[RFC PATCH] spi: add at25 spi eeprom driver
Hubert Feurstein
h.feurstein at gmail.com
Mon Jun 20 03:23:40 EDT 2011
Hi Sascha,
2011/6/20 Sascha Hauer <s.hauer at pengutronix.de>:
> Hi Hubert,
>
> On Thu, Jun 16, 2011 at 10:12:43AM +0200, Hubert Feurstein wrote:
>> obj-y += mfd/
>> obj-$(CONFIG_LED) += led/
>> +obj-y += misc/
>> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
>
> I think we should move the driver up to drivers/eeprom and skip the
> 'misc'. The kernel guys like to get rid of it also.
>
OK
>> +
>> + /* Wait for non-busy status */
>> + start_time = get_time_ns();
>> +
>> + retries = 0;
>> + do {
>> +
>> + sr = spi_w8r8(at25->spi, AT25_RDSR);
>> + if (sr < 0 || (sr & AT25_SR_nRDY)) {
>> + dev_dbg(at25->cdev.dev,
>> + "rdsr --> %d (%02x)\n", sr, sr);
>> + mdelay(1);
>> + continue;
>> + }
>> + if (!(sr & AT25_SR_nRDY))
>> + break;
>> + } while (retries++ < 3 || !is_timeout(start_time, EE_TIMEOUT));
>
> I don't understand this. The loop is limited by retries++ < 3. Why this
> additional is_timeout? Is this the same in the kernel?
>
Hmm, I don't know why we have both here. I simply ported the kernel code.
>> +static int at25_init(void)
>> +{
>> + register_driver(&at25_driver);
>> + return 0;
>> +}
>> +
>> +device_initcall(at25_init);
>> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
>> index 4560259..6456897 100644
>> --- a/drivers/spi/spi.c
>> +++ b/drivers/spi/spi.c
>> @@ -75,6 +75,7 @@ struct spi_device *spi_new_device(struct spi_master *master,
>> proxy->chip_select = chip->chip_select;
>> proxy->max_speed_hz = chip->max_speed_hz;
>> proxy->mode = chip->mode;
>> + proxy->dev.platform_data = chip->platform_data;
>
> This should be a seperate patch.
OK
>
>> strcpy(proxy->dev.name, chip->name);
>> proxy->dev.type_data = proxy;
>> status = register_device(&proxy->dev);
>> @@ -194,3 +195,44 @@ int spi_sync(struct spi_device *spi, struct spi_message *message)
>> return spi->master->transfer(spi, message);
>> }
>>
>> +/**
>> + * spi_write_then_read - SPI synchronous write followed by read
>> + * @spi: device with which data will be exchanged
>> + * @txbuf: data to be written
>> + * @n_tx: size of txbuf, in bytes
>> + * @rxbuf: buffer into which data will be read
>> + * @n_rx: size of rxbuf, in bytes
>> + * Context: can sleep
>> + *
>> + * This performs a half duplex MicroWire style transaction with the
>> + * device, sending txbuf and then reading rxbuf. The return value
>> + * is zero for success, else a negative errno status code.
>> + * This call may only be used from a context that may sleep.
>> + */
>> +int spi_write_then_read(struct spi_device *spi,
>> + const void *txbuf, unsigned n_tx,
>> + void *rxbuf, unsigned n_rx)
>> +{
>> + int status;
>> + struct spi_message message;
>> + struct spi_transfer x[2];
>> +
>> + spi_message_init(&message);
>> + memset(x, 0, sizeof x);
>> + if (n_tx) {
>> + x[0].len = n_tx;
>> + spi_message_add_tail(&x[0], &message);
>> + }
>> + if (n_rx) {
>> + x[1].len = n_rx;
>> + spi_message_add_tail(&x[1], &message);
>> + }
>> +
>> + x[0].tx_buf = txbuf;
>> + x[1].rx_buf = rxbuf;
>> +
>> + /* do the i/o */
>> + status = spi_sync(spi, &message);
>> + return status;
>> +}
>> +EXPORT_SYMBOL(spi_write_then_read);
>
> Also a seperate patch.
OK
Hubert
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