lkml.org 
[lkml]   [2013]   [May]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v8] i2c: exynos5: add High Speed I2C controller driver
    Date
    From: Naveen Krishna Chatradhi <ch.naveen@samsung.com>

    Adds support for High Speed I2C driver found in Exynos5 and
    later SoCs from Samsung.

    Driver only supports Device Tree method.

    Changes since v1:
    1. Added FIFO functionality
    2. Added High speed mode functionality
    3. Remove SMBUS_QUICK
    4. Remove the debugfs functionality
    5. Use devm_* functions where ever possible
    6. Driver is free from GPIO configs
    7. Use OF data string "clock-frequency" to get the bus operating frequencies
    8. Split the clock divisor calculation function
    9. Add resets for the failed transacton cases
    10. few other bug fixes and cosmetic changes

    Signed-off-by: Taekgyun Ko <taeggyun.ko@samsung.com>
    Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
    Reviewed-by: Simon Glass <sjg@google.com>
    Tested-by: Andrew Bresticker <abrestic@google.com>
    Signed-off-by: Yuvaraj Kumar C D <yuvaraj.cd@samsung.com>
    Signed-off-by: Andrew Bresticker <abrestic@google.com>
    ---
    Changes since v7:
    1. used devm_ioremap_resource for register base address
    2. merged FIFO fix from Yuvaraj
    https://patchwork.kernel.org/patch/2420351/
    3. merged hsi2c clock config patch from Yuvaraj
    https://patchwork.kernel.org/patch/2464681/

    .../devicetree/bindings/i2c/i2c-exynos5.txt | 41 +
    drivers/i2c/busses/Kconfig | 7 +
    drivers/i2c/busses/Makefile | 1 +
    drivers/i2c/busses/i2c-exynos5.c | 888 ++++++++++++++++++++
    4 files changed, 937 insertions(+)
    create mode 100644 Documentation/devicetree/bindings/i2c/i2c-exynos5.txt
    create mode 100644 drivers/i2c/busses/i2c-exynos5.c

    diff --git a/Documentation/devicetree/bindings/i2c/i2c-exynos5.txt b/Documentation/devicetree/bindings/i2c/i2c-exynos5.txt
    new file mode 100644
    index 0000000..6e613b6
    --- /dev/null
    +++ b/Documentation/devicetree/bindings/i2c/i2c-exynos5.txt
    @@ -0,0 +1,41 @@
    +* Samsung's High Speed I2C controller
    +
    +The Samsung's High Speed I2C controller is used to interface with I2C devices
    +at various speeds ranging from 100khz to 3.4Mhz.
    +
    +Required properties:
    + - compatible: value should be.
    + (a) "samsung,exynos5-hsi2c", for i2c compatible with exynos5 hsi2c.
    + - reg: physical base address of the controller and length of memory mapped
    + region.
    + - interrupts: interrupt number to the cpu.
    +
    + - Pinctrl variant (preferred, if available):
    + - pinctrl-0: Pin control group to be used for this controller.
    + - pinctrl-names: Should contain only one value - "default".
    +
    +Optional properties:
    + - samsung,hs-mode: Mode of operation, High speed or Fast speed mode. If not
    + specified, default value is 0.
    + - clock-frequency: Desired operating frequency in Hz of the bus.
    + If not specified, the default value in Hz is 100000.
    +
    +Example:
    +
    + hsi2c@12ca0000 {
    + compatible = "samsung,exynos5-hsi2c";
    + reg = <0x12ca0000 0x100>;
    + interrupts = <56>;
    + clock-frequency = <100000>;
    + /* Pinctrl variant begins here */
    + pinctrl-0 = <&i2c4_bus>;
    + pinctrl-names = "default";
    + /* Pinctrl variant ends here */
    + #address-cells = <1>;
    + #size-cells = <0>;
    +
    + s2mps11_pmic@66 {
    + compatible = "samsung,s2mps11-pmic";
    + reg = <0x66>;
    + };
    + };
    diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
    index adfee98..49a665f 100644
    --- a/drivers/i2c/busses/Kconfig
    +++ b/drivers/i2c/busses/Kconfig
    @@ -434,6 +434,13 @@ config I2C_EG20T
    ML7213/ML7223/ML7831 is companion chip for Intel Atom E6xx series.
