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linux_dsm_epyc7002/drivers/i2c/busses/i2c-davinci.c
Alexander Sverdlin 35780e860f i2c: davinci: Optimize clock generation on Keystone SoC 
According to "KeyStone Architecture Inter-IC Control Bus User Guide", fixed
additive part of frequency divisors (referred as "d" in the code and datasheet)
always equals to 6, independent of module clock prescaler.

                         module clock frequency
master clock frequency = ----------------------
                         (ICCL + 6) + (ICCH + 6)

It was not the case with original Davinci IP. Introduce new compatible property
"ti,keystone-i2c", which triggers special handling in the driver.

Without this change Keystone-based systems (having 204.8MHz input clock) choose
prescaler 29 (PSC=28). Using d=5 in this case leads to bus bitrate ~353kHz
instead of requested 400kHz. After correction, assuming d=6 bus rate is ~392kHz.
This gives ~11% transfer rate increase.

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Tested-by: Hemanth Guruva Reddy <hemanth.guruva_reddy@nokia.com>
Tested-by: Lukasz Gemborowski <lukasz.gemborowski@nokia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-20 17:05:16 +02:00

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/*
* TI DAVINCI I2C adapter driver.
*
* Copyright (C) 2006 Texas Instruments.
* Copyright (C) 2007 MontaVista Software Inc.
*
* Updated by Vinod & Sudhakar Feb 2005
*
* ----------------------------------------------------------------------------
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* ----------------------------------------------------------------------------
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/clk.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/cpufreq.h>
#include <linux/gpio.h>
#include <linux/of_device.h>
#include <linux/platform_data/i2c-davinci.h>
/* ----- global defines ----------------------------------------------- */
#define DAVINCI_I2C_TIMEOUT (1*HZ)
#define DAVINCI_I2C_MAX_TRIES 2
#define DAVINCI_I2C_OWN_ADDRESS 0x08
#define I2C_DAVINCI_INTR_ALL (DAVINCI_I2C_IMR_SCD | \
DAVINCI_I2C_IMR_ARDY | \
DAVINCI_I2C_IMR_NACK | \
DAVINCI_I2C_IMR_AL)
#define DAVINCI_I2C_OAR_REG 0x00
#define DAVINCI_I2C_IMR_REG 0x04
#define DAVINCI_I2C_STR_REG 0x08
#define DAVINCI_I2C_CLKL_REG 0x0c
#define DAVINCI_I2C_CLKH_REG 0x10
#define DAVINCI_I2C_CNT_REG 0x14
#define DAVINCI_I2C_DRR_REG 0x18
#define DAVINCI_I2C_SAR_REG 0x1c
#define DAVINCI_I2C_DXR_REG 0x20
#define DAVINCI_I2C_MDR_REG 0x24
#define DAVINCI_I2C_IVR_REG 0x28
#define DAVINCI_I2C_EMDR_REG 0x2c
#define DAVINCI_I2C_PSC_REG 0x30
#define DAVINCI_I2C_FUNC_REG 0x48
#define DAVINCI_I2C_DIR_REG 0x4c
#define DAVINCI_I2C_DIN_REG 0x50
#define DAVINCI_I2C_DOUT_REG 0x54
#define DAVINCI_I2C_DSET_REG 0x58
#define DAVINCI_I2C_DCLR_REG 0x5c
#define DAVINCI_I2C_IVR_AAS 0x07
#define DAVINCI_I2C_IVR_SCD 0x06
#define DAVINCI_I2C_IVR_XRDY 0x05
#define DAVINCI_I2C_IVR_RDR 0x04
#define DAVINCI_I2C_IVR_ARDY 0x03
#define DAVINCI_I2C_IVR_NACK 0x02
#define DAVINCI_I2C_IVR_AL 0x01
#define DAVINCI_I2C_STR_BB BIT(12)
#define DAVINCI_I2C_STR_RSFULL BIT(11)
#define DAVINCI_I2C_STR_SCD BIT(5)
#define DAVINCI_I2C_STR_ARDY BIT(2)
#define DAVINCI_I2C_STR_NACK BIT(1)
#define DAVINCI_I2C_STR_AL BIT(0)
#define DAVINCI_I2C_MDR_NACK BIT(15)
#define DAVINCI_I2C_MDR_STT BIT(13)
#define DAVINCI_I2C_MDR_STP BIT(11)
#define DAVINCI_I2C_MDR_MST BIT(10)
#define DAVINCI_I2C_MDR_TRX BIT(9)
#define DAVINCI_I2C_MDR_XA BIT(8)
