redonkable/alistair23-linux
redonkable/alistair23-linux
1
0
Fork 0
Code Releases Activity
alistair23-linux/drivers/i2c/busses/i2c-sh_mobile.c
Wolfram Sang 32e224090f i2c: sh_mobile: terminate DMA reads properly 
DMA read requests could miss proper termination, so two more bytes would
have been read via PIO overwriting the end of the buffer with wrong
data. Make DMA stop handling more readable while we are here.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-01-30 17:58:43 +01:00

1005 lines
28 KiB
C
Raw Blame History

/*
* SuperH Mobile I2C Controller
*
* Copyright (C) 2014 Wolfram Sang <wsa@sang-engineering.com>
*
* Copyright (C) 2008 Magnus Damm
*
* Portions of the code based on out-of-tree driver i2c-sh7343.c
* Copyright (c) 2006 Carlos Munoz <carlos@kenati.com>
*
* 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
*
* 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/clk.h>
#include <linux/delay.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/i2c/i2c-sh_mobile.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>
/* Transmit operation: */
/* */
/* 0 byte transmit */
/* BUS: S A8 ACK P(*) */
/* IRQ: DTE WAIT */
/* ICIC: */
/* ICCR: 0x94 0x90 */
/* ICDR: A8 */
/* */
/* 1 byte transmit */
/* BUS: S A8 ACK D8(1) ACK P(*) */
/* IRQ: DTE WAIT WAIT */
/* ICIC: -DTE */
/* ICCR: 0x94 0x90 */
/* ICDR: A8 D8(1) */
/* */
/* 2 byte transmit */
/* BUS: S A8 ACK D8(1) ACK D8(2) ACK P(*) */
/* IRQ: DTE WAIT WAIT WAIT */
/* ICIC: -DTE */
/* ICCR: 0x94 0x90 */
/* ICDR: A8 D8(1) D8(2) */
/* */
/* 3 bytes or more, +---------+ gets repeated */
/* */
/* */
/* Receive operation: */
/* */
/* 0 byte receive - not supported since slave may hold SDA low */
/* */
/* 1 byte receive [TX] | [RX] */
/* BUS: S A8 ACK | D8(1) ACK P(*) */
/* IRQ: DTE WAIT | WAIT DTE */
/* ICIC: -DTE | +DTE */
/* ICCR: 0x94 0x81 | 0xc0 */
/* ICDR: A8 | D8(1) */
/* */
/* 2 byte receive [TX]| [RX] */
/* BUS: S A8 ACK | D8(1) ACK D8(2) ACK P(*) */
/* IRQ: DTE WAIT | WAIT WAIT DTE */
/* ICIC: -DTE | +DTE */
/* ICCR: 0x94 0x81 | 0xc0 */
/* ICDR: A8 | D8(1) D8(2) */
/* */
/* 3 byte receive [TX] | [RX] (*) */
/* BUS: S A8 ACK | D8(1) ACK D8(2) ACK D8(3) ACK P */
/* IRQ: DTE WAIT | WAIT WAIT WAIT DTE */
/* ICIC: -DTE | +DTE */
/* ICCR: 0x94 0x81 | 0xc0 */
/* ICDR: A8 | D8(1) D8(2) D8(3) */
/* */
/* 4 bytes or more, this part is repeated +---------+ */
/* */
/* */
/* Interrupt order and BUSY flag */
/* ___ _ */
/* SDA ___\___XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXAAAAAAAAA___/ */
/* SCL \_/1\_/2\_/3\_/4\_/5\_/6\_/7\_/8\___/9\_____/ */
/* */
/* S D7 D6 D5 D4 D3 D2 D1 D0 P(*) */
/* ___ */
/* WAIT IRQ ________________________________/ \___________ */
/* TACK IRQ ____________________________________/ \_______ */
/* DTE IRQ __________________________________________/ \_ */
/* AL IRQ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */
/* _______________________________________________ */
