[PATCH 6/6] i2c: designware: Add Baikal-T1 SoC I2C controller support
From: Sergey.Semin
Date: Fri Mar 06 2020 - 08:23:51 EST
From: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx>
A third I2C controller embedded into the Baikal-T1 SoC is also fully
based on the DW APB I2C core, but its registers are indirectly
accessible via "command/data in/data out" trio. There is no difference
other than that. So in order to have that controller supported by the
common DW APB I2C driver we only need to introduce a new flag
ACCESS_INDIRECT and use the access-registers to reach the I2C controller
normal registers space in the dw_readl/dw_writel methods. Currently this
flag is only enabled for the controllers with "be,bt1-i2c" compatible
string.
Signed-off-by: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Alexey Malahov <Alexey.Malahov@xxxxxxxxxxxxxxxxxxxx>
Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: Paul Burton <paulburton@xxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: linux-i2c@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
drivers/i2c/busses/i2c-designware-common.c | 79 ++++++++++++++++++---
drivers/i2c/busses/i2c-designware-core.h | 14 ++++
drivers/i2c/busses/i2c-designware-master.c | 1 +
drivers/i2c/busses/i2c-designware-platdrv.c | 1 +
drivers/i2c/busses/i2c-designware-slave.c | 1 +
5 files changed, 86 insertions(+), 10 deletions(-)
diff --git a/drivers/i2c/busses/i2c-designware-common.c b/drivers/i2c/busses/i2c-designware-common.c
index 72e93c1aa9bc..d3010bb6ad42 100644
--- a/drivers/i2c/busses/i2c-designware-common.c
+++ b/drivers/i2c/busses/i2c-designware-common.c
@@ -15,6 +15,7 @@
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
+#include <linux/spinlock.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
@@ -53,15 +54,75 @@ static char *abort_sources[] = {
"incorrect slave-transmitter mode configuration",
};
+static inline u32 dw_read_reg(struct dw_i2c_dev *dev, int offset)
+{
+ if (dev->flags & ACCESS_16BIT)
+ return readw_relaxed(dev->base + offset) |
+ (readw_relaxed(dev->base + offset + 2) << 16);
+ else
+ return readl_relaxed(dev->base + offset);
+}
+
+static inline void dw_write_reg(struct dw_i2c_dev *dev, u32 b, int offset)
+{
+ if (dev->flags & ACCESS_16BIT) {
+ writew_relaxed((u16)b, dev->base + offset);
+ writew_relaxed((u16)(b >> 16), dev->base + offset + 2);
+ } else {
+ writel_relaxed(b, dev->base + offset);
+ }
+}
+
+static inline u32 dw_read_ind(struct dw_i2c_dev *dev, int offset)
+{
+ unsigned long flags, ok = DW_IC_IND_RETRY;
+ u32 cmd, value = 0;
+
+ cmd = DW_IC_CTL_GO | (offset & DW_IC_CTL_ADDR_MASK);
+
+ spin_lock_irqsave(&dev->ind_lock, flags);
+
+ dw_write_reg(dev, cmd, DW_IC_CTL);
+
+ while ((dw_read_reg(dev, DW_IC_CTL) & DW_IC_CTL_GO) && ok--);
+ if (ok)
+ value = dw_read_reg(dev, DW_IC_DO);
+ else
+ dev_err(dev->dev, "Register 0x%02x read timedout\n", offset);
+
+ spin_unlock_irqrestore(&dev->ind_lock, flags);
+
+ return value;
+}
+
+static inline void dw_write_ind(struct dw_i2c_dev *dev, u32 b, int offset)
+{
+ unsigned long flags, ok = DW_IC_IND_RETRY;
+ u32 cmd;
+
+ cmd = DW_IC_CTL_GO | DW_IC_CTL_WR | (offset & DW_IC_CTL_ADDR_MASK);
+
+ spin_lock_irqsave(&dev->ind_lock, flags);
+
+ dw_write_reg(dev, b, DW_IC_DI);
+ dw_write_reg(dev, cmd, DW_IC_CTL);
+
+ while ((dw_read_reg(dev, DW_IC_CTL) & DW_IC_CTL_GO) && ok--);
+
+ spin_unlock_irqrestore(&dev->ind_lock, flags);
+
+ if (!ok)
+ dev_err(dev->dev, "Register 0x%02x write timedout\n", offset);
