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Subject[PATCH] i2c: aspeed: disable additional device addresses on ast2[56]xx
Date
The ast25xx and ast26xx have, respectively, two and three configurable
slave device addresses to the ast24xx's one. We only support using
one at a time, but the others may come up in an indeterminate state
depending on hardware/bootloader behavior, so we need to make sure we
disable them so as to avoid ending up with phantom devices on the bus.

Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
---
drivers/i2c/busses/i2c-aspeed.c | 50 +++++++++++++++++++++++++++------
1 file changed, 41 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
index a7be6f24450b..20028a7a9f67 100644
--- a/drivers/i2c/busses/i2c-aspeed.c
+++ b/drivers/i2c/busses/i2c-aspeed.c
@@ -117,6 +117,8 @@

/* 0x18 : I2CD Slave Device Address Register */
#define ASPEED_I2CD_DEV_ADDR_MASK GENMASK(6, 0)
+#define ASPEED_I2CD_DEV_ADDR2_ENABLE BIT(15)
+#define ASPEED_I2CD_DEV_ADDR3_ENABLE BIT(23)

enum aspeed_i2c_master_state {
ASPEED_I2C_MASTER_INACTIVE,
@@ -139,6 +141,16 @@ enum aspeed_i2c_slave_state {
ASPEED_I2C_SLAVE_STOP,
};

+struct aspeed_i2c_model {
+ u32 (*get_clk_reg_val)(struct device *dev, u32 divisor);
+
+ /*
+ * Some models support multiple device addresses -- we only support
+ * using one, but we need to disable the others if they're present.
+ */
+ unsigned int num_device_addrs;
+};
+
struct aspeed_i2c_bus {
struct i2c_adapter adap;
struct device *dev;
@@ -147,8 +159,7 @@ struct aspeed_i2c_bus {
/* Synchronizes I/O mem access to base. */
spinlock_t lock;
struct completion cmd_complete;
- u32 (*get_clk_reg_val)(struct device *dev,
- u32 divisor);
+ const struct aspeed_i2c_model *model;
unsigned long parent_clk_frequency;
u32 bus_frequency;
/* Transaction state. */
@@ -726,6 +737,13 @@ static void __aspeed_i2c_reg_slave(struct aspeed_i2c_bus *bus, u16 slave_addr)
addr_reg_val = readl(bus->base + ASPEED_I2C_DEV_ADDR_REG);
addr_reg_val &= ~ASPEED_I2CD_DEV_ADDR_MASK;
addr_reg_val |= slave_addr & ASPEED_I2CD_DEV_ADDR_MASK;
+
+ /* Disable additional addresses on hardware that has them. */
+ if (bus->model->num_device_addrs > 1)
+ addr_reg_val &= ~ASPEED_I2CD_DEV_ADDR2_ENABLE;
+ if (bus->model->num_device_addrs > 2)
+ addr_reg_val &= ~ASPEED_I2CD_DEV_ADDR3_ENABLE;
+
writel(addr_reg_val, bus->base + ASPEED_I2C_DEV_ADDR_REG);

/* Turn on slave mode. */
@@ -863,6 +881,11 @@ static u32 aspeed_i2c_24xx_get_clk_reg_val(struct device *dev, u32 divisor)
return aspeed_i2c_get_clk_reg_val(dev, GENMASK(2, 0), divisor);
}

+static const struct aspeed_i2c_model aspeed_i2c_24xx_bus = {
+ .get_clk_reg_val = aspeed_i2c_24xx_get_clk_reg_val,
+ .num_device_addrs = 1,
+};
+
static u32 aspeed_i2c_25xx_get_clk_reg_val(struct device *dev, u32 divisor)
{
/*
@@ -872,6 +895,16 @@ static u32 aspeed_i2c_25xx_get_clk_reg_val(struct device *dev, u32 divisor)
return aspeed_i2c_get_clk_reg_val(dev, GENMASK(3, 0), divisor);
}

+static const struct aspeed_i2c_model aspeed_i2c_25xx_bus = {
+ .get_clk_reg_val = aspeed_i2c_25xx_get_clk_reg_val,
+ .num_device_addrs = 2,
+};
+
+static const struct aspeed_i2c_model aspeed_i2c_26xx_bus = {
+ .get_clk_reg_val = aspeed_i2c_25xx_get_clk_reg_val,
+ .num_device_addrs = 3,
+};
+
/* precondition: bus.lock has been acquired. */
static int aspeed_i2c_init_clk(struct aspeed_i2c_bus *bus)
{
@@ -882,7 +915,7 @@ static int aspeed_i2c_init_clk(struct aspeed_i2c_bus *bus)
clk_reg_val &= (ASPEED_I2CD_TIME_TBUF_MASK |
ASPEED_I2CD_TIME_THDSTA_MASK |
ASPEED_I2CD_TIME_TACST_MASK);
- clk_reg_val |= bus->get_clk_reg_val(bus->dev, divisor);
+ clk_reg_val |= bus->model->get_clk_reg_val(bus->dev, divisor);
writel(clk_reg_val, bus->base + ASPEED_I2C_AC_TIMING_REG1);
writel(ASPEED_NO_TIMEOUT_CTRL, bus->base + ASPEED_I2C_AC_TIMING_REG2);

@@ -946,15 +979,15 @@ static int aspeed_i2c_reset(struct aspeed_i2c_bus *bus)
static const struct of_device_id aspeed_i2c_bus_of_table[] = {
{
.compatible = "aspeed,ast2400-i2c-bus",
- .data = aspeed_i2c_24xx_get_clk_reg_val,
+ .data = &aspeed_i2c_24xx_bus,
},
{
.compatible = "aspeed,ast2500-i2c-bus",
- .data = aspeed_i2c_25xx_get_clk_reg_val,
+ .data = &aspeed_i2c_25xx_bus,
},
{
.compatible = "aspeed,ast2600-i2c-bus",
- .data = aspeed_i2c_25xx_get_clk_reg_val,
+ .data = &aspeed_i2c_26xx_bus,
},
{ },
};
@@ -1002,10 +1035,9 @@ static int aspeed_i2c_probe_bus(struct platform_device *pdev)

match = of_match_node(aspeed_i2c_bus_of_table, pdev->dev.of_node);
if (!match)
- bus->get_clk_reg_val = aspeed_i2c_24xx_get_clk_reg_val;
+ bus->model = &aspeed_i2c_24xx_bus;
else
- bus->get_clk_reg_val = (u32 (*)(struct device *, u32))
- match->data;
+ bus->model = match->data;

/* Initialize the I2C adapter */
spin_lock_init(&bus->lock);
--
2.28.0
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