#define DAVINCI_I2C_MDR_RM BIT(7)
#define DAVINCI_I2C_MDR_IRS BIT(5)
#define DAVINCI_I2C_IMR_AAS BIT(6)
#define DAVINCI_I2C_IMR_SCD BIT(5)
#define DAVINCI_I2C_IMR_XRDY BIT(4)
#define DAVINCI_I2C_IMR_RRDY BIT(3)
#define DAVINCI_I2C_IMR_ARDY BIT(2)
#define DAVINCI_I2C_IMR_NACK BIT(1)
#define DAVINCI_I2C_IMR_AL BIT(0)
/* set SDA and SCL as GPIO */
#define DAVINCI_I2C_FUNC_PFUNC0 BIT(0)
/* set SCL as output when used as GPIO*/
#define DAVINCI_I2C_DIR_PDIR0 BIT(0)
/* set SDA as output when used as GPIO*/
#define DAVINCI_I2C_DIR_PDIR1 BIT(1)
/* read SCL GPIO level */
#define DAVINCI_I2C_DIN_PDIN0 BIT(0)
/* read SDA GPIO level */
#define DAVINCI_I2C_DIN_PDIN1 BIT(1)
/*set the SCL GPIO high */
#define DAVINCI_I2C_DSET_PDSET0 BIT(0)
/*set the SDA GPIO high */
#define DAVINCI_I2C_DSET_PDSET1 BIT(1)
/* set the SCL GPIO low */
#define DAVINCI_I2C_DCLR_PDCLR0 BIT(0)
/* set the SDA GPIO low */
#define DAVINCI_I2C_DCLR_PDCLR1 BIT(1)
struct davinci_i2c_dev {
struct device *dev;
void __iomem *base;
struct completion cmd_complete;
struct clk *clk;
int cmd_err;
u8 *buf;
size_t buf_len;
int irq;
int stop;
u8 terminate;
struct i2c_adapter adapter;
#ifdef CONFIG_CPU_FREQ
struct completion xfr_complete;
struct notifier_block freq_transition;
#endif
struct davinci_i2c_platform_data *pdata;
};
/* default platform data to use if not supplied in the platform_device */
static struct davinci_i2c_platform_data davinci_i2c_platform_data_default = {
.bus_freq = 100,
.bus_delay = 0,
};
static inline void davinci_i2c_write_reg(struct davinci_i2c_dev *i2c_dev,
int reg, u16 val)
{
writew_relaxed(val, i2c_dev->base + reg);
}
static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
{
return readw_relaxed(i2c_dev->base + reg);
}
static inline void davinci_i2c_reset_ctrl(struct davinci_i2c_dev *i2c_dev,
int val)
{
u16 w;
w = davinci_i2c_read_reg(i2c_dev, DAVINCI_I2C_MDR_REG);
if (!val) /* put I2C into reset */
w &= ~DAVINCI_I2C_MDR_IRS;
else /* take I2C out of reset */
w |= DAVINCI_I2C_MDR_IRS;
davinci_i2c_write_reg(i2c_dev, DAVINCI_I2C_MDR_REG, w);
}
static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev)
{
struct davinci_i2c_platform_data *pdata = dev->pdata;
u16 psc;
u32 clk;
u32 d;
u32 clkh;
u32 clkl;
u32 input_clock = clk_get_rate(dev->clk);
struct device_node *of_node = dev->dev->of_node;
/* NOTE: I2C Clock divider programming info
* As per I2C specs the following formulas provide prescaler
* and low/high divider values
* input clk --> PSC Div -----------> ICCL/H Div --> output clock
* module clk
*
* output clk = module clk / (PSC + 1) [ (ICCL + d) + (ICCH + d) ]
*
* Thus,
* (ICCL + ICCH) = clk = (input clk / ((psc +1) * output clk)) - 2d;
*
* where if PSC == 0, d = 7,
* if PSC == 1, d = 6
* if PSC > 1 , d = 5
*
* Note:
* d is always 6 on Keystone I2C controller
*/
/* get minimum of 7 MHz clock, but max of 12 MHz */
psc = (input_clock / 7000000) - 1;
if ((input_clock / (psc + 1)) > 12000000)
psc++; /* better to run under spec than over */
d = (psc >= 2) ? 5 : 7 - psc;
if (of_node && of_device_is_compatible(of_node, "ti,keystone-i2c"))
d = 6;
clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000));
/* Avoid driving the bus too fast because of rounding errors above */
if (input_clock / (psc + 1) / clk > pdata->bus_freq * 1000)
clk++;
/*
* According to I2C-BUS Spec 2.1, in FAST-MODE LOW period should be at
* least 1.3uS, which is not the case with 50% duty cycle. Driving HIGH
* to LOW ratio as 1 to 2 is more safe.
