--- /dev/null
+/*
+ * Copyright (C) 2014 Uwe Kleine-Koenig for Pengutronix
+ *
+ * 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/module.h>
+#include <linux/platform_device.h>
+#include <linux/i2c.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+
+#define DRIVER_NAME "efm32-i2c"
+
+#define MASK_VAL(mask, val) ((val << __ffs(mask)) & mask)
+
+#define REG_CTRL 0x00
+#define REG_CTRL_EN 0x00001
+#define REG_CTRL_SLAVE 0x00002
+#define REG_CTRL_AUTOACK 0x00004
+#define REG_CTRL_AUTOSE 0x00008
+#define REG_CTRL_AUTOSN 0x00010
+#define REG_CTRL_ARBDIS 0x00020
+#define REG_CTRL_GCAMEN 0x00040
+#define REG_CTRL_CLHR__MASK 0x00300
+#define REG_CTRL_BITO__MASK 0x03000
+#define REG_CTRL_BITO_OFF 0x00000
+#define REG_CTRL_BITO_40PCC 0x01000
+#define REG_CTRL_BITO_80PCC 0x02000
+#define REG_CTRL_BITO_160PCC 0x03000
+#define REG_CTRL_GIBITO 0x08000
+#define REG_CTRL_CLTO__MASK 0x70000
+#define REG_CTRL_CLTO_OFF 0x00000
+
+#define REG_CMD 0x04
+#define REG_CMD_START 0x00001
+#define REG_CMD_STOP 0x00002
+#define REG_CMD_ACK 0x00004
+#define REG_CMD_NACK 0x00008
+#define REG_CMD_CONT 0x00010
+#define REG_CMD_ABORT 0x00020
+#define REG_CMD_CLEARTX 0x00040
+#define REG_CMD_CLEARPC 0x00080
+
+#define REG_STATE 0x08
+#define REG_STATE_BUSY 0x00001
+#define REG_STATE_MASTER 0x00002
+#define REG_STATE_TRANSMITTER 0x00004
+#define REG_STATE_NACKED 0x00008
+#define REG_STATE_BUSHOLD 0x00010
+#define REG_STATE_STATE__MASK 0x000e0
+#define REG_STATE_STATE_IDLE 0x00000
+#define REG_STATE_STATE_WAIT 0x00020
+#define REG_STATE_STATE_START 0x00040
+#define REG_STATE_STATE_ADDR 0x00060
+#define REG_STATE_STATE_ADDRACK 0x00080
+#define REG_STATE_STATE_DATA 0x000a0
+#define REG_STATE_STATE_DATAACK 0x000c0
+
+#define REG_STATUS 0x0c
+#define REG_STATUS_PSTART 0x00001
+#define REG_STATUS_PSTOP 0x00002
+#define REG_STATUS_PACK 0x00004
+#define REG_STATUS_PNACK 0x00008
+#define REG_STATUS_PCONT 0x00010
+#define REG_STATUS_PABORT 0x00020
+#define REG_STATUS_TXC 0x00040
+#define REG_STATUS_TXBL 0x00080
+#define REG_STATUS_RXDATAV 0x00100
+
+#define REG_CLKDIV 0x10
+#define REG_CLKDIV_DIV__MASK 0x001ff
+#define REG_CLKDIV_DIV(div) MASK_VAL(REG_CLKDIV_DIV__MASK, (div))
+
+#define REG_SADDR 0x14
+#define REG_SADDRMASK 0x18
+#define REG_RXDATA 0x1c
+#define REG_RXDATAP 0x20
+#define REG_TXDATA 0x24
+#define REG_IF 0x28
+#define REG_IF_START 0x00001
+#define REG_IF_RSTART 0x00002
+#define REG_IF_ADDR 0x00004
+#define REG_IF_TXC 0x00008
+#define REG_IF_TXBL 0x00010
+#define REG_IF_RXDATAV 0x00020
+#define REG_IF_ACK 0x00040
+#define REG_IF_NACK 0x00080
+#define REG_IF_MSTOP 0x00100
+#define REG_IF_ARBLOST 0x00200
+#define REG_IF_BUSERR 0x00400
+#define REG_IF_BUSHOLD 0x00800
+#define REG_IF_TXOF 0x01000
+#define REG_IF_RXUF 0x02000
+#define REG_IF_BITO 0x04000
+#define REG_IF_CLTO 0x08000
+#define REG_IF_SSTOP 0x10000
+
+#define REG_IFS 0x2c
+#define REG_IFC 0x30
