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i2c: pxa: enable high speed mode for i2c bus
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:
parent
f480adaf1b
commit
9d3dda5c0d
2 changed files with 66 additions and 1 deletions
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@ -110,6 +110,8 @@ MODULE_DEVICE_TABLE(platform, i2c_pxa_id_table);
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#define ICR_SADIE (1 << 13) /* slave address detected int enable */
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#define ICR_UR (1 << 14) /* unit reset */
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#define ICR_FM (1 << 15) /* fast mode */
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#define ICR_HS (1 << 16) /* High Speed mode */
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#define ICR_GPIOEN (1 << 19) /* enable GPIO mode for SCL in HS */
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#define ISR_RWM (1 << 0) /* read/write mode */
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#define ISR_ACKNAK (1 << 1) /* ack/nak status */
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@ -155,6 +157,10 @@ struct pxa_i2c {
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int irq;
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unsigned int use_pio :1;
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unsigned int fast_mode :1;
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unsigned int high_mode:1;
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unsigned char master_code;
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unsigned long rate;
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bool highmode_enter;
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};
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#define _IBMR(i2c) ((i2c)->reg_ibmr)
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@ -459,6 +465,7 @@ static void i2c_pxa_reset(struct pxa_i2c *i2c)
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/* set control register values */
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writel(I2C_ICR_INIT | (i2c->fast_mode ? ICR_FM : 0), _ICR(i2c));
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writel(readl(_ICR(i2c)) | (i2c->high_mode ? ICR_HS : 0), _ICR(i2c));
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#ifdef CONFIG_I2C_PXA_SLAVE
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dev_info(&i2c->adap.dev, "Enabling slave mode\n");
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@ -680,6 +687,34 @@ static int i2c_pxa_pio_set_master(struct pxa_i2c *i2c)
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return 0;
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}
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/*
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* PXA I2C send master code
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* 1. Load master code to IDBR and send it.
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* Note for HS mode, set ICR [GPIOEN].
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* 2. Wait until win arbitration.
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*/
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static int i2c_pxa_send_mastercode(struct pxa_i2c *i2c)
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{
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u32 icr;
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long timeout;
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spin_lock_irq(&i2c->lock);
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i2c->highmode_enter = true;
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writel(i2c->master_code, _IDBR(i2c));
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icr = readl(_ICR(i2c)) & ~(ICR_STOP | ICR_ALDIE);
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icr |= ICR_GPIOEN | ICR_START | ICR_TB | ICR_ITEIE;
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writel(icr, _ICR(i2c));
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spin_unlock_irq(&i2c->lock);
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timeout = wait_event_timeout(i2c->wait,
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i2c->highmode_enter == false, HZ * 1);
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i2c->highmode_enter = false;
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return (timeout == 0) ? I2C_RETRY : 0;
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}
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static int i2c_pxa_do_pio_xfer(struct pxa_i2c *i2c,
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struct i2c_msg *msg, int num)
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{
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@ -743,6 +778,14 @@ static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num)
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goto out;
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}
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if (i2c->high_mode) {
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ret = i2c_pxa_send_mastercode(i2c);
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if (ret) {
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dev_err(&i2c->adap.dev, "i2c_pxa_send_mastercode timeout\n");
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goto out;
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}
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}
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spin_lock_irq(&i2c->lock);
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i2c->msg = msg;
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@ -990,11 +1033,14 @@ static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id)
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i2c_pxa_slave_txempty(i2c, isr);
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if (isr & ISR_IRF)
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i2c_pxa_slave_rxfull(i2c, isr);
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} else if (i2c->msg) {
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} else if (i2c->msg && (!i2c->highmode_enter)) {
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if (isr & ISR_ITE)
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i2c_pxa_irq_txempty(i2c, isr);
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if (isr & ISR_IRF)
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i2c_pxa_irq_rxfull(i2c, isr);
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} else if ((isr & ISR_ITE) && i2c->highmode_enter) {
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i2c->highmode_enter = false;
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wake_up(&i2c->wait);
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} else {
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i2c_pxa_scream_blue_murder(i2c, "spurious irq");
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}
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@ -1079,6 +1125,11 @@ static int i2c_pxa_probe_pdata(struct platform_device *pdev,
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if (plat) {
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i2c->use_pio = plat->use_pio;
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i2c->fast_mode = plat->fast_mode;
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i2c->high_mode = plat->high_mode;
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i2c->master_code = plat->master_code;
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if (!i2c->master_code)
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i2c->master_code = 0xe;
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i2c->rate = plat->rate;
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}
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return 0;
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}
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@ -1151,6 +1202,7 @@ static int i2c_pxa_probe(struct platform_device *dev)
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i2c->irq = irq;
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i2c->slave_addr = I2C_PXA_SLAVE_ADDR;
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i2c->highmode_enter = false;
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if (plat) {
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#ifdef CONFIG_I2C_PXA_SLAVE
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@ -1160,6 +1212,16 @@ static int i2c_pxa_probe(struct platform_device *dev)
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i2c->adap.class = plat->class;
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}
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if (i2c->high_mode) {
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if (i2c->rate) {
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clk_set_rate(i2c->clk, i2c->rate);
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pr_info("i2c: <%s> set rate to %ld\n",
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i2c->adap.name, clk_get_rate(i2c->clk));
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} else
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pr_warn("i2c: <%s> clock rate not set\n",
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i2c->adap.name);
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}
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clk_prepare_enable(i2c->clk);
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if (i2c->use_pio) {
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@ -67,6 +67,9 @@ struct i2c_pxa_platform_data {
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unsigned int class;
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unsigned int use_pio :1;
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unsigned int fast_mode :1;
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unsigned int high_mode:1;
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unsigned char master_code;
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unsigned long rate;
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};
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extern void pxa_set_i2c_info(struct i2c_pxa_platform_data *info);
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