/* BUSY __/ \_ */
/* */
/* (*) The STOP condition is only sent by the master at the end of the last */
/* I2C message or if the I2C_M_STOP flag is set. Similarly, the BUSY bit is */
/* only cleared after the STOP condition, so, between messages we have to */
/* poll for the DTE bit. */
/* */
enum sh_mobile_i2c_op {
OP_START = 0,
OP_TX_FIRST,
OP_TX,
OP_TX_STOP,
OP_TX_STOP_DATA,
OP_TX_TO_RX,
OP_RX,
OP_RX_STOP,
OP_RX_STOP_DATA,
};
struct sh_mobile_i2c_data {
struct device *dev;
void __iomem *reg;
struct i2c_adapter adap;
unsigned long bus_speed;
unsigned int clks_per_count;
struct clk *clk;
u_int8_t icic;
u_int8_t flags;
u_int16_t iccl;
u_int16_t icch;
spinlock_t lock;
wait_queue_head_t wait;
struct i2c_msg *msg;
int pos;
int sr;
bool send_stop;
bool stop_after_dma;
struct resource *res;
struct dma_chan *dma_tx;
struct dma_chan *dma_rx;
struct scatterlist sg;
enum dma_data_direction dma_direction;
};
struct sh_mobile_dt_config {
int clks_per_count;
};
#define IIC_FLAG_HAS_ICIC67 (1 << 0)
#define STANDARD_MODE 100000
#define FAST_MODE 400000
/* Register offsets */
#define ICDR 0x00
#define ICCR 0x04
#define ICSR 0x08
#define ICIC 0x0c
#define ICCL 0x10
#define ICCH 0x14
/* Register bits */
#define ICCR_ICE 0x80
#define ICCR_RACK 0x40
#define ICCR_TRS 0x10
#define ICCR_BBSY 0x04
#define ICCR_SCP 0x01
#define ICSR_SCLM 0x80
#define ICSR_SDAM 0x40
#define SW_DONE 0x20
#define ICSR_BUSY 0x10
#define ICSR_AL 0x08
#define ICSR_TACK 0x04
#define ICSR_WAIT 0x02
#define ICSR_DTE 0x01
#define ICIC_ICCLB8 0x80
#define ICIC_ICCHB8 0x40
#define ICIC_TDMAE 0x20
#define ICIC_RDMAE 0x10
#define ICIC_ALE 0x08
#define ICIC_TACKE 0x04
#define ICIC_WAITE 0x02
#define ICIC_DTEE 0x01
static void iic_wr(struct sh_mobile_i2c_data *pd, int offs, unsigned char data)
{
if (offs == ICIC)
data |= pd->icic;
iowrite8(data, pd->reg + offs);
}
static unsigned char iic_rd(struct sh_mobile_i2c_data *pd, int offs)
{
return ioread8(pd->reg + offs);
}
static void iic_set_clr(struct sh_mobile_i2c_data *pd, int offs,
unsigned char set, unsigned char clr)
{
iic_wr(pd, offs, (iic_rd(pd, offs) | set) & ~clr);
}
static u32 sh_mobile_i2c_iccl(unsigned long count_khz, u32 tLOW, u32 tf)
{
/*
* Conditional expression:
* ICCL >= COUNT_CLK * (tLOW + tf)
*
* SH-Mobile IIC hardware starts counting the LOW period of
* the SCL signal (tLOW) as soon as it pulls the SCL line.
* In order to meet the tLOW timing spec, we need to take into
* account the fall time of SCL signal (tf). Default tf value
* should be 0.3 us, for safety.
*/
return (((count_khz * (tLOW + tf)) + 5000) / 10000);
}
static u32 sh_mobile_i2c_icch(unsigned long count_khz, u32 tHIGH, u32 tf)
{
/*
* Conditional expression:
* ICCH >= COUNT_CLK * (tHIGH + tf)
*
* SH-Mobile IIC hardware is aware of SCL transition period 'tr',
* and can ignore it. SH-Mobile IIC controller starts counting
* the HIGH period of the SCL signal (tHIGH) after the SCL input
* voltage increases at VIH.
