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i2c: i2c-ocores: support for 16bit and 32bit IO 

Some architectures supports only 16-bit or 32-bit read/write access to
their IO space. Add a 'reg-io-width' platform and OF parameter which
specifies the IO width to support these platforms.

reg-io-width can be specified as 1, 2 or 4, and has a default value
of 1 if it is unspecified.

Signed-off-by: Ganesan Ramalingam <ganesanr@broadcom.com>
Signed-off-by: Jayachandran C <jayachandranc@netlogicmicro.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
This commit is contained in:
Ganesan Ramalingam 2012-07-13 19:14:25 +05:30 committed by Wolfram Sang
parent d739a464f3
commit 7326e38ffe
3 changed files with 22 additions and 2 deletions
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2
Documentation/devicetree/bindings/i2c/i2c-ocores.txt
View File

@ -10,6 +10,7 @@ Required properties:
Optional properties:
- reg-shift : device register offsets are shifted by this value
- reg-io-width : io register width in bytes (1, 2 or 4)
- regstep : deprecated, use reg-shift above
Example:
@ -23,6 +24,7 @@ Example:
clock-frequency = <20000000>;
reg-shift = <0>; /* 8 bit registers */
reg-io-width = <1>; /* 8 bit read/write */
dummy@60 {
compatible = "dummy";

21
drivers/i2c/busses/i2c-ocores.c
View File

@ -30,6 +30,7 @@
struct ocores_i2c {
void __iomem *base;
u32 reg_shift;
u32 reg_io_width;
wait_queue_head_t wait;
struct i2c_adapter adap;
struct i2c_msg *msg;
@ -72,12 +73,22 @@ struct ocores_i2c {
static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value)
{
iowrite8(value, i2c->base + (reg << i2c->reg_shift));
if (i2c->reg_io_width == 4)
iowrite32(value, i2c->base + (reg << i2c->reg_shift));
else if (i2c->reg_io_width == 2)
iowrite16(value, i2c->base + (reg << i2c->reg_shift));
else
iowrite8(value, i2c->base + (reg << i2c->reg_shift));
}
static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg)
{
return ioread8(i2c->base + (reg << i2c->reg_shift));
if (i2c->reg_io_width == 4)
return ioread32(i2c->base + (reg << i2c->reg_shift));
else if (i2c->reg_io_width == 2)
return ioread16(i2c->base + (reg << i2c->reg_shift));
else
return ioread8(i2c->base + (reg << i2c->reg_shift));
}
static void ocores_process(struct ocores_i2c *i2c)
@ -244,6 +255,8 @@ static int ocores_i2c_of_probe(struct platform_device *pdev,
}
i2c->clock_khz = val / 1000;
of_property_read_u32(pdev->dev.of_node, "reg-io-width",
&i2c->reg_io_width);
return 0;
}
#else
@ -286,6 +299,7 @@ static int __devinit ocores_i2c_probe(struct platform_device *pdev)
pdata = pdev->dev.platform_data;
if (pdata) {
i2c->reg_shift = pdata->reg_shift;
i2c->reg_io_width = pdata->reg_io_width;
i2c->clock_khz = pdata->clock_khz;
} else {
ret = ocores_i2c_of_probe(pdev, i2c);
@ -293,6 +307,9 @@ static int __devinit ocores_i2c_probe(struct platform_device *pdev)
return ret;
}
if (i2c->reg_io_width == 0)
i2c->reg_io_width = 1; /* Set to default value */
ocores_init(i2c);
init_waitqueue_head(&i2c->wait);

1
include/linux/i2c-ocores.h
View File

@ -13,6 +13,7 @@
struct ocores_i2c_platform_data {
u32 reg_shift; /* register offset shift value */
u32 reg_io_width; /* register io read/write width */
u32 clock_khz; /* input clock in kHz */
u8 num_devices; /* number of devices in the devices list */
struct i2c_board_info const *devices; /* devices connected to the bus */