[PATCH 1/6] spi-imx: add CSPI and eCSPI support for i.MX51 MCU
Jason Wang
jason77.wang at gmail.com
Fri Sep 3 02:16:11 EDT 2010
Uwe Kleine-König wrote:
> Hello Jason,
>
> On Thu, Sep 02, 2010 at 03:51:59PM +0800, Jason Wang wrote:
>
>> There are 3 SPI controllers on i.MX51, one is called CSPI and is
>> 100% compatible with the one on i.MX35, the other two are called
>> eCSPI and are not compatible with existing controllers on other
>> i.MX platforms, here we add support of these three controllers in
>> the imx spi driver.
>>
>> Signed-off-by: Jason Wang <jason77.wang at gmail.com>
>> ---
>> drivers/spi/spi_imx.c | 135 +++++++++++++++++++++++++++++++++++++++++++++++--
>> 1 files changed, 131 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/spi/spi_imx.c b/drivers/spi/spi_imx.c
>> index 7972e90..8d9c9da 100644
>> --- a/drivers/spi/spi_imx.c
>> +++ b/drivers/spi/spi_imx.c
>> @@ -155,6 +155,120 @@ static unsigned int spi_imx_clkdiv_2(unsigned int fin,
>> return 7;
>> }
>>
>> +/* MX51 eCSPI post divider */
>> +static unsigned int spi_imx_clkdiv_3(unsigned int fin,
>> + unsigned int fspi)
>> +{
>> + int i, div = 1;
>> +
>> + for (i = 0; i < 15; i++) {
>> + if (fspi * div >= fin)
>> + return i;
>> + div <<= 1;
>> + }
>> +
>> + return 15;
>> +}
>>
> This is different in Sascha's patch. Didn't try yet to understand the
> difference.
>
>
To change the spi clock frequency, we can set pre-divider and post-divider,
here, to be simple, i only change post-divider(set pre-divider to 1), while
sascha handle both pre-divider and post-divider.
>> +
>> +#define MX51_INTREG_TEEN (1 << 0)
>> +#define MX51_INTREG_RREN (1 << 3)
>> +
>> +#define MX51_CSPICTRL_ENABLE (1 << 0)
>> +#define MX51_CSPICTRL_XCH (1 << 2)
>> +
>> +#define MX51_CSPICTRL_BL_SHIFT 20
>> +#define MX51_CSPICTRL_CS_SHIFT 18
>> +#define MX51_CSPICTRL_DR_SHIFT 8
>> +#define MX51_CSPICTRL_MODE_SHIFT 4
>> +#define MX51_CSPICONF_PHA_SHIFT 0
>> +#define MX51_CSPICONF_POL_SHIFT 4
>> +#define MX51_CSPICONF_SSPOL_SHIFT 12
>> +#define MX51_CSPICONF_SSCTL_SHIFT 8
>> +
>> +#define MX51_CSPICTRL_CSMASK 0x3
>> +#define MX51_CSPIINT 0x10
>> +#define MX51_CSPICONF 0xC
>> +#define MX51_CSPISTATUS 0x18
>> +#define MX51_STATUS_RR (1 << 3)
>> +
>> +#define MAX_CHIPSELECT_NUM 4
>> +
>> +static int get_chipselect(struct spi_imx_data *spi_imx,
>> + struct spi_imx_config *config)
>> +{
>> + int i;
>> +
>> + for (i = 0; i < MAX_CHIPSELECT_NUM; i++) {
>> + if (config->cs == spi_imx->chipselect[i])
>> + return i;
>> + }
>> +
>> + return -EINVAL;
>> +}
>> +static void mx51_intctrl(struct spi_imx_data *spi_imx, int enable)
>> +{
>> + unsigned int val = 0;
>> +
>> + if (enable & MXC_INT_TE)
>> + val |= MX51_INTREG_TEEN;
>> + if (enable & MXC_INT_RR)
>> + val |= MX51_INTREG_RREN;
>> +
>> + writel(val, spi_imx->base + MX51_CSPIINT);
>> +}
>> +
>> +static void mx51_trigger(struct spi_imx_data *spi_imx)
>> +{
>> + unsigned int reg;
>> +
>> + reg = readl(spi_imx->base + MXC_CSPICTRL);
>> + reg |= MX51_CSPICTRL_XCH;
>> + writel(reg, spi_imx->base + MXC_CSPICTRL);
>> +}
>> +
>> +static int mx51_config(struct spi_imx_data *spi_imx,
>> + struct spi_imx_config *config)
>> +{
>> + unsigned int config_reg = 0;
>> + unsigned int ctrl_reg = MX51_CSPICTRL_ENABLE;
>> + int chan;
>> +
>> + chan = get_chipselect(spi_imx, config);
>> + if (chan < 0)
>> + return chan;
>>
> can this happen? Does that have to do with using a GPIO for CS?
>
If we use 4 GPIOs for 4 SPI client devices, we can assign each to a
separate channel.
each channel has its own transfer mode(like clk edge...).
>
>> + ctrl_reg |= (chan & MX51_CSPICTRL_CSMASK) << MX51_CSPICTRL_CS_SHIFT;
>> + ctrl_reg |= (1 << (chan & MX51_CSPICTRL_CSMASK)) <<
>> + MX51_CSPICTRL_MODE_SHIFT;
>> + ctrl_reg |= spi_imx_clkdiv_3(spi_imx->spi_clk, config->speed_hz) <<
>> + MX51_CSPICTRL_DR_SHIFT;
>> +
>> + ctrl_reg |= (config->bpw - 1) << MX51_CSPICTRL_BL_SHIFT;
>> +
>> +
>>
> duplicated empty line
>
>
OK.