    ML7213/ML7223/ML7831 is completely compatible for Intel EG20T PCH.

    +config I2C_EXYNOS5
    + tristate "Exynos5 high-speed I2C driver"
    + depends on ARCH_EXYNOS5 && OF
    + help
    + Say Y here to include support for high-speed I2C controller in the
    + Exynos5 based Samsung SoCs.
    +
    config I2C_GPIO
    tristate "GPIO-based bitbanging I2C"
    depends on GENERIC_GPIO
    diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
    index 8f4fc23..b19366c 100644
    --- a/drivers/i2c/busses/Makefile
    +++ b/drivers/i2c/busses/Makefile
    @@ -42,6 +42,7 @@ i2c-designware-platform-objs := i2c-designware-platdrv.o
    obj-$(CONFIG_I2C_DESIGNWARE_PCI) += i2c-designware-pci.o
    i2c-designware-pci-objs := i2c-designware-pcidrv.o
    obj-$(CONFIG_I2C_EG20T) += i2c-eg20t.o
    +obj-$(CONFIG_I2C_EXYNOS5) += i2c-exynos5.o
    obj-$(CONFIG_I2C_GPIO) += i2c-gpio.o
    obj-$(CONFIG_I2C_HIGHLANDER) += i2c-highlander.o
    obj-$(CONFIG_I2C_IBM_IIC) += i2c-ibm_iic.o
    diff --git a/drivers/i2c/busses/i2c-exynos5.c b/drivers/i2c/busses/i2c-exynos5.c
    new file mode 100644
    index 0000000..ef88fde
    --- /dev/null
    +++ b/drivers/i2c/busses/i2c-exynos5.c
    @@ -0,0 +1,888 @@
    +/**
    + * i2c-exynos5.c - Samsung Exynos5 I2C Controller Driver
    + *
    + * Copyright (C) 2013 Samsung Electronics Co., Ltd.
    + *
    + * 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.
    +*/
    +
    +#include <linux/kernel.h>
    +#include <linux/module.h>
    +
    +#include <linux/i2c.h>
    +#include <linux/init.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/pm_runtime.h>
    +#include <linux/clk.h>
    +#include <linux/slab.h>
    +#include <linux/io.h>
    +#include <linux/of_address.h>
    +#include <linux/of_irq.h>
    +#include <linux/of_i2c.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_FIFO_MAX (0x40)
    +#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)
    +#define HSI2C_INT_I2C_EN (1u << 9)
    +
    +/* 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_RX_INT (HSI2C_INT_RX_ALMOSTFULL | \
    + HSI2C_INT_RX_UNDERRUN | \
    + HSI2C_INT_RX_OVERRUN | \
    + HSI2C_INT_TRAILING)
    +
    +/* 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)
    +#define HSI2C_FIFO_EMPTY (HSI2C_RX_FIFO_EMPTY | \
    + HSI2C_TX_FIFO_EMPTY)
    +
    +/* 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_DONE (1u << 0)
    +
    +/* 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)
    +
    +/*
    + * Controller operating frequency, timing values for operation
    + * are calculated against this frequency
    + */
    +#define HSI2C_HS_TX_CLOCK 1000000
    +#define HSI2C_FS_TX_CLOCK 1000000
    +#define HSI2C_HIGH_SPD 1
    +#define HSI2C_FAST_SPD 0
    +
    +#define EXYNOS5_I2C_TIMEOUT (msecs_to_jiffies(1000))
    +
    +/* timeout for pm runtime autosuspend */
    +#define EXYNOS5_I2C_PM_TIMEOUT 1000 /* ms */
    +
    +struct exynos5_i2c {
    + struct i2c_adapter adap;
    + unsigned int suspended:1;
    +
    + struct i2c_msg *msg;
    + struct completion msg_complete;
    + unsigned int msg_ptr;
    + unsigned int msg_len;
    +
    + unsigned int irq;
    +
    + void __iomem *regs;
    + struct clk *clk;
    + struct device *dev;
    + int state;
    +
    + /*
    + * 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 fs_clock;
    + unsigned int hs_clock;
    +
    + /*
    + * HSI2C Controller can operate in
    + * 1. High speed upto 3.4Mbps
    + * 2. Fast speed upto 1Mbps
    + */
    + int speed_mode;
    + int bus_id;
    +};
    +
    +static const struct of_device_id exynos5_i2c_match[] = {
    + { .compatible = "samsung,exynos5-hsi2c" },
    + {},
    +};
    +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
    + *
    + * Returns 0 on success, -EINVAL if the cycle length cannot
    + * be calculated.
