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Commit faf8180b authored by Ludovic Desroches's avatar Ludovic Desroches Committed by Chris Ball
Browse files

mmc: atmel-mci: add support for odd clock dividers 



Add an odd clock divider capability available from v5xx. It also involves
changing the clock divider calculation, and changing the switch-case
statement to use top-down fallthrough.

Signed-off-by: default avatarLudovic Desroches <ludovic.desroches@atmel.com>
Acked-by: default avatarNicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent 33ab4bbb

drivers/mmc/host/atmel-mci-regs.h

+1 −0
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
# define ATMCI_MR_PDCFBYTE		(  1 << 13)	/* Force Byte Transfer */

# define ATMCI_MR_PDCPADV		(  1 << 14)	/* Padding Value */

# define ATMCI_MR_PDCMODE		(  1 << 15)	/* PDC-oriented Mode */

# define ATMCI_MR_CLKODD(x)		((x) << 16)	/* LSB of Clock Divider */

#define ATMCI_DTOR			0x0008	/* Data Timeout */

# define ATMCI_DTOCYC(x)		((x) <<  0)	/* Data Timeout Cycles */

# define ATMCI_DTOMUL(x)		((x) <<  4)	/* Data Timeout Multiplier */

drivers/mmc/host/atmel-mci.c

+29 −19
Original line number Diff line number Diff line
@@ -77,6 +77,7 @@ struct atmel_mci_caps { 
	bool    has_cstor_reg;

	bool    has_highspeed;

	bool    has_rwproof;

	bool	has_odd_clk_div;

};



struct atmel_mci_dma {
@@ -1134,6 +1135,17 @@ static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) 
		}



		/* Calculate clock divider */

		if (host->caps.has_odd_clk_div) {

			clkdiv = DIV_ROUND_UP(host->bus_hz, clock_min) - 2;

			if (clkdiv > 511) {

				dev_warn(&mmc->class_dev,

				         "clock %u too slow; using %lu\n",

				         clock_min, host->bus_hz / (511 + 2));

				clkdiv = 511;

			}

			host->mode_reg = ATMCI_MR_CLKDIV(clkdiv >> 1)

			                 | ATMCI_MR_CLKODD(clkdiv & 1);

		} else {

			clkdiv = DIV_ROUND_UP(host->bus_hz, 2 * clock_min) - 1;

			if (clkdiv > 255) {

				dev_warn(&mmc->class_dev,
@@ -1141,8 +1153,8 @@ static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) 
				         clock_min, host->bus_hz / (2 * 256));

				clkdiv = 255;

			}



			host->mode_reg = ATMCI_MR_CLKDIV(clkdiv);

		}



		/*

		 * WRPROOF and RDPROOF prevent overruns/underruns by
@@ -2014,37 +2026,35 @@ static void __init atmci_get_cap(struct atmel_mci *host) 
			"version: 0x%x\n", version);



	host->caps.has_dma = 0;

	host->caps.has_pdc = 0;

	host->caps.has_pdc = 1;

	host->caps.has_cfg_reg = 0;

	host->caps.has_cstor_reg = 0;

	host->caps.has_highspeed = 0;

	host->caps.has_rwproof = 0;

	host->caps.has_odd_clk_div = 0;



	/* keep only major version number */

	switch (version & 0xf00) {

	case 0x100:

		host->caps.has_pdc = 1;

		break;

	case 0x200:

		host->caps.has_pdc = 1;

		host->caps.has_rwproof = 1;

		break;

	case 0x300:

	case 0x400:

	case 0x500:

		host->caps.has_odd_clk_div = 1;

	case 0x400:

	case 0x300:

#ifdef CONFIG_AT_HDMAC

		host->caps.has_dma = 1;

#else

		host->caps.has_dma = 0;

		dev_info(&host->pdev->dev,

			"has dma capability but dma engine is not selected, then use pio\n");

#endif

		host->caps.has_pdc = 0;

		host->caps.has_cfg_reg = 1;

		host->caps.has_cstor_reg = 1;

		host->caps.has_highspeed = 1;

	case 0x200:

		host->caps.has_rwproof = 1;

	case 0x100:

		break;

	default:

		host->caps.has_pdc = 0;

		dev_warn(&host->pdev->dev,

				"Unmanaged mci version, set minimum capabilities\n");

		break;