diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-imx.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-imx.c | 169 |
1 files changed, 108 insertions, 61 deletions
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index db895fb22e65..aa8bc146718b 100644 --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -183,6 +183,8 @@ struct imx_i2c_struct { unsigned int disable_delay; int stopped; unsigned int ifdr; /* IMX_I2C_IFDR */ + unsigned int cur_clk; + unsigned int bitrate; const struct imx_i2c_hwdata *hwdata; }; @@ -305,6 +307,48 @@ static int i2c_imx_acked(struct imx_i2c_struct *i2c_imx) return 0; } +static void i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx) +{ + struct imx_i2c_clk_pair *i2c_clk_div = i2c_imx->hwdata->clk_div; + unsigned int i2c_clk_rate; + unsigned int div; + int i; + + /* Divider value calculation */ + i2c_clk_rate = clk_get_rate(i2c_imx->clk); + if (i2c_imx->cur_clk == i2c_clk_rate) + return; + else + i2c_imx->cur_clk = i2c_clk_rate; + + div = (i2c_clk_rate + i2c_imx->bitrate - 1) / i2c_imx->bitrate; + if (div < i2c_clk_div[0].div) + i = 0; + else if (div > i2c_clk_div[i2c_imx->hwdata->ndivs - 1].div) + i = i2c_imx->hwdata->ndivs - 1; + else + for (i = 0; i2c_clk_div[i].div < div; i++); + + /* Store divider value */ + i2c_imx->ifdr = i2c_clk_div[i].val; + + /* + * There dummy delay is calculated. + * It should be about one I2C clock period long. + * This delay is used in I2C bus disable function + * to fix chip hardware bug. + */ + i2c_imx->disable_delay = (500000U * i2c_clk_div[i].div + + (i2c_clk_rate / 2) - 1) / (i2c_clk_rate / 2); + +#ifdef CONFIG_I2C_DEBUG_BUS + dev_dbg(&i2c_imx->adapter.dev, "I2C_CLK=%d, REQ DIV=%d\n", + i2c_clk_rate, div); + dev_dbg(&i2c_imx->adapter.dev, "IFDR[IC]=0x%x, REAL DIV=%d\n", + i2c_clk_div[i].val, i2c_clk_div[i].div); +#endif +} + static int i2c_imx_start(struct imx_i2c_struct *i2c_imx) { unsigned int temp = 0; @@ -312,6 +356,8 @@ static int i2c_imx_start(struct imx_i2c_struct *i2c_imx) dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); + i2c_imx_set_clk(i2c_imx); + result = clk_prepare_enable(i2c_imx->clk); if (result) return result; @@ -367,45 +413,6 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx) clk_disable_unprepare(i2c_imx->clk); } -static void i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx, - unsigned int rate) -{ - struct imx_i2c_clk_pair *i2c_clk_div = i2c_imx->hwdata->clk_div; - unsigned int i2c_clk_rate; - unsigned int div; - int i; - - /* Divider value calculation */ - i2c_clk_rate = clk_get_rate(i2c_imx->clk); - div = (i2c_clk_rate + rate - 1) / rate; - if (div < i2c_clk_div[0].div) - i = 0; - else if (div > i2c_clk_div[i2c_imx->hwdata->ndivs - 1].div) - i = i2c_imx->hwdata->ndivs - 1; - else - for (i = 0; i2c_clk_div[i].div < div; i++); - - /* Store divider value */ - i2c_imx->ifdr = i2c_clk_div[i].val; - - /* - * There dummy delay is calculated. - * It should be about one I2C clock period long. - * This delay is used in I2C bus disable function - * to fix chip hardware bug. - */ - i2c_imx->disable_delay = (500000U * i2c_clk_div[i].div - + (i2c_clk_rate / 2) - 1) / (i2c_clk_rate / 2); - - /* dev_dbg() can't be used, because adapter is not yet registered */ -#ifdef CONFIG_I2C_DEBUG_BUS - dev_dbg(&i2c_imx->adapter.dev, "<%s> I2C_CLK=%d, REQ DIV=%d\n", - __func__, i2c_clk_rate, div); - dev_dbg(&i2c_imx->adapter.dev, "<%s> IFDR[IC]=0x%x, REAL DIV=%d\n", - __func__, i2c_clk_div[i].val, i2c_clk_div[i].div); -#endif -} - static irqreturn_t i2c_imx_isr(int irq, void *dev_id) { struct imx_i2c_struct *i2c_imx = dev_id; @@ -458,10 +465,11 @@ static int i2c_imx_write(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) return 0; } -static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) +static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs, bool is_lastmsg) { int i, result; unsigned int temp; + int block_data = msgs->flags & I2C_M_RECV_LEN; dev_dbg(&i2c_imx->adapter.dev, "<%s> write slave address: addr=0x%x\n", @@ -481,7 +489,12 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) /* setup bus to read data */ temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); temp &= ~I2CR_MTX; - if (msgs->len - 1) + + /* + * Reset the I2CR_TXAK flag initially for SMBus block read since the + * length is unknown + */ + if ((msgs->len - 1) || block_data) temp &= ~I2CR_TXAK; imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); /* dummy read */ @@ -490,19 +503,49 