    + */
    +static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c, int mode)
    +{
    + 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 div, utemp0 = 0, utemp1 = 0, clk_cycle;
    + unsigned int op_clk = (mode == HSI2C_HIGH_SPD) ?
    + i2c->hs_clock : i2c->fs_clock;
    +
    + /*
    + * 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)
    + */
    + t_ftl_cycle = (readl(i2c->regs + HSI2C_CONF) >> 16) & 0x7;
    + utemp0 = (clkin / op_clk) - 8 - 2 * t_ftl_cycle;
    +
    + /* CLK_DIV max is 256 */
    + for (div = 0; div < 256; div++) {
    + utemp1 = utemp0 / (div + 1);
    +
    + /*
    + * SCL_L and SCL_H each has max value of 255
    + * Hence, For the clk_cycle to the have right value
    + * utemp1 has to be less then 512 and more than 4.
    + */
    + if ((utemp1 < 512) && (utemp1 > 4)) {
    + clk_cycle = utemp1 - 2;
    + break;
    + } else if (div == 255) {
    + dev_warn(i2c->dev, "Failed to calculate divisor");
    + 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 (mode == HSI2C_HIGH_SPD) {
    + 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)
    +{
    + /*
    + * Configure the Fast speed timing values
    + * Even the High Speed mode initially starts with Fast mode
    + */
    + if (exynos5_i2c_set_timing(i2c, HSI2C_FAST_SPD)) {
    + dev_err(i2c->dev, "HSI2C FS Clock set up failed\n");
    + return -EINVAL;
    + }
    +
    + /* configure the High speed timing values */
    + if (i2c->speed_mode == HSI2C_HIGH_SPD) {
    + if (exynos5_i2c_set_timing(i2c, HSI2C_HIGH_SPD)) {
    + dev_err(i2c->dev, "HSI2C HS Clock set up failed\n");
    + return -EINVAL;
    + }
    + }
    +
    + return 0;
    +}
    +
    +/*
    + * 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);
    +
    + writel((HSI2C_FUNC_MODE_I2C | HSI2C_MASTER),
    + i2c->regs + HSI2C_CTL);
    + writel(HSI2C_TRAILING_COUNT, i2c->regs + HSI2C_TRAILIG_CTL);
    +
    + if (i2c->speed_mode == HSI2C_HIGH_SPD) {
    + writel(HSI2C_MASTER_ID(MASTER_ID(i2c->bus_id)),
    + 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;
    +
    + int_status = readl(i2c->regs + HSI2C_INT_STATUS);
    + fifo_status = readl(i2c->regs + HSI2C_FIFO_STATUS);
    +
    + if (int_status & HSI2C_INT_I2C) {
    + 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;
    + } else if (trans_status & HSI2C_NO_DEV) {
    + dev_dbg(i2c->dev, "No device\n");
    + i2c->state = -ENXIO;
    + } else if (trans_status & HSI2C_TRANS_ABORT) {
    + dev_dbg(i2c->dev, "Deal with arbitration lose\n");
    + i2c->state = -EAGAIN;
    + } else if (trans_status & HSI2C_TIMEOUT_AUTO) {
    + dev_dbg(i2c->dev, "Accessing device timed out\n");
    + i2c->state = -EAGAIN;
    + } else if (trans_status & HSI2C_TRANS_DONE) {
    + i2c->trans_done = 1;
    + i2c->state = 0;
