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    Subject[PATCH 3/3] [V2] mpc52xx_spi: add gpio chipselect
    Date
    This one enables the mpc52xx_spi driver for usage of user defined gpio lines
    as chipselect. This way we can control some more spi devices than only one

    V2 Changes:
    * preinitialize the gpio as output in probe function and call gpio_set_value in
    the chip select function instead of calling direction_output every time.
    * initialize the gpio line with output high, since we don't support CS_HIGH
    in the driver currently any way. change gpio value setting to default active
    low in chip select call.
    * free the gpio array while error or removing.

    Signed-off-by: Luotao Fu <l.fu@pengutronix.de>
    ---
    drivers/spi/mpc52xx_spi.c | 64 ++++++++++++++++++++++++++++++++++++++++++---
    1 files changed, 60 insertions(+), 4 deletions(-)

    diff --git a/drivers/spi/mpc52xx_spi.c b/drivers/spi/mpc52xx_spi.c
    index 64862cf..97beba2 100644
    --- a/drivers/spi/mpc52xx_spi.c
    +++ b/drivers/spi/mpc52xx_spi.c
    @@ -21,6 +21,7 @@
    #include <linux/spi/mpc52xx_spi.h>
    #include <linux/of_spi.h>
    #include <linux/io.h>
    +#include <linux/of_gpio.h>
    #include <asm/time.h>
    #include <asm/mpc52xx.h>

    @@ -79,7 +80,6 @@ struct mpc52xx_spi {
    spinlock_t lock;
    struct work_struct work;

    -
    /* Details of current transfer (length, and buffer pointers) */
    struct spi_message *message; /* current message */
    struct spi_transfer *transfer; /* current transfer */
    @@ -89,6 +89,8 @@ struct mpc52xx_spi {
    u8 *rx_buf;
    const u8 *tx_buf;
    int cs_change;
    + int gpio_cs_count;
    + unsigned int *gpio_cs;
    };

    /*
    @@ -96,7 +98,13 @@ struct mpc52xx_spi {
    */
    static void mpc52xx_spi_chipsel(struct mpc52xx_spi *ms, int value)
    {
    - out_8(ms->regs + SPI_PORTDATA, value ? 0 : 0x08);
    + int cs;
    +
    + if (ms->gpio_cs_count > 0) {
    + cs = ms->message->spi->chip_select;
    + gpio_set_value(ms->gpio_cs[cs], value ? 0 : 1);
    + } else
    + out_8(ms->regs + SPI_PORTDATA, value ? 0 : 0x08);
    }

    /*
    @@ -390,8 +398,9 @@ static int __devinit mpc52xx_spi_probe(struct of_device *op,
    struct spi_master *master;
    struct mpc52xx_spi *ms;
    void __iomem *regs;
    - int rc;
    u8 ctrl1;
    + int rc, i = 0;
    + int gpio_cs;

    /* MMIO registers */
    dev_dbg(&op->dev, "probing mpc5200 SPI device\n");
    @@ -426,8 +435,8 @@ static int __devinit mpc52xx_spi_probe(struct of_device *op,
    rc = -ENOMEM;
    goto err_alloc;
    }
    +
    master->bus_num = -1;
    - master->num_chipselect = 1;
    master->setup = mpc52xx_spi_setup;
    master->transfer = mpc52xx_spi_transfer;
    master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST;
    @@ -441,6 +450,40 @@ static int __devinit mpc52xx_spi_probe(struct of_device *op,
    ms->irq1 = irq_of_parse_and_map(op->node, 1);
    ms->state = mpc52xx_spi_fsmstate_idle;
    ms->ipb_freq = mpc5xxx_get_bus_frequency(op->node);
    + ms->gpio_cs_count = of_gpio_count(op->node);
    + if (ms->gpio_cs_count > 0) {
    + master->num_chipselect = ms->gpio_cs_count;
    + ms->gpio_cs = kmalloc(ms->gpio_cs_count * sizeof(unsigned int),
    + GFP_KERNEL);
    + if (!ms->gpio_cs) {
    + rc = -ENOMEM;
    + goto err_alloc;
    + }
    +
    + for (i = 0; i < ms->gpio_cs_count; i++) {
    + gpio_cs = of_get_gpio(op->node, i);
    + if (gpio_cs < 0) {
    + dev_err(&op->dev,
    + "could not parse the gpio field "
    + "in oftree\n");
    + rc = -ENODEV;
    + goto err_gpio;
    + }
    +
    + rc = gpio_request(gpio_cs, dev_name(&op->dev));
    + if (rc) {
    + dev_err(&op->dev,
    + "can't request spi cs gpio #%d "
    + "on gpio line %d\n", i, gpio_cs);
    + goto err_gpio;
    + }
    +
    + gpio_direction_output(gpio_cs, 1);
    + ms->gpio_cs[i] = gpio_cs;
    + }
    + } else
    + master->num_chipselect = 1;
    +
    spin_lock_init(&ms->lock);
    INIT_LIST_HEAD(&ms->queue);
    INIT_WORK(&ms->work, mpc52xx_spi_wq);
    @@ -477,6 +520,12 @@ static int __devinit mpc52xx_spi_probe(struct of_device *op,
    err_register:
    dev_err(&ms->master->dev, "initialization failed\n");
    spi_master_put(master);
    + err_gpio:
    + while (i-- > 0)
    + gpio_free(ms->gpio_cs[i]);
    +
    + if (ms->gpio_cs != NULL)
    + kfree(ms->gpio_cs);
    err_alloc:
    err_init:
    iounmap(regs);
    @@ -487,10 +536,17 @@ static int __devexit mpc52xx_spi_remove(struct of_device *op)
    {
    struct spi_master *master = dev_get_drvdata(&op->dev);
    struct mpc52xx_spi *ms = spi_master_get_devdata(master);
    + int i;

    free_irq(ms->irq0, ms);
    free_irq(ms->irq1, ms);

    + for (i = 0; i < ms->gpio_cs_count; i++)
    + gpio_free(ms->gpio_cs[i]);
    +
    + if (ms->gpio_cs != NULL)
    + kfree(ms->gpio_cs);
    +
    spi_unregister_master(master);
    spi_master_put(master);
    iounmap(ms->regs);
    --
    1.6.5.2


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