On 10/14/22 18:44, Jonathan Cameron wrote:
On Fri, 14 Oct 2022 15:37:24 +0300
Cosmin Tanislav <demonsingur@xxxxxxxxx> wrote:
From: Cosmin Tanislav <cosmin.tanislav@xxxxxxxxxx>
Add support for the following parts:
* LTC2984
* LTC2986
* LTM2985
The LTC2984 is a variant of the LTC2983 with EEPROM.
The LTC2986 is a variant of the LTC2983 with only 10 channels,
EEPROM and support for active analog temperature sensors.
The LTM2985 is software-compatible with the LTC2986.
Signed-off-by: Cosmin Tanislav <cosmin.tanislav@xxxxxxxxxx>
...
Hi Cosmin,
Looks good except, I think we are still in the position that
regmap for spi doesn't guarantee to bounce buffer the bulk accesses
(last time I checked it actually did do so, but before that it didn't
and there are obvious optimizations to take it back to not doing so -
IRC Mark Brown's answer was we shouldn't rely on it..)
Anyhow, the existing driver has instances of this so its no worse
but we should really clean those up.
Jonathan
I can submit another patch for it. Although I'm pretty sure that
SPI regmap implementation doesn't need DMA safe access for it,
as I checked when I wrote the code.
+static int ltc2983_eeprom_cmd(struct ltc2983_data *st, unsigned int cmd,
+ unsigned int wait_time, unsigned int status_reg,
+ unsigned long status_fail_mask)
+{
+ __be32 bval = cpu_to_be32(LTC2983_EEPROM_KEY);
+ unsigned long time;
+ unsigned int val;
+ int ret;
+
+ ret = regmap_bulk_write(st->regmap, LTC2983_EEPROM_KEY_REG, &bval,
+ sizeof(bval));
SPI device and I was clearly dozing on existing driver but normally
we avoid assuming that regmap will always use a bounce buffer for bulk
accessors. Hence this should be a DMA safe buffer.
+ if (ret)
+ return ret;
+
+ reinit_completion(&st->completion);
+
+ ret = regmap_write(st->regmap, LTC2983_STATUS_REG,
+ LTC2983_STATUS_START(true) | cmd);
+ if (ret)
+ return ret;
+
+ time = wait_for_completion_timeout(&st->completion,
+ msecs_to_jiffies(wait_time));
+ if (!time) {
+ dev_err(&st->spi->dev, "EEPROM command timed out\n");
+ return -ETIMEDOUT;
+ }
+
+ ret = regmap_read(st->regmap, status_reg, &val);
+ if (ret)
+ return ret;
+
+ if (val & status_fail_mask) {
+ dev_err(&st->spi->dev, "EEPROM command failed: 0x%02X\n", val);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