    + }
    + }
    + /* TX_ALMOSTEMPTY can happen along with HSI2C_INT_I2C */
    + else if (int_status &
    + (HSI2C_INT_TX_UNDERRUN | HSI2C_INT_TX_ALMOSTEMPTY)) {
    + fifo_level = HSI2C_TX_FIFO_LVL(fifo_status);
    +
    + /* To support probing the devices for detection */
    + if (i2c->msg->len == 0) {
    + i2c->state = -ENXIO;
    + goto stop;
    + }
    +
    + len = HSI2C_FIFO_MAX - fifo_level;
    + if (len > i2c->msg->len)
    + len = i2c->msg->len;
    +
    + i2c->msg_len += len;
    + while (len > 0) {
    + byte = i2c->msg->buf[i2c->msg_ptr++];
    + writel(byte, i2c->regs + HSI2C_TX_DATA);
    + len--;
    + }
    + i2c->state = 0;
    + goto stop;
    + }
    + /* If TX FIFO is full (give chance to clear) */
    + else if (int_status & HSI2C_INT_TX_OVERRUN)
    + i2c->state = 0;
    +
    + if (int_status & (HSI2C_INT_RX_OVERRUN | HSI2C_INT_TRAILING |
    + HSI2C_INT_RX_UNDERRUN | HSI2C_INT_RX_ALMOSTFULL)) {
    + fifo_level = HSI2C_RX_FIFO_LVL(fifo_status);
    +
    + if (fifo_level >= i2c->msg->len)
    + len = i2c->msg->len;
    + else
    + len = fifo_level;
    +
    + i2c->msg_len += len;
    + while (len > 0) {
    + byte = (unsigned char)
    + readl(i2c->regs + HSI2C_RX_DATA);
    + i2c->msg->buf[i2c->msg_ptr++] = byte;
    + len--;
    + }
    + i2c->state = 0;
    + }
    +
    +
    + stop:
    + if ((i2c->msg_len == i2c->msg->len) || (i2c->state < 0)) {
    + writel(0, i2c->regs + HSI2C_INT_ENABLE);
    + complete(&i2c->msg_complete);
    + }
    +
    + exynos5_i2c_clr_pend_irq(i2c);
    +
    + return IRQ_HANDLED;
    +}
    +
    +/*
    + * exynos5_i2c_wait_bus_idle
    + *
    + * Wait for the transaction to complete (indicated by the TRANS_DONE bit
    + * being set), and, if this is the last message in a transfer, wait for the
    + * MASTER_BUSY bit to be cleared.
    + *
    + * Returns -EBUSY if the bus cannot be bought to idle
    + */
    +static int exynos5_i2c_wait_bus_idle(struct exynos5_i2c *i2c, int stop)
    +{
    + 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_TRANS_DONE)
    + i2c->trans_done = 1;
    + /*
    + * Only wait for MASTER_BUSY to be cleared if this is the last
    + * message.
    + */
    + if ((!stop || !(trans_status & HSI2C_MASTER_BUSY)) &&
    + i2c->trans_done)
    + return 0;
    +
    + usleep_range(50, 200);
    + } while (time_before(jiffies, stop_time));
    +
    + return -EBUSY;
    +}
    +
    +/*
    + * 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 = HSI2C_INT_I2C_EN;
    + u32 i2c_auto_conf = 0;
    + u32 fifo_ctl;
    + u32 i2c_timeout;
    +
    + /*
    + * When the message length is > FIFO depth, set the FIFO trigger
    + * at FIFO_MAX - 4. Just for ease of handling.
    + */
    + unsigned short len = (i2c->msg->len > HSI2C_FIFO_MAX) ?
