Sigma Designs chips use a variant of this controller with the following differences:
- The BUSY bit in the STATUS register is inverted - Bit 8 of the CONFIG register must be set - The controller can generate interrupts This patch adds support for the first two of these. It also calculates and sets the correct clock divisor if a clk is provided. The bus frequency is optionally speficied in the device tree node. Signed-off-by: Mans Rullgard <m...@mansr.com> --- drivers/i2c/busses/Kconfig | 6 ++-- drivers/i2c/busses/i2c-xlr.c | 81 +++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 80 insertions(+), 7 deletions(-) diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index f764e3a..fdedf59 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -944,11 +944,11 @@ config I2C_XILINX will be called xilinx_i2c. config I2C_XLR - tristate "XLR I2C support" - depends on CPU_XLR + tristate "Netlogic XLR and Sigma Designs I2C support" + depends on CPU_XLR || ARCH_TANGOX help This driver enables support for the on-chip I2C interface of - the Netlogic XLR/XLS MIPS processors. + the Netlogic XLR/XLS MIPS processors and Sigma Designs SOCs. This driver can also be built as a module. If so, the module will be called i2c-xlr. diff --git a/drivers/i2c/busses/i2c-xlr.c b/drivers/i2c/busses/i2c-xlr.c index 8b36bcf..10fb916 100644 --- a/drivers/i2c/busses/i2c-xlr.c +++ b/drivers/i2c/busses/i2c-xlr.c @@ -17,6 +17,8 @@ #include <linux/i2c.h> #include <linux/io.h> #include <linux/platform_device.h> +#include <linux/of_device.h> +#include <linux/clk.h> /* XLR I2C REGISTERS */ #define XLR_I2C_CFG 0x00 @@ -63,11 +65,23 @@ static inline u32 xlr_i2c_rdreg(u32 __iomem *base, unsigned int reg) return __raw_readl(base + reg); } +struct xlr_i2c_config { + u32 status_busy; /* value of STATUS[0] when busy */ + u32 cfg_extra; /* extra CFG bits to set */ +}; + struct xlr_i2c_private { struct i2c_adapter adap; u32 __iomem *iobase; + const struct xlr_i2c_config *cfg; + struct clk *clk; }; +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_tx(struct xlr_i2c_private *priv, u16 len, u8 *buf, u16 addr) { @@ -80,7 +94,8 @@ static int xlr_i2c_tx(struct xlr_i2c_private *priv, u16 len, offset = buf[0]; xlr_i2c_wreg(priv->iobase, XLR_I2C_ADDR, offset); xlr_i2c_wreg(priv->iobase, XLR_I2C_DEVADDR, addr); - xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG, XLR_I2C_CFG_ADDR); + xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG, + XLR_I2C_CFG_ADDR | priv->cfg->cfg_extra); xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len - 1); timeout = msecs_to_jiffies(XLR_I2C_TIMEOUT); @@ -121,7 +136,7 @@ retry: if (i2c_status & XLR_I2C_ACK_ERR) return -EIO; - if ((i2c_status & XLR_I2C_BUS_BUSY) == 0 && pos >= len) + if (!xlr_i2c_busy(priv, i2c_status) && pos >= len) return 0; } dev_err(&adap->dev, "I2C transmit timeout\n"); @@ -136,7 +151,8 @@ static int xlr_i2c_rx(struct xlr_i2c_private *priv, u16 len, u8 *buf, u16 addr) int nbytes, timedout; u8 byte; - xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG, XLR_I2C_CFG_NOADDR); + xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG, + XLR_I2C_CFG_NOADDR | priv->cfg->cfg_extra); xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len); xlr_i2c_wreg(priv->iobase, XLR_I2C_DEVADDR, addr); @@ -174,7 +190,7 @@ retry: if (i2c_status & XLR_I2C_ACK_ERR) return -EIO; - if ((i2c_status & XLR_I2C_BUS_BUSY) == 0) + if (!xlr_i2c_busy(priv, i2c_status)) return 0; } @@ -190,6 +206,10 @@ static int xlr_i2c_xfer(struct i2c_adapter *adap, int ret = 0; struct xlr_i2c_private *priv = i2c_get_adapdata(adap); + ret = clk_enable(priv->clk); + if (ret) + return ret; + for (i = 0; ret == 0 && i < num; i++) { msg = &msgs[i]; if (msg->flags & I2C_M_RD) @@ -200,6 +220,8 @@ static int xlr_i2c_xfer(struct i2c_adapter *adap, msg->addr); } + clk_disable(priv->clk); + return (ret != 0) ? ret : num; } @@ -214,22 +236,70 @@ static struct i2c_algorithm xlr_i2c_algo = { .functionality = xlr_func, }; +static const struct xlr_i2c_config xlr_i2c_config_default = { + .status_busy = XLR_I2C_BUS_BUSY, + .cfg_extra = 0, +}; + +static const struct xlr_i2c_config xlr_i2c_config_tangox = { + .status_busy = 0, + .cfg_extra = 1 << 8, +}; + +static const struct of_device_id xlr_i2c_dt_ids[] = { + { + .compatible = "sigma,smp8642-i2c", + .data = &xlr_i2c_config_tangox, + }, + { } +}; + static int xlr_i2c_probe(struct platform_device *pdev) { + const struct of_device_id *match; struct xlr_i2c_private *priv; struct resource *res; + struct clk *clk; + unsigned long clk_rate; + unsigned long clk_div; + u32 busfreq; int ret; priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; + match = of_match_device(xlr_i2c_dt_ids, &pdev->dev); + if (match) + priv->cfg = match->data; + else + priv->cfg = &xlr_i2c_config_default; + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); priv->iobase = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(priv->iobase)) return PTR_ERR(priv->iobase); + if (of_property_read_u32(pdev->dev.of_node, "clock-frequency", + &busfreq)) + busfreq = 100000; + + clk = devm_clk_get(&pdev->dev, NULL); + if (!IS_ERR(clk)) { + ret = clk_prepare_enable(clk); + if (ret) + return ret; + + clk_rate = clk_get_rate(clk); + clk_div = DIV_ROUND_UP(clk_rate, 2 * busfreq); + xlr_i2c_wreg(priv->iobase, XLR_I2C_CLKDIV, clk_div); + + clk_disable(clk); + priv->clk = clk; + } + priv->adap.dev.parent = &pdev->dev; + priv->adap.dev.of_node = pdev->dev.of_node; priv->adap.owner = THIS_MODULE; priv->adap.algo_data = priv; priv->adap.algo = &xlr_i2c_algo; @@ -255,6 +325,8 @@ static int xlr_i2c_remove(struct platform_device *pdev) priv = platform_get_drvdata(pdev); i2c_del_adapter(&priv->adap); + clk_unprepare(priv->clk); + return 0; } @@ -263,6 +335,7 @@ static struct platform_driver xlr_i2c_driver = { .remove = xlr_i2c_remove, .driver = { .name = "xlr-i2cbus", + .of_match_table = xlr_i2c_dt_ids, }, }; -- 2.6.2 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html