Re: [PATCH v2 1/3] spi: meson-axg: support MAX 80M clock

[Sunny Luo <sunny.luo@xxxxxxxxxxx>]

Hi Neil,

On 2018/12/13 16:49, Neil Armstrong wrote:
> Hi Sunny,
>
> On 13/12/2018 09:39, Sunny Luo wrote:
> > The SPICC controller in Meson-AXG is capable of running at 80M clock.
> > The ASIC IP is improved and the clock is actually running higher than
> > previous old SoCs.
> >
> > Signed-off-by: Sunny Luo <sunny.luo@xxxxxxxxxxx>
> > Signed-off-by: Yixun Lan <yixun.lan@xxxxxxxxxxx>
> > ---
> >   drivers/spi/spi-meson-spicc.c | 37 +++++++++++++++++++++++++++++--------
> >   1 file changed, 29 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/spi/spi-meson-spicc.c b/drivers/spi/spi-meson-spicc.c
> > index 7fe4488..b56249d 100644
> > --- a/drivers/spi/spi-meson-spicc.c
> > +++ b/drivers/spi/spi-meson-spicc.c
> > @@ -9,11 +9,13 @@
> >   
> >   #include <linux/bitfield.h>
> >   #include <linux/clk.h>
> > +#include <linux/clk-provider.h>
> >   #include <linux/device.h>
> >   #include <linux/io.h>
> >   #include <linux/kernel.h>
> >   #include <linux/module.h>
> >   #include <linux/of.h>
> > +#include <linux/of_device.h>
> >   #include <linux/platform_device.h>
> >   #include <linux/spi/spi.h>
> >   #include <linux/types.h>
> > @@ -34,7 +36,6 @@
> >    *   to have a CS go down over the full transfer
> >    */
> >   
> > -#define SPICC_MAX_FREQ	30000000
> >   #define SPICC_MAX_BURST	128
> >   
> >   /* Register Map */
> > @@ -120,6 +121,10 @@
> >   #define SPICC_BURST_MAX	16
> >   #define SPICC_FIFO_HALF 10
> >   
> > +struct meson_spicc_data {
> > +	unsigned int			max_speed_hz;
> > +};
> > +
> >   struct meson_spicc_device {
> >   	struct spi_master		*master;
> >   	struct platform_device		*pdev;
> > @@ -127,6 +132,7 @@ struct meson_spicc_device {
> >   	struct clk			*core;
> >   	struct spi_message		*message;
> >   	struct spi_transfer		*xfer;
> > +	const struct meson_spicc_data	*data;
> >   	u8				*tx_buf;
> >   	u8				*rx_buf;
> >   	unsigned int			bytes_per_word;
> > @@ -517,6 +523,9 @@ static int meson_spicc_probe(struct platform_device *pdev)
> >   	spicc->pdev = pdev;
> >   	platform_set_drvdata(pdev, spicc);
> >   
> > +	spicc->data = (const struct meson_spicc_data *)
> > +		of_device_get_match_data(&pdev->dev);
> > +
> >   	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> >   	spicc->base = devm_ioremap_resource(&pdev->dev, res);
> >   	if (IS_ERR(spicc->base)) {
> > @@ -567,11 +576,9 @@ static int meson_spicc_probe(struct platform_device *pdev)
> >   	master->unprepare_transfer_hardware = meson_spicc_unprepare_transfer;
> >   	master->transfer_one = meson_spicc_transfer_one;
> >   
> > -	/* Setup max rate according to the Meson GX datasheet */
> > -	if ((rate >> 2) > SPICC_MAX_FREQ)
> > -		master->max_speed_hz = SPICC_MAX_FREQ;
> > -	else
> > -		master->max_speed_hz = rate >> 2;
> > +	/* Setup max rate according to the Meson datasheet */
> > +	master->max_speed_hz = min_t(unsigned int, rate >> 1,
> > +				     spicc->data->max_speed_hz);
>
> I think "rate >> 1" here depends on patch 3, either move patch 3 before this one
> or keep "rate >> 2" and change it back to "rate >> 1" on patch 3.
Yes, this change should be in patch 3.

> >   
> >   	ret = devm_spi_register_master(&pdev->dev, master);
> >   	if (ret) {
> > @@ -602,9 +609,23 @@ static int meson_spicc_remove(struct platform_device *pdev)
> >   	return 0;
> >   }
> >   
> > +static const struct meson_spicc_data meson_spicc_gx_data = {
> > +	.max_speed_hz	= 30000000,
> > +};
> > +
> > +static const struct meson_spicc_data meson_spicc_axg_data = {
> > +	.max_speed_hz	= 80000000,
> > +};
> > +
> >   static const struct of_device_id meson_spicc_of_match[] = {
> > -	{ .compatible = "amlogic,meson-gx-spicc", },
> > -	{ .compatible = "amlogic,meson-axg-spicc", },
> > +	{
> > +		.compatible	= "amlogic,meson-gx-spicc",
> > +		.data		= &meson_spicc_gx_data,
> > +	},
> > +	{
> > +		.compatible = "amlogic,meson-axg-spicc",
> > +		.data		= &meson_spicc_axg_data,
> > +	},
> >   	{ /* sentinel */ }
> >   };
> >   MODULE_DEVICE_TABLE(of, meson_spicc_of_match);
>
> .