+#define REG_IFC__MASK 0x1ffcf
+
+#define REG_IEN 0x34
+
+#define REG_ROUTE 0x38
+#define REG_ROUTE_SDAPEN 0x00001
+#define REG_ROUTE_SCLPEN 0x00002
+#define REG_ROUTE_LOCATION__MASK 0x00700
+#define REG_ROUTE_LOCATION(n) MASK_VAL(REG_ROUTE_LOCATION__MASK, (n))
+
+struct efm32_i2c_ddata {
+ struct i2c_adapter adapter;
+
+ struct clk *clk;
+ void __iomem *base;
+ unsigned int irq;
+ u8 location;
+ unsigned long frequency;
+
+ /* transfer data */
+ struct completion done;
+ struct i2c_msg *msgs;
+ size_t num_msgs;
+ size_t current_word, current_msg;
+ int retval;
+};
+
+static u32 efm32_i2c_read32(struct efm32_i2c_ddata *ddata, unsigned offset)
+{
+ return readl(ddata->base + offset);
+}
+
+static void efm32_i2c_write32(struct efm32_i2c_ddata *ddata,
+ unsigned offset, u32 value)
+{
+ writel(value, ddata->base + offset);
+}
+
+static void efm32_i2c_send_next_msg(struct efm32_i2c_ddata *ddata)
+{
+ struct i2c_msg *cur_msg = &ddata->msgs[ddata->current_msg];
+
+ efm32_i2c_write32(ddata, REG_CMD, REG_CMD_START);
+ efm32_i2c_write32(ddata, REG_TXDATA, cur_msg->addr << 1 |
+ (cur_msg->flags & I2C_M_RD ? 1 : 0));
+}
+
+static void efm32_i2c_send_next_byte(struct efm32_i2c_ddata *ddata)
+{
+ struct i2c_msg *cur_msg = &ddata->msgs[ddata->current_msg];
+
+ if (ddata->current_word >= cur_msg->len) {
+ /* cur_msg completely transferred */
+ ddata->current_word = 0;
+ ddata->current_msg += 1;
+
+ if (ddata->current_msg >= ddata->num_msgs) {
+ efm32_i2c_write32(ddata, REG_CMD, REG_CMD_STOP);
+ complete(&ddata->done);
+ } else {
+ efm32_i2c_send_next_msg(ddata);
+ }
+ } else {
+ efm32_i2c_write32(ddata, REG_TXDATA,
+ cur_msg->buf[ddata->current_word++]);
+ }
+}
+
+static void efm32_i2c_recv_next_byte(struct efm32_i2c_ddata *ddata)
+{
+ struct i2c_msg *cur_msg = &ddata->msgs[ddata->current_msg];
+
+ cur_msg->buf[ddata->current_word] = efm32_i2c_read32(ddata, REG_RXDATA);
+ ddata->current_word += 1;
+ if (ddata->current_word >= cur_msg->len) {
+ /* cur_msg completely transferred */
+ ddata->current_word = 0;
+ ddata->current_msg += 1;
+
+ efm32_i2c_write32(ddata, REG_CMD, REG_CMD_NACK);
+
+ if (ddata->current_msg >= ddata->num_msgs) {
+ efm32_i2c_write32(ddata, REG_CMD, REG_CMD_STOP);
+ complete(&ddata->done);
+ } else {
+ efm32_i2c_send_next_msg(ddata);
+ }
+ } else {
+ efm32_i2c_write32(ddata, REG_CMD, REG_CMD_ACK);
+ }
+}
+
+static irqreturn_t efm32_i2c_irq(int irq, void *dev_id)
+{
+ struct efm32_i2c_ddata *ddata = dev_id;
+ struct i2c_msg *cur_msg = &ddata->msgs[ddata->current_msg];
+ u32 irqflag = efm32_i2c_read32(ddata, REG_IF);
+ u32 state = efm32_i2c_read32(ddata, REG_STATE);
+
+ efm32_i2c_write32(ddata, REG_IFC, irqflag & REG_IFC__MASK);
+
+ switch (state & REG_STATE_STATE__MASK) {
+ case REG_STATE_STATE_IDLE:
+ /* arbitration lost? */
+ ddata->retval = -EAGAIN;
+ complete(&ddata->done);
+ break;
+ case REG_STATE_STATE_WAIT:
+ /*
+ * huh, this shouldn't happen.