*
* Afterward it turned out calculating ICCH using only tHIGH spec
* will result in violation of the tHD;STA timing spec. We need
* to take into account the fall time of SDA signal (tf) at START
* condition, in order to meet both tHIGH and tHD;STA specs.
*/
return (((count_khz * (tHIGH + tf)) + 5000) / 10000);
}
static int sh_mobile_i2c_init(struct sh_mobile_i2c_data *pd)
{
unsigned long i2c_clk_khz;
u32 tHIGH, tLOW, tf;
uint16_t max_val;
/* Get clock rate after clock is enabled */
clk_prepare_enable(pd->clk);
i2c_clk_khz = clk_get_rate(pd->clk) / 1000;
clk_disable_unprepare(pd->clk);
i2c_clk_khz /= pd->clks_per_count;
if (pd->bus_speed == STANDARD_MODE) {
tLOW = 47; /* tLOW = 4.7 us */
tHIGH = 40; /* tHD;STA = tHIGH = 4.0 us */
tf = 3; /* tf = 0.3 us */
} else if (pd->bus_speed == FAST_MODE) {
tLOW = 13; /* tLOW = 1.3 us */
tHIGH = 6; /* tHD;STA = tHIGH = 0.6 us */
tf = 3; /* tf = 0.3 us */
} else {
dev_err(pd->dev, "unrecognized bus speed %lu Hz\n",
pd->bus_speed);
return -EINVAL;
}
pd->iccl = sh_mobile_i2c_iccl(i2c_clk_khz, tLOW, tf);
pd->icch = sh_mobile_i2c_icch(i2c_clk_khz, tHIGH, tf);
max_val = pd->flags & IIC_FLAG_HAS_ICIC67 ? 0x1ff : 0xff;
if (pd->iccl > max_val || pd->icch > max_val) {
dev_err(pd->dev, "timing values out of range: L/H=0x%x/0x%x\n",
pd->iccl, pd->icch);
return -EINVAL;
}
/* one more bit of ICCL in ICIC */
if (pd->iccl & 0x100)
pd->icic |= ICIC_ICCLB8;
else
pd->icic &= ~ICIC_ICCLB8;
/* one more bit of ICCH in ICIC */
if (pd->icch & 0x100)
pd->icic |= ICIC_ICCHB8;
else
pd->icic &= ~ICIC_ICCHB8;
dev_dbg(pd->dev, "timing values: L/H=0x%x/0x%x\n", pd->iccl, pd->icch);
return 0;
}
static void activate_ch(struct sh_mobile_i2c_data *pd)
{
/* Wake up device and enable clock */
pm_runtime_get_sync(pd->dev);
clk_prepare_enable(pd->clk);
/* Enable channel and configure rx ack */
iic_set_clr(pd, ICCR, ICCR_ICE, 0);
/* Mask all interrupts */
iic_wr(pd, ICIC, 0);
/* Set the clock */
iic_wr(pd, ICCL, pd->iccl & 0xff);
iic_wr(pd, ICCH, pd->icch & 0xff);
}
static void deactivate_ch(struct sh_mobile_i2c_data *pd)
{
/* Clear/disable interrupts */
iic_wr(pd, ICSR, 0);
iic_wr(pd, ICIC, 0);
/* Disable channel */
iic_set_clr(pd, ICCR, 0, ICCR_ICE);
/* Disable clock and mark device as idle */
clk_disable_unprepare(pd->clk);
pm_runtime_put_sync(pd->dev);
}
static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
enum sh_mobile_i2c_op op, unsigned char data)
{
unsigned char ret = 0;
unsigned long flags;
dev_dbg(pd->dev, "op %d, data in 0x%02x\n", op, data);
spin_lock_irqsave(&pd->lock, flags);
switch (op) {
case OP_START: /* issue start and trigger DTE interrupt */
iic_wr(pd, ICCR, ICCR_ICE | ICCR_TRS | ICCR_BBSY);
break;
case OP_TX_FIRST: /* disable DTE interrupt and write data */
