| // SPDX-License-Identifier: GPL-2.0+ |
| /* |
| * (C) Copyright 2002 |
| * David Mueller, ELSOFT AG, d.mueller@elsoft.ch |
| */ |
| |
| #include <errno.h> |
| #include <dm.h> |
| #include <fdtdec.h> |
| #include <time.h> |
| #include <log.h> |
| #if IS_ENABLED(CONFIG_ARCH_EXYNOS4) || IS_ENABLED(CONFIG_ARCH_EXYNOS5) |
| #include <asm/arch/clk.h> |
| #include <asm/arch/cpu.h> |
| #include <asm/arch/pinmux.h> |
| #endif |
| #include <asm/global_data.h> |
| #include <asm/io.h> |
| #include <i2c.h> |
| #include <clk.h> |
| #include "s3c24x0_i2c.h" |
| |
| DECLARE_GLOBAL_DATA_PTR; |
| |
| /* |
| * Wait til the byte transfer is completed. |
| * |
| * @param i2c- pointer to the appropriate i2c register bank. |
| * Return: I2C_OK, if transmission was ACKED |
| * I2C_NACK, if transmission was NACKED |
| * I2C_NOK_TIMEOUT, if transaction did not complete in I2C_TIMEOUT_MS |
| */ |
| |
| static int WaitForXfer(struct s3c24x0_i2c *i2c) |
| { |
| ulong start_time = get_timer(0); |
| |
| do { |
| if (readl(&i2c->iiccon) & I2CCON_IRPND) |
| return (readl(&i2c->iicstat) & I2CSTAT_NACK) ? |
| I2C_NACK : I2C_OK; |
| } while (get_timer(start_time) < I2C_TIMEOUT_MS); |
| |
| return I2C_NOK_TOUT; |
| } |
| |
| static void read_write_byte(struct s3c24x0_i2c *i2c) |
| { |
| clrbits_le32(&i2c->iiccon, I2CCON_IRPND); |
| } |
| |
| static int i2c_ch_init(struct udevice *dev, int speed, int slaveadd) |
| { |
| struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev); |
| struct s3c24x0_i2c *i2c = i2c_bus->regs; |
| ulong freq, pres = 16, div; |
| |
| #if IS_ENABLED(CONFIG_ARCH_EXYNOS4) || defined(CONFIG_ARCH_EXYNOS5) |
| freq = get_i2c_clk(); |
| #else |
| struct clk clk; |
| int ret; |
| |
| ret = clk_get_by_name(dev, "i2c", &clk); |
| if (ret < 0) |
| return ret; |
| freq = clk_get_rate(&clk); |
| #endif |
| /* calculate prescaler and divisor values */ |
| if ((freq / pres / (16 + 1)) > speed) |
| /* set prescaler to 512 */ |
| pres = 512; |
| |
| div = 0; |
| while ((freq / pres / (div + 1)) > speed) |
| div++; |
| |
| /* set prescaler, divisor according to freq, also set ACKGEN, IRQ */ |
| writel((div & 0x0F) | 0xA0 | ((pres == 512) ? 0x40 : 0), &i2c->iiccon); |
| |
| /* init to SLAVE REVEIVE and set slaveaddr */ |
| writel(0, &i2c->iicstat); |
| writel(slaveadd, &i2c->iicadd); |
| /* program Master Transmit (and implicit STOP) */ |
| writel(I2C_MODE_MT | I2C_TXRX_ENA, &i2c->iicstat); |
| return 0; |
| } |
| |
| #define SYS_I2C_S3C24X0_SLAVE_ADDR 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 (i2c_ch_init(dev, i2c_bus->clock_frequency, |
| SYS_I2C_S3C24X0_SLAVE_ADDR)) |
| return -EFAULT; |
| |
| return 0; |
| } |
| |
| /* |
| * cmd_type is 0 for write, 1 for read. |
| * |
| * addr_len can take any value from 0-255, it is only limited |
| * by the char, we could make it larger if needed. If it is |
| * 0 we skip the address write cycle. |
| */ |
| static int i2c_transfer(struct s3c24x0_i2c *i2c, |
| unsigned char cmd_type, |
| unsigned char chip, |
| unsigned char addr[], |
| unsigned char addr_len, |