*/
if (pdata->bus_freq > 100)
clkl = (clk << 1) / 3;
else
clkl = (clk >> 1);
/*
* It's not always possible to have 1 to 2 ratio when d=7, so fall back
* to minimal possible clkh in this case.
*/
if (clk >= clkl + d) {
clkh = clk - clkl - d;
clkl -= d;
} else {
clkh = 0;
clkl = clk - (d << 1);
}
davinci_i2c_write_reg(dev, DAVINCI_I2C_PSC_REG, psc);
davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh);
davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl);
dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk);
}
/*
* This function configures I2C and brings I2C out of reset.
* This function is called during I2C init function. This function
* also gets called if I2C encounters any errors.
*/
static int i2c_davinci_init(struct davinci_i2c_dev *dev)
{
struct davinci_i2c_platform_data *pdata = dev->pdata;
/* put I2C into reset */
davinci_i2c_reset_ctrl(dev, 0);
/* compute clock dividers */
i2c_davinci_calc_clk_dividers(dev);
/* Respond at reserved "SMBus Host" slave address" (and zero);
* we seem to have no option to not respond...
*/
davinci_i2c_write_reg(dev, DAVINCI_I2C_OAR_REG, DAVINCI_I2C_OWN_ADDRESS);
dev_dbg(dev->dev, "PSC = %d\n",
davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
dev_dbg(dev->dev, "CLKL = %d\n",
davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG));
dev_dbg(dev->dev, "CLKH = %d\n",
davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG));
dev_dbg(dev->dev, "bus_freq = %dkHz, bus_delay = %d\n",
pdata->bus_freq, pdata->bus_delay);
/* Take the I2C module out of reset: */
davinci_i2c_reset_ctrl(dev, 1);
/* Enable interrupts */
davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL);
return 0;
}
/*
* This routine does i2c bus recovery by using i2c_generic_gpio_recovery
* which is provided by I2C Bus recovery infrastructure.
*/
static void davinci_i2c_prepare_recovery(struct i2c_adapter *adap)
{
struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
/* Disable interrupts */
davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, 0);
/* put I2C into reset */
davinci_i2c_reset_ctrl(dev, 0);
}
static void davinci_i2c_unprepare_recovery(struct i2c_adapter *adap)
{
struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
i2c_davinci_init(dev);
}
static struct i2c_bus_recovery_info davinci_i2c_gpio_recovery_info = {
.recover_bus = i2c_generic_gpio_recovery,
.prepare_recovery = davinci_i2c_prepare_recovery,
.unprepare_recovery = davinci_i2c_unprepare_recovery,
};
static void davinci_i2c_set_scl(struct i2c_adapter *adap, int val)
{
struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
if (val)
davinci_i2c_write_reg(dev, DAVINCI_I2C_DSET_REG,
DAVINCI_I2C_DSET_PDSET0);
else
davinci_i2c_write_reg(dev, DAVINCI_I2C_DCLR_REG,
DAVINCI_I2C_DCLR_PDCLR0);
}
static int davinci_i2c_get_scl(struct i2c_adapter *adap)
{
struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
int val;
/* read the state of SCL */
val = davinci_i2c_read_reg(dev, DAVINCI_I2C_DIN_REG);
return val & DAVINCI_I2C_DIN_PDIN0;
}
static int davinci_i2c_get_sda(struct i2c_adapter *adap)
{
struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
int val;
/* read the state of SDA */
val = davinci_i2c_read_reg(dev, DAVINCI_I2C_DIN_REG);
return val & DAVINCI_I2C_DIN_PDIN1;
}
static void davinci_i2c_scl_prepare_recovery(struct i2c_adapter *adap)
{
struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
davinci_i2c_prepare_recovery(adap);
/* SCL output, SDA input */
davinci_i2c_write_reg(dev, DAVINCI_I2C_DIR_REG, DAVINCI_I2C_DIR_PDIR0);
/* change to GPIO mode */
davinci_i2c_write_reg(dev, DAVINCI_I2C_FUNC_REG,
DAVINCI_I2C_FUNC_PFUNC0);
}
static void davinci_i2c_scl_unprepare_recovery(struct i2c_adapter *adap)
