diff options
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-pxa.c | 133 |
1 files changed, 121 insertions, 12 deletions
diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c index da3ecf5c591..2598d29fd7a 100644 --- a/drivers/i2c/busses/i2c-pxa.c +++ b/drivers/i2c/busses/i2c-pxa.c @@ -65,6 +65,7 @@ struct pxa_i2c { unsigned long iosize; int irq; + int use_pio; }; #define _IBMR(i2c) ((i2c)->reg_base + 0) @@ -163,6 +164,7 @@ static void i2c_pxa_show_state(struct pxa_i2c *i2c, int lno, const char *fname) #define eedbg(lvl, x...) do { if ((lvl) < 1) { printk(KERN_DEBUG "" x); } } while(0) static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret); +static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id); static void i2c_pxa_scream_blue_murder(struct pxa_i2c *i2c, const char *why) { @@ -554,6 +556,71 @@ static inline void i2c_pxa_stop_message(struct pxa_i2c *i2c) writel(icr, _ICR(i2c)); } +static int i2c_pxa_pio_set_master(struct pxa_i2c *i2c) +{ + /* make timeout the same as for interrupt based functions */ + long timeout = 2 * DEF_TIMEOUT; + + /* + * Wait for the bus to become free. + */ + while (timeout-- && readl(_ISR(i2c)) & (ISR_IBB | ISR_UB)) { + udelay(1000); + show_state(i2c); + } + + if (timeout <= 0) { + show_state(i2c); + dev_err(&i2c->adap.dev, + "i2c_pxa: timeout waiting for bus free\n"); + return I2C_RETRY; + } + + /* + * Set master mode. + */ + writel(readl(_ICR(i2c)) | ICR_SCLE, _ICR(i2c)); + + return 0; +} + +static int i2c_pxa_do_pio_xfer(struct pxa_i2c *i2c, + struct i2c_msg *msg, int num) +{ + unsigned long timeout = 500000; /* 5 seconds */ + int ret = 0; + + ret = i2c_pxa_pio_set_master(i2c); + if (ret) + goto out; + + i2c->msg = msg; + i2c->msg_num = num; + i2c->msg_idx = 0; + i2c->msg_ptr = 0; + i2c->irqlogidx = 0; + + i2c_pxa_start_message(i2c); + + while (timeout-- && i2c->msg_num > 0) { + i2c_pxa_handler(0, i2c); + udelay(10); + } + + i2c_pxa_stop_message(i2c); + + /* + * We place the return code in i2c->msg_idx. + */ + ret = i2c->msg_idx; + +out: + if (timeout == 0) + i2c_pxa_scream_blue_murder(i2c, "timeout"); + + return ret; +} + /* * We are protected by the adapter bus mutex. */ @@ -610,6 +677,35 @@ static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num) return ret; } +static int i2c_pxa_pio_xfer(struct i2c_adapter *adap, + struct i2c_msg msgs[], int num) +{ + struct pxa_i2c *i2c = adap->algo_data; + int ret, i; + + /* If the I2C controller is disabled we need to reset it + (probably due to a suspend/resume destroying state). We do + this here as we can then avoid worrying about resuming the + controller before its users. */ + if (!(readl(_ICR(i2c)) & ICR_IUE)) + i2c_pxa_reset(i2c); + + for (i = adap->retries; i >= 0; i--) { + ret = i2c_pxa_do_pio_xfer(i2c, msgs, num); + if (ret != I2C_RETRY) + goto out; + + if (i2c_debug) + dev_dbg(&adap->dev, "Retrying transmission\n"); + udelay(100); + } + i2c_pxa_scream_blue_murder(i2c, "exhausted retries"); + ret = -EREMOTEIO; + out: + i2c_pxa_set_slave(i2c, ret); + return ret; +} + /* * i2c_pxa_master_complete - complete the message and wake up. */ @@ -621,7 +717,8 @@ static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret) i2c->msg_num = 0; if (ret) i2c->msg_idx = ret; - wake_up(&i2c->wait); + if (!i2c->use_pio) + wake_up(&i2c->wait); } static void i2c_pxa_irq_txempty(struct pxa_i2c *i2c, u32 isr) @@ -840,6 +937,11 @@ static const struct i2c_algorithm i2c_pxa_algorithm = { .functionality = i2c_pxa_functionality, }; +static const struct i2c_algorithm i2c_pxa_pio_algorithm = { + .master_xfer = i2c_pxa_pio_xfer, + .functionality = i2c_pxa_functionality, +}; + static void i2c_pxa_enable(struct platform_device *dev) { if (cpu_is_pxa27x()) { @@ -890,7 +992,6 @@ static int i2c_pxa_probe(struct platform_device *dev) } i2c->adap.owner = THIS_MODULE; - i2c->adap.algo = &i2c_pxa_algorithm; i2c->adap.retries = 5; spin_lock_init(&i2c->lock); @@ -927,20 +1028,26 @@ static int i2c_pxa_probe(struct platform_device *dev) clk_enable(i2c->clk); i2c_pxa_enable(dev); - ret = request_irq(irq, i2c_pxa_handler, IRQF_DISABLED, - i2c->adap.name, i2c); - if (ret) - goto ereqirq; + if (plat) { + i2c->adap.class = plat->class; + i2c->use_pio = plat->use_pio; + } + + if (i2c->use_pio) { + i2c->adap.algo = &i2c_pxa_pio_algorithm; + } else { + i2c->adap.algo = &i2c_pxa_algorithm; + ret = request_irq(irq, i2c_pxa_handler, IRQF_DISABLED, + i2c->adap.name, i2c); + if (ret) + goto ereqirq; + } i2c_pxa_reset(i2c); i2c->adap.algo_data = i2c; i2c->adap.dev.parent = &dev->dev; - if (plat) { - i2c->adap.class = plat->class; - } - /* * If "dev->id" is negative we consider it as zero. * The reason to do so is to avoid sysfs names that only make @@ -966,7 +1073,8 @@ static int i2c_pxa_probe(struct platform_device *dev) return 0; eadapt: - free_irq(irq, i2c); + if (!i2c->use_pio) + free_irq(irq, i2c); ereqirq: clk_disable(i2c->clk); i2c_pxa_disable(dev); @@ -986,7 +1094,8 @@ static int i2c_pxa_remove(struct platform_device *dev) platform_set_drvdata(dev, NULL); i2c_del_adapter(&i2c->adap); - free_irq(i2c->irq, i2c); + if (!i2c->use_pio) + free_irq(i2c->irq, i2c); clk_disable(i2c->clk); clk_put(i2c->clk); |