iic_wr(pd, ICIC, ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
iic_wr(pd, ICDR, data);
break;
case OP_TX: /* write data */
iic_wr(pd, ICDR, data);
break;
case OP_TX_STOP_DATA: /* write data and issue a stop afterwards */
iic_wr(pd, ICDR, data);
/* fallthrough */
case OP_TX_STOP: /* issue a stop */
iic_wr(pd, ICCR, pd->send_stop ? ICCR_ICE | ICCR_TRS
: ICCR_ICE | ICCR_TRS | ICCR_BBSY);
break;
case OP_TX_TO_RX: /* select read mode */
iic_wr(pd, ICCR, ICCR_ICE | ICCR_SCP);
break;
case OP_RX: /* just read data */
ret = iic_rd(pd, ICDR);
break;
case OP_RX_STOP: /* enable DTE interrupt, issue stop */
iic_wr(pd, ICIC,
ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK);
break;
case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */
iic_wr(pd, ICIC,
ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
ret = iic_rd(pd, ICDR);
iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK);
break;
}
spin_unlock_irqrestore(&pd->lock, flags);
dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret);
return ret;
}
static bool sh_mobile_i2c_is_first_byte(struct sh_mobile_i2c_data *pd)
{
return pd->pos == -1;
}
static bool sh_mobile_i2c_is_last_byte(struct sh_mobile_i2c_data *pd)
{
return pd->pos == pd->msg->len - 1;
}
static void sh_mobile_i2c_get_data(struct sh_mobile_i2c_data *pd,
unsigned char *buf)
{
switch (pd->pos) {
case -1:
*buf = (pd->msg->addr & 0x7f) << 1;
*buf |= (pd->msg->flags & I2C_M_RD) ? 1 : 0;
break;
default:
*buf = pd->msg->buf[pd->pos];
}
}
static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd)
{
unsigned char data;
if (pd->pos == pd->msg->len) {
/* Send stop if we haven't yet (DMA case) */
if (pd->send_stop && pd->stop_after_dma)
i2c_op(pd, OP_TX_STOP, 0);
return 1;
}
sh_mobile_i2c_get_data(pd, &data);
if (sh_mobile_i2c_is_last_byte(pd))
i2c_op(pd, OP_TX_STOP_DATA, data);
else if (sh_mobile_i2c_is_first_byte(pd))
i2c_op(pd, OP_TX_FIRST, data);
else
i2c_op(pd, OP_TX, data);
pd->pos++;
return 0;
}
static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd)
{
unsigned char data;
int real_pos;
do {
if (pd->pos <= -1) {
sh_mobile_i2c_get_data(pd, &data);
if (sh_mobile_i2c_is_first_byte(pd))
i2c_op(pd, OP_TX_FIRST, data);
else
i2c_op(pd, OP_TX, data);
break;
}
if (pd->pos == 0) {
i2c_op(pd, OP_TX_TO_RX, 0);
break;
}
real_pos = pd->pos - 2;
if (pd->pos == pd->msg->len) {
if (pd->stop_after_dma) {
/* Simulate PIO end condition after DMA transfer */
i2c_op(pd, OP_RX_STOP, 0);
pd->pos++;
break;
}
if (real_pos < 0) {
i2c_op(pd, OP_RX_STOP, 0);
break;
}
data = i2c_op(pd, OP_RX_STOP_DATA, 0);
} else
data = i2c_op(pd, OP_RX, 0);
if (real_pos >= 0)
pd->msg->buf[real_pos] = data;
} while (0);
pd->pos++;
return pd->pos == (pd->msg->len + 2);