{
struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
/* change back to I2C mode */
davinci_i2c_write_reg(dev, DAVINCI_I2C_FUNC_REG, 0);
davinci_i2c_unprepare_recovery(adap);
}
static struct i2c_bus_recovery_info davinci_i2c_scl_recovery_info = {
.recover_bus = i2c_generic_scl_recovery,
.set_scl = davinci_i2c_set_scl,
.get_scl = davinci_i2c_get_scl,
.get_sda = davinci_i2c_get_sda,
.prepare_recovery = davinci_i2c_scl_prepare_recovery,
.unprepare_recovery = davinci_i2c_scl_unprepare_recovery,
};
/*
* Waiting for bus not busy
*/
static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev)
{
unsigned long timeout = jiffies + dev->adapter.timeout;
do {
if (!(davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG) & DAVINCI_I2C_STR_BB))
return 0;
schedule_timeout_uninterruptible(1);
} while (time_before_eq(jiffies, timeout));
dev_warn(dev->dev, "timeout waiting for bus ready\n");
i2c_recover_bus(&dev->adapter);
/*
* if bus is still "busy" here, it's most probably a HW problem like
* short-circuit
*/
if (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG) & DAVINCI_I2C_STR_BB)
return -EIO;
return 0;
}
/*
* Low level master read/write transaction. This function is called
* from i2c_davinci_xfer.
*/
static int
i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
{
struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
struct davinci_i2c_platform_data *pdata = dev->pdata;
u32 flag;
u16 w;
unsigned long time_left;
if (msg->addr == DAVINCI_I2C_OWN_ADDRESS) {
dev_warn(dev->dev, "transfer to own address aborted\n");
return -EADDRNOTAVAIL;
}
/* Introduce a delay, required for some boards (e.g Davinci EVM) */
if (pdata->bus_delay)
udelay(pdata->bus_delay);
/* set the slave address */
davinci_i2c_write_reg(dev, DAVINCI_I2C_SAR_REG, msg->addr);
dev->buf = msg->buf;
dev->buf_len = msg->len;
dev->stop = stop;
davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
reinit_completion(&dev->cmd_complete);
dev->cmd_err = 0;
/* Take I2C out of reset and configure it as master */
flag = DAVINCI_I2C_MDR_IRS | DAVINCI_I2C_MDR_MST;
/* if the slave address is ten bit address, enable XA bit */
if (msg->flags & I2C_M_TEN)
flag |= DAVINCI_I2C_MDR_XA;
if (!(msg->flags & I2C_M_RD))
flag |= DAVINCI_I2C_MDR_TRX;
if (msg->len == 0)
flag |= DAVINCI_I2C_MDR_RM;
/* Enable receive or transmit interrupts */
w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
if (msg->flags & I2C_M_RD)
w |= DAVINCI_I2C_IMR_RRDY;
else
w |= DAVINCI_I2C_IMR_XRDY;
davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
dev->terminate = 0;
/*
* Write mode register first as needed for correct behaviour
* on OMAP-L138, but don't set STT yet to avoid a race with XRDY
* occurring before we have loaded DXR
*/
davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
/*
* First byte should be set here, not after interrupt,
* because transmit-data-ready interrupt can come before
* NACK-interrupt during sending of previous message and
* ICDXR may have wrong data
* It also saves us one interrupt, slightly faster
*/
if ((!(msg->flags & I2C_M_RD)) && dev->buf_len) {
davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG, *dev->buf++);
dev->buf_len--;
}
/* Set STT to begin transmit now DXR is loaded */
flag |= DAVINCI_I2C_MDR_STT;
if (stop && msg->len != 0)
flag |= DAVINCI_I2C_MDR_STP;
davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
time_left = wait_for_completion_timeout(&dev->cmd_complete,
dev->adapter.timeout);
if (!time_left) {
dev_err(dev->dev, "controller timed out\n");
i2c_recover_bus(adap);
dev->buf_len = 0;
return -ETIMEDOUT;
}
if (dev->buf_len) {
/* This should be 0 if all bytes were transferred
* or dev->cmd_err denotes an error.
