Hi Guys
Any comments?
2013/8/9 Leilei Shang <shangll@xxxxxxxxxxx>:
> From: Leilei Shang <shangll@xxxxxxxxxxx>
>
> 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@xxxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-pxa.c | 68 +++++++++++++++++++++++++++++++++++++++++-
> include/linux/i2c/pxa-i2c.h | 3 ++
> 2 files changed, 70 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
> index 3a5c477..da7b9ae 100644
> --- a/drivers/i2c/busses/i2c-pxa.c
> +++ b/drivers/i2c/busses/i2c-pxa.c
> @@ -119,6 +119,8 @@ 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 */
> @@ -164,6 +166,10 @@ 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)
> @@ -468,6 +474,7 @@ 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");
> @@ -689,6 +696,34 @@ 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)
> {
> @@ -752,6 +787,14 @@ 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;
> @@ -999,11 +1042,14 @@ 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");
> }
> @@ -1088,6 +1134,11 @@ 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;
> }
> @@ -1160,6 +1211,7 @@ 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
> @@ -1169,6 +1221,20 @@ static int i2c_pxa_probe(struct platform_device *dev)
> i2c->adap.class = plat->class;
> }
>
> + if (i2c->high_mode) {
> + if (i2c_type != REGS_PXA910) {
> + pr_warn("i2c: <%s> do not support HS mode\n",
> + i2c->adap.name);
> + i2c->high_mode = 0;
> + } else 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) {
> diff --git a/include/linux/i2c/pxa-i2c.h b/include/linux/i2c/pxa-i2c.h
> index 1a9f65e..53aab24 100644
> --- a/include/linux/i2c/pxa-i2c.h
> +++ b/include/linux/i2c/pxa-i2c.h
> @@ -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);
> --
> 1.7.4.1
>
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