}
static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
{
struct sh_mobile_i2c_data *pd = dev_id;
unsigned char sr;
int wakeup = 0;
sr = iic_rd(pd, ICSR);
pd->sr |= sr; /* remember state */
dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
(pd->msg->flags & I2C_M_RD) ? "read" : "write",
pd->pos, pd->msg->len);
/* Kick off TxDMA after preface was done */
if (pd->dma_direction == DMA_TO_DEVICE && pd->pos == 0)
iic_set_clr(pd, ICIC, ICIC_TDMAE, 0);
else if (sr & (ICSR_AL | ICSR_TACK))
/* don't interrupt transaction - continue to issue stop */
iic_wr(pd, ICSR, sr & ~(ICSR_AL | ICSR_TACK));
else if (pd->msg->flags & I2C_M_RD)
wakeup = sh_mobile_i2c_isr_rx(pd);
else
wakeup = sh_mobile_i2c_isr_tx(pd);
/* Kick off RxDMA after preface was done */
if (pd->dma_direction == DMA_FROM_DEVICE && pd->pos == 1)
iic_set_clr(pd, ICIC, ICIC_RDMAE, 0);
if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */
iic_wr(pd, ICSR, sr & ~ICSR_WAIT);
if (wakeup) {
pd->sr |= SW_DONE;
wake_up(&pd->wait);
}
/* defeat write posting to avoid spurious WAIT interrupts */
iic_rd(pd, ICSR);
return IRQ_HANDLED;
}
static void sh_mobile_i2c_dma_unmap(struct sh_mobile_i2c_data *pd)
{
struct dma_chan *chan = pd->dma_direction == DMA_FROM_DEVICE
? pd->dma_rx : pd->dma_tx;
dma_unmap_single(chan->device->dev, sg_dma_address(&pd->sg),
pd->msg->len, pd->dma_direction);
pd->dma_direction = DMA_NONE;
}
static void sh_mobile_i2c_cleanup_dma(struct sh_mobile_i2c_data *pd)
{
if (pd->dma_direction == DMA_NONE)
return;
else if (pd->dma_direction == DMA_FROM_DEVICE)
dmaengine_terminate_all(pd->dma_rx);
else if (pd->dma_direction == DMA_TO_DEVICE)
dmaengine_terminate_all(pd->dma_tx);
sh_mobile_i2c_dma_unmap(pd);
}
static void sh_mobile_i2c_dma_callback(void *data)
{
struct sh_mobile_i2c_data *pd = data;
sh_mobile_i2c_dma_unmap(pd);
pd->pos = pd->msg->len;
pd->stop_after_dma = true;
iic_set_clr(pd, ICIC, 0, ICIC_TDMAE | ICIC_RDMAE);
}
static struct dma_chan *sh_mobile_i2c_request_dma_chan(struct device *dev,
enum dma_transfer_direction dir, dma_addr_t port_addr)
{
struct dma_chan *chan;
struct dma_slave_config cfg;
char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx";
int ret;
chan = dma_request_slave_channel_reason(dev, chan_name);
if (IS_ERR(chan)) {
ret = PTR_ERR(chan);
dev_dbg(dev, "request_channel failed for %s (%d)\n", chan_name, ret);
return chan;
}
memset(&cfg, 0, sizeof(cfg));
cfg.direction = dir;
if (dir == DMA_MEM_TO_DEV) {
cfg.dst_addr = port_addr;
cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
} else {
cfg.src_addr = port_addr;
cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
}
ret = dmaengine_slave_config(chan, &cfg);
if (ret) {
