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
--
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