--- /dev/null
+/*
+ * (C) Copyright 2009-2010
+ * Nokia Siemens Networks, michael.lawnick.ext@nsn.com
+ *
+ * Portions Copyright (C) 2010, 2011 Cavium Networks, Inc.
+ *
+ * This is a driver for the i2c adapter in Cavium Networks' OCTEON processors.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/io.h>
+#include <linux/of.h>
+
+#include <asm/octeon/octeon.h>
+
+#define DRV_NAME "i2c-octeon"
+
+/* The previous out-of-tree version was implicitly version 1.0. */
+#define DRV_VERSION "2.0"
+
+/* register offsets */
+#define SW_TWSI 0x00
+#define TWSI_INT 0x10
+
+/* Controller command patterns */
+#define SW_TWSI_V 0x8000000000000000ull
+#define SW_TWSI_EOP_TWSI_DATA 0x0C00000100000000ull
+#define SW_TWSI_EOP_TWSI_CTL 0x0C00000200000000ull
+#define SW_TWSI_EOP_TWSI_CLKCTL 0x0C00000300000000ull
+#define SW_TWSI_EOP_TWSI_STAT 0x0C00000300000000ull
+#define SW_TWSI_EOP_TWSI_RST 0x0C00000700000000ull
+#define SW_TWSI_OP_TWSI_CLK 0x0800000000000000ull
+#define SW_TWSI_R 0x0100000000000000ull
+
+/* Controller command and status bits */
+#define TWSI_CTL_CE 0x80
+#define TWSI_CTL_ENAB 0x40
+#define TWSI_CTL_STA 0x20
+#define TWSI_CTL_STP 0x10
+#define TWSI_CTL_IFLG 0x08
+#define TWSI_CTL_AAK 0x04
+
+/* Some status values */
+#define STAT_START 0x08
+#define STAT_RSTART 0x10
+#define STAT_TXADDR_ACK 0x18
+#define STAT_TXDATA_ACK 0x28
+#define STAT_RXADDR_ACK 0x40
+#define STAT_RXDATA_ACK 0x50
+#define STAT_IDLE 0xF8
+
+struct octeon_i2c {
+ wait_queue_head_t queue;
+ struct i2c_adapter adap;
+ int irq;
+ u32 twsi_freq;
+ int sys_freq;
+ resource_size_t twsi_phys;
+ void __iomem *twsi_base;
+ resource_size_t regsize;
+ struct device *dev;
+};
+
+/**
+ * octeon_i2c_write_sw - write an I2C core register.
+ * @i2c: The struct octeon_i2c.
+ * @eop_reg: Register selector.
+ * @data: Value to be written.
+ *
+ * The I2C core registers are accessed indirectly via the SW_TWSI CSR.
+ */
+static void octeon_i2c_write_sw(struct octeon_i2c *i2c,
+ u64 eop_reg,
+ u8 data)
+{
+ u64 tmp;
+
+ __raw_writeq(SW_TWSI_V | eop_reg | data, i2c->twsi_base + SW_TWSI);
+ do {
+ tmp = __raw_readq(i2c->twsi_base + SW_TWSI);
+ } while ((tmp & SW_TWSI_V) != 0);
+}
+
+/**
+ * octeon_i2c_read_sw - write an I2C core register.
+ * @i2c: The struct octeon_i2c.
+ * @eop_reg: Register selector.
+ *
+ * Returns the data.
+ *
+ * The I2C core registers are accessed indirectly via the SW_TWSI CSR.
+ */
+static u8 octeon_i2c_read_sw(struct octeon_i2c *i2c, u64 eop_reg)
+{
+ u64 tmp;
+
+ __raw_writeq(SW_TWSI_V | eop_reg | SW_TWSI_R, i2c->twsi_base + SW_TWSI);
+ do {
+ tmp = __raw_readq(i2c->twsi_base + SW_TWSI);
+ } while ((tmp & SW_TWSI_V) != 0);
+
+ return tmp & 0xFF;
+}
+
+/**
+ * octeon_i2c_write_int - write the TWSI_INT register
+ * @i2c: The struct octeon_i2c.
+ * @data: Value to be written.