dev_dbg(dev, "slave_config failed for %s (%d)\n", chan_name, ret);
dma_release_channel(chan);
return ERR_PTR(ret);
}
dev_dbg(dev, "got DMA channel for %s\n", chan_name);
return chan;
}
static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd)
{
bool read = pd->msg->flags & I2C_M_RD;
enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
struct dma_chan *chan = read ? pd->dma_rx : pd->dma_tx;
struct dma_async_tx_descriptor *txdesc;
dma_addr_t dma_addr;
dma_cookie_t cookie;
if (PTR_ERR(chan) == -EPROBE_DEFER) {
if (read)
chan = pd->dma_rx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_DEV_TO_MEM,
pd->res->start + ICDR);
else
chan = pd->dma_tx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_MEM_TO_DEV,
pd->res->start + ICDR);
}
if (IS_ERR(chan))
return;
dma_addr = dma_map_single(chan->device->dev, pd->msg->buf, pd->msg->len, dir);
if (dma_mapping_error(pd->dev, dma_addr)) {
dev_dbg(pd->dev, "dma map failed, using PIO\n");
return;
}
sg_dma_len(&pd->sg) = pd->msg->len;
sg_dma_address(&pd->sg) = dma_addr;
pd->dma_direction = dir;
txdesc = dmaengine_prep_slave_sg(chan, &pd->sg, 1,
read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!txdesc) {
dev_dbg(pd->dev, "dma prep slave sg failed, using PIO\n");
sh_mobile_i2c_cleanup_dma(pd);
return;
}
txdesc->callback = sh_mobile_i2c_dma_callback;
txdesc->callback_param = pd;
cookie = dmaengine_submit(txdesc);
if (dma_submit_error(cookie)) {
dev_dbg(pd->dev, "submitting dma failed, using PIO\n");
sh_mobile_i2c_cleanup_dma(pd);
return;
}
dma_async_issue_pending(chan);
}
static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg,
bool do_init)
{
if (usr_msg->len == 0 && (usr_msg->flags & I2C_M_RD)) {
dev_err(pd->dev, "Unsupported zero length i2c read\n");
return -EOPNOTSUPP;
}
if (do_init) {
/* Initialize channel registers */
iic_set_clr(pd, ICCR, 0, ICCR_ICE);
/* Enable channel and configure rx ack */
iic_set_clr(pd, ICCR, ICCR_ICE, 0);
/* Set the clock */
iic_wr(pd, ICCL, pd->iccl & 0xff);
iic_wr(pd, ICCH, pd->icch & 0xff);
}
pd->msg = usr_msg;
pd->pos = -1;
pd->sr = 0;
if (pd->msg->len > 8)
sh_mobile_i2c_xfer_dma(pd);
/* Enable all interrupts to begin with */
iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
return 0;
}
static int poll_dte(struct sh_mobile_i2c_data *pd)
{
int i;
for (i = 1000; i; i--) {
u_int8_t val = iic_rd(pd, ICSR);
if (val & ICSR_DTE)
break;
if (val & ICSR_TACK)
return -ENXIO;
udelay(10);
}
return i ? 0 : -ETIMEDOUT;
}
static int poll_busy(struct sh_mobile_i2c_data *pd)
{
int i;
for (i = 1000; i; i--) {
u_int8_t val = iic_rd(pd, ICSR);
dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);
/* the interrupt handler may wake us up before the
* transfer is finished, so poll the hardware
* until we're done.
