/* * Copyright (c) 2016, Google Inc * * (C) Copyright 2002 * David Mueller, ELSOFT AG, d.mueller@elsoft.ch * * SPDX-License-Identifier: GPL-2.0+ */ #include #include #include #include #include #include #include "s3c24x0_i2c.h" DECLARE_GLOBAL_DATA_PTR; /* HSI2C-specific register description */ /* I2C_CTL Register bits */ #define HSI2C_FUNC_MODE_I2C (1u << 0) #define HSI2C_MASTER (1u << 3) #define HSI2C_RXCHON (1u << 6) /* Write/Send */ #define HSI2C_TXCHON (1u << 7) /* Read/Receive */ #define HSI2C_SW_RST (1u << 31) /* I2C_FIFO_CTL Register bits */ #define HSI2C_RXFIFO_EN (1u << 0) #define HSI2C_TXFIFO_EN (1u << 1) #define HSI2C_TXFIFO_TRIGGER_LEVEL (0x20 << 16) #define HSI2C_RXFIFO_TRIGGER_LEVEL (0x20 << 4) /* I2C_TRAILING_CTL Register bits */ #define HSI2C_TRAILING_COUNT (0xff) /* I2C_INT_EN Register bits */ #define HSI2C_TX_UNDERRUN_EN (1u << 2) #define HSI2C_TX_OVERRUN_EN (1u << 3) #define HSI2C_RX_UNDERRUN_EN (1u << 4) #define HSI2C_RX_OVERRUN_EN (1u << 5) #define HSI2C_INT_TRAILING_EN (1u << 6) #define HSI2C_INT_I2C_EN (1u << 9) #define HSI2C_INT_ERROR_MASK (HSI2C_TX_UNDERRUN_EN |\ HSI2C_TX_OVERRUN_EN |\ HSI2C_RX_UNDERRUN_EN |\ HSI2C_RX_OVERRUN_EN |\ HSI2C_INT_TRAILING_EN) /* I2C_CONF Register bits */ #define HSI2C_AUTO_MODE (1u << 31) #define HSI2C_10BIT_ADDR_MODE (1u << 30) #define HSI2C_HS_MODE (1u << 29) /* I2C_AUTO_CONF Register bits */ #define HSI2C_READ_WRITE (1u << 16) #define HSI2C_STOP_AFTER_TRANS (1u << 17) #define HSI2C_MASTER_RUN (1u << 31) /* I2C_TIMEOUT Register bits */ #define HSI2C_TIMEOUT_EN (1u << 31) /* I2C_TRANS_STATUS register bits */ #define HSI2C_MASTER_BUSY (1u << 17) #define HSI2C_SLAVE_BUSY (1u << 16) #define HSI2C_TIMEOUT_AUTO (1u << 4) #define HSI2C_NO_DEV (1u << 3) #define HSI2C_NO_DEV_ACK (1u << 2) #define HSI2C_TRANS_ABORT (1u << 1) #define HSI2C_TRANS_SUCCESS (1u << 0) #define HSI2C_TRANS_ERROR_MASK (HSI2C_TIMEOUT_AUTO |\ HSI2C_NO_DEV | HSI2C_NO_DEV_ACK |\ HSI2C_TRANS_ABORT) #define HSI2C_TRANS_FINISHED_MASK (HSI2C_TRANS_ERROR_MASK | HSI2C_TRANS_SUCCESS) /* I2C_FIFO_STAT Register bits */ #define HSI2C_RX_FIFO_EMPTY (1u << 24) #define HSI2C_RX_FIFO_FULL (1u << 23) #define HSI2C_TX_FIFO_EMPTY (1u << 8) #define HSI2C_TX_FIFO_FULL (1u << 7) #define HSI2C_RX_FIFO_LEVEL(x) (((x) >> 16) & 0x7f) #define HSI2C_TX_FIFO_LEVEL(x) ((x) & 0x7f) #define HSI2C_SLV_ADDR_MAS(x) ((x & 0x3ff) << 10) #define HSI2C_TIMEOUT_US 10000 /* 10 ms, finer granularity */ /* * Wait for transfer completion. * * This function reads the interrupt status register waiting for the INT_I2C * bit to be set, which indicates copletion of a transaction. * * @param i2c: pointer to the appropriate register bank * * @return: I2C_OK in case of successful completion, I2C_NOK_TIMEOUT in case * the status bits do not get set in time, or an approrpiate error * value in case of transfer errors. */ static int hsi2c_wait_for_trx(struct exynos5_hsi2c *i2c) { int i = HSI2C_TIMEOUT_US; while (i-- > 0) { u32 int_status = readl(&i2c->usi_int_stat); if (int_status & HSI2C_INT_I2C_EN) { u32 trans_status = readl(&i2c->usi_trans_status); /* Deassert pending interrupt. */ writel(int_status, &i2c->usi_int_stat); if (trans_status & HSI2C_NO_DEV_ACK) { debug("%s: no ACK from device\n", __func__); return I2C_NACK; } if (trans_status & HSI2C_NO_DEV) { debug("%s: no device\n", __func__); return I2C_NOK; } if (trans_status & HSI2C_TRANS_ABORT) { debug("%s: arbitration lost\n", __func__); return I2C_NOK_LA; } if (trans_status & HSI2C_TIMEOUT_AUTO) { debug("%s: device timed out\n", __func__); return I2C_NOK_TOUT; } return I2C_OK; } udelay(1); } debug("%s: transaction timeout!