diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-exynos5.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-exynos5.c | 955 |
1 files changed, 955 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-exynos5.c b/drivers/i2c/busses/i2c-exynos5.c new file mode 100644 index 000000000..2b0b9cdff --- /dev/null +++ b/drivers/i2c/busses/i2c-exynos5.c @@ -0,0 +1,955 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * i2c-exynos5.c - Samsung Exynos5 I2C Controller Driver + * + * Copyright (C) 2013 Samsung Electronics Co., Ltd. +*/ + +#include <linux/kernel.h> +#include <linux/module.h> + +#include <linux/i2c.h> +#include <linux/time.h> +#include <linux/interrupt.h> +#include <linux/delay.h> +#include <linux/errno.h> +#include <linux/err.h> +#include <linux/platform_device.h> +#include <linux/clk.h> +#include <linux/slab.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/spinlock.h> + +/* + * HSI2C controller from Samsung supports 2 modes of operation + * 1. Auto mode: Where in master automatically controls the whole transaction + * 2. Manual mode: Software controls the transaction by issuing commands + * START, READ, WRITE, STOP, RESTART in I2C_MANUAL_CMD register. + * + * Operation mode can be selected by setting AUTO_MODE bit in I2C_CONF register + * + * Special bits are available for both modes of operation to set commands + * and for checking transfer status + */ + +/* Register Map */ +#define HSI2C_CTL 0x00 +#define HSI2C_FIFO_CTL 0x04 +#define HSI2C_TRAILIG_CTL 0x08 +#define HSI2C_CLK_CTL 0x0C +#define HSI2C_CLK_SLOT 0x10 +#define HSI2C_INT_ENABLE 0x20 +#define HSI2C_INT_STATUS 0x24 +#define HSI2C_ERR_STATUS 0x2C +#define HSI2C_FIFO_STATUS 0x30 +#define HSI2C_TX_DATA 0x34 +#define HSI2C_RX_DATA 0x38 +#define HSI2C_CONF 0x40 +#define HSI2C_AUTO_CONF 0x44 +#define HSI2C_TIMEOUT 0x48 +#define HSI2C_MANUAL_CMD 0x4C +#define HSI2C_TRANS_STATUS 0x50 +#define HSI2C_TIMING_HS1 0x54 +#define HSI2C_TIMING_HS2 0x58 +#define HSI2C_TIMING_HS3 0x5C +#define HSI2C_TIMING_FS1 0x60 +#define HSI2C_TIMING_FS2 0x64 +#define HSI2C_TIMING_FS3 0x68 +#define HSI2C_TIMING_SLA 0x6C +#define HSI2C_ADDR 0x70 + +/* I2C_CTL Register bits */ +#define HSI2C_FUNC_MODE_I2C (1u << 0) +#define HSI2C_MASTER (1u << 3) +#define HSI2C_RXCHON (1u << 6) +#define HSI2C_TXCHON (1u << 7) +#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_RXFIFO_TRIGGER_LEVEL(x) ((x) << 4) +#define HSI2C_TXFIFO_TRIGGER_LEVEL(x) ((x) << 16) + +/* I2C_TRAILING_CTL Register bits */ +#define HSI2C_TRAILING_COUNT (0xf) + +/* I2C_INT_EN Register bits */ +#define HSI2C_INT_TX_ALMOSTEMPTY_EN (1u << 0) +#define HSI2C_INT_RX_ALMOSTFULL_EN (1u << 1) +#define HSI2C_INT_TRAILING_EN (1u << 6) + +/* I2C_INT_STAT Register bits */ +#define HSI2C_INT_TX_ALMOSTEMPTY (1u << 0) +#define HSI2C_INT_RX_ALMOSTFULL (1u << 1) +#define HSI2C_INT_TX_UNDERRUN (1u << 2) +#define HSI2C_INT_TX_OVERRUN (1u << 3) +#define HSI2C_INT_RX_UNDERRUN (1u << 4) +#define HSI2C_INT_RX_OVERRUN (1u << 5) +#define HSI2C_INT_TRAILING (1u << 6) +#define HSI2C_INT_I2C (1u << 9) + +#define HSI2C_INT_TRANS_DONE (1u << 7) +#define HSI2C_INT_TRANS_ABORT (1u << 8) +#define HSI2C_INT_NO_DEV_ACK (1u << 9) +#define