diff options
| author | Raul E Rangel <rrangel@chromium.org> | 2020-04-22 10:13:54 -0600 |
|---|---|---|
| committer | Heiko Schocher <hs@denx.de> | 2020-05-28 05:50:47 +0200 |
| commit | f6f9a016899e62cb65016421a09fd3fe06ce660f (patch) | |
| tree | 7299dc642a1add52341f36fbae4c008dbf8e1dcf /drivers/i2c | |
| parent | bcf08503f571553074a4e9563977225446c183fa (diff) | |
i2c: designware_i2c: Check if the device is powered
If the device doesn't return a version that means the device is
non-functional.
The dw_i2c_regs had invalid offsets for the version field. I got the
correct value from the DesignWare databook. It also matches what the
Picasso PPR says.
Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@chromium.org>
Tested on chromebook_coral:
Signed-off-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/designware_i2c.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/drivers/i2c/designware_i2c.c b/drivers/i2c/designware_i2c.c index c6a20721f6..3616e2105f 100644 --- a/drivers/i2c/designware_i2c.c +++ b/drivers/i2c/designware_i2c.c @@ -18,6 +18,12 @@ #include <dm/device_compat.h> #include <linux/err.h> +/* + * This assigned unique hex value is constant and is derived from the two ASCII + * letters 'DW' followed by a 16-bit unsigned number + */ +#define DW_I2C_COMP_TYPE 0x44570140 + #ifdef CONFIG_SYS_I2C_DW_ENABLE_STATUS_UNSUPPORTED static int dw_i2c_enable(struct i2c_regs *i2c_base, bool enable) { @@ -766,6 +772,17 @@ int designware_i2c_ofdata_to_platdata(struct udevice *bus) int designware_i2c_probe(struct udevice *bus) { struct dw_i2c *priv = dev_get_priv(bus); + uint comp_type; + + comp_type = readl(&priv->regs->comp_type); + if (comp_type != DW_I2C_COMP_TYPE) { + log_err("I2C bus %s has unknown type %#x\n", bus->name, + comp_type); + return -ENXIO; + } + + log_info("I2C bus %s version %#x\n", bus->name, + readl(&priv->regs->comp_version)); return __dw_i2c_init(priv->regs, 0, 0); } |