\n", __func__); return I2C_NOK_TOUT; } static int hsi2c_get_clk_details(struct s3c24x0_i2c_bus *i2c_bus) { struct exynos5_hsi2c *hsregs = i2c_bus->hsregs; ulong clkin; unsigned int op_clk = i2c_bus->clock_frequency; unsigned int i = 0, utemp0 = 0, utemp1 = 0; unsigned int t_ftl_cycle; #if (defined CONFIG_EXYNOS4 || defined CONFIG_EXYNOS5) clkin = get_i2c_clk(); #else clkin = get_PCLK(); #endif /* FPCLK / FI2C = * (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) + 8 + 2 * FLT_CYCLE * uTemp0 = (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) * uTemp1 = (TSCLK_L + TSCLK_H + 2) * uTemp2 = TSCLK_L + TSCLK_H */ t_ftl_cycle = (readl(&hsregs->usi_conf) >> 16) & 0x7; utemp0 = (clkin / op_clk) - 8 - 2 * t_ftl_cycle; /* CLK_DIV max is 256 */ for (i = 0; i < 256; i++) { utemp1 = utemp0 / (i + 1); if ((utemp1 < 512) && (utemp1 > 4)) { i2c_bus->clk_cycle = utemp1 - 2; i2c_bus->clk_div = i; return 0; } } return -EINVAL; } static void hsi2c_ch_init(struct s3c24x0_i2c_bus *i2c_bus) { struct exynos5_hsi2c *hsregs = i2c_bus->hsregs; unsigned int t_sr_release; unsigned int n_clkdiv; unsigned int t_start_su, t_start_hd; unsigned int t_stop_su; unsigned int t_data_su, t_data_hd; unsigned int t_scl_l, t_scl_h; u32 i2c_timing_s1; u32 i2c_timing_s2; u32 i2c_timing_s3; u32 i2c_timing_sla; n_clkdiv = i2c_bus->clk_div; t_scl_l = i2c_bus->clk_cycle / 2; t_scl_h = i2c_bus->clk_cycle / 2; t_start_su = t_scl_l; t_start_hd = t_scl_l; t_stop_su = t_scl_l; t_data_su = t_scl_l / 2; t_data_hd = t_scl_l / 2; t_sr_release = i2c_bus->clk_cycle; i2c_timing_s1 = t_start_su << 24 | t_start_hd << 16 | t_stop_su << 8; i2c_timing_s2 = t_data_su << 24 | t_scl_l << 8 | t_scl_h << 0; i2c_timing_s3 = n_clkdiv << 16 | t_sr_release << 0; i2c_timing_sla = t_data_hd << 0; writel(HSI2C_TRAILING_COUNT, &hsregs->usi_trailing_ctl); /* Clear to enable Timeout */ clrsetbits_le32(&hsregs->usi_timeout, HSI2C_TIMEOUT_EN, 0); /* set AUTO mode */ writel(readl(&hsregs->usi_conf) | HSI2C_AUTO_MODE, &hsregs->usi_conf); /* Enable completion conditions' reporting. */ writel(HSI2C_INT_I2C_EN, &hsregs->usi_int_en); /* Enable FIFOs */ writel(HSI2C_RXFIFO_EN | HSI2C_TXFIFO_EN, &hsregs->usi_fifo_ctl); /* Currently operating in Fast speed mode. */ writel(i2c_timing_s1, &hsregs->usi_timing_fs1); writel(i2c_timing_s2, &hsregs->usi_timing_fs2); writel(i2c_timing_s3, &hsregs->usi_timing_fs3); writel(i2c_timing_sla, &hsregs->usi_timing_sla); } /* SW reset for the high speed bus */ static void exynos5_i2c_reset(struct s3c24x0_i2c_bus *i2c_bus) { struct exynos5_hsi2c *i2c = i2c_bus->hsregs; u32 i2c_ctl; /* Set and clear the bit for reset */ i2c_ctl = readl(&i2c->usi_ctl); i2c_ctl |= HSI2C_SW_RST; writel(i2c_ctl, &i2c->usi_ctl); i2c_ctl = readl(&i2c->usi_ctl); i2c_ctl &= ~HSI2C_SW_RST; writel(i2c_ctl, &i2c->usi_ctl); /* Initialize the configure registers */ hsi2c_ch_init(i2c_bus); } /* * Poll the appropriate bit of the fifo status register until the interface is * ready to process the next byte or timeout expires. * * In addition to the FIFO status register this function also polls the * interrupt status register to be able to detect unexpected transaction * completion. * * When FIFO is ready to process the next byte, this function returns I2C_OK. * If in course of polling the INT_I2C assertion is detected, the function * returns I2C_NOK. If timeout happens before any of the above conditions is * met - the function returns I2C_NOK_TOUT; * @param