x len %d\n", i, num - 1, pmsg->flags, pmsg->buf ? pmsg->buf[0] : '0', pmsg->len); if (i < (num - 1) && (msgs[i + 1].flags & I2C_M_NOSTART)) cond = ~COND_START_STOP; else cond = COND_RESTART | COND_NOSTOP; brcmstb_set_i2c_start_stop(dev, cond); /* Send slave address */ if (!(pmsg->flags & I2C_M_NOSTART)) { rc = brcmstb_i2c_do_addr(dev, pmsg); if (rc < 0) { dev_dbg(dev->device, "NACK for addr %2.2x msg#%d rc = %d\n", pmsg->addr, i, rc); goto out; } } cond_per_msg = cond; /* Perform data transfer */ while (len) { bytes_to_xfer = min(len, xfersz); if (len <= xfersz) { if (i == (num - 1)) cond_per_msg = cond_per_msg & ~(COND_RESTART | COND_NOSTOP); else cond_per_msg = cond; } else { cond_per_msg = (cond_per_msg & ~COND_RESTART) | COND_NOSTOP; } brcmstb_set_i2c_start_stop(dev, cond_per_msg); rc = brcmstb_i2c_xfer_bsc_data(dev, tmp_buf, bytes_to_xfer, pmsg); if (rc < 0) goto out; len -= bytes_to_xfer; tmp_buf += bytes_to_xfer; cond_per_msg = COND_NOSTART | COND_NOSTOP; } } rc = num; out: return rc; } static u32 brcmstb_i2c_functionality(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR | I2C_FUNC_NOSTART | I2C_FUNC_PROTOCOL_MANGLING; } static const struct i2c_algorithm brcmstb_i2c_algo = { .master_xfer = brcmstb_i2c_xfer, .functionality = brcmstb_i2c_functionality, }; static void brcmstb_i2c_set_bus_speed(struct brcmstb_i2c_dev *dev) { int i = 0, num_speeds = ARRAY_SIZE(bsc_clk); u32 clk_freq_hz = dev->clk_freq_hz; for (i = 0; i < num_speeds; i++) { if (bsc_clk[i].hz == clk_freq_hz) { dev->bsc_regmap->ctl_reg &= ~(BSC_CTL_REG_SCL_SEL_MASK | BSC_CTL_REG_DIV_CLK_MASK); dev->bsc_regmap->ctl_reg |= (bsc_clk[i].scl_mask | bsc_clk[i].div_mask); bsc_writel(dev, dev->bsc_regmap->ctl_reg, ctl_reg); break; } } /* in case we did not get find a valid speed */ if (i == num_speeds) { i = (bsc_readl(dev, ctl_reg) & BSC_CTL_REG_SCL_SEL_MASK) >> BSC_CTL_REG_SCL_SEL_SHIFT; dev_warn(dev->device, "leaving current clock-frequency @ %dHz\n", bsc_clk[i].hz); } } static void brcmstb_i2c_set_bsc_reg_defaults(struct brcmstb_i2c_dev *dev) { if (brcmstb_i2c_get_data_regsz(dev) == sizeof(u32)) /* set 4 byte data in/out xfers */ dev->bsc_regmap->ctlhi_reg = BSC_CTLHI_REG_DATAREG_SIZE_MASK; else dev->bsc_regmap->ctlhi_reg &= ~BSC_CTLHI_REG_DATAREG_SIZE_MASK; bsc_writel(dev, dev->bsc_regmap->ctlhi_reg, ctlhi_reg); /* set bus speed */ brcmstb_i2c_set_bus_speed(dev); } static int brcmstb_i2c_probe(struct platform_device *pdev) { int rc = 0; struct brcmstb_i2c_dev *dev; struct i2c_adapter *adap; struct resource *iomem; const char *int_name; /* Allocate memory for private data structure */ dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL); if (!dev) return -ENOMEM; dev->bsc_regmap = devm_kzalloc(&pdev->dev, sizeof(*dev->bsc_regmap), GFP_KERNEL); if (!dev->bsc_regmap) return -ENOMEM; platform_set_drvdata(pdev, dev); dev->device = &pdev->dev; init_completion(&dev->done); /* Map hardware registers */ iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0); dev->base = devm_ioremap_resource(dev->device, iomem); if (IS_ERR(dev->base)) { rc = -ENOMEM; goto probe_errorout; } rc = of_property_read_string(dev->device->of_node, "interrupt-names", &int_name); if (rc < 0) int_name = NULL; /* Get the interrupt number */ dev->irq = platform_get_irq(pdev, 0); /* disable the bsc interrupt line */ brcmstb_i2c_enable_disable_irq(dev, INT_DISABLE); /* register the ISR handler */ rc = devm_request_irq(&pdev->dev, dev->irq, brcmstb_i2c_isr, IRQF_SHARED, int_name ? int_name : pdev->name, dev); if (rc) { dev_dbg(dev->device, "falling back to polling mode"); dev->irq = -1; } if (of_property_read_u32(dev->device->of_node, "clock-frequency", &dev->clk_freq_hz)) { dev_warn(dev->device, "setting clock-frequency@%dHz\n", bsc_clk[0].hz); dev->clk_freq_hz = bsc_clk[0].hz; } /* set the data in/out register size for compatible SoCs */ if (of_device_is_compatible(dev->device->of_node, "brcm,brcmper-i2c")) dev->data_regsz = sizeof(u8); else dev->data_regsz = sizeof(u32); brcmstb_i2c_set_bsc_reg_defaults(dev); /* Add the i2c adapter */ adap = &dev->adapter; i2c_set_adapdata(adap, dev); adap->owner = THIS_MODULE; strlcpy(adap->name, "Broadcom STB : ", sizeof(adap->name)); if (int_name) strlcat(adap->name, int_name, sizeof(adap->name)); adap->algo = &brcmstb_i2c_algo; adap->dev.parent = &pdev->dev; adap->dev.of_node = pdev->dev.of_node; rc = i2c_add_adapter(adap); if (rc) goto probe_errorout; dev_info(dev->device, "%s@%dhz registered in %s mode\n", int_name ? int_name : " ", dev->clk_freq_hz, (dev->irq >= 0) ? "interrupt" : "polling"); return 0; probe_errorout: return rc; } static int brcmstb_i2c_remove(struct platform_device *pdev) { struct brcmstb_i2c_dev *dev = platform_get_drvdata(pdev); i2c_del_adapter(&dev->adapter); return 0; } #ifdef CONFIG_PM_SLEEP static int brcmstb_i2c_suspend(struct device *dev) { struct brcmstb_i2c_dev *i2c_dev = dev_get_drvdata(dev); i2c_lock_bus(&i2c_dev->adapter, I2C_LOCK_ROOT_ADAPTER); i2c_dev->is_suspended = true; i2c_unlock_bus(&i2c_dev->adapter, I2C_LOCK_ROOT_ADAPTER); return 0; } static int brcmstb_i2c_resume(struct device *dev) { struct brcmstb_i2c_dev *i2c_dev = dev_get_drvdata(dev); i2c_lock_bus(&i2c_dev->adapter, I2C_LOCK_ROOT_ADAPTER); brcmstb_i2c_set_bsc_reg_defaults(i2c_dev); i2c_dev->is_suspended = false; i2c_unlock_bus(&i2c_dev->adapter, I2C_LOCK_ROOT_ADAPTER); return 0; } #endif static SIMPLE_DEV_PM_OPS(brcmstb_i2c_pm, brcmstb_i2c_suspend, brcmstb_i2c_resume); static const struct of_device_id brcmstb_i2c_of_match[] = { {.compatible = "brcm,brcmstb-i2c"}, {.compatible = "brcm,brcmper-i2c"}, {}, }; MODULE_DEVICE_TABLE(of, brcmstb_i2c_of_match); static struct platform_driver brcmstb_i2c_driver = { .driver = { .name = "brcmstb-i2c", .of_match_table = brcmstb_i2c_of_match, .pm = &brcmstb_i2c_pm, }, .probe = brcmstb_i2c_probe, .remove = brcmstb_i2c_remove, }; module_platform_driver(brcmstb_i2c_driver); MODULE_AUTHOR("Kamal Dasu "); MODULE_DESCRIPTION("Broadcom Settop I2C Driver"); MODULE_LICENSE("GPL v2");