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linux/drivers/i2c/busses/i2c-efm32.c
Uwe Kleine-König 281ec367bf i2c: efm32: correct namespacing of location property 
Olof Johansson pointed out that usually the company name is picked as
namespace prefix to specific properties. So expect "energymicro,location"
but fall back to the previously introduced name "efm32,location".

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2014-07-17 15:38:49 +02:00

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/*
* 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)
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, "energymicro,location", &location);
if (ret)
/* fall back to wrongly namespaced property */
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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