+ */
+static void octeon_i2c_write_int(struct octeon_i2c *i2c, u64 data)
+{
+ __raw_writeq(data, i2c->twsi_base + TWSI_INT);
+ __raw_readq(i2c->twsi_base + TWSI_INT);
+}
+
+/**
+ * octeon_i2c_int_enable - enable the TS interrupt.
+ * @i2c: The struct octeon_i2c.
+ *
+ * The interrupt will be asserted when there is non-STAT_IDLE state in
+ * the SW_TWSI_EOP_TWSI_STAT register.
+ */
+static void octeon_i2c_int_enable(struct octeon_i2c *i2c)
+{
+ octeon_i2c_write_int(i2c, 0x40);
+}
+
+/**
+ * octeon_i2c_int_disable - disable the TS interrupt.
+ * @i2c: The struct octeon_i2c.
+ */
+static void octeon_i2c_int_disable(struct octeon_i2c *i2c)
+{
+ octeon_i2c_write_int(i2c, 0);
+}
+
+/**
+ * octeon_i2c_unblock - unblock the bus.
+ * @i2c: The struct octeon_i2c.
+ *
+ * If there was a reset while a device was driving 0 to bus,
+ * bus is blocked. We toggle it free manually by some clock
+ * cycles and send a stop.
+ */
+static void octeon_i2c_unblock(struct octeon_i2c *i2c)
+{
+ int i;
+
+ dev_dbg(i2c->dev, "%s\n", __func__);
+ for (i = 0; i < 9; i++) {
+ octeon_i2c_write_int(i2c, 0x0);
+ udelay(5);
+ octeon_i2c_write_int(i2c, 0x200);
+ udelay(5);
+ }
+ octeon_i2c_write_int(i2c, 0x300);
+ udelay(5);
+ octeon_i2c_write_int(i2c, 0x100);
+ udelay(5);
+ octeon_i2c_write_int(i2c, 0x0);
+}
+
+/**
+ * octeon_i2c_isr - the interrupt service routine.
+ * @int: The irq, unused.
+ * @dev_id: Our struct octeon_i2c.
+ */
+static irqreturn_t octeon_i2c_isr(int irq, void *dev_id)
+{
+ struct octeon_i2c *i2c = dev_id;
+
+ octeon_i2c_int_disable(i2c);
+ wake_up(&i2c->queue);
+
+ return IRQ_HANDLED;
+}
+
+
+static int octeon_i2c_test_iflg(struct octeon_i2c *i2c)
+{
+ return (octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_CTL) & TWSI_CTL_IFLG) != 0;
+}
+
+/**
+ * octeon_i2c_wait - wait for the IFLG to be set.
+ * @i2c: The struct octeon_i2c.
+ *
+ * Returns 0 on success, otherwise a negative errno.
+ */
+static int octeon_i2c_wait(struct octeon_i2c *i2c)
+{
+ int result;
+
+ octeon_i2c_int_enable(i2c);
+
+ result = wait_event_timeout(i2c->queue,
+ octeon_i2c_test_iflg(i2c),
+ i2c->adap.timeout);
+
+ octeon_i2c_int_disable(i2c);
+
+ if (result < 0) {
+ dev_dbg(i2c->dev, "%s: wait interrupted\n", __func__);
+ return result;
+ } else if (result == 0) {
+ dev_dbg(i2c->dev, "%s: timeout\n", __func__);
+ return -ETIMEDOUT;
+ }
+
+ return 0;
+}
+
+/**
+ * octeon_i2c_start - send START to the bus.
+ * @i2c: The struct octeon_i2c.
+ *
+ * Returns 0 on success, otherwise a negative errno.
+ */
+static int octeon_i2c_start(struct octeon_i2c *i2c)
+{
+ u8 data;
+ int result;
+
+ octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
+ TWSI_CTL_ENAB | TWSI_CTL_STA);
+
+ result = octeon_i2c_wait(i2c);
+ if (result) {
+ if (octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT) == STAT_IDLE) {
+ /*
+ * Controller refused to send start flag May
+ * be a client is holding SDA low - let's try
+ * to free it.