>> + if (config->mode & SPI_CPHA)
>> + config_reg |= (1 << (chan & MX51_CSPICTRL_CSMASK)) <<
>> + MX51_CSPICONF_PHA_SHIFT;
>> + if (config->mode & SPI_CPOL)
>> + config_reg |= (1 << (chan & MX51_CSPICTRL_CSMASK)) <<
>> + MX51_CSPICONF_POL_SHIFT;
>> + if (config->mode & SPI_CS_HIGH)
>> + config_reg |= (1 << (chan & MX51_CSPICTRL_CSMASK)) <<
>> + MX51_CSPICONF_SSPOL_SHIFT;
>> +
>> + config_reg |= (1 << (chan & MX51_CSPICTRL_CSMASK)) <<
>> + MX51_CSPICONF_SSCTL_SHIFT;
>> +
>> + writel(ctrl_reg, spi_imx->base + MXC_CSPICTRL);
>> + writel(config_reg, spi_imx->base + MX51_CSPICONF);
>> +
>> + return 0;
>> +}
>> +
>> +static int mx51_rx_available(struct spi_imx_data *spi_imx)
>> +{
>> + return readl(spi_imx->base + MX51_CSPISTATUS) & MX51_STATUS_RR;
>> +}
>> +
>> #define MX31_INTREG_TEEN (1 << 0)
>> #define MX31_INTREG_RREN (1 << 3)
>>
>> @@ -209,7 +323,7 @@ static int mx31_config(struct spi_imx_data *spi_imx,
>>
>> if (cpu_is_mx31())
>> reg |= (config->bpw - 1) << MX31_CSPICTRL_BC_SHIFT;
>> - else if (cpu_is_mx25() || cpu_is_mx35()) {
>> + else if (cpu_is_mx25() || cpu_is_mx35() || cpu_is_mx51()) {
>> reg |= (config->bpw - 1) << MX35_CSPICTRL_BL_SHIFT;
>> reg |= MX31_CSPICTRL_SSCTL;
>> }
>> @@ -223,7 +337,7 @@ static int mx31_config(struct spi_imx_data *spi_imx,
>> if (config->cs < 0) {
>> if (cpu_is_mx31())
>> reg |= (config->cs + 32) << MX31_CSPICTRL_CS_SHIFT;
>> - else if (cpu_is_mx25() || cpu_is_mx35())
>> + else if (cpu_is_mx25() || cpu_is_mx35() || cpu_is_mx51())
>> reg |= (config->cs + 32) << MX35_CSPICTRL_CS_SHIFT;
>> }
>>
>> @@ -567,7 +681,14 @@ static int __devinit spi_imx_probe(struct platform_device *pdev)
>> goto out_iounmap;
>> }
>>
>> - if (cpu_is_mx25() || cpu_is_mx31() || cpu_is_mx35()) {
>> + /* i.MX51 has two eCSPI and one CSPI controllers, eCSPI controllers are
>> + * not compatible with existing SPI controllers on other i.MX platforms,
>> + * while CSPI controller is 100% compatible with the one on the i.MX35.
>> + * We set the platform device id to 2 for this CSPI at i.MX51 board init
>> + * level to distinguish it from two eCSPI controllers.
>> + */
>>
> This comment is missing in Sascha's driver. I like it.
> BTW, I'd like to make use of platform ids in this driver. This would
> make this ugly "on imx51 id2 is a cspi" distinction unnecessary.
>
>
agree, i like both your and lothar's solution.
Either platform ids or flags in platform_data.
>> + if (cpu_is_mx25() || cpu_is_mx31() || cpu_is_mx35() ||
>> + (cpu_is_mx51() && (pdev->id == 2))) {
>> spi_imx->intctrl = mx31_intctrl;
>> spi_imx->config = mx31_config;
>> spi_imx->trigger = mx31_trigger;
>> @@ -582,6 +703,11 @@ static int __devinit spi_imx_probe(struct platform_device *pdev)
>> spi_imx->config = mx1_config;
>> spi_imx->trigger = mx1_trigger;
>> spi_imx->rx_available = mx1_rx_available;
>> + } else if (cpu_is_mx51()) {
>> + spi_imx->intctrl = mx51_intctrl;
>> + spi_imx->config = mx51_config;
>> + spi_imx->trigger = mx51_trigger;
>> + spi_imx->rx_available = mx51_rx_available;
>> } else
>> BUG();
>>
>> @@ -599,7 +725,8 @@ static int __devinit spi_imx_probe(struct platform_device *pdev)
>> writel(1, spi_imx->base + MXC_RESET);
>>
>> /* drain receive buffer */
>> - if (cpu_is_mx25() || cpu_is_mx31() || cpu_is_mx35())
>> + if (cpu_is_mx25() || cpu_is_mx31() || cpu_is_mx35() ||
>> + (cpu_is_mx51() && (pdev->id == 2)))
>> while (readl(spi_imx->base + MX3_CSPISTAT) & MX3_CSPISTAT_RR)
>> readl(spi_imx->base + MXC_CSPIRXDATA);
>>
> Best regards
> Uwe
>
>
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