HSI2C_INT_NO_DEV (1u << 10) +#define HSI2C_INT_TIMEOUT (1u << 11) +#define HSI2C_INT_I2C_TRANS (HSI2C_INT_TRANS_DONE | \ + HSI2C_INT_TRANS_ABORT | \ + HSI2C_INT_NO_DEV_ACK | \ + HSI2C_INT_NO_DEV | \ + HSI2C_INT_TIMEOUT) + +/* I2C_FIFO_STAT Register bits */ +#define HSI2C_RX_FIFO_EMPTY (1u << 24) +#define HSI2C_RX_FIFO_FULL (1u << 23) +#define HSI2C_RX_FIFO_LVL(x) ((x >> 16) & 0x7f) +#define HSI2C_TX_FIFO_EMPTY (1u << 8) +#define HSI2C_TX_FIFO_FULL (1u << 7) +#define HSI2C_TX_FIFO_LVL(x) ((x >> 0) & 0x7f) + +/* 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) +#define HSI2C_TIMEOUT_MASK 0xff + +/* I2C_MANUAL_CMD register bits */ +#define HSI2C_CMD_READ_DATA (1u << 4) +#define HSI2C_CMD_SEND_STOP (1u << 2) + +/* I2C_TRANS_STATUS register bits */ +#define HSI2C_MASTER_BUSY (1u << 17) +#define HSI2C_SLAVE_BUSY (1u << 16) + +/* I2C_TRANS_STATUS register bits for Exynos5 variant */ +#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_DONE (1u << 0) + +/* I2C_TRANS_STATUS register bits for Exynos7 variant */ +#define HSI2C_MASTER_ST_MASK 0xf +#define HSI2C_MASTER_ST_IDLE 0x0 +#define HSI2C_MASTER_ST_START 0x1 +#define HSI2C_MASTER_ST_RESTART 0x2 +#define HSI2C_MASTER_ST_STOP 0x3 +#define HSI2C_MASTER_ST_MASTER_ID 0x4 +#define HSI2C_MASTER_ST_ADDR0 0x5 +#define HSI2C_MASTER_ST_ADDR1 0x6 +#define HSI2C_MASTER_ST_ADDR2 0x7 +#define HSI2C_MASTER_ST_ADDR_SR 0x8 +#define HSI2C_MASTER_ST_READ 0x9 +#define HSI2C_MASTER_ST_WRITE 0xa +#define HSI2C_MASTER_ST_NO_ACK 0xb +#define HSI2C_MASTER_ST_LOSE 0xc +#define HSI2C_MASTER_ST_WAIT 0xd +#define HSI2C_MASTER_ST_WAIT_CMD 0xe + +/* I2C_ADDR register bits */ +#define HSI2C_SLV_ADDR_SLV(x) ((x & 0x3ff) << 0) +#define HSI2C_SLV_ADDR_MAS(x) ((x & 0x3ff) << 10) +#define HSI2C_MASTER_ID(x) ((x & 0xff) << 24) +#define MASTER_ID(x) ((x & 0x7) + 0x08) + +#define EXYNOS5_I2C_TIMEOUT (msecs_to_jiffies(100)) + +enum i2c_type_exynos { + I2C_TYPE_EXYNOS5, + I2C_TYPE_EXYNOS7, + I2C_TYPE_EXYNOSAUTOV9, +}; + +struct exynos5_i2c { + struct i2c_adapter adap; + + struct i2c_msg *msg; + struct completion msg_complete; + unsigned int msg_ptr; + + unsigned int irq; + + void __iomem *regs; + struct clk *clk; /* operating clock */ + struct clk *pclk; /* bus clock */ + struct device *dev; + int state; + + spinlock_t lock; /* IRQ synchronization */ + + /* + * Since the TRANS_DONE bit is cleared on read, and we may read it + * either during an IRQ or after a transaction, keep track of its + * state here. + */ + int trans_done; + + /* Controller operating frequency */ + unsigned int op_clock; + + /* Version of HS-I2C Hardware */ + const struct exynos_hsi2c_variant *variant; +}; + +/** + * struct exynos_hsi2c_variant - platform specific HSI2C driver data + * @fifo_depth: the fifo depth supported by the HSI2C module + * @hw: the hardware variant of Exynos I2C controller + * + * Specifies platform specific configuration of HSI2C module. + * Note: A structure for driver specific platform data is used for future + * expansion of its usage. + */ +struct exynos_hsi2c_variant { + unsigned int fifo_depth; + enum i2c_type_exynos hw; +}; + +static const struct exynos_hsi2c_variant exynos5250_hsi2c_data = { + .fifo_depth = 64, + .hw = I2C_TYPE_EXYNOS5, +}; + +static const struct exynos_hsi2c_variant exynos5260_hsi2c_data = { + .fifo_depth = 16, + .hw = I2C_TYPE_EXYNOS5, +}; + +static const struct exynos_hsi2c_variant exynos7_hsi2c_data = { + .fifo_depth = 16, + .hw = I2C_TYPE_EXYNOS7, +}; + +static const struct exynos_hsi2c_variant exynosautov9_hsi2c_data = { + .fifo_depth = 64, + .hw = I2C_TYPE_EXYNOSAUTOV9, +}; + +static const struct of_device_id exynos5_i2c_match[] = { + { + .compatible = "samsung,exynos5-hsi2c", + .data = &exynos5250_hsi2c_data + }, { + .compatible = "samsung,exynos5250-hsi2c", + .data = &exynos5250_hsi2c_data + }, { + .compatible = "samsung,exynos5260-hsi2c", + .data = &exynos5260_hsi2c_data + }, { + .compatible = "samsung,exynos7-hsi2c", + .data = &exynos7_hsi2c_data + }, { + .compatible = "samsung,exynosautov9-hsi2c", + .data = &exynosautov9_hsi2c_data + }, {}, +}; +MODULE_DEVICE_TABLE(of, exynos5_i2c_match); + +static void exynos5_i2c_clr_pend_irq(struct exynos5_i2c *i2c) +{ + writel(readl(i2c->regs + HSI2C_INT_STATUS), + i2c->regs + HSI2C_INT_STATUS); +} + +/* + * exynos5_i2c_set_timing: updates the registers with appropriate + * timing values calculated + * + * Timing values for operation are calculated against either 100kHz + * or 1MHz controller operating frequency. + * + * Returns 0 on success, -EINVAL if the cycle length cannot + * be calculated. + */ +static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c, bool hs_timings) +{ + u32 i2c_timing_s1; + u32 i2c_timing_s2; + u32 i2c_timing_s3; + u32 i2c_timing_sla; + 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; + unsigned int t_sr_release; + unsigned int t_ftl_cycle; + unsigned int clkin = clk_get_rate(i2c->clk); + unsigned int op_clk = hs_timings ? i2c->op_clock : + (i2c->op_clock >= I2C_MAX_FAST_MODE_PLUS_FREQ) ? I2C_MAX_STANDARD_MODE_FREQ : + i2c->op_clock; + int div, clk_cycle, temp; + + /* + * In case of HSI2C controllers in ExynosAutoV9: + * + * FSCL = IPCLK / ((CLK_DIV + 1) * 16) + * T_SCL_LOW = IPCLK * (CLK_DIV + 1) * (N + M) + * [N : number of 0's in the TSCL_H_HS] + * [M : number of 0's in the TSCL_L_HS] + * T_SCL_HIGH = IPCLK * (CLK_DIV + 1) * (N + M) + * [N : number of 1's in the TSCL_H_HS] + * [M : number of 1's in the TSCL_L_HS] + * + * Result of (N + M) is always 8. + * In general case, we don't need to control timing_s1 and timing_s2. + */ + if (i2c->variant->hw == I2C_TYPE_EXYNOSAUTOV9) { + div = ((clkin / (16 * i2c->op_clock)) - 1); + i2c_timing_s3 = div << 16; + if (hs_timings) + writel(i2c_timing_s3, i2c->regs + HSI2C_TIMING_HS3); + else + writel(i2c_timing_s3, i2c->regs + HSI2C_TIMING_FS3); + + return 0; + } + + /* + * In case of HSI2C controller in Exynos5 series + * FPCLK / FI2C = + * (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) + 8 + 2 * FLT_CYCLE + * + * In case of HSI2C controllers in Exynos7 series + * FPCLK / FI2C = + * (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) + 8 + FLT_CYCLE + * + * clk_cycle := TSCLK_L + TSCLK_H + * temp := (CLK_DIV + 1) * (clk_cycle + 2) + * + * Constraints: 4 <= temp, 0 <= CLK_DIV < 256, 2 <= clk_cycle <= 510 + * + */ + t_ftl_cycle = (readl(i2c->regs + HSI2C_CONF) >> 16) & 0x7; + temp = clkin / op_clk - 8 - t_ftl_cycle; + if (i2c->variant->hw != I2C_TYPE_EXYNOS7) + temp -= t_ftl_cycle; + div = temp / 512; + clk_cycle = temp / (div + 1) - 2; + if (temp < 4 || div >= 256 || clk_cycle < 2) { + dev_err(i2c->dev, "%s clock set-up failed\n", + hs_timings ? "HS" : "FS"); + return -EINVAL; + } + + t_scl_l = clk_cycle / 2; + t_scl_h = 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 = 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 = div << 16 | t_sr_release << 0; + i2c_timing_sla = t_data_hd << 0; + + dev_dbg(i2c->dev, "tSTART_SU: %X, tSTART_HD: %X, tSTOP_SU: %X\n", + t_start_su, t_start_hd, t_stop_su); + dev_dbg(i2c->dev, "tDATA_SU: %X, tSCL_L: %X, tSCL_H: %X\n", + t_data_su, t_scl_l, t_scl_h); + dev_dbg(i2c->dev, "nClkDiv: %X, tSR_RELEASE: %X\n", + div, t_sr_release); + dev_dbg(i2c->dev, "tDATA_HD: %X\n", t_data_hd); + + if (hs_timings) { + writel(i2c_timing_s1, i2c->regs + HSI2C_TIMING_HS1); + writel(i2c_timing_s2, i2c->regs + HSI2C_TIMING_HS2); + writel(i2c_timing_s3, i2c->regs + HSI2C_TIMING_HS3); + } else { + writel(i2c_timing_s1, i2c->regs + HSI2C_TIMING_FS1); + writel(i2c_timing_s2, i2c->regs + HSI2C_TIMING_FS2); + writel(i2c_timing_s3, i2c->regs + HSI2C_TIMING_FS3); + } + writel(i2c_timing_sla, i2c->regs + HSI2C_TIMING_SLA); + + return 0; +} + +static int exynos5_hsi2c_clock_setup(struct exynos5_i2c *i2c) +{ + /* always set Fast Speed timings */ + int ret = exynos5_i2c_set_timing(i2c, false); + + if (ret < 0 || i2c->op_clock < I2C_MAX_FAST_MODE_PLUS_FREQ) + return ret; + + return exynos5_i2c_set_timing(i2c, true); +} + +/* + * exynos5_i2c_init: configures the controller for I2C functionality + * Programs I2C controller for Master mode operation + */ +static void exynos5_i2c_init(struct exynos5_i2c *i2c) +{ + u32 i2c_conf = readl(i2c->regs + HSI2C_CONF); + u32 i2c_timeout = readl(i2c->regs + HSI2C_TIMEOUT); + + /* Clear to disable Timeout */ + i2c_timeout &= ~HSI2C_TIMEOUT_EN; + writel(i2c_timeout, i2c->regs + HSI2C_TIMEOUT); + + writel((HSI2C_FUNC_MODE_I2C | HSI2C_MASTER), + i2c->regs + HSI2C_CTL); + writel(HSI2C_TRAILING_COUNT, i2c->regs + HSI2C_TRAILIG_CTL); + + if (i2c->op_clock >= I2C_MAX_FAST_MODE_PLUS_FREQ) { + writel(HSI2C_MASTER_ID(MASTER_ID(i2c->adap.nr)), + i2c->regs + HSI2C_ADDR); + i2c_conf |= HSI2C_HS_MODE; + } + + writel(i2c_conf | HSI2C_AUTO_MODE, i2c->regs + HSI2C_CONF); +} + +static void exynos5_i2c_reset(struct exynos5_i2c *i2c) +{ + u32 i2c_ctl; + + /* Set and clear the bit for reset */ + i2c_ctl = readl(i2c->regs + HSI2C_CTL); + i2c_ctl |= HSI2C_SW_RST; + writel(i2c_ctl, i2c->regs + HSI2C_CTL); + + i2c_ctl = readl(i2c->regs + HSI2C_CTL); + i2c_ctl &= ~HSI2C_SW_RST; + writel(i2c_ctl, i2c->regs + HSI2C_CTL); + + /* We don't expect calculations to fail during the run */ + exynos5_hsi2c_clock_setup(i2c); + /* Initialize the configure registers */ + exynos5_i2c_init(i2c); +} + +/* + * exynos5_i2c_irq: top level IRQ servicing routine + * + * INT_STATUS registers gives the interrupt details. Further, + * FIFO_STATUS or TRANS_STATUS registers are to be check for detailed + * state of the bus. + */ +static irqreturn_t exynos5_i2c_irq(int irqno, void *dev_id) +{ + struct exynos5_i2c *i2c = dev_id; + u32 fifo_level, int_status, fifo_status, trans_status; + unsigned char byte; + int len = 0; + + i2c->state = -EINVAL; + + spin_lock(&i2c->lock); + + int_status = readl(i2c->regs + HSI2C_INT_STATUS); + writel(int_status, i2c->regs + HSI2C_INT_STATUS); + + /* handle interrupt related to the transfer status */ + switch (i2c->variant->hw) { + case I2C_TYPE_EXYNOSAUTOV9: + fallthrough; + case I2C_TYPE_EXYNOS7: + if (int_status & HSI2C_INT_TRANS_DONE) { + i2c->trans_done = 1; + i2c->state = 0; + } else if (int_status & HSI2C_INT_TRANS_ABORT) { + dev_dbg(i2c->dev, "Deal with arbitration lose\n"); + i2c->state = -EAGAIN; + goto stop; + } else if (int_status & HSI2C_INT_NO_DEV_ACK) { + dev_dbg(i2c->dev, "No ACK from device\n"); + i2c->state = -ENXIO; + goto stop; + } else if (int_status & HSI2C_INT_NO_DEV) { + dev_dbg(i2c->dev, "No device\n"); + i2c->state = -ENXIO; + goto stop; + } else if (int_status & HSI2C_INT_TIMEOUT) { + dev_dbg(i2c->dev, "Accessing device timed out\n"); + i2c->state = -ETIMEDOUT; + goto stop; + } + + break; + case I2C_TYPE_EXYNOS5: + if (!(int_status & HSI2C_INT_I2C)) + break; + + trans_status = readl(i2c->regs + HSI2C_TRANS_STATUS); + if (trans_status & HSI2C_NO_DEV_ACK) { + dev_dbg(i2c->dev, "No ACK from device\n"); + i2c->state = -ENXIO; + goto stop; + } else if (trans_status & HSI2C_NO_DEV) { + dev_dbg(i2c->dev, "No device\n"); + i2c->state = -ENXIO; + goto stop; + } else if (trans_status & HSI2C_TRANS_ABORT) { + dev_dbg(i2c->dev, "Deal with arbitration lose\n"); + i2c->state = -EAGAIN; + goto stop; + } else if (trans_status & HSI2C_TIMEOUT_AUTO) { + dev_dbg(i2c->dev, "Accessing device timed out\n"); + i2c->state = -ETIMEDOUT; + goto stop; + } else if (trans_status & HSI2C_TRANS_DONE) { + i2c->trans_done = 1; + i2c->state = 0; + } + + break; + } + + if ((i2c->msg->flags & I2C_M_RD) && (int_status & + (HSI2C_INT_TRAILING | HSI2C_INT_RX_ALMOSTFULL))) { + fifo_status = readl(i2c->regs + HSI2C_FIFO_STATUS); + fifo_level = HSI2C_RX_FIFO_LVL(fifo_status); + len = min(fifo_level, i2c->msg->len - i2c->msg_ptr); + + while (len > 0) { + byte = (unsigned char) + readl(i2c->regs + HSI2C_RX_DATA); + i2c->msg->buf[i2c->msg_ptr++] = byte; + len--; + } + i2c->state = 0; + } else if (int_status & HSI2C_INT_TX_ALMOSTEMPTY) { + fifo_status = readl(i2c->regs + HSI2C_FIFO_STATUS); + fifo_level = HSI2C_TX_FIFO_LVL(fifo_status); + + len = i2c->variant->fifo_depth - fifo_level; + if (len > (i2c->msg->len - i2c->msg_ptr)) { + u32 int_en = readl(i2c->regs + HSI2C_INT_ENABLE); + + int_en &= ~HSI2C_INT_TX_ALMOSTEMPTY_EN; + writel(int_en, i2c->regs + HSI2C_INT_ENABLE); + len = i2c->msg->len - i2c->msg_ptr; + } + + while (len > 0) { + byte = i2c->msg->buf[i2c->msg_ptr++]; + writel(byte, i2c->regs + HSI2C_TX_DATA); + len--; + } + i2c->state = 0; + } + + stop: + if ((i2c->trans_done && (i2c->msg->len == i2c->msg_ptr)) || + (i2c->state < 0)) { + writel(0, i2c->regs + HSI2C_INT_ENABLE); + exynos5_i2c_clr_pend_irq(i2c); + complete(&i2c->msg_complete); + } + + spin_unlock(&i2c->lock); + + return IRQ_HANDLED; +} + +/* + * exynos5_i2c_wait_bus_idle + * + * Wait for the bus to go idle, indicated by the MASTER_BUSY bit being + * cleared. + * + * Returns -EBUSY if the bus cannot be bought to idle + */ +static int exynos5_i2c_wait_bus_idle(struct exynos5_i2c *i2c) +{ + unsigned long stop_time; + u32 trans_status; + + /* wait for 100 milli seconds for the bus to be idle */ + stop_time = jiffies + msecs_to_jiffies(100) + 1; + do { + trans_status = readl(i2c->regs + HSI2C_TRANS_STATUS); + if (!