+ */
+ octeon_i2c_unblock(i2c);
+ octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
+ TWSI_CTL_ENAB | TWSI_CTL_STA);
+
+ result = octeon_i2c_wait(i2c);
+ }
+ if (result)
+ return result;
+ }
+
+ data = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
+ if ((data != STAT_START) && (data != STAT_RSTART)) {
+ dev_err(i2c->dev, "%s: bad status (0x%x)\n", __func__, data);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+/**
+ * octeon_i2c_stop - send STOP to the bus.
+ * @i2c: The struct octeon_i2c.
+ *
+ * Returns 0 on success, otherwise a negative errno.
+ */
+static int octeon_i2c_stop(struct octeon_i2c *i2c)
+{
+ u8 data;
+
+ octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
+ TWSI_CTL_ENAB | TWSI_CTL_STP);
+
+ data = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
+
+ if (data != STAT_IDLE) {
+ dev_err(i2c->dev, "%s: bad status(0x%x)\n", __func__, data);
+ return -EIO;
+ }
+ return 0;
+}
+
+/**
+ * octeon_i2c_write - send data to the bus.
+ * @i2c: The struct octeon_i2c.
+ * @target: Target address.
+ * @data: Pointer to the data to be sent.
+ * @length: Length of the data.
+ *
+ * The address is sent over the bus, then the data.
+ *
+ * Returns 0 on success, otherwise a negative errno.
+ */
+static int octeon_i2c_write(struct octeon_i2c *i2c, int target,
+ const u8 *data, int length)
+{
+ int i, result;
+ u8 tmp;
+
+ result = octeon_i2c_start(i2c);
+ if (result)
+ return result;
+
+ octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_DATA, target << 1);
+ octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL, TWSI_CTL_ENAB);
+
+ result = octeon_i2c_wait(i2c);
+ if (result)
+ return result;
+
+ for (i = 0; i < length; i++) {
+ tmp = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
+ if ((tmp != STAT_TXADDR_ACK) && (tmp != STAT_TXDATA_ACK)) {
+ dev_err(i2c->dev,
+ "%s: bad status before write (0x%x)\n",
+ __func__, tmp);
+ return -EIO;
+ }
+
+ octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_DATA, data[i]);
+ octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL, TWSI_CTL_ENAB);
+
+ result = octeon_i2c_wait(i2c);
+ if (result)
+ return result;
+ }
+
+ return 0;
+}
+
+/**
+ * octeon_i2c_read - receive data from the bus.
+ * @i2c: The struct octeon_i2c.
+ * @target: Target address.
+ * @data: Pointer to the location to store the datae .
+ * @length: Length of the data.
+ *
+ * The address is sent over the bus, then the data is read.
+ *
+ * Returns 0 on success, otherwise a negative errno.
+ */
+static int octeon_i2c_read(struct octeon_i2c *i2c, int target,
+ u8 *data, int length)
+{
+ int i, result;
+ u8 tmp;
+
+ if (length < 1)
+ return -EINVAL;
+
+ result = octeon_i2c_start(i2c);
+ if (result)
+ return result;
+
+ octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_DATA, (target<<1) | 1);
+ octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL, TWSI_CTL_ENAB);
+
+ result = octeon_i2c_wait(i2c);
+ if (result)
+ return result;
+
+ for (i = 0; i < length; i++) {
+ tmp = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
+ if ((tmp != STAT_RXDATA_ACK) && (tmp != STAT_RXADDR_ACK)) {
+ dev_err(i2c->dev,
+ "%s: bad status before read (0x%x)\n",
+ __func__, tmp);
+ return -EIO;
+ }
+
+ if (i+1 < length)
+ octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
+ TWSI_CTL_ENAB | TWSI_CTL_AAK);
+ else
+ octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
+ TWSI_CTL_ENAB);
+
+ result = octeon_i2c_wait(i2c);
+ if (result)
+ return result;
+
+ data[i] = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_DATA);
+ }
+ return 0;
+}
+
+/**
+ * octeon_i2c_xfer - The driver's master_xfer function.
+ * @adap: Pointer to the i2c_adapter structure.
+ * @msgs: Pointer to the messages to be processed.
+ * @num: Length of the MSGS array.