| unsigned char data[], |
| unsigned short data_len) |
| { |
| int i = 0, result; |
| ulong start_time = get_timer(0); |
| |
| if (data == 0 || data_len == 0) { |
| /*Don't support data transfer of no length or to address 0 */ |
| debug("i2c_transfer: bad call\n"); |
| return I2C_NOK; |
| } |
| |
| while (readl(&i2c->iicstat) & I2CSTAT_BSY) { |
| if (get_timer(start_time) > I2C_TIMEOUT_MS) |
| return I2C_NOK_TOUT; |
| } |
| |
| writel(readl(&i2c->iiccon) | I2CCON_ACKGEN, &i2c->iiccon); |
| |
| /* Get the slave chip address going */ |
| writel(chip, &i2c->iicds); |
| if ((cmd_type == I2C_WRITE) || (addr && addr_len)) |
| writel(I2C_MODE_MT | I2C_TXRX_ENA | I2C_START_STOP, |
| &i2c->iicstat); |
| else |
| writel(I2C_MODE_MR | I2C_TXRX_ENA | I2C_START_STOP, |
| &i2c->iicstat); |
| |
| /* Wait for chip address to transmit. */ |
| result = WaitForXfer(i2c); |
| if (result != I2C_OK) |
| goto bailout; |
| |
| /* If register address needs to be transmitted - do it now. */ |
| if (addr && addr_len) { |
| while ((i < addr_len) && (result == I2C_OK)) { |
| writel(addr[i++], &i2c->iicds); |
| read_write_byte(i2c); |
| result = WaitForXfer(i2c); |
| } |
| i = 0; |
| if (result != I2C_OK) |
| goto bailout; |
| } |
| |
| switch (cmd_type) { |
| case I2C_WRITE: |
| while ((i < data_len) && (result == I2C_OK)) { |
| writel(data[i++], &i2c->iicds); |
| read_write_byte(i2c); |
| result = WaitForXfer(i2c); |
| } |
| break; |
| |
| case I2C_READ: |
| if (addr && addr_len) { |
| /* |
| * Register address has been sent, now send slave chip |
| * address again to start the actual read transaction. |
| */ |
| writel(chip, &i2c->iicds); |
| |
| /* Generate a re-START. */ |
| writel(I2C_MODE_MR | I2C_TXRX_ENA | I2C_START_STOP, |
| &i2c->iicstat); |
| read_write_byte(i2c); |
| result = WaitForXfer(i2c); |
| |
| if (result != I2C_OK) |
| goto bailout; |
| } |
| |
| while ((i < data_len) && (result == I2C_OK)) { |
| /* disable ACK for final READ */ |
| if (i == data_len - 1) |
| writel(readl(&i2c->iiccon) |
| & ~I2CCON_ACKGEN, |
| &i2c->iiccon); |
| read_write_byte(i2c); |
| result = WaitForXfer(i2c); |
| data[i++] = readl(&i2c->iicds); |
| } |
| if (result == I2C_NACK) |
| result = I2C_OK; /* Normal terminated read. */ |
| break; |
| |
| default: |
| debug("i2c_transfer: bad call\n"); |
| result = I2C_NOK; |
| break; |
| } |
| |
| bailout: |
| /* Send STOP. */ |
| writel(I2C_MODE_MR | I2C_TXRX_ENA, &i2c->iicstat); |
| read_write_byte(i2c); |
| |
| return result; |
| } |
| |
| 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 <ACK>ed (i.e. there was a chip at that address which |
| * drove the data line low). |
| */ |
| ret = i2c_transfer(i2c_bus->regs, I2C_READ, chip << 1, 0, 0, buf, 1); |
| |
| return ret != I2C_OK; |
| } |
| |
| static int s3c24x0_do_msg(struct s3c24x0_i2c_bus *i2c_bus, struct i2c_msg *msg, |
| int seq) |
| { |
| struct s3c24x0_i2c *i2c = i2c_bus->regs; |
| bool is_read = msg->flags & I2C_M_RD; |
| uint status; |
| uint addr; |
| int ret, i; |
| |
| if (!seq) |
| setbits_le32(&i2c->iiccon, I2CCON_ACKGEN); |