    + (HSI2C_FIFO_MAX - 4) : i2c->msg->len;
    +
    + /* Clear to enable Timeout */
    + i2c_timeout = readl(i2c->regs + HSI2C_TIMEOUT);
    + i2c_timeout &= ~HSI2C_TIMEOUT_EN;
    + writel(i2c_timeout, i2c->regs + HSI2C_TIMEOUT);
    +
    + fifo_ctl = HSI2C_RXFIFO_EN | HSI2C_TXFIFO_EN;
    + writel(fifo_ctl, i2c->regs + HSI2C_FIFO_CTL);
    +
    + i2c_ctl = readl(i2c->regs + HSI2C_CTL);
    + i2c_ctl &= ~(HSI2C_TXCHON | HSI2C_RXCHON);
    + if (i2c->msg->flags & I2C_M_RD) {
    + i2c_ctl |= HSI2C_RXCHON;
    +
    + i2c_auto_conf |= HSI2C_READ_WRITE;
    +
    + fifo_ctl |= HSI2C_RXFIFO_TRIGGER_LEVEL(len);
    + int_en |= (HSI2C_INT_RX_ALMOSTFULL_EN |
    + HSI2C_INT_TRAILING_EN);
    + } else {
    + i2c_ctl |= HSI2C_TXCHON;
    +
    + fifo_ctl |= HSI2C_TXFIFO_TRIGGER_LEVEL(len);
    + int_en |= HSI2C_INT_TX_ALMOSTEMPTY_EN;
    + }
    +
    + if (stop == 1)
    + i2c_auto_conf |= HSI2C_STOP_AFTER_TRANS;
    +
    + writel(HSI2C_SLV_ADDR_MAS(i2c->msg->addr), i2c->regs + HSI2C_ADDR);
    +
    + writel(fifo_ctl, i2c->regs + HSI2C_FIFO_CTL);
    + writel(i2c_ctl, i2c->regs + HSI2C_CTL);
    +
    + /* In auto mode the length of xfer cannot be 0 */
    + if (i2c->msg->len == 0)
    + i2c_auto_conf |= 0x1;
    + else
    + i2c_auto_conf |= i2c->msg->len;
    +
    + writel(i2c_auto_conf, i2c->regs + HSI2C_AUTO_CONF);
    +
    + /* Start data transfer in Master mode */
    + i2c_auto_conf = readl(i2c->regs + HSI2C_AUTO_CONF);
    + i2c_auto_conf |= HSI2C_MASTER_RUN;
    + writel(i2c_auto_conf, i2c->regs + HSI2C_AUTO_CONF);
    +
    + writel(int_en, i2c->regs + HSI2C_INT_ENABLE);
    +}
    +
    +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->msg_len = 0;
    + i2c->trans_done = 0;
    +
    + INIT_COMPLETION(i2c->msg_complete);
    +
    + exynos5_i2c_message_start(i2c, stop);
    +
    + ret = wait_for_completion_interruptible_timeout
    + (&i2c->msg_complete, EXYNOS5_I2C_TIMEOUT);
    + if (ret >= 0)
    + timeout = ret;
    + else
    + return ret;
    +
    + ret = i2c->state;
    +
    + if ((timeout == 0) || (ret < 0)) {
    + exynos5_i2c_reset(i2c);
    + if (timeout == 0) {
    + dev_warn(i2c->dev, "%s timeout\n",
    + (msgs->flags & I2C_M_RD) ? "rx" : "tx");
    + return ret;
    + } else if (ret == -EAGAIN) {
    + return ret;
    + }
    + }
    +
    + /*
    + * If this is the last message to be transfered (stop == 1)
    + * Then check if the bus can be brought back to idle.
    + *
    + * Return -EBUSY if the bus still busy.
