From 819062219abf8a78e54cad5c1c8716e6c8e7b870 Mon Sep 17 00:00:00 2001 From: Ben Dooks Date: Sat, 23 Jun 2007 17:16:30 -0700 Subject: [PATCH] SM501: Clock updates and checks Ensure that the M1XCLK and MCLK are sourced from the same PLL (and refuse to bind the driver if they are not). Update the PCI to safe initialisation values, as 72MHz is the maximum clock for 33MHz PCI bus mastering. Signed-off-by: Ben Dooks Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/mfd/sm501.c | 33 +++++++++++++++++++++++++++++++-- include/linux/sm501-regs.h | 5 +++++ 2 files changed, 36 insertions(+), 2 deletions(-) diff --git a/drivers/mfd/sm501.c b/drivers/mfd/sm501.c index 3a0ecfc404..e14d70e074 100644 --- a/drivers/mfd/sm501.c +++ b/drivers/mfd/sm501.c @@ -855,6 +855,24 @@ static void sm501_init_regs(struct sm501_devdata *sm, dev_info(sm->dev, "setting MCLK to %ld\n", init->mclk); sm501_set_clock(sm->dev, SM501_CLOCK_MCLK, init->mclk); } + +} + +/* Check the PLL sources for the M1CLK and M1XCLK + * + * If the M1CLK and M1XCLKs are not sourced from the same PLL, then + * there is a risk (see errata AB-5) that the SM501 will cease proper + * function. If this happens, then it is likely the SM501 will + * hang the system. +*/ + +static int sm501_check_clocks(struct sm501_devdata *sm) +{ + unsigned long pwrmode = readl(sm->regs + SM501_CURRENT_CLOCK); + unsigned long msrc = (pwrmode & SM501_POWERMODE_M_SRC); + unsigned long m1src = (pwrmode & SM501_POWERMODE_M1_SRC); + + return ((msrc == 0 && m1src != 0) || (msrc != 0 && m1src == 0)); } static unsigned int sm501_mem_local[] = { @@ -911,6 +929,13 @@ static int sm501_init_dev(struct sm501_devdata *sm) } } + ret = sm501_check_clocks(sm); + if (ret) { + dev_err(sm->dev, "M1X and M clocks sourced from different " + "PLLs\n"); + return -EINVAL; + } + /* always create a framebuffer */ sm501_register_display(sm, &mem_avail); @@ -1048,8 +1073,12 @@ static struct sm501_initdata sm501_pci_initdata = { }, .devices = SM501_USE_ALL, - .mclk = 100 * MHZ, - .m1xclk = 160 * MHZ, + + /* Errata AB-3 says that 72MHz is the fastest available + * for 33MHZ PCI with proper bus-mastering operation */ + + .mclk = 72 * MHZ, + .m1xclk = 144 * MHZ, }; static struct sm501_platdata_fbsub sm501_pdata_fbsub = { diff --git a/include/linux/sm501-regs.h b/include/linux/sm501-regs.h index cc9be4a118..8b4ecf02f9 100644 --- a/include/linux/sm501-regs.h +++ b/include/linux/sm501-regs.h @@ -64,6 +64,11 @@ #define SM501_DEBUG_CONTROL (0x000034) /* power management */ +#define SM501_POWERMODE_P2X_SRC (1<<29) +#define SM501_POWERMODE_V2X_SRC (1<<20) +#define SM501_POWERMODE_M_SRC (1<<12) +#define SM501_POWERMODE_M1_SRC (1<<4) + #define SM501_CURRENT_GATE (0x000038) #define SM501_CURRENT_CLOCK (0x00003C) #define SM501_POWER_MODE_0_GATE (0x000040) -- 2.20.1