(trans_status & HSI2C_MASTER_BUSY)) + return 0; + + usleep_range(50, 200); + } while (time_before(jiffies, stop_time)); + + return -EBUSY; +} + +static void exynos5_i2c_bus_recover(struct exynos5_i2c *i2c) +{ + u32 val; + + val = readl(i2c->regs + HSI2C_CTL) | HSI2C_RXCHON; + writel(val, i2c->regs + HSI2C_CTL); + val = readl(i2c->regs + HSI2C_CONF) & ~HSI2C_AUTO_MODE; + writel(val, i2c->regs + HSI2C_CONF); + + /* + * Specification says master should send nine clock pulses. It can be + * emulated by sending manual read command (nine pulses for read eight + * bits + one pulse for NACK). + */ + writel(HSI2C_CMD_READ_DATA, i2c->regs + HSI2C_MANUAL_CMD); + exynos5_i2c_wait_bus_idle(i2c); + writel(HSI2C_CMD_SEND_STOP, i2c->regs + HSI2C_MANUAL_CMD); + exynos5_i2c_wait_bus_idle(i2c); + + val = readl(i2c->regs + HSI2C_CTL) & ~HSI2C_RXCHON; + writel(val, i2c->regs + HSI2C_CTL); + val = readl(i2c->regs + HSI2C_CONF) | HSI2C_AUTO_MODE; + writel(val, i2c->regs + HSI2C_CONF); +} + +static void exynos5_i2c_bus_check(struct exynos5_i2c *i2c) +{ + unsigned long timeout; + + if (i2c->variant->hw == I2C_TYPE_EXYNOS5) + return; + + /* + * HSI2C_MASTER_ST_LOSE state (in Exynos7 and ExynosAutoV9 variants) + * before transaction indicates that bus is stuck (SDA is low). + * In such case bus recovery can be performed. + */ + timeout = jiffies + msecs_to_jiffies(100); + for (;;) { + u32 st = readl(i2c->regs + HSI2C_TRANS_STATUS); + + if ((st & HSI2C_MASTER_ST_MASK) != HSI2C_MASTER_ST_LOSE) + return; + + if (time_is_before_jiffies(timeout)) + return; + + exynos5_i2c_bus_recover(i2c); + } +} + +/* + * exynos5_i2c_message_start: Configures the bus and starts the xfer + * i2c: struct exynos5_i2c pointer for the current bus + * stop: Enables stop after transfer if set. Set for last transfer of + * in the list of messages. + * + * Configures the bus for read/write function + * Sets chip address to talk to, message length to be sent. + * Enables appropriate interrupts and sends start xfer command. + */ +static void exynos5_i2c_message_start(struct exynos5_i2c *i2c, int stop) +{ + u32 i2c_ctl; + u32 int_en = 0; + u32 i2c_auto_conf = 0; + u32 i2c_addr = 0; + u32 fifo_ctl; + unsigned long flags; + unsigned short trig_lvl; + + if (i2c->variant->hw == I2C_TYPE_EXYNOS5) + int_en |= HSI2C_INT_I2C; + else + int_en |= HSI2C_INT_I2C_TRANS; + + i2c_ctl = readl(i2c->regs + HSI2C_CTL); + i2c_ctl &= ~(HSI2C_TXCHON | HSI2C_RXCHON); + fifo_ctl = HSI2C_RXFIFO_EN | HSI2C_TXFIFO_EN; + + if (i2c->msg->flags & I2C_M_RD) { + i2c_ctl |= HSI2C_RXCHON; + + i2c_auto_conf |= HSI2C_READ_WRITE; + + trig_lvl = (i2c->msg->len > i2c->variant->fifo_depth) ? + (i2c->variant->fifo_depth * 3 / 4) : i2c->msg->len; + fifo_ctl |= HSI2C_RXFIFO_TRIGGER_LEVEL(trig_lvl); + + int_en |= (HSI2C_INT_RX_ALMOSTFULL_EN | + HSI2C_INT_TRAILING_EN); + } else { + i2c_ctl |= HSI2C_TXCHON; + + trig_lvl = (i2c->msg->len > i2c->variant->fifo_depth) ? + (i2c->variant->fifo_depth * 1 / 4) : i2c->msg->len; + fifo_ctl |= HSI2C_TXFIFO_TRIGGER_LEVEL(trig_lvl); + + int_en |= HSI2C_INT_TX_ALMOSTEMPTY_EN; + } + + i2c_addr = HSI2C_SLV_ADDR_MAS(i2c->msg->addr); + + if (i2c->op_clock >= I2C_MAX_FAST_MODE_PLUS_FREQ) + i2c_addr |= HSI2C_MASTER_ID(MASTER_ID(i2c->adap.nr)); + + writel(i2c_addr, i2c->regs + HSI2C_ADDR); + + writel(fifo_ctl, i2c->regs + HSI2C_FIFO_CTL); + writel(i2c_ctl, i2c->regs + HSI2C_CTL); + + exynos5_i2c_bus_check(i2c); + + /* + * Enable interrupts before starting the transfer so that we don't + * miss any INT_I2C interrupts. + */ + spin_lock_irqsave(&i2c->lock, flags); + writel(int_en, i2c->regs + HSI2C_INT_ENABLE); + + if (stop == 1) + i2c_auto_conf |= HSI2C_STOP_AFTER_TRANS; + i2c_auto_conf |= i2c->msg->len; + i2c_auto_conf |= HSI2C_MASTER_RUN; + writel(i2c_auto_conf, i2c->regs + HSI2C_AUTO_CONF); + spin_unlock_irqrestore(&i2c->lock, flags); +} + +static int exynos5_i2c_xfer_msg(struct exynos5_i2c *i2c, + struct i2c_msg *msgs, int stop) +{ + unsigned long timeout; + int ret; + + i2c->msg = msgs; + i2c->msg_ptr = 0; + i2c->trans_done = 0; + + reinit_completion(&i2c->msg_complete); + + exynos5_i2c_message_start(i2c, stop); + + timeout = wait_for_completion_timeout(&i2c->msg_complete, + EXYNOS5_I2C_TIMEOUT); + if (timeout == 0) + ret = -ETIMEDOUT; + else + ret = i2c->state; + + /* + * If this is the last message to be transfered (stop == 1) + * Then check if the bus can be brought back to idle. + */ + if (ret == 0 && stop) + ret = exynos5_i2c_wait_bus_idle(i2c); + + if (ret < 0) { + exynos5_i2c_reset(i2c); + if (ret == -ETIMEDOUT) + dev_warn(i2c->dev, "%s timeout\n", + (msgs->flags & I2C_M_RD) ? "rx" : "tx"); + } + + /* Return the state as in interrupt routine */ + return ret; +} + +static int exynos5_i2c_xfer(struct i2c_adapter *adap, + struct i2c_msg *msgs, int num) +{ + struct exynos5_i2c *i2c = adap->algo_data; + int i, ret; + + ret = clk_enable(i2c->pclk); + if (ret) + return ret; + + ret = clk_enable(i2c->clk); + if (ret) + goto err_pclk; + + for (i = 0; i < num; ++i) { + ret = exynos5_i2c_xfer_msg(i2c, msgs + i, i + 1 == num); + if (ret) + break; + } + + clk_disable(i2c->clk); +err_pclk: + clk_disable(i2c->pclk); + + return ret ?: num; +} + +static u32 exynos5_i2c_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK); +} + +static const struct i2c_algorithm exynos5_i2c_algorithm = { + .master_xfer = exynos5_i2c_xfer, + .functionality = exynos5_i2c_func, +}; + +static int exynos5_i2c_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct exynos5_i2c *i2c; + int ret; + + i2c = devm_kzalloc(&pdev->dev, sizeof(struct exynos5_i2c), GFP_KERNEL); + if (!i2c) + return -ENOMEM; + + if (of_property_read_u32(np, "clock-frequency", &i2c->op_clock)) + i2c->op_clock = I2C_MAX_STANDARD_MODE_FREQ; + + strscpy(i2c->adap.name, "exynos5-i2c", sizeof(i2c->adap.name)); + i2c->adap.owner = THIS_MODULE; + i2c->adap.algo = &exynos5_i2c_algorithm; + i2c->adap.retries = 3; + + i2c->dev = &pdev->dev; + i2c->clk = devm_clk_get(&pdev->dev, "hsi2c"); + if (IS_ERR(i2c->clk)) { + dev_err(&pdev->dev, "cannot get clock\n"); + return -ENOENT; + } + + i2c->pclk = devm_clk_get_optional(&pdev->dev, "hsi2c_pclk"); + if (IS_ERR(i2c->pclk)) { + return dev_err_probe(&pdev->dev, PTR_ERR(i2c->pclk), + "cannot get pclk"); + } + + ret = clk_prepare_enable(i2c->pclk); + if (ret) + return ret; + + ret = clk_prepare_enable(i2c->clk); + if (ret) + goto err_pclk; + + i2c->regs = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(i2c->regs)) { + ret = PTR_ERR(i2c->regs); + goto err_clk; + } + + i2c->adap.dev.of_node = np; + i2c->adap.algo_data = i2c; + i2c->adap.dev.parent = &pdev->dev; + + /* Clear pending interrupts from u-boot or misc causes */ + exynos5_i2c_clr_pend_irq(i2c); + + spin_lock_init(&i2c->lock); + init_completion(&i2c->msg_complete); + + i2c->irq = ret = platform_get_irq(pdev, 0); + if (ret < 0) + goto err_clk; + + ret = devm_request_irq(&pdev->dev, i2c->irq, exynos5_i2c_irq, + IRQF_NO_SUSPEND, dev_name(&pdev->dev), i2c); + if (ret != 0) { + dev_err(&pdev->dev, "cannot request HS-I2C IRQ %d\n", i2c->irq); + goto err_clk; + } + + i2c->variant = of_device_get_match_data(&pdev->dev); + + ret = exynos5_hsi2c_clock_setup(i2c); + if (ret) + goto err_clk; + + exynos5_i2c_reset(i2c); + + ret = i2c_add_adapter(&i2c->adap); + if (ret < 0) + goto err_clk; + + platform_set_drvdata(pdev, i2c); + + clk_disable(i2c->clk); + clk_disable(i2c->pclk); + + return 0; + + err_clk: + clk_disable_unprepare(i2c->clk); + + err_pclk: + clk_disable_unprepare(i2c->pclk); + return ret; +} + +static void exynos5_i2c_remove(struct platform_device *pdev) +{ + struct exynos5_i2c *i2c = platform_get_drvdata(pdev); + + i2c_del_adapter(&i2c->adap); + + clk_unprepare(i2c->clk); + clk_unprepare(i2c->pclk); +} + +static int exynos5_i2c_suspend_noirq(struct device *dev) +{ + struct exynos5_i2c *i2c = dev_get_drvdata(dev); + + i2c_mark_adapter_suspended(&i2c->adap); + clk_unprepare(i2c->clk); + clk_unprepare(i2c->pclk); + + return 0; +} + +static int exynos5_i2c_resume_noirq(struct device *dev) +{ + struct exynos5_i2c *i2c = dev_get_drvdata(dev); + int ret = 0; + + ret = clk_prepare_enable(i2c->pclk); + if (ret) + return ret; + + ret = clk_prepare_enable(i2c->clk); + if (ret) + goto err_pclk; + + ret = exynos5_hsi2c_clock_setup(i2c); + if (ret) + goto err_clk; + + exynos5_i2c_init(i2c); + clk_disable(i2c->clk); + clk_disable(i2c->pclk); + i2c_mark_adapter_resumed(&i2c->adap); + + return 0; + +err_clk: + clk_disable_unprepare(i2c->clk); +err_pclk: + clk_disable_unprepare(i2c->pclk); + return ret; +} + +static const struct dev_pm_ops exynos5_i2c_dev_pm_ops = { + NOIRQ_SYSTEM_SLEEP_PM_OPS(exynos5_i2c_suspend_noirq, + exynos5_i2c_resume_noirq) +}; + +static struct platform_driver exynos5_i2c_driver = { + .probe = exynos5_i2c_probe, + .remove_new = exynos5_i2c_remove, + .driver = { + .name = "exynos5-hsi2c", + .pm = pm_sleep_ptr(&exynos5_i2c_dev_pm_ops), + .of_match_table = exynos5_i2c_match, + }, +}; + +module_platform_driver(exynos5_i2c_driver); + +MODULE_DESCRIPTION("Exynos5 HS-I2C Bus driver"); +MODULE_AUTHOR("Naveen Krishna Chatradhi <ch.naveen@samsung.com>"); +MODULE_AUTHOR("Taekgyun Ko <taeggyun.ko@samsung.com>"); +MODULE_LICENSE("GPL v2"); |