[PATCHv2 6/6] mmc: dw_mmc: Add support DW SD/MMC driver on SOCFPGA

[Pavel Machek]

Hi!

> Add platform specific functionality for the DW SD/MMC driver for
> SoCFPGA. Move SDMMC_CMD_USE_HOLD_REG to dw_mmc.h so other platforms
> can use this define.

> --- /dev/null
> +++ b/drivers/mmc/host/dw_mmc-socfpga.c
> @@ -0,0 +1,139 @@
> +/*
> + * Altera SoCFPGA Specific Extensions for Synopsys DW Multimedia Card Interface driver
> + *
> + *  Copyright (C) 2012, Samsung Electronics Co., Ltd.
> + *  Copyright (C) 2013 Altera Corporation
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * Taken from dw_mmc_exynos.c

Actually it is   dw_mmc-exynos.c

> +#define SYSMGR_SDMMCGRP_CTRL_OFFSET		0x108
> +#define DRV_CLK_PHASE_SHIFT_SEL_MASK	0x7
> +#define SYSMGR_SDMMC_CTRL_SET(smplsel, drvsel)		\
> +	((((drvsel) << 0) & 0x7) | (((smplsel) << 3) & 0x38))

Should SYSMGR stuff go to shared header file somewhere?

> +extern void __iomem *sys_manager_base_addr;

This is unused.

> +/* SOCFPGA implementation specific driver private data */
> +struct dw_mci_socfpga_priv_data {
> +	u8	ciu_div;

comment would be nice, something like
/* card interface unit divisor */ ?

> +	u32	hs_timing;

/* card interface unit phase shift for RX/TX mode */
?

> +static int dw_mci_socfpga_setup_clock(struct dw_mci *host)
> +{
> +	struct dw_mci_socfpga_priv_data *priv = host->priv;
> +
> +	clk_disable(host->ciu_clk);
> +	regmap_write(priv->sysreg, SYSMGR_SDMMCGRP_CTRL_OFFSET, priv->hs_timing);
> +	clk_enable(host->ciu_clk);
> +
> +	host->bus_hz /= (priv->ciu_div + 1);

Previous version said:

+       host->bus_hz /= priv->ciu_div;

I see you want to avoid division by zero, but this will introduce
significant error for low divisors, right? Is divisor of 0 valid?

Otherwise it looks good. Thanks,
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html