*/
dev_err(dev->dev, "abnormal termination buf_len=%i\n",
dev->buf_len);
dev->terminate = 1;
wmb();
dev->buf_len = 0;
return -EREMOTEIO;
}
/* no error */
if (likely(!dev->cmd_err))
return msg->len;
/* We have an error */
if (dev->cmd_err & DAVINCI_I2C_STR_AL) {
i2c_davinci_init(dev);
return -EIO;
}
if (dev->cmd_err & DAVINCI_I2C_STR_NACK) {
if (msg->flags & I2C_M_IGNORE_NAK)
return msg->len;
w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
w |= DAVINCI_I2C_MDR_STP;
davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
return -EREMOTEIO;
}
return -EIO;
}
/*
* Prepare controller for a transaction and call i2c_davinci_xfer_msg
*/
static int
i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
int i;
int ret;
dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
ret = i2c_davinci_wait_bus_not_busy(dev);
if (ret < 0) {
dev_warn(dev->dev, "timeout waiting for bus ready\n");
return ret;
}
for (i = 0; i < num; i++) {
ret = i2c_davinci_xfer_msg(adap, &msgs[i], (i == (num - 1)));
dev_dbg(dev->dev, "%s [%d/%d] ret: %d\n", __func__, i + 1, num,
ret);
if (ret < 0)
return ret;
}
#ifdef CONFIG_CPU_FREQ
complete(&dev->xfr_complete);
#endif
return num;
}
static u32 i2c_davinci_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static void terminate_read(struct davinci_i2c_dev *dev)
{
u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
w |= DAVINCI_I2C_MDR_NACK;
davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
/* Throw away data */
davinci_i2c_read_reg(dev, DAVINCI_I2C_DRR_REG);
if (!dev->terminate)
dev_err(dev->dev, "RDR IRQ while no data requested\n");
}
static void terminate_write(struct davinci_i2c_dev *dev)
{
u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
w |= DAVINCI_I2C_MDR_RM | DAVINCI_I2C_MDR_STP;
davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
if (!dev->terminate)
dev_dbg(dev->dev, "TDR IRQ while no data to send\n");
}
/*
* Interrupt service routine. This gets called whenever an I2C interrupt
* occurs.
*/
static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
{
struct davinci_i2c_dev *dev = dev_id;
u32 stat;
int count = 0;
u16 w;
while ((stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG))) {
dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
if (count++ == 100) {
dev_warn(dev->dev, "Too much work in one IRQ\n");
break;
}
switch (stat) {
case DAVINCI_I2C_IVR_AL:
/* Arbitration lost, must retry */
dev->cmd_err |= DAVINCI_I2C_STR_AL;
dev->buf_len = 0;
complete(&dev->cmd_complete);
break;
case DAVINCI_I2C_IVR_NACK:
dev->cmd_err |= DAVINCI_I2C_STR_NACK;
dev->buf_len = 0;
complete(&dev->cmd_complete);
break;
case DAVINCI_I2C_IVR_ARDY:
davinci_i2c_write_reg(dev,
DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY);
if (((dev->buf_len == 0) && (dev->stop != 0)) ||
(dev->cmd_err & DAVINCI_I2C_STR_NACK)) {
w = davinci_i2c_read_reg(dev,
DAVINCI_I2C_MDR_REG);
w |= DAVINCI_I2C_MDR_STP;
davinci_i2c_write_reg(dev,
DAVINCI_I2C_MDR_REG, w);
}
complete(&dev->cmd_complete);
break;
case DAVINCI_I2C_IVR_RDR:
if (dev->buf_len) {
*dev->buf++ =
davinci_i2c_read_reg(dev,
DAVINCI_I2C_DRR_REG);
dev->buf_len--;
if (dev->buf_len)
continue;
davinci_i2c_write_reg(dev,
DAVINCI_I2C_STR_REG,
DAVINCI_I2C_IMR_RRDY);
} else {
/* signal can terminate transfer */
terminate_read(dev);
}
break;