+ *
+ * Returns the number of messages processed, or a negative errno on
+ * failure.
+ */
+static int octeon_i2c_xfer(struct i2c_adapter *adap,
+ struct i2c_msg *msgs,
+ int num)
+{
+ struct i2c_msg *pmsg;
+ int i;
+ int ret = 0;
+ struct octeon_i2c *i2c = i2c_get_adapdata(adap);
+
+ for (i = 0; ret == 0 && i < num; i++) {
+ pmsg = &msgs[i];
+ dev_dbg(i2c->dev,
+ "Doing %s %d byte(s) to/from 0x%02x - %d of %d messages\n",
+ pmsg->flags & I2C_M_RD ? "read" : "write",
+ pmsg->len, pmsg->addr, i + 1, num);
+ if (pmsg->flags & I2C_M_RD)
+ ret = octeon_i2c_read(i2c, pmsg->addr, pmsg->buf,
+ pmsg->len);
+ else
+ ret = octeon_i2c_write(i2c, pmsg->addr, pmsg->buf,
+ pmsg->len);
+ }
+ octeon_i2c_stop(i2c);
+
+ return (ret != 0) ? ret : num;
+}
+
+static u32 octeon_i2c_functionality(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm octeon_i2c_algo = {
+ .master_xfer = octeon_i2c_xfer,
+ .functionality = octeon_i2c_functionality,
+};
+
+static struct i2c_adapter octeon_i2c_ops = {
+ .owner = THIS_MODULE,
+ .name = "OCTEON adapter",
+ .algo = &octeon_i2c_algo,
+ .timeout = HZ / 50,
+};
+
+/**
+ * octeon_i2c_setclock - Calculate and set clock divisors.
+ */
+static int octeon_i2c_setclock(struct octeon_i2c *i2c)
+{
+ int tclk, thp_base, inc, thp_idx, mdiv_idx, ndiv_idx, foscl, diff;
+ int thp = 0x18, mdiv = 2, ndiv = 0, delta_hz = 1000000;
+
+ for (ndiv_idx = 0; ndiv_idx < 8 && delta_hz != 0; ndiv_idx++) {
+ /*
+ * An mdiv value of less than 2 seems to not work well
+ * with ds1337 RTCs, so we constrain it to larger
+ * values.
+ */
+ for (mdiv_idx = 15; mdiv_idx >= 2 && delta_hz != 0; mdiv_idx--) {
+ /*
+ * For given ndiv and mdiv values check the
+ * two closest thp values.
+ */
+ tclk = i2c->twsi_freq * (mdiv_idx + 1) * 10;
+ tclk *= (1 << ndiv_idx);
+ thp_base = (i2c->sys_freq / (tclk * 2)) - 1;
+ for (inc = 0; inc <= 1; inc++) {
+ thp_idx = thp_base + inc;
+ if (thp_idx < 5 || thp_idx > 0xff)
+ continue;
+
+ foscl = i2c->sys_freq / (2 * (thp_idx + 1));
+ foscl = foscl / (1 << ndiv_idx);
+ foscl = foscl / (mdiv_idx + 1) / 10;
+ diff = abs(foscl - i2c->twsi_freq);
+ if (diff < delta_hz) {
+ delta_hz = diff;
+ thp = thp_idx;
+ mdiv = mdiv_idx;
+ ndiv = ndiv_idx;
+ }
+ }
+ }
+ }
+ octeon_i2c_write_sw(i2c, SW_TWSI_OP_TWSI_CLK, thp);
+ octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CLKCTL, (mdiv << 3) | ndiv);
+
+ return 0;
+}
+
+static int octeon_i2c_initlowlevel(struct octeon_i2c *i2c)
+{
+ u8 status;
+ int tries;
+
+ /* disable high level controller, enable bus access */
+ octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL, TWSI_CTL_ENAB);
+
+ /* reset controller */
+ octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_RST, 0);
+
+ for (tries = 10; tries; tries--) {
+ udelay(1);
+ status = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
+ if (status == STAT_IDLE)
+ return 0;
+ }
+ dev_err(i2c->dev, "%s: TWSI_RST failed! (0x%x)\n", __func__, status);
+ return -EIO;
+}
+
+static int octeon_i2c_probe(struct platform_device *pdev)
+{
+ int irq, result = 0;
+ struct octeon_i2c *i2c;
+ struct resource *res_mem;
+
+ /* All adaptors have an irq. */
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return irq;
+
+ i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
+ if (!i2c) {
+ dev_err(&pdev->dev, "kzalloc failed\n");
+ result = -ENOMEM;
+ goto out;
+ }
+ i2c->dev = &pdev->dev;
+
+ res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+ if (res_mem == NULL) {
+ dev_err(i2c->dev, "found no memory resource\n");
+ result = -ENXIO;
+ goto out;
+ }
+ i2c->twsi_phys = res_mem->start;
+ i2c->regsize = resource_size(res_mem);
+
+ /*
+ * "clock-rate" is a legacy binding, the official binding is
+ * "clock-frequency". Try the official one first and then
+ * fall back if it doesn't exist.
