raspi/linux
1
0
Fork 1
mirror of https://github.com/raspberrypi/linux.git synced 2025-12-06 01:49:46 +00:00
Code Issues Projects Releases Wiki Activity

Extend clock timeout, fix modprobe baudrate parameter.

Browse Source 
Set the BSC_CLKT clock streching timeout to 35ms as per SMBus specs.\n- Increase priority of baudrate parameter passed to modprobe (in /etc/modprobe.d/*.conf or command line). Currently custom baudrates don't work because they are overridden by clock-frequency in the platform_device passed to the function.
This commit is contained in:
Devon Fyson
2015-12-30 16:40:47 -05:00
committed by DFyson
parent 853eff4e9b
commit 25215dd3bf
1 changed files with 29 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

45
drivers/i2c/busses/i2c-bcm2708.c
View File

@@ -71,7 +71,8 @@
#define DRV_NAME "bcm2708_i2c"
static unsigned int baudrate = CONFIG_I2C_BCM2708_BAUDRATE;
static unsigned int baudrate_default = CONFIG_I2C_BCM2708_BAUDRATE;
static unsigned int baudrate;
module_param(baudrate, uint, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
MODULE_PARM_DESC(baudrate, "The I2C baudrate");
@@ -87,6 +88,7 @@ struct bcm2708_i2c {
int irq;
struct clk *clk;
u32 cdiv;
u32 clk_tout;
struct completion done;
@@ -154,7 +156,7 @@ static inline void bcm2708_bsc_fifo_fill(struct bcm2708_i2c *bi)
static inline int bcm2708_bsc_setup(struct bcm2708_i2c *bi)
{
u32 cdiv, s;
u32 cdiv, s, clk_tout;
u32 c = BSC_C_I2CEN | BSC_C_INTD | BSC_C_ST | BSC_C_CLEAR_1;
int wait_loops = I2C_WAIT_LOOP_COUNT;
@@ -162,12 +164,14 @@ static inline int bcm2708_bsc_setup(struct bcm2708_i2c *bi)
* Use the value that we cached in the probe.
*/
cdiv = bi->cdiv;
clk_tout = bi->clk_tout;
if (bi->msg->flags & I2C_M_RD)
c |= BSC_C_INTR | BSC_C_READ;
else
c |= BSC_C_INTT;
bcm2708_wr(bi, BSC_CLKT, clk_tout);
bcm2708_wr(bi, BSC_DIV, cdiv);
bcm2708_wr(bi, BSC_A, bi->msg->addr);
bcm2708_wr(bi, BSC_DLEN, bi->msg->len);
@@ -340,21 +344,24 @@ static int bcm2708_i2c_probe(struct platform_device *pdev)
struct bcm2708_i2c *bi;
struct i2c_adapter *adap;
unsigned long bus_hz;
u32 cdiv;
if (pdev->dev.of_node) {
u32 bus_clk_rate;
pdev->id = of_alias_get_id(pdev->dev.of_node, "i2c");
if (pdev->id < 0) {
dev_err(&pdev->dev, "alias is missing\n");
return -EINVAL;
u32 cdiv, clk_tout;
if (!baudrate) {
baudrate = baudrate_default;
if (pdev->dev.of_node) {
u32 bus_clk_rate;
pdev->id = of_alias_get_id(pdev->dev.of_node, "i2c");
if (pdev->id < 0) {
dev_err(&pdev->dev, "alias is missing\n");
return -EINVAL;
}
if (!of_property_read_u32(pdev->dev.of_node,
"clock-frequency", &bus_clk_rate))
baudrate = bus_clk_rate;
else
dev_warn(&pdev->dev,
"Could not read clock-frequency property\n");
}
if (!of_property_read_u32(pdev->dev.of_node,
"clock-frequency", &bus_clk_rate))
baudrate = bus_clk_rate;
else
dev_warn(&pdev->dev,
"Could not read clock-frequency property\n");
}
regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -448,7 +455,13 @@ static int bcm2708_i2c_probe(struct platform_device *pdev)
cdiv = 0xffff;
baudrate = bus_hz / cdiv;
}
clk_tout = 35/1000*baudrate; //35ms timeout as per SMBus specs.
if (clk_tout > 0xffff)
clk_tout = 0xffff;
bi->cdiv = cdiv;
bi->clk_tout = clk_tout;
dev_info(&pdev->dev, "BSC%d Controller at 0x%08lx (irq %d) (baudrate %d)\n",
pdev->id, (unsigned long)regs->start, irq, baudrate);