*/
if (!(val & ICSR_BUSY)) {
/* handle missing acknowledge and arbitration lost */
val |= pd->sr;
if (val & ICSR_TACK)
return -ENXIO;
if (val & ICSR_AL)
return -EAGAIN;
break;
}
udelay(10);
}
return i ? 0 : -ETIMEDOUT;
}
static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
struct i2c_msg *msgs,
int num)
{
struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);
struct i2c_msg *msg;
int err = 0;
int i, k;
activate_ch(pd);
/* Process all messages */
for (i = 0; i < num; i++) {
bool do_start = pd->send_stop || !i;
msg = &msgs[i];
pd->send_stop = i == num - 1 || msg->flags & I2C_M_STOP;
pd->stop_after_dma = false;
err = start_ch(pd, msg, do_start);
if (err)
break;
if (do_start)
i2c_op(pd, OP_START, 0);
/* The interrupt handler takes care of the rest... */
k = wait_event_timeout(pd->wait,
pd->sr & (ICSR_TACK | SW_DONE),
5 * HZ);
if (!k) {
dev_err(pd->dev, "Transfer request timed out\n");
if (pd->dma_direction != DMA_NONE)
sh_mobile_i2c_cleanup_dma(pd);
err = -ETIMEDOUT;
break;
}
if (pd->send_stop)
err = poll_busy(pd);
else
err = poll_dte(pd);
if (err < 0)
break;
}
deactivate_ch(pd);
if (!err)
err = num;
return err;
}
static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
}
static struct i2c_algorithm sh_mobile_i2c_algorithm = {
.functionality = sh_mobile_i2c_func,
.master_xfer = sh_mobile_i2c_xfer,
};
static const struct sh_mobile_dt_config default_dt_config = {
.clks_per_count = 1,
};
static const struct sh_mobile_dt_config fast_clock_dt_config = {
.clks_per_count = 2,
};
static const struct of_device_id sh_mobile_i2c_dt_ids[] = {
{ .compatible = "renesas,rmobile-iic", .data = &default_dt_config },
{ .compatible = "renesas,iic-r8a73a4", .data = &fast_clock_dt_config },
{ .compatible = "renesas,iic-r8a7790", .data = &fast_clock_dt_config },
{ .compatible = "renesas,iic-r8a7791", .data = &fast_clock_dt_config },
{ .compatible = "renesas,iic-r8a7792", .data = &fast_clock_dt_config },
{ .compatible = "renesas,iic-r8a7793", .data = &fast_clock_dt_config },
{ .compatible = "renesas,iic-r8a7794", .data = &fast_clock_dt_config },
{ .compatible = "renesas,iic-sh73a0", .data = &fast_clock_dt_config },
{},
};
MODULE_DEVICE_TABLE(of, sh_mobile_i2c_dt_ids);
static void sh_mobile_i2c_release_dma(struct sh_mobile_i2c_data *pd)
{
if (!IS_ERR(pd->dma_tx)) {
dma_release_channel(pd->dma_tx);
pd->dma_tx = ERR_PTR(-EPROBE_DEFER);
}
if (!IS_ERR(pd->dma_rx)) {
dma_release_channel(pd->dma_rx);
pd->dma_rx = ERR_PTR(-EPROBE_DEFER);
}
}
static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, struct sh_mobile_i2c_data *pd)
{
struct resource *res;
resource_size_t n;
int k = 0, ret;
while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {
for (n = res->start; n <= res->end; n++) {
ret = devm_request_irq(&dev->dev, n, sh_mobile_i2c_isr,
0, dev_name(&dev->dev), pd);
if (ret) {
dev_err(&dev->dev, "cannot request IRQ %pa\n", &n);
return ret;
}
}
k++;
}
return k > 0 ? 0 : -ENOENT;
}
static int sh_mobile_i2c_probe(struct platform_device *dev)
{
struct i2c_sh_mobile_platform_data *pdata = dev_get_platdata(&dev->dev);
struct sh_mobile_i2c_data *pd;
struct i2c_adapter *adap;
struct resource *res;
int ret;
u32 bus_speed;
pd = devm_kzalloc(&dev->dev, sizeof(struct sh_mobile_i2c_data), GFP_KERNEL);
if (!pd)
return -ENOMEM;
pd->clk = devm_clk_get(&dev->dev, NULL);
if (IS_ERR(pd->clk)) {
dev_err(&dev->dev, "cannot get clock\n");
return PTR_ERR(pd->clk);
}
ret = sh_mobile_i2c_hook_irqs(dev, pd);
if (ret)
return ret;
pd->dev = &dev->dev;
platform_set_drvdata(dev, pd);
res = platform_get_resource(dev, IORESOURCE_MEM, 0);
pd->res = res;
pd->reg = devm_ioremap_resource(&dev->dev, res);
if (IS_ERR(pd->reg))
return PTR_ERR(pd->reg);
/* Use platform data bus speed or STANDARD_MODE */
ret = of_property_read_u32(dev->dev.of_node, "clock-frequency", &bus_speed);
pd->bus_speed = ret ? STANDARD_MODE : bus_speed;
pd->clks_per_count = 1;
if (dev->dev.of_node) {
const struct of_device_id *match;
match = of_match_device(sh_mobile_i2c_dt_ids, &dev->dev);
if (match) {
const struct sh_mobile_dt_config *config;
config = match->data;
pd->clks_per_count = config->clks_per_count;
}
} else {
if (pdata && pdata->bus_speed)
pd->bus_speed = pdata->bus_speed;
if (pdata && pdata->clks_per_count)
pd->clks_per_count = pdata->clks_per_count;
}
/* The IIC blocks on SH-Mobile ARM processors
* come with two new bits in ICIC.
