From: Robert Hancock robert.hancock@calian.com
[ Upstream commit 6e7d2de1e000d36990923ed80d2e78dfcb545cee ]
The Si5341 datasheet warns that before accessing any other registers, including the PAGE register, we need to wait for the DEVICE_READY register to indicate the device is ready, or the process of the device loading its state from NVM can be corrupted. Wait for DEVICE_READY on startup before continuing initialization. This is done using a raw I2C register read prior to setting up regmap to avoid any potential unwanted automatic PAGE register accesses from regmap at this stage.
Fixes: 3044a860fd ("clk: Add Si5341/Si5340 driver") Signed-off-by: Robert Hancock robert.hancock@calian.com Link: https://lore.kernel.org/r/20210325192643.2190069-3-robert.hancock@calian.com Signed-off-by: Stephen Boyd sboyd@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/clk/clk-si5341.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+)
diff --git a/drivers/clk/clk-si5341.c b/drivers/clk/clk-si5341.c index e0446e66fa64..b8a960e927bc 100644 --- a/drivers/clk/clk-si5341.c +++ b/drivers/clk/clk-si5341.c @@ -94,6 +94,7 @@ struct clk_si5341_output_config { #define SI5341_STATUS 0x000C #define SI5341_SOFT_RST 0x001C #define SI5341_IN_SEL 0x0021 +#define SI5341_DEVICE_READY 0x00FE #define SI5341_XAXB_CFG 0x090E #define SI5341_IN_EN 0x0949 #define SI5341_INX_TO_PFD_EN 0x094A @@ -1189,6 +1190,32 @@ static const struct regmap_range_cfg si5341_regmap_ranges[] = { }, };
+static int si5341_wait_device_ready(struct i2c_client *client) +{ + int count; + + /* Datasheet warns: Any attempt to read or write any register other + * than DEVICE_READY before DEVICE_READY reads as 0x0F may corrupt the + * NVM programming and may corrupt the register contents, as they are + * read from NVM. Note that this includes accesses to the PAGE register. + * Also: DEVICE_READY is available on every register page, so no page + * change is needed to read it. + * Do this outside regmap to avoid automatic PAGE register access. + * May take up to 300ms to complete. + */ + for (count = 0; count < 15; ++count) { + s32 result = i2c_smbus_read_byte_data(client, + SI5341_DEVICE_READY); + if (result < 0) + return result; + if (result == 0x0F) + return 0; + msleep(20); + } + dev_err(&client->dev, "timeout waiting for DEVICE_READY\n"); + return -EIO; +} + static const struct regmap_config si5341_regmap_config = { .reg_bits = 8, .val_bits = 8, @@ -1385,6 +1412,11 @@ static int si5341_probe(struct i2c_client *client,
data->i2c_client = client;
+ /* Must be done before otherwise touching hardware */ + err = si5341_wait_device_ready(client); + if (err) + return err; + for (i = 0; i < SI5341_NUM_INPUTS; ++i) { input = devm_clk_get(&client->dev, si5341_input_clock_names[i]); if (IS_ERR(input)) {