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) /* read data */ for (i = 0; i < msgs->len; i++) { + u8 len = 0; result = i2c_imx_trx_complete(i2c_imx); if (result) return result; - if (i == (msgs->len - 1)) { - /* It must generate STOP before read I2DR to prevent - controller from generating another clock cycle */ + /* + * First byte is the length of remaining packet + * in the SMBus block data read. Add it to + * msgs->len. + */ + if ((!i) && block_data) { + len = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); + if ((len == 0) || (len > I2C_SMBUS_BLOCK_MAX)) + return -EPROTO; dev_dbg(&i2c_imx->adapter.dev, - "<%s> clear MSTA\n", __func__); - temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); - temp &= ~(I2CR_MSTA | I2CR_MTX); - imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); - i2c_imx_bus_busy(i2c_imx, 0); - i2c_imx->stopped = 1; + "<%s> read length: 0x%X\n", + __func__, len); + msgs->len += len; + } + if (i == (msgs->len - 1)) { + if (is_lastmsg) { + /* + * It must generate STOP before read I2DR to prevent + * controller from generating another clock cycle + */ + dev_dbg(&i2c_imx->adapter.dev, + "<%s> clear MSTA\n", __func__); + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); + temp &= ~(I2CR_MSTA | I2CR_MTX); + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); + i2c_imx_bus_busy(i2c_imx, 0); + i2c_imx->stopped = 1; + } else { + /* + * For i2c master receiver repeat restart operation like: + * read -> repeat MSTA -> read/write + * The controller must set MTX before read the last byte in + * the first read operation, otherwise the first read cost + * one extra clock cycle. + */ + temp = readb(i2c_imx->base + IMX_I2C_I2CR); + temp |= I2CR_MTX; + writeb(temp, i2c_imx->base + IMX_I2C_I2CR); + } } else if (i == (msgs->len - 2)) { dev_dbg(&i2c_imx->adapter.dev, "<%s> set TXAK\n", __func__); @@ -510,7 +553,10 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) temp |= I2CR_TXAK; imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); } - msgs->buf[i] = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); + if ((!i) && block_data) + msgs->buf[0] = len; + else + msgs->buf[i] = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); dev_dbg(&i2c_imx->adapter.dev, "<%s> read byte: B%d=0x%X\n", __func__, i, msgs->buf[i]); @@ -523,6 +569,7 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter, { unsigned int i, temp; int result; + bool is_lastmsg = false; struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(adapter); dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); @@ -534,6 +581,9 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter, /* read/write data */ for (i = 0; i < num; i++) { + if (i == num - 1) + is_lastmsg = true; + if (i) { dev_dbg(&i2c_imx->adapter.dev, "<%s> repeated start\n", __func__); @@ -564,7 +614,7 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter, (temp & I2SR_RXAK ? 1 : 0)); #endif if (msgs[i].flags & I2C_M_RD) - result = i2c_imx_read(i2c_imx, &msgs[i]); + result = i2c_imx_read(i2c_imx, &msgs[i], is_lastmsg); else result = i2c_imx_write(i2c_imx, &msgs[i]); if (result) @@ -583,7 +633,8 @@ fail0: static u32 i2c_imx_func(struct i2c_adapter *adapter) { - return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL + | I2C_FUNC_SMBUS_READ_BLOCK_DATA; } static struct i2c_algorithm i2c_imx_algo = { @@ -600,7 +651,6 @@ static int i2c_imx_probe(struct platform_device *pdev) struct imxi2c_platform_data *pdata = dev_get_platdata(&pdev->dev); void __iomem *base; int irq, ret; - u32 bitrate; dev_dbg(&pdev->dev, "<%s>\n", __func__); @@ -617,10 +667,8 @@ static int i2c_imx_probe(struct platform_device *pdev) i2c_imx = devm_kzalloc(&pdev->dev, sizeof(struct imx_i2c_struct), GFP_KERNEL); - if (!i2c_imx) { - dev_err(&pdev->dev, "can't allocate interface\n"); + if (!i2c_imx) return -ENOMEM; - } if (of_id) i2c_imx->hwdata = of_id->data; @@ -664,12 +712,11 @@ static int i2c_imx_probe(struct platform_device *pdev) i2c_set_adapdata(&i2c_imx->adapter, i2c_imx); /* Set up clock divider */ - bitrate = IMX_I2C_BIT_RATE; + i2c_imx->bitrate = IMX_I2C_BIT_RATE; ret = of_property_read_u32(pdev->dev.of_node, - "clock-frequency", &bitrate); + "clock-frequency", &i2c_imx->bitrate); if (ret < 0 && pdata && pdata->bitrate) - bitrate = pdata->bitrate; - i2c_imx_set_clk(i2c_imx, bitrate); + i2c_imx->bitrate = pdata->bitrate; /* Set up chip registers to defaults */ imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN, |