+}
+
u32 dw_readl(struct dw_i2c_dev *dev, int offset)
{
u32 value;
- if (dev->flags & ACCESS_16BIT)
- value = readw_relaxed(dev->base + offset) |
- (readw_relaxed(dev->base + offset + 2) << 16);
+ if (dev->flags & ACCESS_INDIRECT)
+ value = dw_read_ind(dev, offset);
else
- value = readl_relaxed(dev->base + offset);
+ value = dw_read_reg(dev, offset);
if (dev->flags & ACCESS_SWAP)
return swab32(value);
@@ -74,12 +135,10 @@ void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset)
if (dev->flags & ACCESS_SWAP)
b = swab32(b);
- if (dev->flags & ACCESS_16BIT) {
- writew_relaxed((u16)b, dev->base + offset);
- writew_relaxed((u16)(b >> 16), dev->base + offset + 2);
- } else {
- writel_relaxed(b, dev->base + offset);
- }
+ if (dev->flags & ACCESS_INDIRECT)
+ dw_write_ind(dev, b, offset);
+ else
+ dw_write_reg(dev, b, offset);
}
/**
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index b220ad64c38d..0857b3842283 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -170,11 +170,23 @@
DW_IC_TX_ABRT_TXDATA_NOACK | \
DW_IC_TX_ABRT_GCALL_NOACK)
+/*
+ * Access registers for the IC space described above.
+ */
+#define DW_IC_CTL 0x0
+#define DW_IC_DI 0x4
+#define DW_IC_DO 0x8
+#define DW_IC_IND_RETRY 100
+
+#define DW_IC_CTL_GO BIT(31)
+#define DW_IC_CTL_WR BIT(8)
+#define DW_IC_CTL_ADDR_MASK GENMASK(7, 0)
/**
* struct dw_i2c_dev - private i2c-designware data
* @dev: driver model device node
* @base: IO registers pointer
+ * @ind_lock: Spin-lock for indirectly accesible registers
* @cmd_complete: tx completion indicator
* @clk: input reference clock
* @pclk: clock required to access the registers
@@ -226,6 +238,7 @@ struct dw_i2c_dev {
struct device *dev;
void __iomem *base;
void __iomem *ext;
+ spinlock_t ind_lock;
struct completion cmd_complete;
struct clk *clk;
struct clk *pclk;
@@ -280,6 +293,7 @@ struct dw_i2c_dev {
#define ACCESS_16BIT 0x00000002
#define ACCESS_INTR_MASK 0x00000004
#define ACCESS_NO_IRQ_SUSPEND 0x00000008
+#define ACCESS_INDIRECT 0x00000010
#define MODEL_CHERRYTRAIL 0x00000100
#define MODEL_MSCC_OCELOT 0x00000200
diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c
index 05da900cf375..59365dd4dc66 100644
--- a/drivers/i2c/busses/i2c-designware-master.c
+++ b/drivers/i2c/busses/i2c-designware-master.c
@@ -684,6 +684,7 @@ int i2c_dw_probe(struct dw_i2c_dev *dev)
unsigned long irq_flags;
int ret;
+ spin_lock_init(&dev->ind_lock);
init_completion(&dev->cmd_complete);
dev->init = i2c_dw_init_master;
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index cb494273bb60..683c456c4e1c 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -176,6 +176,7 @@ static int dw_i2c_of_configure(struct platform_device *pdev)
static const struct of_device_id dw_i2c_of_match[] = {
{ .compatible = "snps,designware-i2c", },
{ .compatible = "mscc,ocelot-i2c", .data = (void *)MODEL_MSCC_OCELOT },
+ { .compatible = "be,bt1-i2c", .data = (void *)ACCESS_INDIRECT },
{},
};
MODULE_DEVICE_TABLE(of, dw_i2c_of_match);
diff --git a/drivers/i2c/busses/i2c-designware-slave.c b/drivers/i2c/busses/i2c-designware-slave.c
index 0fc3aa31d46a..a6e65dcc693b 100644
--- a/drivers/i2c/busses/i2c-designware-slave.c
+++ b/drivers/i2c/busses/i2c-designware-slave.c
@@ -246,6 +246,7 @@ int i2c_dw_probe_slave(struct dw_i2c_dev *dev)
struct i2c_adapter *adap = &dev->adapter;
int ret;
+ spin_lock_init(&dev->ind_lock);
init_completion(&dev->cmd_complete);
dev->init = i2c_dw_init_slave;
--
2.25.1