| |
| /* Get the slave chip address going */ |
| addr = msg->addr << 1; |
| writel(addr, &i2c->iicds); |
| status = I2C_TXRX_ENA | I2C_START_STOP; |
| if (is_read) |
| status |= I2C_MODE_MR; |
| else |
| status |= I2C_MODE_MT; |
| writel(status, &i2c->iicstat); |
| if (seq) |
| read_write_byte(i2c); |
| |
| /* Wait for chip address to transmit */ |
| ret = WaitForXfer(i2c); |
| if (ret) |
| goto err; |
| |
| if (is_read) { |
| for (i = 0; !ret && i < msg->len; i++) { |
| /* disable ACK for final READ */ |
| if (i == msg->len - 1) |
| clrbits_le32(&i2c->iiccon, I2CCON_ACKGEN); |
| read_write_byte(i2c); |
| ret = WaitForXfer(i2c); |
| msg->buf[i] = readl(&i2c->iicds); |
| } |
| if (ret == I2C_NACK) |
| ret = I2C_OK; /* Normal terminated read */ |
| } else { |
| for (i = 0; !ret && i < msg->len; i++) { |
| writel(msg->buf[i], &i2c->iicds); |
| read_write_byte(i2c); |
| ret = WaitForXfer(i2c); |
| } |
| } |
| |
| err: |
| return ret; |
| } |
| |
| static int s3c24x0_i2c_xfer(struct udevice *dev, struct i2c_msg *msg, |
| int nmsgs) |
| { |
| struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev); |
| struct s3c24x0_i2c *i2c = i2c_bus->regs; |
| ulong start_time; |
| int ret, i; |
| |
| start_time = get_timer(0); |
| while (readl(&i2c->iicstat) & I2CSTAT_BSY) { |
| if (get_timer(start_time) > I2C_TIMEOUT_MS) { |
| debug("Timeout\n"); |
| return -ETIMEDOUT; |
| } |
| } |
| |
| for (ret = 0, i = 0; !ret && i < nmsgs; i++) |
| ret = s3c24x0_do_msg(i2c_bus, &msg[i], i); |
| |
| /* Send STOP */ |
| writel(I2C_MODE_MR | I2C_TXRX_ENA, &i2c->iicstat); |
| read_write_byte(i2c); |
| |
| return ret ? -EREMOTEIO : 0; |
| } |
| |
| static int s3c_i2c_of_to_plat(struct udevice *dev) |
| { |
| #if IS_ENABLED(CONFIG_ARCH_EXYNOS4) || IS_ENABLED(CONFIG_ARCH_EXYNOS5) |
| const void *blob = gd->fdt_blob; |
| #endif |
| struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev); |
| int node; |
| |
| node = dev_of_offset(dev); |
| |
| i2c_bus->regs = dev_read_addr_ptr(dev); |
| |
| #if IS_ENABLED(CONFIG_ARCH_EXYNOS4) || IS_ENABLED(CONFIG_ARCH_EXYNOS5) |
| i2c_bus->id = pinmux_decode_periph_id(blob, node); |
| #endif |
| |
| i2c_bus->clock_frequency = |
| dev_read_u32_default(dev, "clock-frequency", |
| I2C_SPEED_STANDARD_RATE); |
| i2c_bus->node = node; |
| i2c_bus->bus_num = dev_seq(dev); |
| |
| #if IS_ENABLED(CONFIG_ARCH_EXYNOS4) || IS_ENABLED(CONFIG_ARCH_EXYNOS5) |
| exynos_pinmux_config(i2c_bus->id, 0); |
| #endif |
| |
| i2c_bus->active = true; |
| |
| return 0; |
| } |
| |
| static const struct dm_i2c_ops s3c_i2c_ops = { |
| .xfer = s3c24x0_i2c_xfer, |
| .probe_chip = s3c24x0_i2c_probe, |
| .set_bus_speed = s3c24x0_i2c_set_bus_speed, |
| }; |
| |
| static const struct udevice_id s3c_i2c_ids[] = { |
| { .compatible = "samsung,s3c2440-i2c" }, |
| { } |
| }; |
| |
| U_BOOT_DRIVER(i2c_s3c) = { |
| .name = "i2c_s3c", |
| .id = UCLASS_I2C, |
| .of_match = s3c_i2c_ids, |
| .of_to_plat = s3c_i2c_of_to_plat, |
| .priv_auto = sizeof(struct s3c24x0_i2c_bus), |
| .ops = &s3c_i2c_ops, |
| }; |