diff options
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-xlr.c | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-xlr.c b/drivers/i2c/busses/i2c-xlr.c index 2cfaba7c1f92..613c3a4f2c51 100644 --- a/drivers/i2c/busses/i2c-xlr.c +++ b/drivers/i2c/busses/i2c-xlr.c @@ -19,6 +19,8 @@ #include <linux/platform_device.h> #include <linux/of_device.h> #include <linux/clk.h> +#include <linux/interrupt.h> +#include <linux/wait.h> /* XLR I2C REGISTERS */ #define XLR_I2C_CFG 0x00 @@ -32,6 +34,10 @@ #define XLR_I2C_BYTECNT 0x08 #define XLR_I2C_HDSTATIM 0x09 +/* Sigma Designs additional registers */ +#define XLR_I2C_INT_EN 0x09 +#define XLR_I2C_INT_STAT 0x0a + /* XLR I2C REGISTERS FLAGS */ #define XLR_I2C_BUS_BUSY 0x01 #define XLR_I2C_SDOEMPTY 0x02 @@ -65,7 +71,10 @@ static inline u32 xlr_i2c_rdreg(u32 __iomem *base, unsigned int reg) return __raw_readl(base + reg); } +#define XLR_I2C_FLAG_IRQ 1 + struct xlr_i2c_config { + u32 flags; /* optional feature support */ u32 status_busy; /* value of STATUS[0] when busy */ u32 cfg_extra; /* extra CFG bits to set */ }; @@ -73,7 +82,11 @@ struct xlr_i2c_config { struct xlr_i2c_private { struct i2c_adapter adap; u32 __iomem *iobase; + int irq; + int pos; + struct i2c_msg *msg; const struct xlr_i2c_config *cfg; + wait_queue_head_t wait; struct clk *clk; }; @@ -82,6 +95,74 @@ static int xlr_i2c_busy(struct xlr_i2c_private *priv, u32 status) return (status & XLR_I2C_BUS_BUSY) == priv->cfg->status_busy; } +static int xlr_i2c_idle(struct xlr_i2c_private *priv) +{ + return !xlr_i2c_busy(priv, xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS)); +} + +static int xlr_i2c_wait(struct xlr_i2c_private *priv, unsigned long timeout) +{ + int status; + int t; + + t = wait_event_timeout(priv->wait, xlr_i2c_idle(priv), + msecs_to_jiffies(timeout)); + if (!t) + return -ETIMEDOUT; + + status = xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS); + + return status & XLR_I2C_ACK_ERR ? -EIO : 0; +} + +static void xlr_i2c_tx_irq(struct xlr_i2c_private *priv, u32 status) +{ + struct i2c_msg *msg = priv->msg; + + if (status & XLR_I2C_SDOEMPTY) + xlr_i2c_wreg(priv->iobase, XLR_I2C_DATAOUT, + msg->buf[priv->pos++]); +} + +static void xlr_i2c_rx_irq(struct xlr_i2c_private *priv, u32 status) +{ + struct i2c_msg *msg = priv->msg; + + if (status & XLR_I2C_RXRDY) + msg->buf[priv->pos++] = + xlr_i2c_rdreg(priv->iobase, XLR_I2C_DATAIN); +} + +static irqreturn_t xlr_i2c_irq(int irq, void *dev_id) +{ + struct xlr_i2c_private *priv = dev_id; + struct i2c_msg *msg = priv->msg; + u32 int_stat, status; + + int_stat = xlr_i2c_rdreg(priv->iobase, XLR_I2C_INT_STAT); + if (!int_stat) + return IRQ_NONE; + + xlr_i2c_wreg(priv->iobase, XLR_I2C_INT_STAT, int_stat); + + if (!msg) + return IRQ_HANDLED; + + status = xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS); + + if (priv->pos < msg->len) { + if (msg->flags & I2C_M_RD) + xlr_i2c_rx_irq(priv, status); + else + xlr_i2c_tx_irq(priv, status); + } + + if (!xlr_i2c_busy(priv, status)) + wake_up(&priv->wait); + + return IRQ_HANDLED; +} + static int xlr_i2c_tx(struct xlr_i2c_private *priv, u16 len, u8 *buf, u16 addr) { @@ -116,10 +197,15 @@ static int xlr_i2c_tx(struct xlr_i2c_private *priv, u16 len, pos = 2; } + priv->pos = pos; + retry: /* retry can only happen on the first byte */ xlr_i2c_wreg(priv->iobase, XLR_I2C_STARTXFR, xfer); + if (priv->irq > 0) + return xlr_i2c_wait(priv, XLR_I2C_TIMEOUT * len); + while (!timedout) { checktime = jiffies; i2c_status = xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS); @@ -163,6 +249,8 @@ static int xlr_i2c_rx(struct xlr_i2c_private *priv, u16 len, u8 *buf, u16 addr) xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len - 1); xlr_i2c_wreg(priv->iobase, XLR_I2C_DEVADDR, addr); + priv->pos = 0; + timeout = msecs_to_jiffies(XLR_I2C_TIMEOUT); stoptime = jiffies + timeout; timedout = 0; @@ -170,6 +258,9 @@ static int xlr_i2c_rx(struct xlr_i2c_private *priv, u16 len, u8 *buf, u16 addr) retry: xlr_i2c_wreg(priv->iobase, XLR_I2C_STARTXFR, XLR_I2C_STARTXFR_RD); + if (priv->irq > 0) + return xlr_i2c_wait(priv, XLR_I2C_TIMEOUT * len); + while (!timedout) { checktime = jiffies; i2c_status = xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS); @@ -214,8 +305,13 @@ static int xlr_i2c_xfer(struct i2c_adapter *adap, if (ret) return ret; + if (priv->irq) + xlr_i2c_wreg(priv->iobase, XLR_I2C_INT_EN, 0xf); + + for (i = 0; ret == 0 && i < num; i++) { msg = &msgs[i]; + priv->msg = msg; if (msg->flags & I2C_M_RD) ret = xlr_i2c_rx(priv, msg->len, &msg->buf[0], msg->addr); @@ -224,7 +320,11 @@ static int xlr_i2c_xfer(struct i2c_adapter *adap, msg->addr); } + if (priv->irq) + xlr_i2c_wreg(priv->iobase, XLR_I2C_INT_EN, 0); + clk_disable(priv->clk); + priv->msg = NULL; return (ret != 0) ? ret : num; } @@ -246,6 +346,7 @@ static const struct xlr_i2c_config xlr_i2c_config_default = { }; static const struct xlr_i2c_config xlr_i2c_config_tangox = { + .flags = XLR_I2C_FLAG_IRQ, .status_busy = 0, .cfg_extra = 1 << 8, }; @@ -267,6 +368,7 @@ static int xlr_i2c_probe(struct platform_device *pdev) unsigned long clk_rate; unsigned long clk_div; u32 busfreq; + int irq; int ret; priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); @@ -284,6 +386,23 @@ static int xlr_i2c_probe(struct platform_device *pdev) if (IS_ERR(priv->iobase)) return PTR_ERR(priv->iobase); + irq = platform_get_irq(pdev, 0); + + if (irq > 0 && (priv->cfg->flags & XLR_I2C_FLAG_IRQ)) { + priv->irq = irq; + + xlr_i2c_wreg(priv->iobase, XLR_I2C_INT_EN, 0); + xlr_i2c_wreg(priv->iobase, XLR_I2C_INT_STAT, 0xf); + + ret = devm_request_irq(&pdev->dev, priv->irq, xlr_i2c_irq, + IRQF_SHARED, dev_name(&pdev->dev), + priv); + if (ret) + return ret; + + init_waitqueue_head(&priv->wait); + } + if (of_property_read_u32(pdev->dev.of_node, "clock-frequency", &busfreq)) busfreq = 100000; |