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i2c: pxa: enable high speed mode for i2c bus

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To enter high speed mode, following steps should be done:
1. When running in high speed mode, i2c clock rate is different
from standard mode. Clock rate must be set according to
specification first.
2. When i2c controller sends a master code and wins arbitration,
high speed mode is entered.

If you want to enable high speed mode, the following members of
platform data should be set to proper value:
1. "high_mode" should be set to "1".
2. "master_code" should be set to "8'b 0000_1xxx"(x is 0 or 1).
   If no master_code is set, set to default value 0xe.
3. "rate" should be set according to specification.

Signed-off-by: Leilei Shang <shangll@marvell.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Leilei Shang 2013-06-07 14:38:17 +08:00 committed by Wolfram Sang
parent f480adaf1b
commit 9d3dda5c0d
2 changed files with 66 additions and 1 deletions
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64
drivers/i2c/busses/i2c-pxa.c
View File

@ -110,6 +110,8 @@ MODULE_DEVICE_TABLE(platform, i2c_pxa_id_table);
#define ICR_SADIE (1 << 13) /* slave address detected int enable */
#define ICR_UR (1 << 14) /* unit reset */
#define ICR_FM (1 << 15) /* fast mode */
#define ICR_HS (1 << 16) /* High Speed mode */
#define ICR_GPIOEN (1 << 19) /* enable GPIO mode for SCL in HS */
#define ISR_RWM (1 << 0) /* read/write mode */
#define ISR_ACKNAK (1 << 1) /* ack/nak status */
@ -155,6 +157,10 @@ struct pxa_i2c {
int irq;
unsigned int use_pio :1;
unsigned int fast_mode :1;
unsigned int high_mode:1;
unsigned char master_code;
unsigned long rate;
bool highmode_enter;
};
#define _IBMR(i2c) ((i2c)->reg_ibmr)
@ -459,6 +465,7 @@ static void i2c_pxa_reset(struct pxa_i2c *i2c)
/* set control register values */
writel(I2C_ICR_INIT | (i2c->fast_mode ? ICR_FM : 0), _ICR(i2c));
writel(readl(_ICR(i2c)) | (i2c->high_mode ? ICR_HS : 0), _ICR(i2c));
#ifdef CONFIG_I2C_PXA_SLAVE
dev_info(&i2c->adap.dev, "Enabling slave mode\n");
@ -680,6 +687,34 @@ static int i2c_pxa_pio_set_master(struct pxa_i2c *i2c)
return 0;
}
/*
* PXA I2C send master code
* 1. Load master code to IDBR and send it.
* Note for HS mode, set ICR [GPIOEN].
* 2. Wait until win arbitration.
*/
static int i2c_pxa_send_mastercode(struct pxa_i2c *i2c)
{
u32 icr;
long timeout;
spin_lock_irq(&i2c->lock);
i2c->highmode_enter = true;
writel(i2c->master_code, _IDBR(i2c));
icr = readl(_ICR(i2c)) & ~(ICR_STOP | ICR_ALDIE);
icr |= ICR_GPIOEN | ICR_START | ICR_TB | ICR_ITEIE;
writel(icr, _ICR(i2c));
spin_unlock_irq(&i2c->lock);
timeout = wait_event_timeout(i2c->wait,
i2c->highmode_enter == false, HZ * 1);
i2c->highmode_enter = false;
return (timeout == 0) ? I2C_RETRY : 0;
}
static int i2c_pxa_do_pio_xfer(struct pxa_i2c *i2c,
struct i2c_msg *msg, int num)
{
@ -743,6 +778,14 @@ static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num)
goto out;
}
if (i2c->high_mode) {
ret = i2c_pxa_send_mastercode(i2c);
if (ret) {
dev_err(&i2c->adap.dev, "i2c_pxa_send_mastercode timeout\n");
goto out;
}
}
spin_lock_irq(&i2c->lock);
i2c->msg = msg;
@ -990,11 +1033,14 @@ static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id)
i2c_pxa_slave_txempty(i2c, isr);
if (isr & ISR_IRF)
i2c_pxa_slave_rxfull(i2c, isr);
} else if (i2c->msg) {
} else if (i2c->msg && (!i2c->highmode_enter)) {
if (isr & ISR_ITE)
i2c_pxa_irq_txempty(i2c, isr);
if (isr & ISR_IRF)
i2c_pxa_irq_rxfull(i2c, isr);
} else if ((isr & ISR_ITE) && i2c->highmode_enter) {
i2c->highmode_enter = false;
wake_up(&i2c->wait);
} else {
i2c_pxa_scream_blue_murder(i2c, "spurious irq");
}
@ -1079,6 +1125,11 @@ static int i2c_pxa_probe_pdata(struct platform_device *pdev,
if (plat) {
i2c->use_pio = plat->use_pio;
i2c->fast_mode = plat->fast_mode;
i2c->high_mode = plat->high_mode;
i2c->master_code = plat->master_code;
if (!i2c->master_code)
i2c->master_code = 0xe;
i2c->rate = plat->rate;
}
return 0;
}
@ -1151,6 +1202,7 @@ static int i2c_pxa_probe(struct platform_device *dev)
i2c->irq = irq;
i2c->slave_addr = I2C_PXA_SLAVE_ADDR;
i2c->highmode_enter = false;
if (plat) {
#ifdef CONFIG_I2C_PXA_SLAVE
@ -1160,6 +1212,16 @@ static int i2c_pxa_probe(struct platform_device *dev)
i2c->adap.class = plat->class;
}
if (i2c->high_mode) {
if (i2c->rate) {
clk_set_rate(i2c->clk, i2c->rate);
pr_info("i2c: <%s> set rate to %ld\n",
i2c->adap.name, clk_get_rate(i2c->clk));
} else
pr_warn("i2c: <%s> clock rate not set\n",
i2c->adap.name);
}
clk_prepare_enable(i2c->clk);
if (i2c->use_pio) {

3
include/linux/i2c/pxa-i2c.h
View File

@ -67,6 +67,9 @@ struct i2c_pxa_platform_data {
unsigned int class;
unsigned int use_pio :1;
unsigned int fast_mode :1;
unsigned int high_mode:1;
unsigned char master_code;
unsigned long rate;
};
extern void pxa_set_i2c_info(struct i2c_pxa_platform_data *info);