*/
if (resource_size(res) > 0x17)
pd->flags |= IIC_FLAG_HAS_ICIC67;
ret = sh_mobile_i2c_init(pd);
if (ret)
return ret;
/* Init DMA */
sg_init_table(&pd->sg, 1);
pd->dma_direction = DMA_NONE;
pd->dma_rx = pd->dma_tx = ERR_PTR(-EPROBE_DEFER);
/* Enable Runtime PM for this device.
*
* Also tell the Runtime PM core to ignore children
* for this device since it is valid for us to suspend
* this I2C master driver even though the slave devices
* on the I2C bus may not be suspended.
*
* The state of the I2C hardware bus is unaffected by
* the Runtime PM state.
*/
pm_suspend_ignore_children(&dev->dev, true);
pm_runtime_enable(&dev->dev);
/* setup the private data */
adap = &pd->adap;
i2c_set_adapdata(adap, pd);
adap->owner = THIS_MODULE;
adap->algo = &sh_mobile_i2c_algorithm;
adap->dev.parent = &dev->dev;
adap->retries = 5;
adap->nr = dev->id;
adap->dev.of_node = dev->dev.of_node;
strlcpy(adap->name, dev->name, sizeof(adap->name));
spin_lock_init(&pd->lock);
init_waitqueue_head(&pd->wait);
ret = i2c_add_numbered_adapter(adap);
if (ret < 0) {
sh_mobile_i2c_release_dma(pd);
dev_err(&dev->dev, "cannot add numbered adapter\n");
return ret;
}
dev_info(&dev->dev, "I2C adapter %d, bus speed %lu Hz\n", adap->nr, pd->bus_speed);
return 0;
}
static int sh_mobile_i2c_remove(struct platform_device *dev)
{
struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
i2c_del_adapter(&pd->adap);
sh_mobile_i2c_release_dma(pd);
pm_runtime_disable(&dev->dev);
return 0;
}
static int sh_mobile_i2c_runtime_nop(struct device *dev)
{
/* Runtime PM callback shared between ->runtime_suspend()
* and ->runtime_resume(). Simply returns success.
*
* This driver re-initializes all registers after
* pm_runtime_get_sync() anyway so there is no need
* to save and restore registers here.
*/
return 0;
}
static const struct dev_pm_ops sh_mobile_i2c_dev_pm_ops = {
.runtime_suspend = sh_mobile_i2c_runtime_nop,
.runtime_resume = sh_mobile_i2c_runtime_nop,
};
static struct platform_driver sh_mobile_i2c_driver = {
.driver = {
.name = "i2c-sh_mobile",
.pm = &sh_mobile_i2c_dev_pm_ops,
.of_match_table = sh_mobile_i2c_dt_ids,
},
.probe = sh_mobile_i2c_probe,
.remove = sh_mobile_i2c_remove,
};
static int __init sh_mobile_i2c_adap_init(void)
{
return platform_driver_register(&sh_mobile_i2c_driver);
}
subsys_initcall(sh_mobile_i2c_adap_init);
static void __exit sh_mobile_i2c_adap_exit(void)
{
platform_driver_unregister(&sh_mobile_i2c_driver);
}
module_exit(sh_mobile_i2c_adap_exit);
MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");
MODULE_AUTHOR("Magnus Damm and Wolfram Sang");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:i2c-sh_mobile");
View git blame Copy permalink