+ * Reset hardware state and get out
+ */
+ ddata->retval = -EIO;
+ efm32_i2c_write32(ddata, REG_CMD,
+ REG_CMD_STOP | REG_CMD_ABORT |
+ REG_CMD_CLEARTX | REG_CMD_CLEARPC);
+ complete(&ddata->done);
+ break;
+ case REG_STATE_STATE_START:
+ /* "caller" is expected to send an address */
+ break;
+ case REG_STATE_STATE_ADDR:
+ /* wait for Ack or NAck of slave */
+ break;
+ case REG_STATE_STATE_ADDRACK:
+ if (state & REG_STATE_NACKED) {
+ efm32_i2c_write32(ddata, REG_CMD, REG_CMD_STOP);
+ ddata->retval = -ENXIO;
+ complete(&ddata->done);
+ } else if (cur_msg->flags & I2C_M_RD) {
+ /* wait for slave to send first data byte */
+ } else {
+ efm32_i2c_send_next_byte(ddata);
+ }
+ break;
+ case REG_STATE_STATE_DATA:
+ if (cur_msg->flags & I2C_M_RD) {
+ efm32_i2c_recv_next_byte(ddata);
+ } else {
+ /* wait for Ack or Nack of slave */
+ }
+ break;
+ case REG_STATE_STATE_DATAACK:
+ if (state & REG_STATE_NACKED) {
+ efm32_i2c_write32(ddata, REG_CMD, REG_CMD_STOP);
+ complete(&ddata->done);
+ } else {
+ efm32_i2c_send_next_byte(ddata);
+ }
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int efm32_i2c_master_xfer(struct i2c_adapter *adap,
+ struct i2c_msg *msgs, int num)
+{
+ struct efm32_i2c_ddata *ddata = i2c_get_adapdata(adap);
+ int ret;
+
+ if (ddata->msgs)
+ return -EBUSY;
+
+ ddata->msgs = msgs;
+ ddata->num_msgs = num;
+ ddata->current_word = 0;
+ ddata->current_msg = 0;
+ ddata->retval = -EIO;
+
+ reinit_completion(&ddata->done);
+
+ dev_dbg(&ddata->adapter.dev, "state: %08x, status: %08x\n",
+ efm32_i2c_read32(ddata, REG_STATE),
+ efm32_i2c_read32(ddata, REG_STATUS));
+
+ efm32_i2c_send_next_msg(ddata);
+
+ wait_for_completion(&ddata->done);
+
+ if (ddata->current_msg >= ddata->num_msgs)
+ ret = ddata->num_msgs;
+ else
+ ret = ddata->retval;
+
+ return ret;
+}
+
+static u32 efm32_i2c_functionality(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm efm32_i2c_algo = {
+ .master_xfer = efm32_i2c_master_xfer,
+ .functionality = efm32_i2c_functionality,
+};
+
+static u32 efm32_i2c_get_configured_location(struct efm32_i2c_ddata *ddata)
+{
+ u32 reg = efm32_i2c_read32(ddata, REG_ROUTE);
+
+ return (reg & REG_ROUTE_LOCATION__MASK) >>
+ __ffs(REG_ROUTE_LOCATION__MASK);
+}
+
+static int efm32_i2c_probe(struct platform_device *pdev)
+{
+ struct efm32_i2c_ddata *ddata;
+ struct resource *res;
+ unsigned long rate;
+ struct device_node *np = pdev->dev.of_node;
+ u32 location, frequency;
+ int ret;
+ u32 clkdiv;
+
+ if (!np)
+ return -EINVAL;
+
+ ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL);
+ if (!ddata) {
+ dev_dbg(&pdev->dev, "failed to allocate private data\n");
+ return -ENOMEM;
+ }
+ platform_set_drvdata(pdev, ddata);
+
+ init_completion(&ddata->done);
+ strlcpy(ddata->adapter.name, pdev->name, sizeof(ddata->adapter.name));
+ ddata->adapter.owner = THIS_MODULE;
+ ddata->adapter.algo = &efm32_i2c_algo;
+ ddata->adapter.dev.parent = &pdev->dev;
+ ddata->adapter.dev.of_node = pdev->dev.of_node;
+ i2c_set_adapdata(&ddata->adapter, ddata);
+
+ ddata->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(ddata->clk)) {
+ ret = PTR_ERR(ddata->clk);
+ dev_err(&pdev->dev, "failed to get clock: %d\n", ret);
+ return ret;
+ }
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&pdev->dev, "failed to determine base address\n");
+ return -ENODEV;
+ }
+
+ if (resource_size(res) < 0x42) {
+ dev_err(&pdev->dev, "memory resource too small\n");
+ return -EINVAL;
+ }
+