    + */
    + if (exynos5_i2c_wait_bus_idle(i2c, stop))
    + return -EBUSY;
    +
    + /* 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 = (struct exynos5_i2c *)adap->algo_data;
    + struct i2c_msg *msgs_ptr = msgs;
    + int retry, i = 0;
    + int ret = 0, ret_pm;
    + int stop = 0;
    +
    + if (i2c->suspended) {
    + dev_err(i2c->dev, "HS-I2C is not initialzed.\n");
    + return -EIO;
    + }
    +
    + ret_pm = pm_runtime_get_sync(i2c->dev);
    + if (IS_ERR_VALUE(ret_pm)) {
    + ret = -EIO;
    + goto out;
    + }
    +
    + clk_prepare_enable(i2c->clk);
    +
    + for (retry = 0; retry < adap->retries; retry++) {
    + for (i = 0; i < num; i++) {
    + stop = (i == num - 1);
    +
    + ret = exynos5_i2c_xfer_msg(i2c, msgs_ptr, stop);
    + msgs_ptr++;
    +
    + if (ret == -EAGAIN) {
    + msgs_ptr = msgs;
    + break;
    + } else if (ret < 0) {
    + goto out;
    + }
    + }
    +
    + if ((i == num) && (ret != -EAGAIN))
    + break;
    +
    + dev_dbg(i2c->dev, "retrying transfer (%d)\n", retry);
    +
    + udelay(100);
    + }
    +
    + if (i == num) {
    + ret = num;
    + } else {
    + /* Only one message, cannot access the device */
    + if (i == 1)
    + ret = -EREMOTEIO;
    + else
    + ret = i;
    +
    + dev_warn(i2c->dev, "xfer message failed\n");
    + }
    +
    + out:
    + clk_disable_unprepare(i2c->clk);
    + pm_runtime_mark_last_busy(i2c->dev);
    + pm_runtime_put_autosuspend(i2c->dev);
    + return ret;
    +}
    +
    +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;
    + struct resource *mem;
    + int ret;
    +
    + if (!np) {
    + dev_err(&pdev->dev, "no device node\n");
    + return -ENOENT;
    + }
    +
    + i2c = devm_kzalloc(&pdev->dev, sizeof(struct exynos5_i2c), GFP_KERNEL);
    + if (!i2c) {
    + dev_err(&pdev->dev, "no memory for state\n");
    + return -ENOMEM;
    + }
    +
    + /* Mode of operation High/Fast Speed mode */
    + if (of_get_property(np, "samsung,hs-mode", NULL)) {
    + i2c->speed_mode = HSI2C_HIGH_SPD;
    + i2c->fs_clock = HSI2C_FS_TX_CLOCK;
    + if (of_property_read_u32(np, "clock-frequency", &i2c->hs_clock))
    + i2c->hs_clock = HSI2C_HS_TX_CLOCK;
    + } else {
    + i2c->speed_mode = HSI2C_FAST_SPD;
    + if (of_property_read_u32(np, "clock-frequency", &i2c->fs_clock))
    + i2c->fs_clock = HSI2C_FS_TX_CLOCK;
    + }
    +
    + strlcpy(i2c->adap.name, "exynos5-i2c", sizeof(i2c->adap.name));
    + i2c->adap.owner = THIS_MODULE;
    + i2c->adap.algo = &exynos5_i2c_algorithm;
    + i2c->adap.retries = 2;
    + i2c->adap.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
    +
    + 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;
    + }
    +
    + clk_prepare_enable(i2c->clk);
    +
    + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    + i2c->regs = devm_ioremap_resource(&pdev->dev, mem);
    + if (!i2c->regs) {
    + dev_err(&pdev->dev, "cannot map HS-I2C IO\n");
    + 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);
    +
    + init_completion(&i2c->msg_complete);
    +
    + i2c->irq = ret = irq_of_parse_and_map(np, 0);
    + if (ret <= 0) {
    + dev_err(&pdev->dev, "cannot find HS-I2C IRQ\n");
    + ret = -EINVAL;
    + goto err_clk;
    + }
    +
    + ret = devm_request_irq(&pdev->dev, i2c->irq, exynos5_i2c_irq,
    + 0, dev_name(&pdev->dev), i2c);
    +
    + if (ret != 0) {
    + dev_err(&pdev->dev, "cannot request HS-I2C IRQ %d\n", i2c->irq);
    + goto err_clk;
    + }
    +
    + /*
    + * TODO: Use private lock to avoid race conditions as
