Re: [PATCHv2] drivers: spi: Add qspi flash controller
From: Felipe Balbi
Date: Tue Jul 02 2013 - 06:16:29 EST
Hi,
On Tue, Jul 02, 2013 at 03:30:42PM +0530, Sourav Poddar wrote:
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>>+static int dra7xxx_qspi_setup(struct spi_device *spi)
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>>+{
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>>+ struct dra7xxx_qspi *qspi =
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>>+ spi_master_get_devdata(spi->master);
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>>+
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>>+ int clk_div;
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>>+
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>>+ if (!qspi->spi_max_frequency)
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>>+ clk_div = 0;
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>won't this generate division by zero ?
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>
>
Yes, Probably only an error should be thrown here. ?
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since min clk_div should be kept at 1.
right, if spi_max_frequency isn't passed, this is a broken DT binding.
Bail out.
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>>+ pm_runtime_get_sync(qspi->dev);
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>>+
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>>+ /* disable SCLK */
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>>+ dra7xxx_writel(qspi, dra7xxx_readl(qspi, QSPI_SPI_CLOCK_CNTRL_REG)
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>>+ & ~QSPI_CLK_EN, QSPI_SPI_CLOCK_CNTRL_REG);
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>>+
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>>+ if (clk_div< 0) {
btw, add a space between clk_div and <
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>>+ dra7xxx_writel(qspi, *txbuf++, QSPI_SPI_DATA_REG);
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>>+ dra7xxx_writel(qspi, qspi->dc, QSPI_SPI_DC_REG);
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>>+ dra7xxx_writel(qspi, qspi->cmd | QSPI_WR_SNGL,
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>>+ QSPI_SPI_CMD_REG);
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>>+ status = dra7xxx_readl(qspi, QSPI_SPI_STATUS_REG);
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>>+ timeout = QSPI_TIMEOUT;
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>>+ while ((status& QSPI_WC_BUSY) != QSPI_XFER_DONE) {
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>do you really need to poll ? No IRQ available ?
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>
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There is an interrupt available, I will try using that.
look at how i2c-omap.c synchronizes interrupt with the transfer_msg
code. It just uses a wait_for_completion().
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>>+static int dra7xxx_qspi_start_transfer_one(struct spi_master *master,
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>>+ struct spi_message *m)
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>>+{
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>>+ struct dra7xxx_qspi *qspi = spi_master_get_devdata(master);
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>>+ struct spi_device *spi = m->spi;
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>>+ struct spi_transfer *t;
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>>+ int status = 0;
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>>+ int flags = 0;
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>>+
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>>+ /* setup command reg */
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>>+ qspi->cmd = 0;
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>>+ qspi->cmd |= QSPI_WLEN(8);
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>>+ qspi->cmd |= QSPI_EN_CS(0);
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>>+ qspi->cmd |= 0xfff;
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Since, we dont know the number of frame lenght that need to be
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transferred and it comes from the spi framework, we keep the frame
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lenght to maximum.
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Then depending on the count value above in while loop, we terminate
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our trasnfer.
what ? seriously didn't get what you meant.
--
balbi
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