i2c: pointer to the appropriate i2c register bank. * @param rx_transfer: set to True if the receive transaction is in progress. * @return: as described above. */ static unsigned hsi2c_poll_fifo(struct exynos5_hsi2c *i2c, bool rx_transfer) { u32 fifo_bit = rx_transfer ? HSI2C_RX_FIFO_EMPTY : HSI2C_TX_FIFO_FULL; int i = HSI2C_TIMEOUT_US; while (readl(&i2c->usi_fifo_stat) & fifo_bit) { if (readl(&i2c->usi_int_stat) & HSI2C_INT_I2C_EN) { /* * There is a chance that assertion of * HSI2C_INT_I2C_EN and deassertion of * HSI2C_RX_FIFO_EMPTY happen simultaneously. Let's * give FIFO status priority and check it one more * time before reporting interrupt. The interrupt will * be reported next time this function is called. */ if (rx_transfer && !(readl(&i2c->usi_fifo_stat) & fifo_bit)) break; return I2C_NOK; } if (!i--) { debug("%s: FIFO polling timeout!\n", __func__); return I2C_NOK_TOUT; } udelay(1); } return I2C_OK; } /* * Preapre hsi2c transaction, either read or write. * * Set up transfer as described in section 27.5.1.2 'I2C Channel Auto Mode' of * the 5420 UM. * * @param i2c: pointer to the appropriate i2c register bank. * @param chip: slave address on the i2c bus (with read/write bit exlcuded) * @param len: number of bytes expected to be sent or received * @param rx_transfer: set to true for receive transactions * @param: issue_stop: set to true if i2c stop condition should be generated * after this transaction. * @return: I2C_NOK_TOUT in case the bus remained busy for HSI2C_TIMEOUT_US, * I2C_OK otherwise. */ static int hsi2c_prepare_transaction(struct exynos5_hsi2c *i2c, u8 chip, u16 len, bool rx_transfer, bool issue_stop) { u32 conf; conf = len | HSI2C_MASTER_RUN; if (issue_stop) conf |= HSI2C_STOP_AFTER_TRANS; /* Clear to enable Timeout */ writel(readl(&i2c->usi_timeout) & ~HSI2C_TIMEOUT_EN, &i2c->usi_timeout); /* Set slave address */ writel(HSI2C_SLV_ADDR_MAS(chip), &i2c->i2c_addr); if (rx_transfer) { /* i2c master, read transaction */ writel((HSI2C_RXCHON | HSI2C_FUNC_MODE_I2C | HSI2C_MASTER), &i2c->usi_ctl); /* read up to len bytes, stop after transaction is finished */ writel(conf | HSI2C_READ_WRITE, &i2c->usi_auto_conf); } else { /* i2c master, write transaction */ writel((HSI2C_TXCHON | HSI2C_FUNC_MODE_I2C | HSI2C_MASTER), &i2c->usi_ctl); /* write up to len bytes, stop after transaction is finished */ writel(conf, &i2c->usi_auto_conf); } /* Reset all pending interrupt status bits we care about, if any */ writel(HSI2C_INT_I2C_EN, &i2c->usi_int_stat); return I2C_OK; } /* * Wait while i2c bus is settling down (mostly stop gets completed). */ static int hsi2c_wait_while_busy(struct exynos5_hsi2c *i2c) { int i = HSI2C_TIMEOUT_US; while (readl(&i2c->usi_trans_status) & HSI2C_MASTER_BUSY) { if (!i--) { debug("%s: bus busy\n", __func__); return I2C_NOK_TOUT; } udelay(1); } return I2C_OK; } static int hsi2c_write(struct exynos5_hsi2c *i2c, unsigned char chip, unsigned char addr[], unsigned char alen, unsigned char data[], unsigned short len, bool issue_stop) { int i, rv = 0; if (!