case DAVINCI_I2C_IVR_XRDY:
if (dev->buf_len) {
davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG,
*dev->buf++);
dev->buf_len--;
if (dev->buf_len)
continue;
w = davinci_i2c_read_reg(dev,
DAVINCI_I2C_IMR_REG);
w &= ~DAVINCI_I2C_IMR_XRDY;
davinci_i2c_write_reg(dev,
DAVINCI_I2C_IMR_REG,
w);
} else {
/* signal can terminate transfer */
terminate_write(dev);
}
break;
case DAVINCI_I2C_IVR_SCD:
davinci_i2c_write_reg(dev,
DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_SCD);
complete(&dev->cmd_complete);
break;
case DAVINCI_I2C_IVR_AAS:
dev_dbg(dev->dev, "Address as slave interrupt\n");
break;
default:
dev_warn(dev->dev, "Unrecognized irq stat %d\n", stat);
break;
}
}
return count ? IRQ_HANDLED : IRQ_NONE;
}
#ifdef CONFIG_CPU_FREQ
static int i2c_davinci_cpufreq_transition(struct notifier_block *nb,
unsigned long val, void *data)
{
struct davinci_i2c_dev *dev;
dev = container_of(nb, struct davinci_i2c_dev, freq_transition);
if (val == CPUFREQ_PRECHANGE) {
wait_for_completion(&dev->xfr_complete);
davinci_i2c_reset_ctrl(dev, 0);
} else if (val == CPUFREQ_POSTCHANGE) {
i2c_davinci_calc_clk_dividers(dev);
davinci_i2c_reset_ctrl(dev, 1);
}
return 0;
}
static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
{
dev->freq_transition.notifier_call = i2c_davinci_cpufreq_transition;
return cpufreq_register_notifier(&dev->freq_transition,
CPUFREQ_TRANSITION_NOTIFIER);
}
static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
{
cpufreq_unregister_notifier(&dev->freq_transition,
CPUFREQ_TRANSITION_NOTIFIER);
}
#else
static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
{
return 0;
}
static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
{
}
#endif
static struct i2c_algorithm i2c_davinci_algo = {
.master_xfer = i2c_davinci_xfer,
.functionality = i2c_davinci_func,
};
static const struct of_device_id davinci_i2c_of_match[] = {
{.compatible = "ti,davinci-i2c", },
{.compatible = "ti,keystone-i2c", },
{},
};
MODULE_DEVICE_TABLE(of, davinci_i2c_of_match);
static int davinci_i2c_probe(struct platform_device *pdev)
{
struct davinci_i2c_dev *dev;
struct i2c_adapter *adap;
struct resource *mem;
int r, irq;
irq = platform_get_irq(pdev, 0);
if (irq <= 0) {
if (!irq)
irq = -ENXIO;
if (irq != -EPROBE_DEFER)
dev_err(&pdev->dev,
"can't get irq resource ret=%d\n", irq);
return irq;
}
dev = devm_kzalloc(&pdev->dev, sizeof(struct davinci_i2c_dev),
GFP_KERNEL);
if (!dev) {
dev_err(&pdev->dev, "Memory allocation failed\n");
return -ENOMEM;
}
init_completion(&dev->cmd_complete);
#ifdef CONFIG_CPU_FREQ
init_completion(&dev->xfr_complete);
#endif
dev->dev = &pdev->dev;
dev->irq = irq;
dev->pdata = dev_get_platdata(&pdev->dev);
platform_set_drvdata(pdev, dev);
if (!dev->pdata && pdev->dev.of_node) {
u32 prop;
dev->pdata = devm_kzalloc(&pdev->dev,
sizeof(struct davinci_i2c_platform_data), GFP_KERNEL);
if (!dev->pdata)
return -ENOMEM;
memcpy(dev->pdata, &davinci_i2c_platform_data_default,
sizeof(struct davinci_i2c_platform_data));
if (!of_property_read_u32(pdev->dev.of_node, "clock-frequency",
&prop))
dev->pdata->bus_freq = prop / 1000;
dev->pdata->has_pfunc =
of_property_read_bool(pdev->dev.of_node,
"ti,has-pfunc");
} else if (!dev->pdata) {
dev->pdata = &davinci_i2c_platform_data_default;
}