    + * mentioned in pm_runtime.txt
    + */
    + pm_runtime_enable(i2c->dev);
    + pm_runtime_set_autosuspend_delay(i2c->dev, EXYNOS5_I2C_PM_TIMEOUT);
    + pm_runtime_use_autosuspend(i2c->dev);
    +
    + ret = pm_runtime_get_sync(i2c->dev);
    + if (IS_ERR_VALUE(ret))
    + goto err_clk;
    +
    + ret = exynos5_hsi2c_clock_setup(i2c);
    + if (ret)
    + goto err_pm;
    +
    + i2c->bus_id = of_alias_get_id(i2c->adap.dev.of_node, "hsi2c");
    +
    + exynos5_i2c_init(i2c);
    +
    + i2c->adap.nr = -1;
    + ret = i2c_add_numbered_adapter(&i2c->adap);
    + if (ret < 0) {
    + dev_err(&pdev->dev, "failed to add bus to i2c core\n");
    + goto err_pm;
    + }
    +
    + of_i2c_register_devices(&i2c->adap);
    + platform_set_drvdata(pdev, i2c);
    +
    + clk_disable_unprepare(i2c->clk);
    + pm_runtime_mark_last_busy(i2c->dev);
    + pm_runtime_put_autosuspend(i2c->dev);
    +
    + return 0;
    +
    + err_pm:
    + pm_runtime_put(i2c->dev);
    + pm_runtime_disable(&pdev->dev);
    + err_clk:
    + clk_disable_unprepare(i2c->clk);
    + return ret;
    +}
    +
    +static int exynos5_i2c_remove(struct platform_device *pdev)
    +{
    + struct exynos5_i2c *i2c = platform_get_drvdata(pdev);
    + int ret;
    +
    + ret = pm_runtime_get_sync(&pdev->dev);
    + if (IS_ERR_VALUE(ret))
    + return ret;
    +
    + i2c_del_adapter(&i2c->adap);
    +
    + pm_runtime_put(&pdev->dev);
    + pm_runtime_disable(&pdev->dev);
    +
    + clk_disable_unprepare(i2c->clk);
    +
    + return 0;
    +}
    +
    +#ifdef CONFIG_PM
    +static int exynos5_i2c_suspend_noirq(struct device *dev)
    +{
    + struct platform_device *pdev = to_platform_device(dev);
    + struct exynos5_i2c *i2c = platform_get_drvdata(pdev);
    +
    + i2c->suspended = 1;
    +
    + return 0;
    +}
    +
    +static int exynos5_i2c_resume_noirq(struct device *dev)
    +{
    + struct platform_device *pdev = to_platform_device(dev);
    + struct exynos5_i2c *i2c = platform_get_drvdata(pdev);
    + int ret = 0;
    +
    + clk_prepare_enable(i2c->clk);
    +
    + ret = exynos5_hsi2c_clock_setup(i2c);
    + if (ret) {
    + clk_disable_unprepare(i2c->clk);
    + return ret;
    + }
    +
    + exynos5_i2c_init(i2c);
    + clk_disable_unprepare(i2c->clk);
    + i2c->suspended = 0;
    +
    + return 0;
    +}
    +
    +static const struct dev_pm_ops exynos5_i2c_dev_pm_ops = {
    + .suspend_noirq = exynos5_i2c_suspend_noirq,
    + .resume_noirq = exynos5_i2c_resume_noirq,
    +};
    +
    +#define EXYNOS5_DEV_PM_OPS (&exynos5_i2c_dev_pm_ops)
    +#else
    +#define EXYNOS5_DEV_PM_OPS NULL
    +#endif
    +
    +static struct platform_driver exynos5_i2c_driver = {
    + .probe = exynos5_i2c_probe,
    + .remove = exynos5_i2c_remove,
    + .driver = {
    + .owner = THIS_MODULE,
    + .name = "exynos5-hsi2c",
    + .pm = EXYNOS5_DEV_PM_OPS,
    + .of_match_table = exynos5_i2c_match,
    + },
    +};
    +
    +static int __init i2c_adap_exynos5_init(void)
    +{
    + return platform_driver_register(&exynos5_i2c_driver);
    +}
    +subsys_initcall(i2c_adap_exynos5_init);
    +
    +static void __exit i2c_adap_exynos5_exit(void)
    +{
    + platform_driver_unregister(&exynos5_i2c_driver);
    +}
    +module_exit(i2c_adap_exynos5_exit);
    +
    +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");
    --
    1.7.9.5


    \
     
     \ /
      Last update: 2013-05-07 05:21    [W:4.761 / U:0.296 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site