diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-25 10:59:31 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-25 10:59:31 -0700 |
commit | 72e58063d63c5f0a7bf65312f1e3a5ed9bb5c2ff (patch) | |
tree | df5c21244d46aacef47e6b7fff3ad02c3612b15c /arch/arm/mach-davinci/aemif.c | |
parent | 57c155d51e2f3d7411eeac5e7fd7634d2d1f6b4f (diff) | |
parent | 489e176c71f36654dcb8835926f7e5717b8b4c19 (diff) |
Merge branch 'davinci-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/khilman/linux-davinci
* 'davinci-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/khilman/linux-davinci: (50 commits)
davinci: fix remaining board support after io_pgoffst removal
davinci: mityomapl138: make file local data static
arm/davinci: remove duplicated include
davinci: Initial support for Omapl138-Hawkboard
davinci: MityDSP-L138/MityARM-1808 read MAC address from I2C Prom
davinci: add tnetv107x touchscreen platform device
input: add driver for tnetv107x touchscreen controller
davinci: add keypad config for tnetv107x evm board
davinci: add tnetv107x keypad platform device
input: add driver for tnetv107x on-chip keypad controller
net: davinci_emac: cleanup unused cpdma code
net: davinci_emac: switch to new cpdma layer
net: davinci_emac: separate out cpdma code
net: davinci_emac: cleanup unused mdio emac code
omap: cleanup unused davinci mdio arch code
davinci: cleanup mdio arch code and switch to phy_id
net: davinci_emac: switch to new mdio
omap: add mdio platform devices
davinci: add mdio platform devices
net: davinci_emac: separate out davinci mdio
...
Fix up trivial conflict in drivers/input/keyboard/Kconfig (two entries
added next to each other - one from the davinci merge, one from the
input merge)
Diffstat (limited to 'arch/arm/mach-davinci/aemif.c')
-rw-r--r-- | arch/arm/mach-davinci/aemif.c | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/arch/arm/mach-davinci/aemif.c b/arch/arm/mach-davinci/aemif.c new file mode 100644 index 00000000000..9c3f500fc12 --- /dev/null +++ b/arch/arm/mach-davinci/aemif.c @@ -0,0 +1,133 @@ +/* + * AEMIF support for DaVinci SoCs + * + * Copyright (C) 2010 Texas Instruments Incorporated. http://www.ti.com/ + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/kernel.h> +#include <linux/io.h> +#include <linux/err.h> +#include <linux/clk.h> +#include <linux/module.h> +#include <linux/time.h> + +#include <mach/aemif.h> + +/* Timing value configuration */ + +#define TA(x) ((x) << 2) +#define RHOLD(x) ((x) << 4) +#define RSTROBE(x) ((x) << 7) +#define RSETUP(x) ((x) << 13) +#define WHOLD(x) ((x) << 17) +#define WSTROBE(x) ((x) << 20) +#define WSETUP(x) ((x) << 26) + +#define TA_MAX 0x3 +#define RHOLD_MAX 0x7 +#define RSTROBE_MAX 0x3f +#define RSETUP_MAX 0xf +#define WHOLD_MAX 0x7 +#define WSTROBE_MAX 0x3f +#define WSETUP_MAX 0xf + +#define TIMING_MASK (TA(TA_MAX) | \ + RHOLD(RHOLD_MAX) | \ + RSTROBE(RSTROBE_MAX) | \ + RSETUP(RSETUP_MAX) | \ + WHOLD(WHOLD_MAX) | \ + WSTROBE(WSTROBE_MAX) | \ + WSETUP(WSETUP_MAX)) + +/* + * aemif_calc_rate - calculate timing data. + * @wanted: The cycle time needed in nanoseconds. + * @clk: The input clock rate in kHz. + * @max: The maximum divider value that can be programmed. + * + * On success, returns the calculated timing value minus 1 for easy + * programming into AEMIF timing registers, else negative errno. + */ +static int aemif_calc_rate(int wanted, unsigned long clk, int max) +{ + int result; + + result = DIV_ROUND_UP((wanted * clk), NSEC_PER_MSEC) - 1; + + pr_debug("%s: result %d from %ld, %d\n", __func__, result, clk, wanted); + + /* It is generally OK to have a more relaxed timing than requested... */ + if (result < 0) + result = 0; + + /* ... But configuring tighter timings is not an option. */ + else if (result > max) + result = -EINVAL; + + return result; +} + +/** + * davinci_aemif_setup_timing - setup timing values for a given AEMIF interface + * @t: timing values to be progammed + * @base: The virtual base address of the AEMIF interface + * @cs: chip-select to program the timing values for + * + * This function programs the given timing values (in real clock) into the + * AEMIF registers taking the AEMIF clock into account. + * + * This function does not use any locking while programming the AEMIF + * because it is expected that there is only one user of a given + * chip-select. + * + * Returns 0 on success, else negative errno. + */ +int davinci_aemif_setup_timing(struct davinci_aemif_timing *t, + void __iomem *base, unsigned cs) +{ + unsigned set, val; + unsigned ta, rhold, rstrobe, rsetup, whold, wstrobe, wsetup; + unsigned offset = A1CR_OFFSET + cs * 4; + struct clk *aemif_clk; + unsigned long clkrate; + + if (!t) + return 0; /* Nothing to do */ + + aemif_clk = clk_get(NULL, "aemif"); + if (IS_ERR(aemif_clk)) + return PTR_ERR(aemif_clk); + + clkrate = clk_get_rate(aemif_clk); + + clkrate /= 1000; /* turn clock into kHz for ease of use */ + + ta = aemif_calc_rate(t->ta, clkrate, TA_MAX); + rhold = aemif_calc_rate(t->rhold, clkrate, RHOLD_MAX); + rstrobe = aemif_calc_rate(t->rstrobe, clkrate, RSTROBE_MAX); + rsetup = aemif_calc_rate(t->rsetup, clkrate, RSETUP_MAX); + whold = aemif_calc_rate(t->whold, clkrate, WHOLD_MAX); + wstrobe = aemif_calc_rate(t->wstrobe, clkrate, WSTROBE_MAX); + wsetup = aemif_calc_rate(t->wsetup, clkrate, WSETUP_MAX); + + if (ta < 0 || rhold < 0 || rstrobe < 0 || rsetup < 0 || + whold < 0 || wstrobe < 0 || wsetup < 0) { + pr_err("%s: cannot get suitable timings\n", __func__); + return -EINVAL; + } + + set = TA(ta) | RHOLD(rhold) | RSTROBE(rstrobe) | RSETUP(rsetup) | + WHOLD(whold) | WSTROBE(wstrobe) | WSETUP(wsetup); + + val = __raw_readl(base + offset); + val &= ~TIMING_MASK; + val |= set; + __raw_writel(val, base + offset); + + return 0; +} +EXPORT_SYMBOL(davinci_aemif_setup_timing); |