dev->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(dev->clk))
return -ENODEV;
clk_prepare_enable(dev->clk);
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
dev->base = devm_ioremap_resource(&pdev->dev, mem);
if (IS_ERR(dev->base)) {
r = PTR_ERR(dev->base);
goto err_unuse_clocks;
}
i2c_davinci_init(dev);
r = devm_request_irq(&pdev->dev, dev->irq, i2c_davinci_isr, 0,
pdev->name, dev);
if (r) {
dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
goto err_unuse_clocks;
}
r = i2c_davinci_cpufreq_register(dev);
if (r) {
dev_err(&pdev->dev, "failed to register cpufreq\n");
goto err_unuse_clocks;
}
adap = &dev->adapter;
i2c_set_adapdata(adap, dev);
adap->owner = THIS_MODULE;
adap->class = I2C_CLASS_DEPRECATED;
strlcpy(adap->name, "DaVinci I2C adapter", sizeof(adap->name));
adap->algo = &i2c_davinci_algo;
adap->dev.parent = &pdev->dev;
adap->timeout = DAVINCI_I2C_TIMEOUT;
adap->dev.of_node = pdev->dev.of_node;
if (dev->pdata->has_pfunc)
adap->bus_recovery_info = &davinci_i2c_scl_recovery_info;
else if (dev->pdata->scl_pin) {
adap->bus_recovery_info = &davinci_i2c_gpio_recovery_info;
adap->bus_recovery_info->scl_gpio = dev->pdata->scl_pin;
adap->bus_recovery_info->sda_gpio = dev->pdata->sda_pin;
}
adap->nr = pdev->id;
r = i2c_add_numbered_adapter(adap);
if (r) {
dev_err(&pdev->dev, "failure adding adapter\n");
goto err_unuse_clocks;
}
return 0;
err_unuse_clocks:
clk_disable_unprepare(dev->clk);
dev->clk = NULL;
return r;
}
static int davinci_i2c_remove(struct platform_device *pdev)
{
struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
i2c_davinci_cpufreq_deregister(dev);
i2c_del_adapter(&dev->adapter);
clk_disable_unprepare(dev->clk);
dev->clk = NULL;
davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);
return 0;
}
#ifdef CONFIG_PM
static int davinci_i2c_suspend(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct davinci_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
/* put I2C into reset */
davinci_i2c_reset_ctrl(i2c_dev, 0);
clk_disable_unprepare(i2c_dev->clk);
return 0;
}
static int davinci_i2c_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct davinci_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
clk_prepare_enable(i2c_dev->clk);
/* take I2C out of reset */
davinci_i2c_reset_ctrl(i2c_dev, 1);
return 0;
}
static const struct dev_pm_ops davinci_i2c_pm = {
.suspend = davinci_i2c_suspend,
.resume = davinci_i2c_resume,
};
#define davinci_i2c_pm_ops (&davinci_i2c_pm)
#else
#define davinci_i2c_pm_ops NULL
#endif
/* work with hotplug and coldplug */
MODULE_ALIAS("platform:i2c_davinci");
static struct platform_driver davinci_i2c_driver = {
.probe = davinci_i2c_probe,
.remove = davinci_i2c_remove,
.driver = {
.name = "i2c_davinci",
.pm = davinci_i2c_pm_ops,
.of_match_table = davinci_i2c_of_match,
},
};
/* I2C may be needed to bring up other drivers */
static int __init davinci_i2c_init_driver(void)
{
return platform_driver_register(&davinci_i2c_driver);
}
subsys_initcall(davinci_i2c_init_driver);
static void __exit davinci_i2c_exit_driver(void)
{
platform_driver_unregister(&davinci_i2c_driver);
}
module_exit(davinci_i2c_exit_driver);
MODULE_AUTHOR("Texas Instruments India");
MODULE_DESCRIPTION("TI DaVinci I2C bus adapter");
MODULE_LICENSE("GPL");
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