s/$subject/SPI: Add i.MX 23/28 SPI driver support/
On Mon, Feb 04, 2013 at 06:26:20PM +0100, Michael Grzeschik wrote:
> +
> +/*
> + * Set SSP/MMC bus frequency, in kHz
> + */
> +static void imx_set_ssp_busclock(struct spi_master *master, uint32_t freq)
> +{
> + struct mxs_spi *mxs = to_mxs(master);
> + const uint32_t sspclk = imx_get_sspclk(master->bus_num);
> + uint32_t val;
> + uint32_t divide, rate, tgtclk;
> +
> + /*
> + * SSP bit rate = SSPCLK / (CLOCK_DIVIDE * (1 + CLOCK_RATE)),
> + * CLOCK_DIVIDE has to be an even value from 2 to 254, and
> + * CLOCK_RATE could be any integer from 0 to 255.
> + */
> + for (divide = 2; divide < 254; divide += 2) {
> + rate = sspclk / freq / divide;
> + if (rate <= 256)
> + break;
> + }
> +
> + tgtclk = sspclk / divide / rate;
> + while (tgtclk > freq) {
> + rate++;
> + tgtclk = sspclk / divide / rate;
> + }
> + if (rate > 256)
> + rate = 256;
> +
> + /* Always set timeout the maximum */
> + val = SSP_TIMING_TIMEOUT_MASK |
> + SSP_TIMING_CLOCK_DIVIDE(divide) |
> + SSP_TIMING_CLOCK_RATE(rate - 1);
> + writel(val, mxs->regs + HW_SSP_TIMING);
> +
> + debug("SPI%d: Set freq rate to %d KHz (requested %d KHz)\n",
> + bus, tgtclk, freq);
Use dev_dbg, dev_info, dev_err throughout the driver please.
> +
> +static int mxs_spi_probe(struct device_d *dev)
> +{
> + struct spi_master *master;
> + struct mxs_spi *mxs;
> +
> + mxs = xzalloc(sizeof(*mxs));
> + if (!mxs)
> + return -ENOMEM;
xzalloc always returns memory.
> +
> + master = &mxs->master;
> + master->dev = dev;
> +
> + master->bus_num = dev->id;
> + master->setup = mxs_spi_setup;
> + master->transfer = mxs_spi_transfer;
> + master->num_chipselect = 3;
> + mxs->mode = SPI_CPOL | SPI_CPHA;
> +
> + mxs->regs = dev_request_mem_region(dev, 0);
> +
> + spi_register_master(master);
> +
> + return 0;
> +}
> +
> +static struct driver_d mxs_spi_driver = {
> + .name = "mxs_spi",
> + .probe = mxs_spi_probe,
> +};
> +
> +static int __init mxs_spi_init(void)
> +{
> + platform_driver_register(&mxs_spi_driver);
> + return 0;
return platform_driver_register(&mxs_spi_driver);
Sascha
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