(len + alen)) { /* Writes of zero length not supported in auto mode. */ debug("%s: zero length writes not supported\n", __func__); return I2C_NOK; } rv = hsi2c_prepare_transaction (i2c, chip, len + alen, false, issue_stop); if (rv != I2C_OK) return rv; /* Move address, if any, and the data, if any, into the FIFO. */ for (i = 0; i < alen; i++) { rv = hsi2c_poll_fifo(i2c, false); if (rv != I2C_OK) { debug("%s: address write failed\n", __func__); goto write_error; } writel(addr[i], &i2c->usi_txdata); } for (i = 0; i < len; i++) { rv = hsi2c_poll_fifo(i2c, false); if (rv != I2C_OK) { debug("%s: data write failed\n", __func__); goto write_error; } writel(data[i], &i2c->usi_txdata); } rv = hsi2c_wait_for_trx(i2c); write_error: if (issue_stop) { int tmp_ret = hsi2c_wait_while_busy(i2c); if (rv == I2C_OK) rv = tmp_ret; } writel(HSI2C_FUNC_MODE_I2C, &i2c->usi_ctl); /* done */ return rv; } static int hsi2c_read(struct exynos5_hsi2c *i2c, unsigned char chip, unsigned char addr[], unsigned char alen, unsigned char data[], unsigned short len) { int i, rv, tmp_ret; bool drop_data = false; if (!len) { /* Reads of zero length not supported in auto mode. */ debug("%s: zero length read adjusted\n", __func__); drop_data = true; len = 1; } if (alen) { /* Internal register adress needs to be written first. */ rv = hsi2c_write(i2c, chip, addr, alen, NULL, 0, false); if (rv != I2C_OK) return rv; } rv = hsi2c_prepare_transaction(i2c, chip, len, true, true); if (rv != I2C_OK) return rv; for (i = 0; i < len; i++) { rv = hsi2c_poll_fifo(i2c, true); if (rv != I2C_OK) goto read_err; if (drop_data) continue; data[i] = readl(&i2c->usi_rxdata); } rv = hsi2c_wait_for_trx(i2c); read_err: tmp_ret = hsi2c_wait_while_busy(i2c); if (rv == I2C_OK) rv = tmp_ret; writel(HSI2C_FUNC_MODE_I2C, &i2c->usi_ctl); /* done */ return rv; } static int exynos_hs_i2c_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs) { struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev); struct exynos5_hsi2c *hsregs = i2c_bus->hsregs; int ret; for (; nmsgs > 0; nmsgs--, msg++) { if (msg->flags & I2C_M_RD) { ret = hsi2c_read(hsregs, msg->addr, 0, 0, msg->buf, msg->len); } else { ret = hsi2c_write(hsregs, msg->addr, 0, 0, msg->buf, msg->len, true); } if (ret) { exynos5_i2c_reset(i2c_bus); return -EREMOTEIO; } } return 0; } static int s3c24x0_i2c_set_bus_speed(struct udevice *dev, unsigned int speed) { struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev); i2c_bus->clock_frequency = speed; if (hsi2c_get_clk_details(i2c_bus)) return -EFAULT; hsi2c_ch_init(i2c_bus); return 0; } static int s3c24x0_i2c_probe(struct udevice *dev, uint chip, uint chip_flags) { struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev); uchar buf[1]; int ret; buf[0] = 0; /* * What is needed is to send the chip address and verify that the * address was ed (i.e. there was a chip at that address which * drove the data line low). */ ret = hsi2c_read(i2c_bus->hsregs, chip, 0, 0, buf, 1); return ret != I2C_OK; } static int s3c_i2c_ofdata_to_platdata(struct udevice *dev) { const void *blob = gd->fdt_blob; struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev); int node; node = dev_of_offset(dev); i2c_bus->hsregs = (struct exynos5_hsi2c *)devfdt_get_addr(dev); i2c_bus->id = pinmux_decode_periph_id(blob, node); i2c_bus->clock_frequency = fdtdec_get_int(blob, node, "clock-frequency", 100000); i2c_bus->node = node; i2c_bus->bus_num = dev->seq; exynos_pinmux_config(i2c_bus->id, PINMUX_FLAG_HS_MODE); i2c_bus->active = true; return 0; } static const struct dm_i2c_ops exynos_hs_i2c_ops = { .xfer = exynos_hs_i2c_xfer, .probe_chip = s3c24x0_i2c_probe, .set_bus_speed = s3c24x0_i2c_set_bus_speed, }; static const struct udevice_id exynos_hs_i2c_ids[] = { { .compatible = "samsung,exynos5-hsi2c" }, { } }; U_BOOT_DRIVER(hs_i2c) = { .name = "i2c_s3c_hs", .id = UCLASS_I2C, .of_match = exynos_hs_i2c_ids, .ofdata_to_platdata = s3c_i2c_ofdata_to_platdata, .priv_auto_alloc_size = sizeof(struct s3c24x0_i2c_bus), .ops = &exynos_hs_i2c_ops, };