+ */
+ if (of_property_read_u32(pdev->dev.of_node,
+ "clock-frequency", &i2c->twsi_freq) &&
+ of_property_read_u32(pdev->dev.of_node,
+ "clock-rate", &i2c->twsi_freq)) {
+ dev_err(i2c->dev,
+ "no I2C 'clock-rate' or 'clock-frequency' property\n");
+ result = -ENXIO;
+ goto out;
+ }
+
+ i2c->sys_freq = octeon_get_io_clock_rate();
+
+ if (!devm_request_mem_region(&pdev->dev, i2c->twsi_phys, i2c->regsize,
+ res_mem->name)) {
+ dev_err(i2c->dev, "request_mem_region failed\n");
+ goto out;
+ }
+ i2c->twsi_base = devm_ioremap(&pdev->dev, i2c->twsi_phys, i2c->regsize);
+
+ init_waitqueue_head(&i2c->queue);
+
+ i2c->irq = irq;
+
+ result = devm_request_irq(&pdev->dev, i2c->irq,
+ octeon_i2c_isr, 0, DRV_NAME, i2c);
+ if (result < 0) {
+ dev_err(i2c->dev, "failed to attach interrupt\n");
+ goto out;
+ }
+
+ result = octeon_i2c_initlowlevel(i2c);
+ if (result) {
+ dev_err(i2c->dev, "init low level failed\n");
+ goto out;
+ }
+
+ result = octeon_i2c_setclock(i2c);
+ if (result) {
+ dev_err(i2c->dev, "clock init failed\n");
+ goto out;
+ }
+
+ i2c->adap = octeon_i2c_ops;
+ i2c->adap.dev.parent = &pdev->dev;
+ i2c->adap.dev.of_node = pdev->dev.of_node;
+ i2c_set_adapdata(&i2c->adap, i2c);
+ platform_set_drvdata(pdev, i2c);
+
+ result = i2c_add_adapter(&i2c->adap);
+ if (result < 0) {
+ dev_err(i2c->dev, "failed to add adapter\n");
+ goto out;
+ }
+ dev_info(i2c->dev, "version %s\n", DRV_VERSION);
+
+ return 0;
+
+out:
+ return result;
+};
+
+static int octeon_i2c_remove(struct platform_device *pdev)
+{
+ struct octeon_i2c *i2c = platform_get_drvdata(pdev);
+
+ i2c_del_adapter(&i2c->adap);
+ return 0;
+};
+
+static struct of_device_id octeon_i2c_match[] = {
+ {
+ .compatible = "cavium,octeon-3860-twsi",
+ },
+ {},
+};
+MODULE_DEVICE_TABLE(of, octeon_i2c_match);
+
+static struct platform_driver octeon_i2c_driver = {
+ .probe = octeon_i2c_probe,
+ .remove = octeon_i2c_remove,
+ .driver = {
+ .name = DRV_NAME,
+ .of_match_table = octeon_i2c_match,
+ },
+};
+
+module_platform_driver(octeon_i2c_driver);
+
+MODULE_AUTHOR("Michael Lawnick <michael.lawnick.ext@nsn.com>");
+MODULE_DESCRIPTION("I2C-Bus adapter for Cavium OCTEON processors");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
Code Review / kvmfornfv.git / blobdiff