+ ddata->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(ddata->base))
+ return PTR_ERR(ddata->base);
+
+ ret = platform_get_irq(pdev, 0);
+ if (ret <= 0) {
+ dev_err(&pdev->dev, "failed to get irq (%d)\n", ret);
+ if (!ret)
+ ret = -EINVAL;
+ return ret;
+ }
+
+ ddata->irq = ret;
+
+ ret = clk_prepare_enable(ddata->clk);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to enable clock (%d)\n", ret);
+ return ret;
+ }
+
+ ret = of_property_read_u32(np, "efm32,location", &location);
+ if (!ret) {
+ dev_dbg(&pdev->dev, "using location %u\n", location);
+ } else {
+ /* default to location configured in hardware */
+ location = efm32_i2c_get_configured_location(ddata);
+
+ dev_info(&pdev->dev, "fall back to location %u\n", location);
+ }
+
+ ddata->location = location;
+
+ ret = of_property_read_u32(np, "clock-frequency", &frequency);
+ if (!ret) {
+ dev_dbg(&pdev->dev, "using frequency %u\n", frequency);
+ } else {
+ frequency = 100000;
+ dev_info(&pdev->dev, "defaulting to 100 kHz\n");
+ }
+ ddata->frequency = frequency;
+
+ rate = clk_get_rate(ddata->clk);
+ if (!rate) {
+ dev_err(&pdev->dev, "there is no input clock available\n");
+ ret = -EINVAL;
+ goto err_disable_clk;
+ }
+ clkdiv = DIV_ROUND_UP(rate, 8 * ddata->frequency) - 1;
+ if (clkdiv >= 0x200) {
+ dev_err(&pdev->dev,
+ "input clock too fast (%lu) to divide down to bus freq (%lu)",
+ rate, ddata->frequency);
+ ret = -EINVAL;
+ goto err_disable_clk;
+ }
+
+ dev_dbg(&pdev->dev, "input clock = %lu, bus freq = %lu, clkdiv = %lu\n",
+ rate, ddata->frequency, (unsigned long)clkdiv);
+ efm32_i2c_write32(ddata, REG_CLKDIV, REG_CLKDIV_DIV(clkdiv));
+
+ efm32_i2c_write32(ddata, REG_ROUTE, REG_ROUTE_SDAPEN |
+ REG_ROUTE_SCLPEN |
+ REG_ROUTE_LOCATION(ddata->location));
+
+ efm32_i2c_write32(ddata, REG_CTRL, REG_CTRL_EN |
+ REG_CTRL_BITO_160PCC | 0 * REG_CTRL_GIBITO);
+
+ efm32_i2c_write32(ddata, REG_IFC, REG_IFC__MASK);
+ efm32_i2c_write32(ddata, REG_IEN, REG_IF_TXC | REG_IF_ACK | REG_IF_NACK
+ | REG_IF_ARBLOST | REG_IF_BUSERR | REG_IF_RXDATAV);
+
+ /* to make bus idle */
+ efm32_i2c_write32(ddata, REG_CMD, REG_CMD_ABORT);
+
+ ret = request_irq(ddata->irq, efm32_i2c_irq, 0, DRIVER_NAME, ddata);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to request irq (%d)\n", ret);
+ return ret;
+ }
+
+ ret = i2c_add_adapter(&ddata->adapter);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to add i2c adapter (%d)\n", ret);
+ free_irq(ddata->irq, ddata);
+
+err_disable_clk:
+ clk_disable_unprepare(ddata->clk);
+ }
+ return ret;
+}
+
+static int efm32_i2c_remove(struct platform_device *pdev)
+{
+ struct efm32_i2c_ddata *ddata = platform_get_drvdata(pdev);
+
+ i2c_del_adapter(&ddata->adapter);
+ free_irq(ddata->irq, ddata);
+ clk_disable_unprepare(ddata->clk);
+
+ return 0;
+}
+
+static const struct of_device_id efm32_i2c_dt_ids[] = {
+ {
+ .compatible = "energymicro,efm32-i2c",
+ }, {
+ /* sentinel */
+ }
+};
+MODULE_DEVICE_TABLE(of, efm32_i2c_dt_ids);
+
+static struct platform_driver efm32_i2c_driver = {
+ .probe = efm32_i2c_probe,
+ .remove = efm32_i2c_remove,
+
+ .driver = {
+ .name = DRIVER_NAME,
+ .owner = THIS_MODULE,
+ .of_match_table = efm32_i2c_dt_ids,
+ },
+};
+module_platform_driver(efm32_i2c_driver);
+
+MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>");
+MODULE_DESCRIPTION("EFM32 i2c driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRIVER_NAME);
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